OPERATIONS and MAINTENANCE PLAN

Transcription

1 OPERATIONS and MAINTENANCE PLAN Mendenhall WWTP, Juneau AK Prepared for: The City & Borough Juneau Alaska LAST UPDATE: January 2015

2 TABLE OF CONTENTS Operations and Maintenance Plan A. INTRODUCTION... 3 A.1 MENDENHALL WWTP NPDES PERMIT LIMITS... 4 B. FACILITY DESCRIPTION... 6 B.1 OVERALL PLANT... 6 B.2 LIQUID TRAIN... 7 B.2.1 PRE-TREATMENT... 7 B.2.2 SEQUENCING BATCH REACTOR (SBR) BIOLOGICAL TREATMENT PROCESS... 8 B.2.3 ULTRAVIOLET (UV) DISINFECTION...15 B.2.4 NON-POTABLE WATER SYSTEM...15 B.3 SOLIDS PROCESSING...15 B.3.1 WASTE AND THICKEN SLUDGE TANK...15 B.3.2 DEWATERING...16 B.3.3 OPERATIONAL PARAMETERS...17 B.3.4 PERFORMANCE PARAMETERS...17 B.3.5 POLYMER USE...18 B.3.6 MONITORING, CONTROL AND RESPONSIBILITIES...19 B.4 BEST MANAGEMENT PLANS AND SOPS...19 C. PROCESS CONTROL STRATEGY...19 C.1 CONTROL PARAMETERS...20 D. SAMPLING PLAN...20 D.1 SAMPLING PROGRAM DESIGN...21 D.1.1 NPDES PERMIT MONITORING LOCATIONS, PARAMETERS MEASURED, AND COLLECTION FREQUENCIES...21 D.2 SAMPLING METHOD REQUIREMENTS...21 D.2.1 SAMPLE TYPES...21 D.2.2 SAMPLE EQUIPMENT AND CONTAINERS...22 D.2.3 SAMPLE PRESERVATION REQUIREMENTS...23 D.2.4 CROSS-CONTAMINATION REDUCTION EFFORTS...23 D.3 SAMPLE HANDLING AND CUSTODY REQUIREMENTS...23 D.3.1 FIELD GRAB SAMPLE HANDLING...23 D.3.2 CONTRACTED LABORATORY SAMPLE HANDLING...23 D.4 SPECIAL TRAINING REQUIREMENTS/CERTIFICATION...24 D.4.1 SAMPLE COLLECTION TRAINING...24 D.4.2 METHODS TRAINING...24 E. WEEKLY PROCESS CONTROL MEETING...25 F. OPERATOR SCHEDULE...28

3 A. INTRODUCTION This Operations Plan is prepared to assist the plant staff in Juneau, AK to properly monitor and operate the wastewater treatment plant to consistently meet the objective of compliance. This operations plan is not intended to be all inclusive. Operations and maintenance staff members should review and fully understand state regulations, and the design and operations and maintenance manuals provided by the equipment suppliers for the plant. An overview of the facility, including process components and general operational approach is discussed in the next sections. Detailed process monitoring and target set points are shown later in the Operations Strategy. More detailed discussion of each process is provided in the Unit Process Control Procedures (UPCP) and Standard Operating Procedures (SOPs) for each major process employed in the facility. Please refer to these documents for operational rationale, troubleshooting, and start up and shut down impacts and procedures. This Plan also contains a sampling plan for the facility. While there is some latitude on collecting and analyzing process samples, the permit samples noted in the plan MUST be collected on the time and date specified, unless unusual circumstances prevent their collection at the appointed time. The overall objective of the facility operation is to insure continuous compliance with the permit limits shown in the Exhibit Below. 3

4 A.1 MENDENHALL WWTP NPDES PERMIT LIMITS TABLE 1 - Data Quality Goals for MWWTP Permit Parameters Parameter Units Minimum Daily Effluent Limits Average Monthly Average Weekly Maximum Daily Sample Location Monitoring Requirements Sample Frequency Sample Type Flow MGD --- report effluent continuous recording Dissolved Oxygen mg/l report report effluent 1/month grab Temperature C --- report --- report effluent 1/month grab mg/l lb/day effluent 2/month 24-hr composite BOD 5 mg/l --- report influent 2/month 24-hr composite % removal 85 See Permit AK Part effluent vs influent 1/month calculation mg/l lb/day effluent 2/month 24-hr composite TSS mg/l --- report influent 2/month 24-hr composite % removal 85 See Permit AK Part effluent vs influent 1/month calculation ph (Nov 1 - Jun 30) s.u effluent 5/week grab (Jul 1 - Oct 31) s.u effluent 5/week grab Fecal Coliform Bacteria (Nov 1- Apr 30) FC/100 ml a b 168 b 224 c effluent 2/week grab (May 1- Oct 31) FC/100 ml a b 400 b 800 c effluent 1/week grab Total Ammonia as N mg/l hr composite effluent 1/month (Nov 1 - Apr 30) lb/day calculation (Jun 1 - Oct 31) mg/l --- report --- report effluent 1/month 24-hr composite Copper d µg/l hr composite (Nov 1 - Apr 30) effluent 1/month lb/day calculation µg/l hr composite (May 1 - Oct 31) effluent 1/month lb/day calculation Lead d µg/l --- report --- report effluent 3/year e 24-hr composite Silver d µg/l --- report --- report effluent 3/year e 24-hr composite Zinc d µg/l --- report --- report effluent 3/year e 24-hr composite Whole Effluent Toxicity (Nov 1 - Apr 30) TU c report effluent 1/year 24-hr composite (May 1 - Oct 31) TU c --- report --- report effluent 1/year 24-hr composite Hardness mg/l as CaCO report --- report effluent 1/month 24-hr composite Alkalinity mg/l as CaCO report --- report effluent 1/quarter f 24-hr composite Floating Solids/Visible Foam visual --- See Permit AK Part effluent 1/month visual Notes: a. FC/100 ml = colonies of fecal coliform bacteria (FC) per 100 ml. b. All fecal coliform bacteria average results must be reported as the geometric mean. c. Not more than 10 percent of samples may exceed the daily maximum limit. d. Metals monitoring in the effluent must be analyzed for and reported as total recoverable metal. e. Lead, silver and zinc must be sampled at least once during each of the following periods each year: January through April, May through August, and September through December. Results must be submitted with the April, August, and December DMRs. Quarters are defined as January - March, April - June, July - September, and October - December. Results must be submitted with the DMR for the last month of the quarter TABLE 1a - MWWTP Effluent Discharged Receiving Waters Monitoring Requirements Parameter Units Sampling Location Sampling Frequency Sample Type Reporting Limit Temperature o C upstream and downstream 1/month grab --- Fecal coliform a FC/100 ml upstream and downstream 1/month grab 1.0 Total Ammonia as N mg/l upstream and downstream 4/year b grab 0.05 ph s.u. upstream and downstream 1/month grab --- 4

5 Copper c µg/l upstream and downstream 2/year d grab 2.0 Lead c µg/l upstream 2/year d grab 2.0 Hardness mg/l as CaCO 3 upstream and downstream 1/month grab 10 Dissolved oxygen mg/l upstream and downstream 1/month grab --- Alkalinity mg/l as CaCO 3 upstream 1/month grab 10 Notes: a. All mixing zone fecal coliform bacteria average results must be reported as geometric means. b. Sampling must occur at least twice during each of the following time periods: November through April; and May through October. c. Analysis values for copper and lead must be as dissolved metal. d. Sampling must occur at least once during each of the following: May 1 through October 31; and November 1 through April 30. TABLE 1b - MWWTP Additional Effluent Monitoring for Permit Reissuance Parameter Units Sample Location Sample Frequency Sample Type Total Ammonia as N mg/l effluent 3x/4.5 years 24-hr composite Dissolved Oxygen mg/l effluent 3x/4.5 years grab Nitrate Plus Nitrite Nitrogen mg/l effluent 3x/4.5 years 24-hr composite Total Kjeldahl Nitrogen mg/l effluent 3x/4.5 years 24-hr composite Oil and Grease mg/l effluent 3x/4.5 years grab Total Phosphorous mg/l effluent 3x/4.5 years 24-hr composite Total Dissolved Solids mg/l effluent 3x/4.5 years 24-hr composite Expanded Effluent Testing varies effluent 3x/4.5 years --- Notes: e. Metals monitoring in the receiving water samples must be analyzed for and reported as dissolved metal. f. Sampling must occur at least once during each of the following: November - May, June, July - September, and October. g. Sampling must occur at least once during each of the following: November - May and October - June. h. Sampling required during May, June, July, August, September, and October only. 5

6 B. FACILITY DESCRIPTION This section discusses the basic purpose of each process in the plant and what processes units/equipment that are provided for each. Operating parameters are shown in the Process Control Strategy that follows and in more detail in the UPCPs and SOPs. Figure 1 Process Flow B.1 OVERALL PLANT The Mendenhall Wastewater Treatment Plant (MWWTP) is a 4.9 MG Daily Max activated sludge facility utilizing SBR (Sequential Batch Reactors) technology. Wastewater enters the facility by gravity and debris is removed in the headworks. As it enters the plant it first flows through a grinder and then in a channel auger screen. The raw water then enters the IPS (Influent Pump Station). A combination of five pumps will then pump the raw water to the splitter box in the grit removal system, from there it flows to the SBR tanks that are in Fill Mode. Mixed liquor leaves the SBRs during the Wasting Mode and is pumped either to the waste sludge or thickened sludge tank. Normal operating conditions only require that seven SBRs be operated due to the hydraulic ratios loading on the facility. 6

7 Table 2 Mendenhall WWTP Design Parameters Parameter Units Daily Avg. Metric Flow MGD ,220 mˆ3/d MGD/ Peak ,549 mˆ3/d BOD, Influent mg/l 260 2,655 kg/d Lbs./d 5,855 TSS, Influent mg/l 220 2,247 kg/d Lbs./d 4,954 Ammonia, Influent mg/l kg/d Lbs./d 676 TKN, Influent mg/l kg/d Lbs./d 1013 SBR basin MLSS mg/l 2,200 F/M (unadjusted for aer. Time) 0.15 When the loading on the plant is within the design parameters below, it is capable of meeting the National Pollutant Discharge Elimination System (NPDES) Permit limits listed above. B.2 LIQUID TRAIN B.2.1 PRE-TREATMENT Wastewater enters the IPS through a pair of 30 gate valves into individual channels. It then gravity flows through the main channel into a JWC Auger Monster where debris is shredded, washed and screened. The influent flow may be bypassed through the secondary channel, which employs a manual bar rack, to allow for maintenance to the Auger Monster without interruption of influent flow to the wet well. Immediately following screening, wastewater flows by gravity into the IPS. The pump station is equipped with five submersible pumps, each of which is capable of 2100 GPM (at 64 ft. TDH). The pumps are controlled automatically to activate/ deactivate as the liquid level in the wet well rises/falls. This type of operation allows the pump station to accommodate the wide variations in influent flow rates. During normal operation, the influent pumps operate in Automatic mode. In Manual Mode, the operating sequence of the pumps can be selected by the operator. Fluid from the wet well is pumped to the grit chamber head box at approximate elevation 52.0 Ft to a splitter box where it goes through three centrifugal grit separator vessels (Tea Cups) and concentrated into a slurry. The concentrate then drops down to the main floor level where it enters a clarifier and conveyor (Grit Snail) where it is dewatered and conveyed into a hopper for landfill disposal. 7

8 The influent flow is monitored through two flow meters. IPS pumps 1, 2 & 3 have flow measured by FE-01 with pumps 4 & 5 measured by FE-02. Table 2a Process Unit Quantity Description Location Grinder/screener 1 JWC Auger Monster TM Influent Pump Station Grit separation 1 Eutek Tea Cup Influent Pump Station Grit dewatering 1 Eutek Grit Snail Influent Pump Station Influent Pumps 5 ABS, Pumps Influent Pump Station B.2.2 SEQUENCING BATCH REACTOR (SBR) BIOLOGICAL TREATMENT PROCESS The MWWTP is an eight tank SBR Activated Sludge Wastewater Treatment Plant that operates with one tank serving as flow equalization or emergency storage tank. Each basin has its own dedicated positive displacement blower, jet pump, waste pump, level sensors, influent and mud valve, and jet header mixing/aeration system. Operation of the SBR plant is based on a fill-and-draw principle, which consists of five steps; fill, react, settle, decant, and idle. These steps can be altered for different operational applications. Fill During the fill cycle, the basin receives influent wastewater. The influent flow brings food to the microbes in the activated sludge, creating an environment for biochemical reactions to take place. Mixing and aeration can be varied during the fill cycle to create the following three different scenarios: Static Fill Under a static-fill scenario, there is no mixing or aeration while the influent wastewater is entering the tank. Static fill can be used when there is no need to nitrify or denitrify, and during low flow periods to save power. Because the jet pumps and aerators remain off, this scenario has an energy-saving component. Mixed Fill Under a mixed-fill scenario, the jet pumps are active, but the blowers remain off. The mixing action produces a uniform blend of influent wastewater and biomass. Because there is no aeration, an anoxic condition is present, which promotes denitrification. Anaerobic conditions can also be achieved during the mixed-fill cycle. Under anaerobic conditions the biomass undergoes a release of phosphorous. This release is reabsorbed by the biomass once aerobic conditions are reestablished. This phosphorous release will not happen with anoxic conditions. Aerated Fill Under an aerated-fill scenario, both the aerators and the jet pump are activated. The contents of the basin are aerated to convert the anoxic or anaerobic zone over to an aerobic zone. No adjustments to the aerated-fill cycle are needed to reduce organics and achieve nitrification. However, to achieve denitrification, it is necessary to switch the oxygen off to promote anoxic conditions for denitrification. By switching the oxygen on and off during this cycle with the blowers, anoxic conditions are created, allowing for nitrification and denitrification. Dissolved oxygen (DO) 8

9 should be monitored during this cycle so it does not go over 0.2 mg/l. This ensures that an anoxic condition will occur during the idle cycle. React This cycle allows for further reduction or "polishing" of wastewater parameters. During this cycle, no wastewater enters the basin and the mechanical mixing and aeration units are on. Because there are no additional volume and organic loadings, the rate of organic removal increases dramatically. Most of the carbonaceous biochemical oxygen demand (BOD) removal occurs in the react cycle. Further nitrification occurs by allowing the mixing and aeration to continue the majority of denitrification takes place in the mixed-fill cycle. The phosphorus released during mixed fill, plus some additional phosphorus, is taken up during the react cycle. Settle During this cycle, activated sludge is allowed to settle under quiescent conditions no flow enters the basin and no aeration or mixing takes place. The activated sludge tends to settle as a flocculent mass, forming a distinctive interface with the clear supernatant. The sludge mass is called the sludge blanket. This cycle is a critical part of the treatment process because if the solids do not settle rapidly, some sludge can be drawn off during the subsequent decant cycle and thereby degrade effluent quality. Decant During this cycle, a decanter is used to remove the clear supernatant effluent. Once the settle cycle is complete, a signal is sent to the decanter actuator to initiate the opening of an effluent-discharge valve. The floating decanter maintains the inlet orifice slightly below the water surface to minimize the removal of solids in the effluent removed during the decant cycle. It is optimal that the decanted volume is the same as the volume that enters the basin during the fill cycle. It is also important that no surface foam or scum is decanted. The vertical distance from the decanter to the bottom of the tank should be maximized to avoid disturbing the settled biomass. Wasting/Idle This step occurs between the decant and the fill cycles. The time varies, based on the influent flow rate and the operating strategy. During this cycle, a small amount of activated sludge at the bottom of the SBR basin is pumped out a process called wasting. Sludge wasting should occur during the idle cycle to provide the highest concentration of mixed liquor suspended solids (MLSS). The plant should be operated on pounds of MLSS and not concentration. Sludge from the SBR basins is wasted to a holding tank for future processing and disposal. The sludge-holding-tank capacity is not sized for extended storage of the wasted sludge and should be processed daily to allow room for additional wasting. 9

