21 st Century Biofilm Reactors High Quality Yet Simple Operations Northport/Leelanau Township Wastewater Treatment Facility Presented by: Rich Grant, PE Carey Bond, PE Date Presented by: Rich Grant, PE Carey Bond, PE November 7, 2012
AGENDA Background: Project & MBBR/IFAS process Business Case what IS green? MBBR/IFAS is. GPS x for Dynamic Process Modeling MODFLOW Groundwater Fate/Transport Modeling Site Challenges Lagoon Simplicity on a hillside Treating for Trout 38F Nitrification/De Nite Natural Polishing & Cooling Operations Results Simple & Consistent Performance Performance Approaching Limit of technology
Project Background Project Issues Small lots with old/failing drainfields (or no system) Locally high groundwater table Poor draining soils Steep slopes Health Dept. not approving on site wastewater disposal Service District Village of Northport Leelanau Township (portion) REUs 450 Residential & 215 Institutional & Commercial
Project Background Wastewater Treatment Facility Design 132,000 gpd 20 yr Avg. Day Design Flow Design Influent Wastewater Strength Design: 275 mg/l BOD 5&TSS 34 mg/l NH 3, 46 mg/l TKN 8 mg/l Total Phosphorus Effluent Limits (Groundwater Discharge Venting to Surface Water) 0.3 mg/l Total Phosphorus 30 mg/l BOD 5 (8 mg/l) Total Nitrogen (treatment goal; not effluent limit)
Project Background Treatment Processes: Influent Fine Screening Pre Anoxic Basin/Influent Equalization Moving Bed Biological Reactors (MBBRs) Cavitation Air Flotation (CAF) Effluent Equalization/Settling Basin Tertiary Filtration (2 Sand Filters in Series) Chemical Storage & Feed (Ferric Chloride) 2 nd Treatment Basin (Future 2 nd MBBR reactor) Storage/Stdby Biosolids Storage Basin Rapid Infiltration Basins for final discharge
¼ Perforated basket Screen Small footprint, cost effective
Highly polished effluent before discharge at R.I.B.s Entirely Gravity Flow Hydraulic Design
Removal of sloughed biofilm Small footprint, cost effective
Odor Capped Curbed Concrete Ramp & Sump for Easy Solids Removal, Protects Liner
3New RIBs at Base of Hillside 2 Ex. Facultative Lagoons Re Constructed to Serve as RIBs
MBBR Process Description MBBR: Moving Bed Biofilm Reactor(see also Mixed Bed, IFAS ) Technology developed in Norway for 1992 Lillehammer Winter Olympics Attached growth system; similar to trickling filter, RBCs Biofilm grows inside free floating plastic media carriers in the tank(s) Biofilm acclimates to operating conditions, with reactors for anoxic and/or aerobic treatment
MBBR with Biofilm Inside Carriers
Northport WWTP Site Plan MBBR
MBBR is Energy Efficient 50% to 90% smaller footprint required for the same treatment as conventional activated sludge Reduces mixing energy required Aeration design is due to oxygen demand not mixing requirement
MBBR is Green Smaller carbon footprint lifecycle Source Mark Steichen, et al Carbon Footprinting of Wastewater Treatment Technologies
MBBR Green Business Case Current DEQ standards for green show the Northport WWTP Project meets the definition of a "Categorical GPR Project under 1) "Energy Efficiency" guidelines "use of improved technologies & practices to reduce energy consumption of water quality projects use energy in a more efficient way MBBR blower energy used for dual purposes, mixing and aeration. Smaller reactor = less energy for mixing Mixing energy = aeration energy (not typical of conventional RAS) MBBR biofilm carriers provide increased oxygen mass transfer efficiency, Increased Transfer Efficiency = reduced aeration and energy requirements. 2) "Environmentally Innovative" guidelines, "... demonstrating new and/or innovative approaches to delivering services or managing water resources in a more sustainable way.
Energy Production & Conservation at Wastewater Utilities Too Small for Cost Effective Biomass Biogas Heat Process Selection reduces energy consumption over 40% Business Case for MBBR Demonstrated: MBBR designs qualify for Green Project Reserve Membrane technology for clarifiers. NOT Qualifying SolarBee for blending and odor capping Business Case for SolarBee Demonstrated Green Project Reserve Lift stations not always a good candidate for energy reduction velocity 3-5 ft/sec Smaller WWTPs: I/I storage slower treatment rates And/or attached growth Energy audits at wastewater plants Wind? A go at Northport WWTP
MBBR/IFAS Cost Comparisons Example 25mgd WWTP Source: When is IFAS the Right Choice? Johnson et al, Black & Veatch WEFTEC 2006
MBBR is Innovative MDEQ Northport is first full scale MBBR in Michigan ACEC/MI Honorable Conceptor Award for Engineering Excellence National ACEC recognition award
GPS x Process Modeling Dynamic process modeling was completed during design phase Screenshot from the dynamic process model
GPS x Process Modeling The modeling work was essential to: Determine/validate the MBBR reactor sizing Determine/validate MBBR media volume necessary ea. reactor Determine/validate D.O. set points for each reactor Evaluate septage receiving Predict treatment performance (e.g. effluent quality) at variety of operating conditions (influent temperature, flow rate, etc)
Pre Anoxic Basin Tri Fecta Maintain Heat Address Oxygen Depletion Failures (others) Advantage of Free Carbon Source
Maintain Heat Traditional Nitrification Cut off: 50 55F This Project: Consistent Nitrification/De Nite to 38F
Complex GW Flow S MODFLO Modeling Required
Site Challenges Best available project site located on a hillside Wetlands bordering bottom of hillside & surrounding area Adjacent ex. facultative lagoons property donated to Village to incorporate with new WWTF Loamy or clay soils a challenge for groundwater discharge Installation and prove out of infiltration/collection trenches
Biosolids Reuse Fertilizer Product Accumulation in Solar Energy Mixed Pond Land Applied at Agronomic Rates
Treating for Trout important for discharge in Northport Creek Watershed Millpond stocked annually with trout for the Derby Some trout remain and Northport Creek is so designated Preferred temperatures: 52 62F summer Low nutrients Low BOD High D.O. Trout like the typical Michigan Groundwater temperatures!