10 Figure 2 SBR Phases Wasting Rates Wasting rates are an essential control in every activated sludge plant. It affects sludge age, ratio of loading to biology, and biology characteristics. MWWTP s design information indicates that at design loading, the intended F/M is 0.15, the design Solids Retention Time (SRT) would be 7.67 days, and the Mixed Liquor Suspended Solids (MLSS) will be 2,200mg/L. When not at full loading, we can run with a higher SRT to reduce yield and provide greater stabilization of solids. To determine Waste Activated Sludge (WAS) rates we can use a modified version of SRT. To establish wasting we start with calculation of inventory. If we select say, a 10 day target SRT, we need to waste 1/10th of the inventory each day. The calculation looks like this: Pounds per day to waste = (7cells)( MG/cell)(average MLSS)(8.34) Desired SRT Gallons per day to waste = (Pounds per day to waste)( ) (WASSS)(8.34) Minutes per cycle to waste = Gallons per day to waste (number of SBR cycles per daily wasting period)(1200 gal/min) Anoxic Time 10

11 MWWTP does not have strict limits on effluent nitrogen, thus anoxic time is not needed for denitrification. Brief anoxic conditions are useful however to exert a selector effect against filamentous organisms that interfere with settling. Most filaments are obligate aerobes and are out-competed by facultative floc forming bacteria in taking up BOD under unaerated conditions. Sufficient anoxic time usually occurs passively during the fill cycle. An operator should just be aware that if aeration times are set very high, it may encroach on the anoxic time during the fill cycle and reduce the selector effect. Reaction/Aeration Times and DO Concentrations In Flow Proportioned Mode, the control system adjusts the aeration time per cycle (between a minimum and a maximum that is set) to be proportional to the percent of plant capacity being used at the time (with the value entered as the air slope set point defining the aeration time at 100% of plant capacity). However, the usual way of operation is Full Cell Mode. In this mode the same amount of wastewater is treated in each cycle, therefore, we want to deliver nearly the same amount of air each cycle. So, we set the minimum and maximum air settings close together. Assume actual air time will match the setting entered into the minimum air set point. Now, how much air time is just right? Aeration in each cycle should be long enough that biology has an opportunity to take up the BOD that came in during the Fill Cycle. Operators can become familiar with the behavior of D.O. compared to the rate of application of air. View this behavior on the Supervisory Control and Data Acquisition (SCADA) screen. Number of Cells in Operation MWWTP SBR is an eight-cell reactor. The plant is designed to treat its capacity with seven cells in operation and the eighth left as a redundant (backup) unit. Operators have the option of using all eight cells during periods of high loading if desired, but operators should recognize that if a mechanical failure occurs requiring a cell to need to be emptied, the other seven cells would then need to accept the volume and the mixed liquor solids from the cell being dewatered as well as treating the forward flow through the plant. It could introduce additional stress to the plant at a time when it is already stressed. While standing by as a redundant unit, the eighth cell serves a function as an EQ vessel (as does any empty cell not in auto ). It is available to accept influent when the incoming flow rate exceeds the ability of the other seven cells to receive it. The stored influent can then be feed into the plant at a later, less stressed time. SBR Automated Control Access to the control system is through a graphical computer interface Supervisory Control And Data Acquisition (SCADA) interface running on a dedicated pair of PCs. One PC functions as the principal control interface and the second, as a hot backup and ancillary terminal. This enables process adjustments and logging data/trends of levels and alarms. Operator adjustable process variables are accessible through the computer interface. The interface also enables access to logged information on DO levels, tank levels, alarms, hour meter readings, elapsed step times, pump and blower running status, etc. The levels in the reactors, IPS and sludge holding tanks are monitored by level sensors mounted in each tank. The control system provides accurate metering of the flow through the plant eliminating the need for a plant effluent flow meter. 11

12 The control system can be accessed from virtually anywhere in the world using a remote computer, software and electrical communication access. By this method the operator and support personnel can remotely adjust process variables, check plant status and operational trends. This is particularly useful for alarm 'call outs' so the operator can check the nature of the call and determine before leaving home, the type of response required. Also if the operator is away for a period of time, the operator can monitor plant status and adjust process settings from anywhere in the world. The data acquisition is particularly useful for troubleshooting the plant. The system also incorporates an auto-dialer for alarm conditions while the plant is unmanned. The control system interacts with field devices and equipment through a programmable logic controller (PLC). A PLC consists of two basic sections: the central processing unit (CPU) and the input/output interface system. The CPU controls all PLC activity and the input/output system is physically connected to field devices (e.g., actuators, level sensors, pumps, blowers, etc.) and provides the interface between the CPU and the information providers (inputs) and controllable devices (outputs). To operate, the CPU "reads" input data from connected field devices through the use of its input interfaces, and then performs the control program that is stored in its memory system. Programs are created in ladder logic, a language that closely resembles a wiring schematic, and are entered into the CPU's memory prior to operation. Finally, based on the program, the PLC updates output devices via the output interfaces. This process continues in the same sequence without interruption, and changes only when a change is made to the control program. Table 2b SBR Process Troubleshooting Guide Problem or Observation Sequencing Batch Reactor Troubleshooting Chart Condition Process Control Analysis Possible Causes Control Action Loss of solids from reactor due to a high blanket Poor sludge settling velocity and compaction SSV, SVI, diluted SSV, microscopic examination, NH3 - N, COD, D.O., SOUR Glutting (old sludge) Classic bulking (young sludge) Filamentous bulking Decrease MCRT. Increase MCRT. Identify conditions contributing to filamentous growth and correct. See comments in narrative below. Slime bulking Add nutrients. Foam Trapping Optimize pretreatment removal of oil and grease. Highly nitrified or oxidized sludge Increase anoxic cycle, reduce aerobic cycle. Toxicity Isolate or split flow, identify source of toxic influent and eliminate, increase aeration cycle, increase MCRT. 12

13 Problem or Observation Sequencing Batch Reactor Troubleshooting Chart Condition Process Control Analysis Possible Causes Control Action Rapidly settling blanket leaving particulate. Difficulty in maintaining waste concentration Rapid sludge settling velocity and compaction SSV, SVI, F/M, SOUR Low F/M ratio Increase F/M ratio by decreasing MLVSS. Turbid or cloudy effluent, disinfection problems A.High effluent BOD or TS MLSS, MLVSS, D.O., ph, temperature, Low MLSS or MLVSS Increase MLSS/MLVSS. Influent COD or TOC, Influent NH3 N, D.O., SOUR Low D.O., temperature or ph Increase aeration cycle in fill react, increase MLSS, add alkalinity. High organic loading If long-term, increase MLSS/MLVSS and aeration cycle. High nitrogenous loading If long-term, increase MLSS/MLVSS and aeration cycle. Toxicity Isolate or split flow, identify source of toxic influent and eliminate, increase aeration cycle, increase MCRT. B. High effluent NH3 N (Incomplete nitrification) Influent and process NH3 N, influent and process alkalinity, ph, temperature, SOUR, D.O. Influent NH3-N overload Low D.O. Low temperature Inadequate aerobic retention time Increase aerobic cycle. Increase aerobic cycle. Increase aerobic cycle. Increase aerobic cycle. Low ph or alkalinity Add alkalinity. Low MLVSS (nitrifiers) Increase MLVSS. Toxicity Isolate or split flow, identify source of toxic influent and eliminate, increase aeration cycle, increase MCRT. High-effluent TSS Individual particle washout Effluent and recycle TSS or turbidity, F/M, microscopic exam, SOUR Pin floc low F/M Pin floc denitrification Increase waste cycle, decrease MLSS. Increase waste cycle, decease MLSS, increase anoxic cycle. Pin floc solids recycle Optimize solids handling. Straggler floc high F/M Decrease waste cycle, 13

14 Problem or Observation Sequencing Batch Reactor Troubleshooting Chart Condition Process Control Analysis Possible Causes Control Action increase MLSS, increase aeration cycle. Straggler floc filamentous Identify filamentous organism (see filamentous control above). Straggler floc hydraulic See mechanical troubleshooting section. Individual bacterial cells in effluent Decrease waste cycle, raise MLSS, increase aeration cycle, if toxicity, remove source of toxic influent. High-effluent NO3 - N High effluent NO3 N NO3 N, ph, TOC or COD Lack of or inadequate anoxic conditions Increase anoxic cycle (may require decreasing oxic cycle). Lack of or inadequate carbon source Add carbon (methanol or acetic acid). Low ph, temperature or MCRT Add alkalinity, increase MCRT. Foam Excessive foam or scum on surface of SBR, flow EQ tank or chlorine contact chamber Microbiological examination, NO3-N, C-N-P ratio, SRT, oils and grease, D.O. The presence of hydrophobic filamentous bacteria may lead to excessive scum and foam. See section I.5. The presence of hydrophobic filamentous bacteria may lead to excessive scum and foam. See section I.5. Denitrification can result in sludge and foam on surface of SBR. Denitrification can result in sludge and foam on surface of SBR. Foam may also indicate a possible nutrient deficiency. This type of foam may be due to bacteria producing a natural polymer when subjected to nutrient deficient conditions for an excessive period of time. Foam may also indicate a possible nutrient deficiency. This type of foam may be due to bacteria producing a natural polymer when subjected to nutrient deficient conditions for an excessive period of time. Both too low and too high an SRT can cause foam problems. Both too low and too high an SRT can cause foam problems. Fats, oils grease and other non-degraded surface active organics can cause foam problems. Fats, oils grease and other non-degraded surface active organics can cause foam problems. Excessive (D.O. > 4.0 mg/l) may cause foaming. Excessive (D.O. > 4.0 mg/l) may cause foaming. 14

15 B.2.3 ULTRAVIOLET (UV) DISINFECTION MWWTP converted its chlorine and sulfur dioxide disinfection system because of changing regulations and public safety concerns. As a result, UV disinfection became the choice for wastewater disinfection due to some significant advantages over chlorine-based disinfection. Specifically, UV has been proven effective in various types of effluent, requires less maintenance, non-hazardous and is cost-effective. The Mendenhall UV 3000 system consists of three banks of 24 modules each. Each module has eight lamps and sleeves. Staff should consult the UV SOP as it covers routine inspection and cleaning of UV lamps and sleeves in each bank. Typically we clean one bank each week, thus the lamp cleaning frequency is once every three weeks. Microorganisms in the water are exposed to ultraviolet light when they pass by special lamps. The UV energy instantly destroys the genetic material (DNA) within bacteria, viruses and protozoa, eliminating their ability to reproduce and cause infection. Unable to multiply, the microorganisms die and no longer pose a health risk. B.2.4 NON-POTABLE WATER SYSTEM The Non-Potable Water (NPW) system is a side-stream system located in the disinfection building. NPW pumps collect chlorinated water out of the downstream end of the contact chambers, and pump it into a 2,500 gallon pneumatic storage tank located in the NPW supply room. An air compressor in the same room keeps the tank pressurized. A 6" diameter pipe carries NPW from the pneumatic tank to the SBR facility. B.3 SOLIDS PROCESSING B.3.1 WASTE AND THICKEN SLUDGE TANK Below the blower room are two tanks. These tanks provide storage of waste sludge. During the wasting cycle the waste sludge pump will energize and pump WAS to the waste sludge tank. Table 2c Process Unit Quantity Description Location Waste Sludge Tank 1 62x24x16 ft Each 178,000 gallons Thickened Sludge Tank 1 62x24x16 ft Each 178,000 gallons Recycle/Jet Mix Pumps 1 per tank Centrifugal, 1500 gpm 5 HP Under Blower Room Under Blower Room Under Blower Room Each tank has its own continuously operated jet aeration pump, with START/STOP controls located in the blower room. Waste sludge flow into the waste sludge basin is monitored by two Polysonics Model LCDT single head doppler ultrasonic flow meters (FE03and FE04). Thickened sludge flow going to the belt filter press is monitored by a 4" MAG Meter (PE08). These three meters transmit 4 to 20 ma signals to the PLC, and flow information is displayed on both the control panel and on 15

16 the IDT screens. Actual flows are presented on the control panel on analog gauges, while IDT screens provide digital readouts of actual and total flows. Flow ranges for the three sludge flow meters are as follows: FE03 (waste sludge) gpm FE04 (waste sludge) gpm FE08 (belt press sludge) gpm B.3.2 DEWATERING The belt filter press (BFP) receives sludge from the Thickened Sludge Tanks (TSTs). Polymer is added to help drain water from the sludge. Sludge is squeezed between two belts to produce a cake that is between 10 percent and 20 percent solids. It is in this manner that the sludge is dewatered. The dewatered sludge cake is transferred from the press to a hauling truck via a conveyer belt for offsite disposal. The purpose of sludge dewatering is to capture the solids in the dry cake and minimize the return solids to the liquid treatment process, while removing as much as water from the sludge as possible. This reduces the total volume and cost of material to be disposed of by hauling. The BFP is fed directly from the aerobic Thicken sludge tanks by a variable speed, progressive cavity filter press feed pump. The sludge is injected with a polymer in a venturi tube apparatus upstream of the BFP on the discharge side of the pump. The venturi tube facilitates sufficient mixing of the sludge and polymer. Polymer is used to flocculate the sludge in a step known as conditioning, where polymer pulls solids particles together releasing water that is then drained away. After polymer addition, sludge is deposited on the BFP. Dewatering of sludge on the BFP consists of two phases. The first is free drainage. The conditioned sludge is spread onto the moving belt. Water drains through the belt, leaving the flocculated sludge. As the belt moves, plows suspended above the belt cause the sludge to turn over, which allows water on the top to move down to the belt and drain away. Nearly all of the free water should drain from the sludge by the end of the drainage zone. The second is the use of pressure to remove water from the sludge, which occurs in the remainder of the BFP. After the sludge on the top belt has been thickened by gravity the sludge is sandwiched between the top and bottom belts. Pressure on the belts is increased as they travel through a series of rollers. The increased pressure and shear forces remove more water from the sludge until all that is left is a relatively dry cake. At the end of the press the belts separate and the dried sludge cake is deposited in a roll-off container. Once the belts drop the dewatered sludge onto the conveyer, both the upper and lower belts are washed with a high pressure water supply to clean any remaining sludge from the belts prior to the belt beginning the process again. A wash water booster pump installed in line with BFP provides adequate spray nozzle pressure for effective belt cleaning. Plant reuse water is used as wash water. Filtered water from the press (filtrate) flows to the plant recycle pump station via 8-inch drain line. Table 2d 16

17 Process Unit Quantity Description Location Belt Filter Press meter Press Building Press Feed Pump 1 Progressive cavity, Seepex pump with variable gpm, 7.5 HP Motor Polymer Feed System 1 Fluid Dynamics feed system. 1.0 HP High pressure injector 100 PSI Press Building Press Building Wash Water Pump 1 Unknown gpm, 15 HP Press Building B.3.3 OPERATIONAL PARAMETERS There are a number of different parameters that will help the operator control the belt press operation. These parameters are listed in Table 2. Included with each parameter are the unit measurement, range of values, target value, and frequency of monitoring. Following the table is a brief explanation of each parameter, its importance, how and when it is used, and how it relates to other parameters. It should be noted that when making adjustments to parameters the operator should keep in mind that it takes time for the system to respond. Changes should be made in increments and the process allowed to stabilize before additional actions are taken. Table 2e Operation Parameters Parameter Units Range Target Frequency Sludge feed rate % VFD speed /shift Sludge feed conc. % /shift Sludge cake conc. % /shift Polymer conc. % by vol varies each batch Polymer feed rate % varies 4/shift Belt speed ft./min varies 1/shift Belt tension psi TBD 350 psi 1/shift B.3.4 PERFORMANCE PARAMETERS The performance parameters listed in Table 2f are used to analyze the efficiency of the dewatering operation and to help make decisions on how to improve that efficiency. Table 2f Belt Filter Press Performance Parameters Parameter Units Range Target Frequency Sludge cake conc. % >15 daily Cake production DT/D TBD TBD daily Solids capture % daily Solids loading rate lbs/hr < 500 Varies daily 17

18 Polymer use lb/dt 8-16 Varies daily Sludge Cake Concentration This parameter is an average of the solids in cake samples collected over entire day. The cake concentration, along with the quantity of sludge processed and the percent capture, determine the volume of sludge to be hauled to the landfill. If a downward trend is detected the operator should evaluate the operation parameters and correct the problem in order to maintain the efficiency of the operation. Cake Production This is the quantity of sludge dewatered by the press in dry tons per day. Tracking this measurement will help the operator monitor the effectiveness of dewatering. Solids Capture Filtrate samples are collected from the press every two hours and measured for total solids. Solids capture is calculated by subtracting the filtrate concentration from the sludge feed concentration, and dividing the remainder by the feed concentration and expressing the result as a percentage. Solids capture % = ((feed lbs/hr filtrate lbs/hr) * 100) / feed lbs/hr Solids capture is important because solids in the filtrate return to secondary treatment and impact that process. Solids Loading Rate The operator calculates the press loading by use of the standard pounds formula (MGD * TSS * 8.34) and dividing by the run time. Solids loading rate, lb/hr = (feed mg/l * feed MGD * 8.34 Lb/gal) / (24 hrs/day) The loading rate is important so that the BFP is not overloaded and percent capture and percent cake deteriorate. B.3.5 POLYMER USE Polymer use is the quantity of concentrated polymer, in pounds, used to dewater a dry ton of sludge. Keeping track of polymer use is important since the cost of polymer is a major belt press operating expense. The following formulas are used to calculate the polymer usage. 18

19 B.3.6 MONITORING, CONTROL AND RESPONSIBILITIES Operation and Monitoring Tasks At the beginning of each shift, the operator receives a verbal update from the Senior Operator, reviews the belt filter press data collection sheet, and reads the operations log to become familiar with any problems and conditions noted by the previous shift. The operator then monitors the system for sludge characteristics, polymer dosage, drainage conditions and appearance of the cake, and makes adjustments as needed. After the press operation has been optimized, the operator collects samples of sludge feed, cake, and filtrate for solids measurement. The operator also notes the polymer feed, sludge feed settings, and the speed of the belt. Control Tasks In order to operate the BFP effectively, the operator will need to monitor and adjust certain operation parameters as described in this procedure. These parameters include sludge feed rate, feed sludge concentration, polymer concentration, polymer feed rate, belt speed and belt tension. Control of the equipment associated with BFP operation are generally located on the BFP control panels located next to the BFP s in the Solids Handling Building. Duties of the Operator The operator is responsible for monitoring the operation and controlling the performance of the sludge dewatering process, documenting its status, and changes made to it. The operator also collects cake and filtrate samples. B.4 BEST MANAGEMENT PLANS AND SOPS The following Best Management Plans are developed in the form of Unit Process Control Procedures and SOPs and are included as attachments for MWWTP: 1. UPCP - Influent Screening 2. UPCP - Influent Grit Removal 3. UPCP - UV Disinfection 4. SOP - SBR 5. SOP - Solids Management Straight WAS SOP 6. SOP - Solids Management SOP 7. SOP - Belt Filter Press 8. SOP - MWWTP Effluent Flow Measurement UPCPs and SOPs are reviewed and modified at least once each year. Additional documents are being developed as process and equipment adjustments are made. C. PROCESS CONTROL STRATEGY 19

20 C.1 CONTROL PARAMETERS Process Control Strategy Facility Name MWWTP Date/ 4 November 2014 Rev. No. Revision # The Mendenhall Wastewater Treatment Plant is a 2.7 mgd activated sludge process utilizing SBR Technology. The plant has the following processes: Influent screening, influent pumping, Process and SBR Tanks with jet aeration system, UV disinfection. The sludge system consists of a waste Overview sludge and thickened sludge tanks and belt press dewatering with final disposal in a landfill in Oregon. Control Strategy Wastewater is passed thru the preliminary treatment and pumped to one of seven on line SBRs (SBR 8 is for Stand-by) Plant loading is highly seasonal and corresponds to the local tourist season. Sludge is wasted to maintain a constant solids inventory in the SBR system. Inventory is determined and changed based on SRT, and base line average MLSS concentrations. Waste sludge stored in the waste sludge tank and transferred to the thickened sludge tank if and when decant occurs. The sludge is then dewatered through a belt press and sent to a landfill in Oregan Control Parameters Parameter Units Design Minimum Maximum Process Bar Screens Automatic screw 1 Bar Screens Manual clean 1 On demand Activated Sludge DO mg/l > Activated Sludge MLSS mg/l Activated Sludge System Pounds Lbs 50,000 75,000 Activated Sludge SRT days 9 15 Activated Sludge F:M #/d / # Activated Sludge Temperature C Dewatering Press Feed Rate gpm Dewatering Cake Solids % 15-18% Dewatering Polymer Usage #/Ton dry 16 slg Dewatering Percent Capture % 95 >99 Troubleshooting SEE UPCP FOR PROCESS Alternate Modes of SEE UPCP FOR PROCESS Operation Reference Documents D. SAMPLING PLAN Proper sampling is required to determine the efficiency of the process, to meet company standards and to comply with State and Federal Law. The samples that are routinely collected at MWWTP are shown in the exhibit below. Samples are required by the NPDES Permit under which the facility operates. All sampling points are labeled to clearly identify where the sample is to be collected. The sampling points are shown on the attached sampling location drawing. Refer to the QAPP for proper collection and storage of samples, chain of custody (COC) requirements and quality assurance/quality control requirements. MWWTP Sampling Schedule is shown in Table 4a. A plant layout showing the sampling locations is shown in Table 4b. 20

21 D.1 SAMPLING PROGRAM DESIGN Sample collection locations, required sampling parameters, and frequency of collection are specified in the MWWTP NPDES Permit AK Sample collection locations have been indicated on Figure 3, while sampling parameters and collection frequencies have been summarized in Tables 1a, 1b and 1c. Influent samples assess the chemical/physical characteristics of wastewater entering the MWWTP and are used to calculate the percent removal for BOD and TSS (as compared to the effluent sample results). Effluent samples assess the chemical/physical characteristics of the treated wastewater discharged from the plant. Ambient receiving water samples are collected, around the mixing zone, to assess any potential water quality impacts generated by discharge of the treated effluent to the receiving water body. The MWWTP mixing zone extends 150 meters upstream and downstream from the discharge. D.1.1 NPDES PERMIT MONITORING LOCATIONS, PARAMETERS MEASURED, AND COLLECTION FREQUENCIES Monitoring locations established in the NPDES permit for MWWTP (AK ) are shown in Table 7 with a site description and site location rationale. Table 4 - MWWTP Monitoring Locations, Site Descriptions and Site Selection Rationale Site Description Latitude Longitude Sampling Site Location Rationale MWWTP MWWTP Influent N W Beginning of the treatment process MWWTP Effluent N W End of the treatment process Mendenhall River Discharge N W --- Mendenhall River Mixing Zone Upstream boundary used to monitor for any deterioration in N W Upstream Sample Site receiving water quality due to the discharge of treated effluent Mendenhall River Mixing Zone Downstream boundary used to monitor for any deterioration in N W Downstream Sample Site receiving water quality due to the discharge of treated effluent Plant-specific sampling parameters and collection frequencies have been denoted in Tables 2a, 2b, and 2c for the MWWTP from NPDES Permit AK D.2 SAMPLING METHOD REQUIREMENTS This section describes the procedures that will be used to collect, preserve, transport, and store samples in compliance with NPDES requirements. Samplers should wear disposable gloves and safety eyewear, be aware of the potential hazards, and take care not to touch the inside of bottles or lids/caps during sampling. D.2.1 SAMPLE TYPES Water quality samples collected under the NPDES permit are either composite or grab, as shown in Tables 1, 1a, 1b. Composite samples are collected over a given timeframe directly into a refrigerated sample carboy. Small aliquots are taken from the sample stream and deposited directly 21

22 into the sample container; the volume of the aliquots can vary based upon system operations (i.e., flow-paced or standard volume). The sample container is held at 4 C + 2 C for sample preservation. The time of the first sample aliquot, composite intervals, and the final compositing time are noted in logbooks or on bench sheets. The final compositing time is the sample collection time noted on the COC form. Grab samples are collected in one collection bottle at a discrete time. D.2.2 SAMPLE EQUIPMENT AND CONTAINERS City and Borough of Juneau (CBJ) sample collection equipment and field instrumentation is detailed in Table 4a. Table 4a - CBJ Sample Collection Equipment and Field Instrumentation Vendor Model Description Site Location Sigma hour composite sampler MWWTP Influent Sigma hour composite sampler MWWTP Effluent Hach 2100Q Turbidimeter MWWTP Hach SS6 Online Turbidimeter MWWTP H-B S/N Thermometer MWWTP Thermo-Scientific Orion Star A212 Conductivity MWWTP Thermo-Scientific A3265 ph, temperature, and DO meter MWWTP Samples are collected in either polyethylene or glass containers. Shown in Table 4b is a summary of sample containers, types of preservation, sample volume, and permissible hold times associated with sample collection. Sample containers are provided by the contracted laboratory. Fecal coliform samples are collected in sterile, disposable specimen containers. Table 4b - Summary of Sample Containers, Preservation, Volumes, and Hold Times Group Parameter Container a Preservation Maximum Holding Time Minimum Volume ph P, G None required < 15 min 100 ml Temperature P, G None required in-situ 100 ml General Water Quality Dissolved Oxygen P, G None required < 15 min/in-situ 300 ml TSS P, G 0 < 6 C 7 days 1 L TDS P, G 0 < 6 C 7 days 1 L BOD 5 P, G 0 < 6 C 48 hours 1 L Turbidity P, G 0 < 6 C (store in dark) 48 hours 100 ml Hardness P, G HNO 3 to ph < 2 6 months 100 ml Alkalinity P, G 0 < 6 C 14 days 200 ml Fecal Coliform Fecal coliform P, G 0 < 10 C 6-24 hours b 100 ml Toxicity Whole Effluent Toxicity P, G 0 < 6 C 36 hours 10 L Inorganics Copper P, G HNO 3 to ph < 2 6 months 1 L Lead P, G HNO 3 to ph < 2 6 months 1 L Silver P, G HNO 3 to ph < 2 6 months 1 L Zinc P, G HNO 3 to ph < 2 6 months 1 L 22

23 Total Phosphorous P, G 0 < 6 C, H 2SO 4 to ph < 2 28 days 100 ml Nutrients Total Kjeldahl Nitrogen P, G 0 < 6 C, H 2SO 4 to ph < 2 28 days 500 ml Total Ammonia as N P, G 0 < 6 C, H 2SO 4 to ph < 2 28 days 500 ml Nitrate + Nitrite as N P, G 0 < 6 C, H 2SO 4 to ph < 2 28 days 200 ml Notes: a. P = polyethylene, G = glass b. Maximum hold time is dependent on the geographical proximity of sample source to the laboratory D.2.3 SAMPLE PRESERVATION REQUIREMENTS Samples collected are preserved in accordance of the methods specified in Table 4b above. D.2.4 CROSS-CONTAMINATION REDUCTION EFFORTS In an effort to reduce the potential for cross-contamination, the influent and effluent samplers have dedicated collection carboys. All sampling carboys and glassware are washed with laboratory-grade soap, rinsed with tap water, rinsed with distilled water, and dried immediately after use. D.3 SAMPLE HANDLING AND CUSTODY REQUIREMENTS Samples are identified, handled, documented, and custody controlled in compliance with the following sections. Samples may be analyzed in the field, CBJ lab, or in a contracted laboratory. Contracted non-alaska laboratories must be members of the National Environmental Laboratory Accreditation Conference (NELAC) and/or State certified for the respective waste water analytical methods. All sampling equipment and sample containers will be cleaned according to the equipment specifications and/or the analytical laboratory. Bottles supplied by a contracted laboratory are new or pre-cleaned and should never be rinsed or reused. A temperature blank shall accompany each cooler. D.3.1 FIELD GRAB SAMPLE HANDLING Field grab samples analysis begins within the timeframe specified on Table 4b where sample collection and analysis information is recorded on laboratory bench sheets or in logbooks. D.3.2 CONTRACTED LABORATORY SAMPLE HANDLING Sample containers are provided by the contracted laboratory. Container types and preservatives are listed in Table 4b. Samples are labeled with waterproof ink and prepared as described on the COC. At a minimum, each label will contain the following information: Site location Sample identification Sample type (grab or 24-hr composite) Date and time of sample collection Sampler s initials Analyzes required Method of preservation (as needed) Contracted Laboratory for Wastewater Analyzes (Local Drop-off) Analytical samples are hand delivered to the local contracted lab for wastewater analyzes (Admiralty Environmental, LLC) with complete COC paperwork. QAPP Appendix D contains Admiralty documents, such as the laboratory contract with CBJ, QAM, SOPs, and Microbac s QAP. Company contact information is as follows: Admiralty Environmental, LCC. David Wetzel, President 641 W. Willoughby Ave., Suite 301 Hope O Neill, Manager 23

24 Juneau, Alaska Phone: (907) / Fax: (480) Admiralty prepares a summary report (both written and electronic) of the following findings: Title page COC copies QC summary and documentation of any discrepancies affecting system measurement Sampling and analysis dates Test methods Method detection limits Recovery percentages QC data (including method blank, MS data, MS duplicate data, and laboratory control sample data) D.4 SPECIAL TRAINING REQUIREMENTS/CERTIFICATION The purpose of this section is to ensure that necessary training requirements are known and provided. D.4.1 SAMPLE COLLECTION TRAINING MWWTP Senior Operators and Lab Technician ensure that all operators are trained in proper sample collection, handling, and analysis techniques. Prior to conducting sampling activities, personnel will review field procedures and sampling requirements discussed in this document to ensure permit required samples are collected and handled appropriately. D.4.2 METHODS TRAINING Personnel are required to review the applicable laboratory analysis SOP for all analyzes they conduct. CBJ and contracted laboratory SOPs have been included the current QAPP on file in the lab and at ADEC. Particular attention should be paid to any quality control requirements implemented for the particular analysis. 24

25 Figure 3 Compliance Sample Locations MWWTP NPDES general water quality parameter monitoring requirements and effluent limits are listed in Table 1a. Fecal coliform monitoring requirements and effluent limits for the MWWTP are shown in Table 1b. Shown in Table 1c are the MWWTP effluent discharged receiving waters monitoring requirements E. WEEKLY PROCESS CONTROL MEETING The Weekly Process Control Meeting is designed to keep all operations staff informed about process control decisions at the plant, discuss process issues, to look for changing trends in process parameters and to train new operators. The data for the process control meeting should be readily available in the plant data spreadsheet used at the plant. Process Control and Compliance Weekly Report Date: Attending: MWWTP 25

26 Safety concerns: Permit compliance: Parameter Actual Limit Parameter Actual Limit BOD 30 ph TSS 30 NH3N 1.4 D.O. 6.0 Process activities since last meeting: FECAL 200 EFF FLOW 4.0 TRC TOTAL P Process Performance: Unit Process Parameter Target value Actual value Trend New target SBR D.O. MLSS Settleability SVI 125 Actions to take WAS TSS Digester TS 2% ph > 6.0 D.O. 1.0 Mass Balance Proposed changes and expected results: Staffing/Scheduling issues: Energy management: Chemical management: Operations: 26

27 Maintenance: Laboratory: Solids Processing: Other: 27

28 F. OPERATOR SCHEDULE The schedule for routine operations tasks has been established to insure the major tasks required for proper operation of the facility and required by the operating permit are completed as required. Variation in the schedule that are required based on operating conditions will be discussed at the daily meeting during normal work days. Other schedule changes during the normal work day or after hours or on weekends should be reviewed with the Plant Supervisor or Senior Operator to insure that all required tasks are being completed. The Routine Operator Schedule is included below: CITY AND BUROUGH OF JUNEAU WASTEWATER TREATMENT PLANTS Date of last modification: 8/05/2014 GT Mendenhall Operations Checklist Week of: 6:00 Check plant SCADA for: Any alarms Jet pump and blower operation in solids tanks Influent valve of E tank in auto Influent pumps and IPS level status PLC clock correct Disinfection building screen DO trends Calculated flow make proc adjust for high flow Check event printer Monitor SCADA for plant operation throughout the day Check plant for unusual conditions Check and Change turbidity circular chart Establish press target using press target tool DOB each SBRs before decant phase - record Measure MLSS by Royce Measure DO in WAS and Thickened tank. Enter daily plant data into Mendenhall data sheet Check that daily operator task sheet is complete Check any new data for exceedences, (report if any) Enter noteworthy facts in plant log Calc WAS rate using WAS Calc tool. Set on SCADA Make process changes to SCADA per conditions Check and wash down basins MON TUE WED THUR FRI SAT SUN Calibrate Royce by TSS test Print Operations W.O.s/ Close W.O.s Set call-out dialer to on call person 28

29 UPCP: Influent Screening Plant: Mendenhall WWTP Location: Juneau, Alaska Author: CJ Schneider Date: October, 2014 Summary The headworks of any facility should be designed to protect downstream process and equipment. The Mendenhall WWTF s headworks include grinding and screening of the influent raw water. The grinder is installed to grind larger debris to aid the downstream screen. The screen is designed to remove solids from the raw waste stream. The captured screenings are then washed, compacted and collected in a trash container. This section describes the Channel Monster Double Drum (CDD) Series high flow waste management device (Figure 1-1). Included is a description of the CDD, Process overview and drive specifications, defines support guidelines, and summarizes the safety concerns relating to the use and operation of the CDD. Figure 1-1. Channel Monster CDD Series

30 Process Overview Influent flows by gravity from the sewer line through to the control manhole. It then flows through the grinder/screener (Auger Monster) into the influent wet well. From the wet well it is pumped into the head-box of the grit removal system, where the pretreatment process is initiated. The control manhole contains one 36" diameter inlet line, two (2) valved 36" diameter discharge lines to the SBR plant. By opening and/ or closing the appropriate discharge lines, the mechanical Auger Monster and manual bar rack can be used independently or both simultaneously. Flows through the individual screening devices are controlled by opening or closing slide gate valves that control flow from the control manhole. The valves are located in separate channels, ahead of the Auger Monster and bar rack. The slide gates valves are controlled by crank mechanisms at the main floor level. First, a grinder shreds clumps of rags, sticks, plastics, fecal matter and inorganic/organic material. Next, solids are captured by a perforated plate screen and removed by a rotating auger. As solids are removed, dual wash water zones clean-off fecal material. The rotating auger then conveys solids to the discharge point. 1.0 Influent Screening The CDD cutter cartridge is an integrated, electrically driven horizontal screen and cutter assembly that screens and reduces raw sewage and solids and serves as an alternative for treatment plant bar screens, rakes, etc. It was specifically designed to fit the existing influent channel width and sit across channel (perpendicular to the influent flow) in the MWWTP Influent Pump Station. Functionally, when power is applied, the screens rotate horizontally in synchronization with dual counter rotating cutter stacks. The rotating screens directs solids toward and into the cutters where the influent solids are ground into fine particles (to an approx. diameter of.33 x up to 2.5 varying lengths and acceptable to all process pumps) to facilitate free flow and easy disposal of sludge. 1.1 EQUIPMENT SPECIFICATIONS The following paragraphs define the specifications of the CDD. See the Controller and Drive Assembly manuals for the specifications and details related to the Controller and drive assembly. Maximum design flow 8.5 MGD.

31 Physically the CDD consists of the following: A. Cutter Assembly - Two (2) parallel shafts alternately stacked with individual intermeshing cutters and spacers positioned on the shaft to form a helical pattern. The shafts counter-rotate with the driven shaft rotating approximately two-thirds the speed of the drive shaft. The cutter assembly is a 32 (813mm) cutter chamber configuration. The cutters consist of standard 7 tooth cam cutters and spacers stacked on the drive and driven shaft. B. Screen Drum Assembly - Dual single shaft horizontally rotating screen drums that divert waste stream solids towards and into the cutter assembly. The assemblies utilize stainless steel perforated screening drums with 1/4 (6mm) circular openings for high capture efficiency. C. Side Rails - Baffle drum side rails are installed on each screen side of the CDD. The side rails deflect solids into the cutting chamber. The side rails are concave, follow the curvature of the screens, and extend the full length of the screen assembly.this design provides a rigid structure between end housings to allow the screen and cutter assembly seal cartridges to float, which reduces shaft fatigue. Clearance between the side rails and screen assemblies is set to maintain fineness of grind, uniform particle size, and consistent flow through the CDD. D. End Housings - Top and bottom end housing protect the screen and cutter assembly seals and bearings while guiding particles directly into the cutting chamber. The top end housing provides access to the stack tightening nut to enable cutter stack tightening without removing the CDD from the channel. E. Seals and Bearings - Sealed ball bearings bear the radial and axial loads of the cutter assembly drive and driven shafts and the screen assembly driven shaft. Each end-housing contains seal cartridge assemblies which, in turn, contain the seals and bearings. Each seal is: independent of the cutter stack and screen, functioning even if the cutter stack or screen becomes loose and remains an integral part of the end housing during almost all maintenance actions. F. Cutter Stack Tightening - An access cover on the discharge side of the top housing and an access opening in the top cover allows maintenance personnel to adjust the cutter stack compression for maximum cutting efficiency without having to remove the CDD from the channel or performing any unit disassembly. The adjustment requires power lock out, removal of the access cover and opening, locking the cutter assembly drive shaft nut through the top housing access cover and torqueing a stack screw through the access opening in the top cover. G. Frame - An adjustable channel frame and Controller complete the CDD system Installation. The frame is the enclosure for the CDD assembly. It is lowered into the channel, bolted into place, and the CDD assembly is lowered into and secured in the frame. H. Controller - The Controller is a power panel, designed to control and protect the CDD. I. Drive Assemblies - An electric motor and gear reducers drive the CDD.

32 1.2 GRINDER ASSEMBLY Each grinder assembly is constructed from materials selected for strength, corrosion resistance, and long life. Cutter shafts are fabricated from two (2)-inch 4140 steel hexagon stock supported on each end by heavy duty sealed Conrad type bearings protected by mechanical shaft seals. A. Castings are constructed of ductile iron. B. Cutters are constructed from 4130 steel and thru hardened to Rockwell C scale. C. Bearings/seals: Operating pressure:10 PSI (69 kpa) Maximum. No sealing water required. D. System Weight without drive system components: 1275 pounds 1.3 PROBLEM ANALYSIS The CDD is designed to operate smoothly and quietly. If ANY excessive noise or temperature rise is noted, stop operation, and inspect the unit. Table1-1 identifies potential problems and possible solutions. Refer to the Controller and Drive Assembly manuals for potential Controller and Drive Assembly related problems and possible solutions. Table 1-1 Troubleshooting Guide Potential Problems Possible Solutions Grinder making noise Inspect cutters for burrs. Check side rails and cutters for evidence that offcenter cutter is hitting side rail. Check for broken cutter or spacer. Inspect top and bottom seals for any indication of seal failure. Inspect bearing. Contamination found in the end housing indicates that the seals and bearings have worn and must be replaced. Check the drive and driven shaft for any indication of a bent or broken shaft. Cutter stack driven shaft Check gear key. Replace gear key if broken or missing. NOT turning Check for broken shaft. Cutter stack drive shaft not Check for broken shaft below the gear. turning Cutter stack drive and Check gear key. Replace gear key if broken or missing driven shaft NOT turning Check for broken shaft. Check for broken shaft below the gear Screen seal failure Inspect bearing/seal assemblies for wear. Replace if wear is indicated.

33 Potential Problems Possible Solutions Cutter stack shaft bobbing up and down Inspect bearing /seals. Contamination in the end housing indicates that the bearing/seal assembly must be replaced. Inspect retaining rings and keys. Replace if damaged. Check shaft tightening components. If loose tighten. Cutter stack seal failure Inspect bearings/seal assemblies for wear. Replace if obvious signs of wear are observed. Inspect cutters/spacers for wear. If worn thin, replace. Hole worn through a side rail Inspect bearing. Contamination found in the end housing indicates that the seals and bearings have worn and must be replaced. Check the drive and driven shaft for any indication of a bent or broken shaft. Screen drum makes noise Inspect screen drum for damage. Do not attempt to repair the stainless steel drum, cage, or shaft stubs. Inspect bearing/seal assembly. Contamination found in the end housing indicates bearing/seal assembly have worn and must be replaced. Inspect seals for wear. Replace parts indicating wear. Check the screen drum for any indication of a bent or broken shaft stub. Do not attempt to repair the stainless steel drum, cage, or shaft stubs. Screen not turning Check gear drive. Replace defective components. Screen shaft bobbing up and down Check for broken screen shaft stub. Do not attempt to repair the stainless steel drum, cage, or shaft stubs. Inspect bearing/seal assembly. Contamination found in the end housing indicates bearing/seal assembly have worn and must be replaced. Inspect retaining hardware. If broken replace. Table 1-2 Design Specifications Parameter Specification Wastewater Type Domestic/Commercial Average Daily Flow (MGD) 3.0 Peak Flow Rate (MGD) 8.5 Flow Channel Width 48 Flow Channel Depth 48 Overall Height w/ Motor & (1864) Reducer Overall Height w/o Motor & 44 (1118) Reducer Weight w/o Motor & Reducer 1275 (580 kg) Drum Screen Perforations 1/4 (6mm)

34 2.0 Auger Assembly This section describes and defines the operation, specifications, and support information related to the auger and its components. Refer to the Controller, Channel/Muffin Monster manuals/instructions for the details on the operation, equipment and options associated with the auger. See Figure 2-1 below for the MWWTP auger/frame installation. Figure 2-1. Auger Frame Installation 2.1 OPERATION Operationally, when power is applied to the controller and the auger start cycle is initiated, power is applied to the drive segment and spiral rotation is initiated. The rotating spiral captures and pulls effluent particles upward, above the channel liquid level, and out the discharge chute. As the spiral rotates, the spiral brush is always in contact with the perforated portion of the stainless steel screen trough to prevent clogging of the perforations. The screen openings separate liquids and biological solids from the mostly inorganic solid materials. The particulates are carried upward and out of the channel. A spray wash system, mounted over the screen trough, rinses the organic material from the processed solids back into the waste stream, reducing the odor of the particles being discharged.

35 The Auger is integrated with the CDD Channel Monster grinder. The auger is installed at a 45 angle to the influent flow at the output of the grinder cutting chamber. The Muffin/Channel Monster grinds the waste stream solids and the auger conveys the resulting particles above the liquid level of the channel. This allows the channel flow to continue downstream while grinding the influent solids into smaller particle sizes. The biological materials enter the auger section and pass through a perforated screen trough, while the inorganic particulates are dewatered, and discharged from the auger discharge segment. The auger spiral is programmed to rotate through forward and reverse cycles based on the time of day and operating conditions in the channel. The reverse function has been disabled due to the spirals violent shuddering reaction and excessive brush wear. A float signals the controller to operate the spiral continuously during periods of high-level channel flow and, when the channel level returns to a normal level, it returns the auger to the normal operational mode. 2.2 DESCRIPTION The Auger consists of the following assemblies: A. Drive Segment - The drive segment is electrically driven and provides the rotary force for the auger. B. Screen Segment - The screen is a one piece, perforated stainless steel trough that partially encloses the spiral from the non-drive end to the transport segment. The screen openings are ¼ (6mm). C. Transport Segment - The transport segment encloses the spiral and provides a controlled solids flow path to the discharge segment. The transport segment is a one-piece cylindrical stainless steel casing with mating flanges permanently affixed to each end and a removable inspection port cover. D. Discharge Segment - The discharge segment provides a controlled discharge flow path out of the auger to the trash receptacle. The discharge segment is a one-piece cylindrical stainless steel casing with mating flanges permanently affixed to each end and side discharge outlet. A removable inspection port cover is located opposite the discharge outlet for inspection. E. Spiral - The spiral assembly is a one-piece center-less spiral with brushes attached along the outside edge of the spiral. The spiral captures and pulls effluent particles upward, above the channel, and out the discharge chute. As the spiral rotates, the spiral brush is always in contact with the screen trough to prevent clogging of the perforated openings. The spiral is connected to the drive assembly through a drive plate on the discharge end of the auger. P. Spray Wash - The spray wash assembly is constructed of stainless steel and consists of manifold pipes, basket strainer, manual valve and solenoid valve. The manually valve is

36 provided to control and adjust the rate of flow to the spray wash system. The assembly is located above the screen trough and held in position by S/S brackets on each side of the trough. G. Frame - The Auger support frame (Figure 2-1) is specifically designed for the MWWTP influent channel dimensions, grinder type and required auger length. 2.3 MECHANICAL SPECIFICATIONS A. Materials - Screening, transport, discharge segments, and spray wash: stainless steel. Spiral: constructed of a carbon steel alloy enclosed in a stainless steel casing Spiral Brush: Nylon B. Dimensions - Auger assembly: Overall length 132 (3353mm) Spray Wash: 1 dia. (25.4mm) x L (1200mm) C. Drive - Electric motor, submersion duty D. Spiral tip speed - 33-ft/min (0.17m/sec) maximum E. Spiral transport speed ft/min (0.03m/sec) maximum F. Weight - Auger minimum-weight: 540-lbs (243 Kg) 2.4 PROBLEM ANALYSIS The auger is designed to operate smoothly and quietly. If ANY unusual or excessive noise or temperature rise is noted, stop operation and inspect the unit. Table 2-1 identifies potential auger problems and possible solutions. Refer to the auger configuration related equipment manuals/instructions for potential problems and possible solutions related to these units. Table 2-1 Troubleshooting Guide Potential Problem Auger makes noise. Possible Solutions Inspect screen flange, transport, and discharge segment inspection port covers for looseness. Tighten fasteners if found loose. Inspect transport and discharge segments for clogging. Clogging may indicate oversized particulates are being transported through the auger. If oversized particles are observed and the grinder turning, refer to the grinder manual. Check for ANY indication of a bent or broken lifting spiral.

37 High fluid content in particulate discharge. Particulate discharge slow or stopped. Spiral not turning. Replace the spiral if defective. Do not attempt to repair the spiral. Auger may be running with little or no solids. If auger is passing little or no solids a rumbling (vibration) noise will echo in the transport and discharge segments. Auger may be running dry. If running dry the spiral will produce load vibration. Inspect screen segment for clogging. Clear the perforated trough and spiral as necessary to resolve clogging. Check spiral brush for uneven wear. Clean/replace as necessary. Check for bent or broken spiral. Replace the spiral if defective. Do not attempt to repair the spiral. Check transport segment and spiral for clogging. Clean as necessary. Check discharge segment and spiral for clogging. Clean as necessary. _ Verify spiral has not dropped. Correct spiral installation if required. Check Drive Assembly-to-auger spiral coupling as described in the Drive Assembly Instruction. Check spiral and screen, discharge, and transport segments for clogging. Clean as necessary. Check for broken spiral below the transport segment flange. Replace the spiral if defective. Do not attempt to repair the spiral. Table 2-2 Design Specifications Parameter Specification Wastewater Type: Domestic/Commercial Peak Flow Rate (MGD): 8.0 Flow Channel Width: 48 Flow Channel Depth: 48 Drive Motor, HP: 2HP TEXP 3PH 60HZ Speed Reducer Assembly: 160:1 Ratio Performance Monitoring The actual performance of the screening process is measured subjectively through observation. The operator should expect to find the usual amount and particle size of screenings in the receptacle. This will change some with influent flow changes. Screening

38 performance can also be inferred by looking for the presence of objects in other parts of the plant that should have been captured by the Auger Monster. Control Parameters The CDD screen/grinder assembly runs continuously. The signal for activation of the screen/auger assembly comes from a programmable 24 hour timer or the high level float, or a combination of both. When the control unit receives a RUN signal, the spiral starts a complete working cycle and stops again when the timer times out. If the channel water level does not decrease after this working cycle and the water level in front of the screen/auger assembly continues to increase, the spiral starts a continuous run mode until the water level in front of the screen/auger assembly is below the high float set point. For protection from high current conditions (auger jam) the control unit has an electronic current overload sensor that stops the spiral forward rotation and then reverses rotation for half a revolution. It then returns to normal forward operation if jam is cleared. If the jam condition does not clear the controller goes into stop mode, the auger run relay is de-energized and a fail indicator light is energized and an alarm is generated. Alternate Modes of Operation Manual operation, in the event of failure or major maintenance the screen may be by-passed and flow diverted to the manual bar rack channel. Relation to Other Process Units Failure to provide proper screening will have a detrimental effect on downstream mechanical equipment. Ragging of cables, impellers and other equipment will increase maintenance activities and could affect mixing and oxygen transfer. Safety Before performing any maintenance or repairs to the equipment, personnel should review all governing Safety policies in effect. Note that the material handled by the equipment may come under the classification "Bio-hazardous material ". Additionally, the equipment can be controlled by remote controls, and can start automatically at any time. Follow the established Lock out Tag out procedures to isolate the equipment and prevent automatic starts, prior to performing any work on the equipment. In general, the following safety precautions must be observed: Ensure that persons cannot be put at risk when working on or in the machine. Before performing any maintenance, the power must be locked out to the main control panel.

39 Follow the local lock out tag out procedure to make sure there is no possibility of the equipment starting, or being connected back to power until all necessary work is performed. Only trained personnel should be allowed to make adjustments or repairs on any part of the electrical system. Protective covers and guards may be removed only after the power has been disconnected. All protective covers and guards must be in place before operating the equipment. Do not attempt any repairs or adjustments while the machine is in operation.

40 UPCP: Influent Screening Plant: Mendenhall WWTP Author: CJ Schneider Date: November 2014 Summary- Grit Removal Influent grit removal is provided at the head-works of the facility with the purpose of removing grit and other inorganic debris that may travel through the sewer system. After screenings removal, the grit is separated, dewatered and conveyed into a roll off bin for disposal. The main objective of grit removal is to: Protect moving and mechanical equipment from abrasion and accompanying abnormal wear. Reduce clogging in pipes. Prevent grit accumulations in SBR and sludge basins. Process Overview Teacups TM and Grit Snail TM Flows from the raw wastewater pump station wet well are pumped into the grit removal system head box where the pretreatment process is initiated. From the head box, liquid flows by gravity through the grit removal system and then into the secondary treatment process. The pretreatment system consists of: Grit separation Grit dewatering Grit collection and disposal The grit system head box provides hydraulic head and distributes flow to the three grit removal units (Fluidyne TeaCups TM ). The units operate simultaneously during all flow conditions. To separate grit from the wastewater, inflow is introduced into the units upper chamber causing the fluid mass to rotate. This rotation induces a centrifugal force which propels discrete particles away from the center, towards the tank wall. At the tank wall, particles settle towards the bottom (grit discharge area) where they are discharged to the grit dewatering unit (Eutek Grit Snail TM ) where it is conveyed to a hopper and disposed of.

41 Figure 1-1 Fluidyne TeaCup TM Grit Separators 1.0 TeaCups TM 1.1 OPERATION The grit system head box provides hydraulic head and distributes flow to the three grit removal units. The units operate simultaneously during all flow conditions. During normal operation, all grit separation units should be on-line with all isolation valves open. Hydro-Circ valves should be open to their adjusted positions, and plug valves associated with the non-restrictive vortex flow controller should be open. The Hydro-Circ valves should be adjusted to provide constant velocities in the upper grit chamber. In the event a grit separator must be shut down, the associated slide gate in the head box must be closed using the hand-wheel operator. 1.2 DESCRIPTION The grit removal system is a hydraulic process that uses no mechanical or electrical components. The grit removal system consists of a head-box that supplies flow to three centrifugal grit separators, each having six basic components: Head-box, Stainless Steel construction Vessel, Hydro-Grit unit, Stainless Steel construction Valve, Vessel Isolation, 12, Stainless Steel construction Vortex Breaker, 2, Stainless Steel construction Valve, 2, Flow controller, Stainless Steel construction Valve, 4, Hydro-Circ, PVC construction

42 1.3 MECHANICAL SPECIFICATION A. Materials 304 Stainless Steel throughout. 3/16 min. wall thickness B. Dimensions Dia. 96, vessel height 102, head-box height 168 C. Head loss Shall not exceed 65 D. Removal 95% of all grit 100 microns or larger and < 15% organic material E. Peak Q capacity 4.0 MGD each (3) 1.4 PROBLEM ANALYSIS Table 1-1 Troubleshooting Guide Potential Problem No discharge flow from vortex breaker If flushing is unsuccessful High organic content in grit Low fine particle recovery in grit Possible Solutions Flush 1 fluidizing port with non-potable water Flush vortex 2 tee with 1 1/2 hose Check for ANY indication of a bent or broken lifting spiral. Take vessel offline. Remove access cover above vortex breaker. Remove obstructions. Remove vortex breaker. Use a plumbers snake to clear obstruction Increase flow velocity in vessel by adjusting the position of the Hydro-Circ valve further open Remove one vessel from service to increase flow velocity through other vessels Decrease flow velocity in vessel by adjusting the position of the Hydro-Circ valve further closed Place additional vessel in service to decrease flow velocity through vessels Table 1-2 Design Specification Parameter Specification Wastewater type Domestic/Commercial Peak Flow Rate (MGD) 4.0 MGD (3) Each / 12.0 MGD Total Removal 95% of all grit, 100 microns or larger at a peak flow Capture rate: % Organic % Inorganic < 15 > 85 Head loss Not to exceed 65

43 2.0 Grit Snail TM 2.1 OPERATION Discharged flow from each grit removal unit flows via 2" pipes where the abrasive slurry is settled in the clarifier section of the grit dewaterer. Abrasives deposit on the conveyor belt cleats in the clarifier and slowly escalate out of the water. As the cleats break the water surface the water drains from the flat cleats back into the clarifier. Any discrete particles that settle in the clarifier section are dewatered. The supernatant from the clarifier is discharged back in to the influent pump station. The dewatered abrasives are carried to the top of the grit snail, scraped off, and collected in the hopper for disposal. The final product is dewatered grit at approximately 70% solids. In general, the grit dewaterer is intended to be in operation at all times when the grit removal system is in operation. The magnetic starter HOA switch should be in the HAND position, and the START pushbutton control should be in. Figure 2.1 Eutek Grit Snail TM Dewaterer

44 2.2 MECHANICAL SPECIFICATION GRIT DEWATERING ESCALATOR BELT The grit dewatering belt is 12 wide, aluminum reinforced neoprene, hinged type, with 3-3/8 x 4-9/16" cleats vulcanized on 3/16" two-ply polyester reinforced continuous conductor belting. Head and tail rolls are of 304 stainless steel. The 1/4" lagged head roll is designed for adjustable take-up without affecting the head roll retainer plate, scraper, or drive unit adjustment. The tail roll mounts internally to the Grit Dewatering Escalator belt housing with external sealed bearings. The belt clears is made of molded 60 Durometer neoprene construction, aluminum reinforced, with minimum 5/32" thick neoprene hinge. HEAD ROLL, RETAINER PLATE AND SCRAPER The Grit Dewatering Escalator is provided with a head roll scraper having 1/4" thick HDPE contact surfaces and a 1/4" thick HDPE retainer plate. Both retainer plate and scraper is loaded to keep cleats closed tight around head roll during operation. SELF-CLEANING TAIL ROLL MECHANISM The belt cleats are neoprene hinged with fulcrums to provide at least 1" cleat opening when rotated about the tail roll. 2" openings are provided in the Grit Dewatering Escalator belt to allow transfer of fine solids internal to the belt to the underside of each cleat. The tail roll is fitted with a scraper which also functions as an internal belt scraper. GRIT DEWATERING ESCALATOR BELT HOUSING AND CLARIFIER The belt housing is constructed of.135" thick 304 stainless steel. The housing has a cleanout plate and drain in the tail roll end and discharge at the head end. The housing is fitted with a 48 square clarifier with walls sloping 45 degrees from the horizontal. The clarifier has 3" of free board at design flow. The clarifier is fitted with an 42 overflow weir with a 6 (40) discharge pipe opposite the belt discharge. Surfaces are bead blasted. DRIVE UNIT The drive is a helical gear reducer with hardened alloy steel gears accurately cut to shape. The housing is steel or case iron and is oil tight. Bearings is ball or roller type anti-friction throughout. The motor is 1/3 HP, 460 VAC 60 Hz. 3-Phase NEMA Design B, TEFC with a 1.15 S.F. which in turn is mounted integrally with the helical reducer above. The motor speed is selectable by adjusting a VFD output. Complete unit is treated for severe outdoor duty and shall have epoxy treated windings.

45 CONTROLS The operating controls provides for manual operation. They consist of a magnetic starter with a HAND-OFF automatic selector switch with cover and a separate STOP- START push-pull button station. All controls are in NEMA type 4 cases. The belt is ON whenever grit slurry is being transported to it. BOLTS All assembly and anchor bolts are 304 stainless steel. 2.3 PROBLEM ANALYSIS GRIT SNAIL TROUBLESHOOTING GUIDE To ensure trouble-free operation, the EUTEK SYSTEMS GRIT SNAIL requires a regular maintenance program. The following step-by-step guide should be used for ( a) routinely troubleshooting GRIT SNAIL as part of a regular m aintenance program, (b) pinpointing the cause of a slipping belt, or (c) pinpointing the cause of a cleat or belt failure. See the attached drawings to identify components referenced by bold numbers in parentheses. 1. Investigate the normal operation of the GRIT SNAIL. Does it run continuously? If not, how long does it run before and after each grit blowdown? THE GRIT SNAIL MUST BE RUNNING BEFORE GRIT ENTERS THE CLARIFIER (1). Otherwise, the belt will be under a tremendous load if the GRIT SNAIL TM tries to start with grit packed in the clarifier. After flow to the GRIT SNAIL TM stops, the belt must run until there is no more grit on the cleats (approximately minutes). If grit is not removed, the belt will be under excess tension the next time it is started. 2. If the belt stops or the GRIT SNAIL TM must be shut down during operation, manually remove as much grit as possible from the GRIT SNAIL TM belt and clarifier first. DO NOT MAKE ANY ADJUSTMENTS WITH GRIT IN THE CLARIFIER.. 3. Next, check the wall-to-wall clearance in the belt housing FIGURE 2-2 (2) from the head roll to the tail roll. You should be able to lift up each cleat slightly. If you cannot, the belt may be operating under too much tension. Make sure that the head roll is square with the head roll take-up frame and with the belt housing. If not, the head roll could pull the belt to one side and cause excess tension. Adjust the head roll bearings and shaft as necessary. 4. The grit leveler FIGURE 2-2(3) is the piece of HDPE that levels the grit off to the top of each cleat. Is the grit leveler adjusted so that it just clears the tops of the cleats? If there is more clearance than this, it will leave too much grit on the cleats, which can overload the belt. If the leveler pulls on the cleats excessively, it could damage them after a long period of time. Adjust the grit leveler as necessary.

46 5. To check the head roll retainer adjustment FIGURE 2-2 (4), remove the circular HDPE head roll skirts and inspect the full travel of each cleat around the head roll with the belt running. a. When the cleats enter the retainer, are the cleats compressed between the retainer and the head roll? If so, use stainless steel washers to shim the screws that bolt the retainer to the take-up frame until the retainer gently closes the cleats FIGURE 2-2(4). To prevent from springing out of position, only loosen one side of the retainer at a time. b. Make sure the cleats cannot flop open away from the belt. If so, the cleats could flop open as they go around the head roll, allowing grit to accumulate under them. This condition would also cause grit to build up inside the GRIT SNAIL TM in front of the internal scraper. Adjust the 4 ea. 1/2 threaded rods as necessary FIGURE 2-3 (4B). c. Make sure that the retainer does not hold the cleats against the belt too tightly. This could rip cleats off as they enter the retainer or compress cleats between the retainer and the head roll. Adjust the 4 ea. 1/2" threaded rods as necessary FIGURE 2-3 (4C). 6. If cleats are still compressed as they enter the retainer, check the location of the pillow block bearings FIGURE 2-3 (5) that support the head roll. If the bolts holding the bearings are loose, the bearings could shift out of place. If necessary, relocate the bearings evenly until the retainer gently closes the cleats. For reference, this dimension is nominally 8-3/16" to the center of the bearings. 7. Check the head roll scraper FIGURE 2-2 (6) to see if it has been catching cleats. Clean the grit off the scraper. Does it hit the cleats violently? Is its HDPE bent toward the tail roll? If either of these are true, the scraper may have too many counterweights attached. This could cause the belt to slip or the scraper to "hook" the cleats and eventually rip them off the belt. There should be only enough counterweights to scrape the cleats clean. Remove or add counterweights as necessary. 8. To inspect the internal scraper, drain the clarifier and remove both access cover plates FIGURE 2-2(7). A reversed cleat would cause a hump in the belt that could get jammed under the internal scraper. Grit building up under the cleats (visible through the 2"Ø holes in the belt) could also cause cleats to jam under the internal scraper FIGURE 2-4. Check for any humps in the belt all the way up the belt housing. Also, make sure there are no large pieces of debris that could jam the belt. If there are, maintenance and inspection schedules should be increased to deal with this potentially serious problem. 9. Check the clearance between the internal scraper and the tail roll inside the FIGURE 2-2(8A). There should be about 1/16" clearance between the top edge of the internal scraper and the tail roll FIGURE 2-4 (8B). If the tail roll rubs on the internal scraper, the extra tension could cause the belt to slip. Loosen the (6) bolts holding the internal scraper in place and try to move it slightly. If this does not help, remove the flange bearings holding the tail roll shaft. Replace the HDPE press fit bushings FIGURE 2-4 (8C) if they are worn to properly relocate the tail roll.

47 10. Now check to make sure that the cleats move freely around the tail roll. Remove the tail plate FIGURE 2-2 (9A) and measure the distance from the inside of the tail plate to the wear side of the HDPE liner FIGURE 2-5. This distance should measure approximately 1/2". Now, measure this same distance from the end of the belt housing toward the tail roll. This should leave enough clearance to open each cleat about 1" so that the grit under it can drop on top of the next cleat. Make sure that the cleats are not being held down tight or compressed by the tail plate. This will put tremendous pressure on the cleats and belt and should be corrected immediately. Also check HDPE liner for wear. Figure 2-2 Grit Snail General Arrangement Figure 2-3 Grit Snail Head Roller Assembly

48 Figure 2-4 Grit Snail Tail Roller Figure 2-5 Grit Snail Tail Plate

49 Performance Monitoring The actual performance of the Grit Removal process is measured subjectively through observation. The operator should expect to find the usual amount of grit in the hopper. This will change some with influent flow changes. Grit removal performance can also be inferred by looking for the presence of heavy inorganics in other parts of the plant that should have been captured by the TeaCups TM. Control Parameters The TeaCups TM are designed to be operated continuously and should only need to be removed from service for repair or to remove oversized obstruction. One of three units may be taken off-line at a time and still accommodate normal influent flows. If the TeaCup TM needs to be serviced for any extended period of time it should be isolated at the headbox inlet valve, to prevent excessive accumulations from plugging the discharge end of the unit. The Grit Snail TM unit is designed for continuous operation. Flow to the unit should be isolated or rerouted from the clarifier portion to prevent excessive accumulations of grit over loading the unit when re-energized. The best practice for bypassing the clarifier is to route the discharge hoses back to the Influent Pump Station wet well using a 6 collapsible hose. Safety Before performing any maintenance or repairs to the equipment, personnel should review all governing Safety policies in effect. Note that the material handled by the equipment may come under the classification "Bio-hazardous material ". Additionally, the equipment are be controlled by remote controls, and can start automatically at any time. Follow the established Lock out Tag out procedures to isolate the equipment and prevent automatic starts, prior to performing any work on the equipment. Caution, the Grit Snail TM can start automatically and have multiple sources of hazardous energy! In general, the following safety precautions must be observed: Ensure that persons cannot be put at risk when working on or in the machine. Before performing any maintenance, the power must be turned off to the main control panel. Follow your local lock out tag out procedure to make sure there is no possibility of the equipment starting, or being connected back to power until all necessary work is performed.

50 Only trained electricians should be allowed to make adjustments or repairs on any part of the electrical system. Protective covers and guards may be removed only after the power has been disconnected. All protective covers and guards must be in place before operating the equipment. Do not attempt any repairs or adjustments while the machine is in operation.

51 UPCP: UV DISINFECTION Plant: Mendenhall WWTP Author: CJ Schneider Date: November 2014 Summary Wastewater effluent disinfection is the tertiary treatment process applied after the wastewater has undergone primary and secondary treatment. Disinfection is treatment of the effluent for the destruction of pathogens. Whenever wastewater effluents are discharged to receiving waters which may be used for water supply, swimming or shell fish harvesting, the reduction of pathogenic bacteria to minimize health hazards is essential. 1.0 Process Overview The Mendenhall WWTP utilizes a Trojan UV3000 disinfection system. It uses ultraviolet light to disinfect wastewater effluent. It operates in the UV-C spectrum at a short wavelength of to nm. Unlike chemical disinfection, UV does not require the handling of dangerous substances and adds no toxic compounds to the effluent. The disinfection system occupies a separate structure from the SBR and ABF buildings, located in the northwest portion of the treatment plant site. Flow is supplied by 2-30 decant lines from the SBR basins after they have completed the secondary treatment sequence. It is then metered into the UV Disinfection channel with manually set butterfly valves located on each decant line. The channel depth is regulated with an Automatic Level Controller (ALC) weir to maintain adequate liquid level above the lamps and insure proper disinfection. Figure 1.0 Trojan UV3000 Module

52 1.1 Ultra Violet Disinfection Microorganisms in the treated wastewater are exposed to ultraviolet light when they pass by special lamps. The UV energy instantly destroys the genetic material (DNA) within bacteria, viruses and protozoa, eliminating their ability to reproduce and cause infection. Unable to multiply, the microorganisms die and no longer pose a health risk. The Trojan UV3000 is made up of several components: UV Module Electronic Ballast UV Sensor Power Distribution Center (PDC) System Control Center (SCC) Water Level Control (ALC) UV Module The UV module is the basic unit of the flow through UV bank. A bank is made up of 24 UV modules placed in parallel, 3 inches apart. UV modules consist of a 316 stainless steel frame that holds 8 high-intensity UV lamps in position, and houses all connecting wires and electronic ballasts in a watertight enclosure. Electronic Ballast The ballast is mounted within a watertight enclosure on top of the module frame. There is no need for mechanical cooling since normal convection cooling is adequate. UV Sensor The submersible UV Sensor measures the UV intensity within each bank of UV lamp modules. The UV Sensor is mounted on a representative UV lamp module. The UV Sensor is calibrated in the factory and should not be altered, or its calibration changed.

53 Power Distribution Center (PDC) The Power Distribution Center spans the width of the effluent channel and distributes power from the main electrical service to the UV modules in the UV banks. Molded connectors connect the UV modules to the PDC by plugging them into the stainless steel receptacles on the PDC's front panel. The PDC is a stainless steel enclosure that is weather resistant. It houses the power distribution bus bar, relay board for each module, and the communication controller board. The main power service is connected through the electric service entrance power and distributed through the bus bar. Communications between the PDC and System Control Center is via an RS422 Serial Communication Link. System Control Center (SCC) The operation of the Trojan UV3000 is managed by the System Control Center (SCC). The SCC is a menu-driven workstation that supplies the operator interface to the disinfection system. It allows the operator to monitor and control all UV system functions. An alarm reporting system provides the operator with the tools needed for accurate diagnosis of various system processes and failures. Water Level Control An Automatic Level Controller (ALC) device controls the effluent level within the UV channel. 1.2 Operations Overview The modular design makes it versatile and permits easy access to the equipment for routine maintenance and repair. The system is sized and programmed to meet the MWWTP objectives and permit requirements. Operation of the system is managed at the System Control Center (SCC) which continuously monitors, controls system functions and sends basic data to the SCADA control system. The SCC is the brain of UV Disinfection control system and communicates with the operator interface and UV modules. Meters, switches, and sensors provide the SCC with the necessary system parameters.

54 The system is designed to be operated in automatic or manual mode. In automatic mode the SCC will: turn off all UV banks in-between decant cycles turn off all UV banks if a low water condition exists turn on the stand-by bank if NTU s exceed the operators selected limit turn on the stand-by bank if UV intensity drops below preset limits alternate banks to maintain equivalent hours on each bank The system is currently operated in manual mode with all 3 banks energized at all times. This assures that the maximum disinfection capabilities are being utilized. It also reduces wear and tear on the lamps and electronics, rated for 4 on/off cycles per day, caused by excessive on/off cycles produced by automatic operation. Table 1-1 UV Disinfection System Troubleshooting Guide Condition Possible Cause Solutions 1) Minor Low UV Warning Alarm UV intensity has dropped below the preset point due to sleeve fouling. 2) Major Low UV Alarm UV intensity has dropped below the preset point due to sleeve fouling. Clean quartz sleeves. Clean quartz sleeves. 3) Minor Lamp Fail Alarm A single identified lamp has failed. Replace lamp. 4) Major Lamp Fail Alarm More than a preset minimum number of UV lamps are not illuminated. 5) Major Module Err Alarm The UV module is not properly connected to the PDC Moisture in the UV module has caused the ground fault circuit interrupter to trip. Communication between the UV module and the PDC is interrupted (i.e. all lamps in the module are ON). Communication chip of the UV module or communication board requires replacement. Replace lamps. Reconnect (tight). Check for broken quartz sleeves or defective O-Rings. Dry out module and replace fault parts. GFCI will reset itself when faults are corrected. Disconnect and reconnect the UV module. Consult factory for parts and procedure.

55 Condition Possible Cause Solutions 6) Major Adjacent Lamp Alarm Two or more adjacent lamps have failed. Wire connections inside the UV module may be loose. Bad ballast i.e. adjacent lamps are not illuminated. (lamps within the same module are powered by the same ballast; lamps #1 & #2 use a common ballast, #3 & #4 use a common ballast, etc.) 7) Major Device Error Alarm Communication between the SCC and PDC has been interrupted. Replace faulty lamps. Fix faulty connection(s). Replace ballast (the ballast located nearest to the circuit board powers the bottom two lamps). Ensure power to PDC is ON. Reset communication board by turning power to the PDC OFF and ON. 8) UV intensity sensor reads higher than nromal readings. Intensity monitoring system components have failed. Photodiode within sensor may be faulty. Contact Trojan Technologies 9) UV intensity sensor reads lower than normal readings. 10) Complete UV module stays ON when system is asked to shut down. Lamp sleeves and sensor have become fouled. Communication between PDC and UV module has been corrupted. Clean sensor and sleeves with Trojan approved cleaning agent. Ensure UV module cable connection to PDC is tight. Connect UV module to a different PDC connection (at least 3 connectors away from original). Restart modules. If problem follows the original UV module, replace the communication chip on the UV module circuit board. If the problem stays with the PDC connector, replace the PAL communication chip on the communication board located inside the PD. Acknowledge all alarms. 11) Screen shows false alarm. A previous alarm condition is no longer evident and has not been acknowledged. Acknowledge all alarms. 12) System does not respond to commands Communication is lost between PDC and SCC. Ensure Tx and Rx LEDs on the SCC circuit board flash ON and OFF at least once every minute. The Lc1 LED stays on all the time.

56 Condition Possible Cause Solutions 13) Disinfection not being met Sleeves are fouled. Clean sleeves with Trojan approved cleaning agent. Peak flow is higher than system design thus affecting head loss through UV system and level control device. (See performance guarantee for sites specified limits) Level control device is not functioning properly causing effluent levels to rise to levels to high above top module lamp. This is referred to as short circuiting as effluent passes over the top lamp without being disinfected. Return flow rates to disinfection levels. - If ALC is being used check for debris may be caught in ALC. - If weir is in use debris may be built up on weir crest. TSS levels higher than design limits. (See performance guarantee for sites specified limits) UVT lower than design limits. (See performance guarantee for sites specified limits) Plant process needs to be reviewed. Plant process needs to be reviewed. Table 1-2 Design Specifications Parameter Specification Wastewater Type Domestic Average Daily Flow (MGD) 10.0 Peak Flow Rate (MGD) 15.0 Min Flow Rate (MGD) 1.0 TSS 30 mg/l Temp Range 40 to 70 deg. F 5-Day B.O.D. 30 mg/l 30 Day FC Geometric Means 200 / 100 ml UV nm: 55% No of Lamps 576 Mean Particle Size < 30 microns Flow Channel Width 6 feet Flow Channel Depth 4 feet Flow Channel Length 36 feet

57 Routine Maintenance DAILY: Check Bank Status, Alarm Status and UV Intensity status screens for any new faults. Record. Check for debris build-up on module leg or in the channel. WEEKLY: Check & record lamp hours. MONTHLY: Check electronic ballast replace if necessary. Clean any algae or debris build-up from UV Sensor. Clean quartz sleeve from algae build up, hosing off the sleeves may be all that Is required, but a coating will build-up over time in which case a thorough cleaning will be necessary. Clean SCC enclosure. Do not use high-pressure hose or corrosive cleansers. Check SCC door seal. Ensure moisture is not present. Clean PDC enclosure. Do not use high-pressure hose or corrosive cleansers. Check module cables. Ensure module cables are tightly mated to female receptacles. Check level control device for algae buildup hose off if necessary. Performance Monitoring The actual performance of the UV Disinfection can be measured subjectively through observation of the Fecal Coliform laboratory test results. The operator should create and maintain a trending chart graph of the results and expect to see an increasing Fecal Coliform count over a several month interval. This will indicate the UV lamps overall effectiveness and condition. It will alert the operator to replace all UV lamps if cumulative hours correlate with the increased FC counts. An increased FC count over a very short term is a possible indication that the UV lamp sleeves are contaminated and in need of cleaning.

58 Lamp Age and Sleeve Fouling UV intensity gradually decreases with time and use, due to lamp aging and sleeve fouling. This is factored into the design, so that equipment will maintain the required UV dose throughout the life of the UV lamps. For proper performance, UV lamps should be replaced after the specified lamp life in the warranty. Lamps are guaranteed for a useful life of 10,000 hours. Lamp life depends on the number of ON/OFF cycles used for flow pacing during disinfection. Uniform intensity in a system can be managed with a staged lamp replacement schedule. An accumulation of inorganic and organic solids on the quartz sleeve decreases the intensity of UV light that enters the surrounding water. The fouling rate varies with effluent quality and may be more rapid in the presence of high concentrations of iron, calcium and magnesium ions. Alternate Modes of Operation There is no redundancy incorporated with the installed configuration. In the event of a catastrophic equipment failure, effluent will be discharged into the Mendenhall River with no disinfection. Effects of Improper Disinfection Failure to provide proper disinfection will have a detrimental effect on downstream ecology. Wastewater contains the body wastes from both healthy and diseased persons. Failure to properly treat the wastes could result in the release of disease causing organisms into the environment. Failure to provide adequate treatment can result in contamination of water bodies which could be used as public water supplies. Consumption of shellfish from contaminated waters can also result in disease. Failure to remove poisonous (toxic) materials can reduce available oxygen and cause destruction of aquatic life. Safety Before performing any maintenance or repairs to the equipment, personnel should review all governing Safety policies in effect. Note that the material handled by the equipment may come under the classification "Bio-hazardous material ". Additionally, the equipment are be controlled by remote controls, and can start automatically at any time. Follow the established Lock out Tag out procedures to isolate the equipment and prevent automatic starts, prior to performing any work on the equipment.

59 In general, the following safety precautions must be observed: Ensure that persons cannot be put at risk when working on or in the equipment. Before performing any maintenance, the power must be turned off to the main control panel. Proper PPE, including UV resistant eye protection, must be used. Follow your local lock out tag out procedure to make sure there is no possibility of the equipment starting, or being connected back to power until all necessary work is performed. Only trained electricians should be allowed to make adjustments or repairs on any part of the electrical system. Protective covers and guards may be removed only after the power has been disconnected. All protective covers and guards must be in place before operating the equipment. Do not attempt any repairs or adjustments while the machine is in operation.

60 SOP# Date of last modification: 2/21/14 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS Standard Operating Procedure MWWTP SBR SOP Created by: JSA by: 1. PURPOSE AND SCOPE: This procedure describes the strategy to be used by the Mendenhall staff to manage the SBR process and identifies parameters available for manipulation by the operator to achieve treatment goals. This SOP assumes a general understanding of the principles of activated sludge. It is important that the strategy and status of this process is understood in detail by several staff members and in general by all operations staff. The goals of the strategy are to maintain a steady state activated sludge biology that behaves consistently, separates from effluent in the decant stage, and produces an acceptable effluent. 2. STRATEGY AND PROCEDURE: Operational Mode A treatment cycle consists of these stages: Fill- consist of Static Fill (no air or mixing), Mixed Fill (mixing but no air while filling), and Aerated fill React, - consists of Aerated React and Mixed React Settle, - consist of Settle-prep (recirculation continues briefly without aeration to displace air from the recirculation header) prior to Settle, a quiescent period to allow settling Decant, - supernatant is withdrawn to become effluent, and wasting occurs. Waste WAS is withdrawn per time set by operators Idle, - time between cycles The Mendenhall SBR can be run in one of two modes (and each has variations). If in flow proportioned mode, reactor cells fill for a selected amount of time before progressing to the react stage. The operator controls these times by setting maximum fill set points on the SCADA for each of the three segments of the fill stage. When running this way, cells process varying amounts of wastewater each cycle, thus variation in influent flow rate is managed. Alternatively, if the Operator enters large numbers as maximum fill set points, then fill cycles will not be time-limited and each cell will fill to the top water level before beginning a cycle (we can call this full cell mode ) Cells will treat the same amount of wastewater each cycle. The variation in influent flow rate then, is taken up by differing lengths of idle periods between each cycle. This mode has the potentially disadvantageous feature of longer idle periods during which biology is not fed or aerated, but has the advantage of introducing a consistent BOD loading to each cell each times it cycles. Mendenhall operates in the full cell mode. Features of the SBR that we can manipulate to exert control over the process are described below: Wasting rates Wasting rate is an essential control in every activated sludge plant. It affects sludge age, ratio of loading to biology, and biology characteristics. The Mendenhall plant s design information indicates that at design loading, the intended f/m is 0.15, the design SRT would be 7.67 days, Page 1 of 6

61 SOP# Date of last modification: 2/21/14 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS Standard Operating Procedure MWWTP SBR SOP Created by: JSA by: and the MLSS will be 2,200mg/L. When not at full loading, we can run with a higher SRT to reduce yield and provide greater stabilization of solids. To determine WAS rates we can use a modified version of SRT. To establish wasting we start with calculation of inventory. If we select say, a 10 day target SRT, we need to waste 1/10 th of the inventory each day. The calculation looks like this: Pounds per day to waste = (7cells)( MG/cell)(average MLSS)(8.34) Desired SRT Gallons per day to waste = (Pounds per day to waste)( ) (WASSS)(8.34) Minutes per cycle to waste = Gallons per day to waste (number of SBR cycles per daily wasting period)(1200 gal/min) This calculation is in the plant spreadsheet on the I drive. Scroll down to the current date. In green columns C, D and E, enter target SRT, recent measurement or estimate of WASSS concentration, and cycles per daily wasting period (we might waste less than 24 hours per day if we leave wasting off for a period to harvest decant from the WAS tank). The calculation will produce minutes per cycle in yellow column J. If some cells have higher MLSS than others, adjust waste minutes up or down for individual cells, but in a way that preserves the average across the seven cells. The block of cells in the upper right is a tool for doing this. MENDENHALL 7-Cell Target Adjust to balance MLSS cell to cell Date Average desired SRT Estiamted cycles per daily during wasting period Measured or estimated WASSS concentration mg/l Inventory pounds to waste gallons to waste (total) minutes per cycle to waste 1/1/ /2/ /3/ /4/ Independent of the calculated WAS amount, an operator must also watch MLSS concentration and settling characteristics. If we are at risk of dipping decanters into blankets, we need to temporarily abandon our SRT-based program and waste more heavily until the risk is minimised. Anoxic time The Mendenhall plant does not have strict limits on effluent nitrogen, thus anoxic time is not needed for denitrification. Brief anoxic conditions are useful however to exert a selector effect against filamentous organisms that interfere with settling. Most filaments are obligate aerobes and are out-competed by facultative floc forming bacteria in taking up BOD under unaerated Page 2 of 6

62 SOP# Date of last modification: 2/21/14 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS Standard Operating Procedure MWWTP SBR SOP Created by: JSA by: conditions. Sufficient anoxic time usually occurs passively during the fill cycle. An operator should just be aware that if he/she sets very high aeration times, it may encroach on the anoxic time during the fill cycle and reduce the selector effect. Reaction/Aeration times and D.O. concentrations In flow proportioned mode, the control system adjusts the aeration time per cycle (between a minimum and a maximum that we set) to be proportional to the percent of plant capacity being used at the time (with the value entered as the air slope set point defining the aeration time at 100% of plant capacity) However, our usual way of operation is full cell mode. In this mode we are treating the same amount of wastewater in each cycle, therefore, we want to deliver nearly the same amount of air each cycle. So, we set the minimum and maximum air settings close together. Assume actual air time will match the setting entered into the minimum air set point. Now, how much air time is just right? Aeration in each cycle should be long enough that biology has an opportunity to take up the BOD that came in during the Fill Cycle. Operators can become familiar with the behaviour of D.O. compared to the rate of application of air. View this behaviour on the SCADA screen. In the cycle depicted below the red line is the blower speed and the white is D.O. The first third of the graph shows very high blower output to raise D.O. despite the high oxygen uptake rate that is typical at the beginning of of a cycle. The middle part of the graph is of particular interest. Note how blower output decreases to its flat minimum level and stays there. While aeration is steady, the D.O. turns a corner and begins to increase until the end of the cycle. This shows most of the BOD has been consumed and it has become easier to increase D.O. Page 3 of 6

63 SOP# Date of last modification: 2/21/14 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS Standard Operating Procedure MWWTP SBR SOP Created by: JSA by: The below image, showing D.O. trends in all cells, is best consulted after understanding the image above. One can see that the air demand more than met in most of those cycles. Adjust air so that the second peak goes above, but not way above, the first bump. Understand that this method of adjusting air is specific to the Mendenhall plant as it depends on the particular features of the Mendenhall blower control system. Settle times Settleometers allow an operator to determine sludge volume index or SVI (the 30 minute settled volume divided by concentration of MLSS in grams/liter). It is difficult to measure SVI on Mendenhall activated sludge as it tends to float in the settleometer. The best way to monitor settling characteristic is to DOB an SBR when in Settle just before decant. At least 10 feet of clear supernatant liquid is the target; if the clear layer is less than that, increase settle time. Top and bottom level settings. The usual Mendenhall SBR top and bottom levels are 18 feet and 24 feet, leaving six feet to fill then decant each cycle. If ten feet of supernatant cannot be achieved even after lengthening settle time to over 100 minutes, an operator can raise the bottom level to prevent the decanter from drawing solids from the top of the mixed liquor blanket. Note that this action will cause more cycles in a day and would affect number of wasting cycles and thus total WAS volume from that Cell. It may also increase the possibility that the react portion of cycles will be truncated when the plant is hydraulically stressed. Page 4 of 6

64 SOP# Date of last modification: 2/21/14 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS Standard Operating Procedure MWWTP SBR SOP Created by: JSA by: An Operator can lower top level (or lower top and bottom levels together) when foaming is occurring, to prevent foam from coming out onto the walkways between cells. Note that this will increase MLSS concentration 4%-5% per foot. Number of cells in operation The Mendenhall SBR is an eight-cell reactor. The plant is designed to treat its capacity with seven cells in operation and the eighth left as a redundant (back-up) unit. Operators have the option of using all eight cells during periods of high loading if desired, but operators should recognize that if a mechanical failure occurs requiring a cell to need to be emptied, the other seven cells would then need to accept the volume and the mixed liquor solids from the cell being dewatered as well as treating the forward flow through the plant. It could introduce additional stress to the plant at a time when it is already stressed. While standing by as a redundant unit, the eighth cell serves a function as an EQ vessel (as does any empty cell not in auto ). It is available to accept influent when the incoming flow rate exceeds the ability of the other seven cells to receive it. The stored influent can then be feed into the plant at a later, less stressed time. 3. CONTROL INTERFACE: The operator needs an authorization and a password to manipulate settings on the SCADA interface. The below screen is the location to select cells in service and set Top Water Level, Bottom Water Level and WAS minutes per cycle (when in full cell mode the operator will not need the Air adjust on this page) Page 5 of 6

65 SOP# Date of last modification: 2/21/14 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS Standard Operating Procedure MWWTP SBR SOP Created by: JSA by: The below is the screen where air time is set (lower left: 7 cell set points) 4. RECORDS AND ANALYSIS: Record cycle times, WAS amounts, TSS results, and level settings on daily sheet for direct reference when making control decisions the next day. Also, enter the day s data into the Mendenhall Operational Database. Evaluate data trends, using excel graphing capabilities where useful, and compare to observations regarding biology characteristics and plant performance. When recording MLSS, if the top levels are not at 24 feet, mathematically dilute the number to represent that amount of MLSS in a full cell (multiply the measured concentration by the actual depth in feet then divide by 24). 5. REFERENCES: Mendenhall, AK WWTP Controls, Operation and Maintenance Manual, September 21, 2000, US Filter Jet Tech Inc. Page 6 of 6

66 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: 6/9/2014 Standard Operating Procedure MWWTP Solids Management Straight WAS SOP Created by: JSA by: S. Blair 1. PURPOSE AND SCOPE: This procedure identifies a strategy and actions we can use to manage the movement of WAS solids from the SBR through the WAS/Thickener tanks, through the Belt Filter press, and into conex containers. The goals are: To always have available tank volume to waste per the need of the SBR process; To partially digest WAS or at least keep it fresh by aeration, and To provide predictability and flexibility in the timing of container changes to help our hauler in planning. This is an alternative to the Decant and Digest procedure. 2. PREPARATION AND PRECAUTIONS: This process requires attention to tank levels as they are manually managed to meet the goals of the process and to prevent overflow during wasting and to prevent dropping a tank level below the minimum operating level while withdrawing (pressing). 3. PROCEDURE: a. Configuration In the Straight WAS mode, set WAS from SBRs to enter both sludge tanks simultaneously. Keep valves to the BFP from both tanks open so that the two tanks equalize with one another. We are using the two tanks as one. Some manipulation of valves from tanks to BFP may be necessary to keep tank levels even as it tends to preferentially draw from the Thickened tank. b. Mixing and Aeration Keep both tanks fresh, aerating each tank to a target of 0.5 to 2.0 mg/l D.O. This can usually be done by running the jet mixers in both tanks and using blower B-10 in flip-flop mode that is, alternately aerating each tank for 600 seconds (ten minutes) each. This mode is selected on the SCADA under Air Valve AV1S at the bottom center of the Sludge Handling screen. If D.O. targets cannot be maintained, you will need to run a dedicated blower for each tank. c. Level Management The Press Target Calc tool calculates tank level targets and press target amounts for each day of the week. Using it, we will leave room in the tanks at the end of each shift to accept wasting until the next morning, and we will accumulate enough room through the week so that by the end of Saturday, we will have room to waste until Monday morning with no pressing. Page 1 of 3 The maximum operating level in the WAS and Thickened tanks is 24 feet. We need to identify and operate to a practical high level some number of feet below that. Here are the trade-offs that go into selecting that level: It needs to be low enough to leave room for foam and to prevent overflow, We will benefit by selecting a high level low enough to leave some room to store sludge as a contingency for unexpected high wasting or a BFP problem, We benefit by setting the high level high enough to retaining as much sludge under aeration for as much time as possible to achieve a small amount of sludge stabilization. A practical high level of around 20 or 21 feed is a starting point and can be modified per experience. 1) Enter the chosen high level into Press Target Calc tool in the Mendenhall Data

67 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: 6/9/2014 Standard Operating Procedure MWWTP Solids Management Straight WAS SOP Created by: JSA by: S. Blair Spreadsheet under M (Monday) in the row labelled Target Start level (all entry cells are green). 2) Enter total gallons WAS from SBRs for a most recent full day in the top green row, writing over the number that was there for the previous week (leave previous week s gallons in the cells until written over with new data; this allows the calc tool to look back and use a running 7day average waste rate) 3) Enter Actual start level. The actual tank level is likely to be different by some small amount than the target each day. The tool makes a correction for the difference 4) Enter the number of hours the press can be run that day (optional to calculate needed feed rate). Gallons WAS/day M T W Th F S Su Target Start level 6:00am Target end level 6:00pm Unadjusted press target gal Actual Start level 6: Delta feet Daily adjustment gal Adjusted press target gal Feed rate in gpm to press in hrs feet WAS/day 5.18 ave volume held gal Ave WAS/day HRT 3.0 days Note that while using the two tanks as a single tank, there are 19,480 gallons per foot of sidewall depth. The Press Target Calc tool tells you in yellow cells: What the approximate level should be at the beginning and end of each day, The number of gallons to press each day, The BFP feed rate that will be necessary each day at a selected number of BFP run hours, The HRT (hydraulic Retention Time) we are achieving in the process. Press the number of gallons from the tanks that the Press Target Calc tool indicates. Gallons rather than level will likely be a better guide since wasting to and pressing from the tanks will occur simultaneously. Monitor tank levels and monitor or change blower and mixer run status on this Sludge Handling screen: Page 2 of 3

68 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: 6/9/2014 Standard Operating Procedure MWWTP Solids Management Straight WAS SOP Created by: JSA by: S. Blair This shows general pattern of tank levels at start and end of shifts as we go through weekly cycles. It peaks Monday mornings at a level that is operator-settable in the WAS target Calc Tool Page 3 of 3

69 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: 2/21/14 Standard Operating Procedure MWWTP Solids Management SOP Created by: JSA by: S. Blair 1. PURPOSE AND SCOPE: This procedure identifies a strategy and actions we can use to manage the movement of WAS solids from the SBR through the WAS/Thickener tanks, through the Belt Filter press, and into conex containers. The goals are: to always have available tank volume to waste per the need of the SBR process; to partially digest and concentrate the WAS in the WAS/Thickener tanks by aeration and decantation when possible; and to control the need to change containers so that it occurs, as often as possible, only during weekdays and with enough predictability to help our hauler in planning. 2. PREPARATION AND PRECAUTIONS: At present, there are no high level float switches to shut off transfer pump or wasting to prevent overflow of the WAS/Thickener tanks. Operators must set timers and be attentive when transferring liquid. Working around the tank hatches to use the DOB pole and the decant pump requires care and use of the chain barrier. This process requires attentive management of timing of the movement of volumes of sludges. If for whatever reason the process is abandoned, expect to process high volumes of WAS through the BFP. 3. PROCEDURE: a. Keep both tanks fresh, aerating each tank to a target of 0.5 to 2.0 mg/l D.O. b. This is a cyclic process. We begin at approximately 6:00 am, after WAS has been unaerated since midnight or other selected hour the night before. c. Solids begin to settle overnight with the aeration off but we may not be able to harvest supernate until the tank gets a few hours without incoming WAS stirring it up. Change WAS to 0 on each cell at around 6:00 am. Shut off WAS pumps to ensure they do not run. DOB the WAS tank 4 or 6 hours later. Establish the elevation in the tank above which the supernatant is acceptable (Using Royce or your trained eye to estimate TSS less than 300 mg/l). Decant the liquid above this point to the IPS. If the clear layer is disappointingly thin, an option is to leave wasting off and give it another couple hours to settle. To Decant: 1. Two valves in the gallery on the old centrate line need to be open (they should be left that way). 2. In Blower room, establish safety barricade around open hatch. 3. Confirm 4 semi-ridged hose is securely connected and camlock levers are closed. 4. Lower pump using overhead crane to a point midway into the clear supernatant layer Page 1 of 3

70 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: 2/21/14 Standard Operating Procedure MWWTP Solids Management SOP Created by: JSA by: S. Blair or deep enough to promote priming. Tug the crane cables back and forth to jostle the pump letting bubbles escape 5. Turn the P2WS pump on and confirm that it has primed, repeat step d. as necessary. Check and lower the pump as you decant. View liquid clarity through the hose by shining a strong flashlight through it. The goal is to draw off all the clear liquid possible without drawing up TSS from the blanket. d. Set valves for transfer from the bottom of the WAS tank to the Thickener tank using the P9S pump. The valves on the pipe from the submersible pump (yellow arrow) in the WAS tank to the drop into the Thickened tank need to be open, all valves on pipes leading away from this pumping route need to be closed. Start P9S the transfer until the WAS tank is between 5 and 6 feet of depth (needed to immerse diffusers). Alternatively, the transfer can be done first and decant second. e. The space in the WAS tank between the 6 low and 23 high operating levels, will hold 165,000 gallons of WAS. This is enough for typical daily wasting volumes. If experiencing a period of high wasting, calculate expected WAS volume: (expected cycles)(minutes WAS per cycle)(1200gpm) to confirm you have adequate room, If not, you may need to transfer an additional volume from bottom of WAS to Thickener tank at the end of a day shift to make room for the nights wasting. Set SCADA to cease aeration of WAS tank at midnight so settling can begin. f. Set target volume to press out of the Thickener tank: The volume to press each day will need to keep pace with the sludge transferred to the Thickener tank from the WAS tank, plus an additional amount in order to accumulate room through the week to allow transfer without pressing on Sunday. Page 2 of 3 Use the calculator on the Press target calc tab on the Mendenhall data sheet on the I drive. It looks like what you see below. Green cells are for entry, yellow cells are results. Monday Start level and Sunday Transfer feet cells are parameters you enter but will not need to change daily. On a given day, enter into the Transfer Feet row, the amount you need to transfer after decant to achieve the 5 to 6-foot bottom level we target in WAS tank. Also enter the day s actual start level (will be identical to the level at the end of the previous day) in the Actual end level row. The calculator will provide the press target gal for the current day in gallons in the yellow cell for that day, Note that there are 9740 gallons per foot of sidewall depth. We can fill the Thickener tank up

71 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: 2/21/14 Standard Operating Procedure MWWTP Solids Management SOP Created by: JSA by: S. Blair to 23 feet if ever necessary but a lower maximum is better to reduce the risk of foam coming out of the hatch. Spread the difference over remaining days Su M T W Th F S Su M Target Start level Actual Start Level 18 Transfer Feet 5 8 Press feet Target end level Delta feet Daily adjustment Press target gal You can enter an experienced-based estimate of Transfer Feet in the calculator at the beginning of the day to get an idea of the amount we will need to press that day. You can re-enter the number after you have actually performed the transfer so the calculator will display a correct target amount to press. Monitor tank levels and monitor/change blower/ mixer run status on this Sludge Handling screen: Page 3 of 3

72 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: July 2, 2014 Standard Operating Procedure Belt Filter Press Created by: JSA by: R. Hosman S. Blair 1. PURPOSE AND SCOPE: This procedure applies to daily start-up and shut-down of the Belt Filter Press at the Mendenhall Plant. 2. PREPARATION AND PRECAUTIONS: The BFT is usually fed by the Sepex pump in the pipe gallery, which can be started from the sludge pump drive control key pad in the BFP room. Two Marlow piston pumps in the gallery are back-up to the Sepex but can only be started locally. Valves in the gallery will usually stay configured to use the Sepex pump but confirm valve position if there is a possibility that the Marlows have been used. Inspect/prepare the system: a. No tools, rags, or other item are on belt or in machine b. The reservoir oil level should be visible and above center in the sight window c. A conex container is under the chute. d. The head box drain valve is closed. e. Chicanes lowered so that they rest on gravity belt f. Red plastic wash water valves are open. g. Doctor blades are free of stringy debris and lowered so that they are resting against belts. h. Weather board removed from chute i. Auto light above auto-start button must be lit (if not check that emergency stop switch is not tripped). j. Hand/Off/Auto switch is in Auto (see picture) k. Valves open from polymer tote to mixing system and from mixing system to injection point. 3. START-UP: Start the Belt Filter Press as follows: a. Press the auto start button located on center of second row of buttons on the BFP panel (see picture). This starts the wash water pump, opens the wash water solenoid, and starts the hydraulic system (which drives the belt steering system). Later, both belt drives will automatically start. b. Open three wash water box hand wheels all the way, then close them (this brushes dirt from backs of spray nozzles and flushes with water). c. After belts begin to run, check that the sensing paddles are properly engaged with the belts and that belts are aligned properly and evenly on the rollers no more than 1/2 inch difference one belt to another. Page 1 of 6

73 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: July 2, 2014 Standard Operating Procedure Belt Filter Press Created by: JSA by: R. Hosman S. Blair d. To clear an EXT51 fault (which may exist from the shut-down sequence the day before), reset sludge/poly feed control panel by turning the main disconnect off (upper right on panel) for ten seconds. Turn it back on, then hit reset on the sludge pump drive control key pad. e. Based on the previous day s running record. Select starting sludge and polymer feed rates and enter them by scrolling to desired settings using up/down arrows on their respective control key pads. Turn on polymer feed by pressing the identified button on sludge/polymer feed control panel. Immediately visually verify polymer injection (milky white bursts into polymer mixing chamber). f. Turn on sludge feed (green start button on sludge pump drive control key pad). g. With wheels on the mobile stairs disengaged so that the unit rests stably on the floor, ascend stair to view flow from headbox onto gravity belt. There should be clear water between floc and water drainage through the belt. Expect furrows by about halfway down the belt. h. It is common for appearance to change within fifteen minutes of start-up. Monitor until stable. If floc quality deteriorates, reduce sludge feed rate rather than increasing polymer. If eventually able to increase feed rate, you can tweak them up together. Page 2 of 6

74 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: July 2, 2014 Standard Operating Procedure Belt Filter Press Created by: JSA by: R. Hosman S. Blair i. Once performance on the gravity belt is as desired, you dial in performance on the pressure belts. Confirm the pressure plate butters out the sludge after it is deposited onto the pressure belt. The height of the pressure plate is adjusted by pulling a pin, lifting or lowering the plate using a lever that fits over a square lug, then replacing the pin. j. The next steps involve an interplay between BFP feed rate, belt speed, and belt pressure. Time under pressure is what gets free water out of the sludge cake. Look at sludge between the pressure belts. Adjust belt speed using lowest knob on the BFP panel. View belt speed on the gauge at the left side of the window at the top of the panel. A slower belt means a thicker layer of sludge going into the pressure zone and more time under pressure between the belts. As a starting point, adjust so that approximately one inch of sludge stands on the belt just prior to the wedge zone. k. The baseline setting for belt pressure is 400 psi on the hydraulic gauge. Lower pressure may reduce cake dryness, higher pressure may shorten belt life and elongate and close pores in the belt weave. Belt pressure adjustment is made by loosening the locknut, adjusting, then re-snugging the lock nut. l. Look at where the edge of the belts bend around the series of pressure rollers. There must not be squeeze-out, (sludge squirting out between the belts). Squeeze-out represents the functional limits of feed rate, belt speed and pressure settings. If it occurs, eliminate it by one or a combination of the following per current operational priority: Belt speed can be increased. This spreads the solids out over more belt surface area, reducing the amount on a given area of belt thus reducing the tendency for it to squish sideways when under pressure. Belt pressure can be reduced. This reduces the tendency for solids to migrate sideways. BFP feed rate can be reduced. Both of the above two responses might reduce cake dryness as they reduce time under pressure. The other option is to reduce BFP feed rate (and corresponding polymer feed). Possible loss of cake dryness needs to be weighed against the need for processing speed. We may instead eliminate squeeze-out by operating the BFP at a lower feed rate. View cake as it falls off the belt. It should look dry and hairy not smooth and pasty! m. Belts should look clean not smeared after the doctor blade. If a layer of sludge remains after the doctor blade, the blade may need to be adjusted so it contacts the belt properly. If belts look dirty, or have a muddy stripe after the shower boxes, a spray nozzle is plugged. n. Once per day, clean strainer for BFP NPW near door from collections building (it is a duplex strainer so it can be cleaned while in service) Page 3 of 6

75 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: July 2, 2014 Standard Operating Procedure Belt Filter Press Created by: JSA by: R. Hosman S. Blair o. Record time that press and feed were started on BFP sheet. p. Once the machine has stabilized, visit the press at least once per hour to confirm continuing performance. Record all operational parameters on the daily belt press sheet throughout the press run. q. Monitor cake in conex. Rake as necessary to keep peak of pile below rim of conex. A stepladder is necessary. Make sure it is does not rock. Do not ascend past highest acceptable step. Do not attempt to move too much cake mass at a time as it may risk a twisting back injury or fall from the ladder. r. Predict when conex will be full (approximately two feet from the top when you mentally level the cake). Keep driver appraised of time container will be full and in need of swap-out. Page 4 of 6

76 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: July 2, 2014 Standard Operating Procedure Belt Filter Press Created by: JSA by: R. Hosman S. Blair 4. Troubleshooting: There are many interacting factors that contribute to overall performance of the Belt Filter Press. When its performance falls off, it can be challenging to find the cause. Factors are listed below. Consult literature and support resources as necessary. Flocculation Sludge quality Age (digested or fresh) ORP (fresh or stale) Sheer (mechanical abuse to which floc has been subjected) Polymer quality Match to sludge (polymer must be selected to perform on a particular sludge) Page 5 of 6

77 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: July 2, 2014 Standard Operating Procedure Belt Filter Press Created by: JSA by: R. Hosman S. Blair Dosage (performance can suffer both above and below ideal dosage) Delivery (is feed system reliably delivering presumed amount) Makedown (polymer effectively dissolved in carrier water and aged) Mixing energy (enough for flocculation but not sheer, also time to belt) Equipment Belt clean Sprayers effective? Need pressure/chemical wash? Belt wear (wear from chicanes can flatten weave closing pores) Settings Feed rate (achievable sludge feed depends on TSS and poly effectiveness) Gravity belt speed (time to drain free water v.s. sludge thickness to drain through) Pressure belt speed (time under pressure=drier sludge) Belt hydraulic pressure (affects squeeze-out, sludge dryness, excessive harms belt) 5. SHUT DOWN PROCEDURE FOR DEWATERING OPERATION: a. Press the red stop button on the sludge pump drive control key pad in the BFP room. Observe that gpm reading drops to 0. b. Press the polymer system stop button on the control panel. c. Drain the head box by opening red plastic 2 valve. d. Lift chicanes, wash machine and floor with fire hose. e. After five minutes, confirm pressure belts are free of cake, then turn off belts ( HOA to off) f. In cold season, place weather board in chute. g. Record day s total gallons processed then reset totalizer. Record hours ran. Page 6 of 6

78 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: 4/28/14 Quick Reference MWWTP Effluent Flow Measurement Created by: JSA by: T.Geib 1. PURPOSE: The Mendenhall Wastewater Treatment Plant s NPDES Permit identifies monitoring, measurement and reporting requirements specified by the State of Alaska and the EPA. Effluent flow measurement is one of these requirements. 2. SCOPE AND APPLICATION: The rate of effluent flow from the Mendenhall Wastewater Treatment Facility (MWWTF) to the receiving water is continuously monitored, measured, and recorded. The effluent flow rate is also used to generate a flow proportional signal to the effluent composite sampler that samples based on flow rate. 3. SUMMARY OF METHOD: The MWWTF effluent flow rate is derived from a volumetric calculation based upon the measured level drawdown of a sequential batch reactor (SBR) basin of known dimensions during the decant phase of SBR operation. Level instruments utilizing radar measure the SBR drawdown and the Supervisory and Data Acquisition (SCADA) programmable logic controller (PLC) calculates the rate of effluent flow. 4. Equipment and Supplies: a. Vega Instruments VEGAPULS 51K Operating Instructions. b. Vega Instruments VEGACONNECT 4 with connection box and Operating Instructions c. Vega Instruments PACTWARE d. Laptop computer e. 50ft measuring tape f. Personal protective equipment i.e. rubber gloves and safety glasses. 5. METHOD: The MWWTF effluent flow rate is derived from a volumetric calculation utilizing the known uniform dimensions of the 8 SBR basins and the change in level over time. There are 12,985 gallons per foot of level in an SBR. SBR levels are measured with calibrated radar level instruments. Change in level in the SBR data is only used in an effluent flow calculation during the Decant phase of the SBR operations sequence. The calculated result is displayed as a rate of effluent flow and totalized daily and monthly flow. 6. FREQUENCY/MEASUREMENTS: The MWWTF SCADA system monitors effluent flow continuously. Effluent flow only occurs during the Decant phase of the SBR cycle. Effluent flow is recorded on a daily basis with a day defined as midnight to midnight. Page 1 of 2

79 CITY AND BOROUGH OFJUNEAU WASTEWATER TREATMENT PLANTS SOP# Date of last modification: 4/28/14 Quick Reference MWWTP Effluent Flow Measurement Created by: JSA by: T.Geib 7. CALIBRATION: Overall system accuracy is largely dependent on the VEGAPULS 51K radar level transmitters. The VEGAPULS 51K radar level transmitters are calibrated following procedures in their O&M manual. Each transmitter is calibrated independently and each calibration is verified with manual direct level measurements. The SCADA system indications are verified for consistency with locally measured and/or observed indications. 8. QUALITY CONTROL: The SBRs are typically completely emptied for servicing at least once annually. At this time the zero or low end of the measurement range is checked for accuracy. Upon filling the high end is checked by direct measurement at top fill water level. Direct measurement is used to verify instrument and SCADA system accuracy locally at the SBR semi-annually. Measurement performance can also be verified in two other ways. Flow from the four even numbered SBRs flows through an electromagnetic flow meter providing an indication that can be compared to the SCADA calculation. Lastly the effluent flow data can be compared to the influent flow data. This latter method is the least desirable because of the lead/lag effect of varying influent flow rates to a batch plant. 9. DATA ARCHIVAL: Data is backed up by an external hard drive continuously. The SCADA database and alarm log are also backed up and written to an appropriately labeled backup DVD monthly for archival purposes. These DVDs are stored onsite. The MWWTF effluent flow is recorded daily on the Mendenhall wastewater Treatment Plant Process Monitor Sheet by the process operator. The effluent flow is also recorded daily on the Mendenhall Wastewater Treatment Facility Data Sheet. References: Vega Instruments VEGAPULS 51K Operating Instructions Manual; /February 2002 Vega Instruments VEGACONNECT 4 with connection box and Operating Instructions EPA NPDES Compliance Sampling Manual-1977 Page 2 of 2