38F Nitrification/De Nite Not required, but highly recommended Highly recommended, given venting location to Northport Creek Highly recommended, for groundwater quality, nitrates control Included in the Design Year Round with Cold Weather Operations Classic Activated Sludge Performance: TYPICALLY LIMITED TO 50F Consistent Performance This MBBR At 38F! 1.4 mg/l Ammonia avg 6.8 mg/l TIN avg
Natural Polishing & Cooling important for discharge in Northport Creek Watershed Secondary + Tertiary Treatment RIB Discharge to Groundwater, polishing and cooling in ground Groundwater Venting to Surface Water
Operations Overview Northport WWTF & Collection System Operations & Maintenance Provided by OMI, Inc. Lead Operator Mark Huggard District Manager Chris Keister Operation Manager Scott Blair
Operations Overview Typical Weekly Operations Tasks (Mon. Wed. Fri.) Collect effluent sample for Ortho P test, adjust ferric feed (2x/wk) Measure effluent D.O. and ph (2x/week) Record plant flow meters & equipment readings/run times Record chemical and electrical usage (1/week) Pump solids from Settling Basin to Biosolids Basin (1/week) Pump Scum Pit as needed Rotate RIB and record effluent discharge information Check all plant equipment for proper operation
Operations Overview Process Monitoring (Once/Week) MBBR Cells #1 & #5 check nitrate levels MBBR Cell #5 check ammonia level MBBR Cells #1 #5 dissolved oxygen & ph MBBR Recycle Flow Rate check, adjust Sand Filter Influent/Effluent TSS level Sand Filter Effluent check effluent Ortho P Check influent & effluent temperature
Date: 11/02/12 Project: Northport Plant: NWWTP Weekly Process Performance Data: Unit Process Parameter Target value Actual value Trend New target Actions to take Influent Flow Gallons/day N/A 39,525 down N/A Fine Screen cuft/day N/A 0.1 even N/A Influent Temp C N/A 16.1 even N/A Effluent Temp C N/A 13.9 down N/A Bench MBBR Cell 1 NO3 mg/l <1.0 0.4 even <1.0 Bench MBBR Cell 1 DO mg/l <1.0 <1 even <.5 Bench MBBR Cell 5 NO3 mg/l <5.0 4.50 down <5.0 increased recycle rate Bench MBBR Cell 5 NH3 mg/l <1.0 0.00 even 0.25 Solids Basin Sludge Level Level (feet) <1.5 2.0 even N/A Sand Filter Influent TSS mg/l N/A 16.60 even N/A Sample taken: Monthly Sand Filter Effluent TSS mg/l <3.0 2.3 up <5.0 Sand Filter Effluent Ortho Phos mg/l 0.11 0.16 even N/A Recycle Flow Rate Gallons/day 3 5 x's inf. flow 280,000 down N/A Pump set at 27 hz. Ferric Chloride Feed Gallons/day 7 3.4 down N/A pump is in manual Electrical Usage KW/Hrs Weekly avg. N/A 464 down N/A
Operations Overview Dissolved Oxygen Targets to Manage De Nitrification Primary Anoxic D.O. <1 mg/l MBBR Cells #1 D.O. <1 mg/l* MBBR Cells #2 D.O. 1 3mg/L MBBR Cells #3 D.O. 3 5mg/L* MBBR Cells #4 D.O. 3 5mg/L MBBRCells #5 D.O. 1 3mg/L* (recycle pulled from this cell) MBBR Cells #6 D.O. >5 mg/l *Critical cells for D.O. levels
Operations Overview De Nitrification Control Tips Good Bench Test Results (i.e., No Process Adjustment Needed): MBBR Cells #1 Nitrate <1 mg/l MBBR Cells #5 Nitrate 4 6mg/L MBBR Cells #5 NH3 <1 mg/l If NO3 levels high in #1, make following adjustments one at a time: Decrease recycle rate Check cell #5 D.O., decrease if necessary Check D.O. in Primary Anoxic & cell #1, if > 1 ppm, decrease D.O in cell #5 Convert cell #2 to an anoxic zone (typ. done during cold weather months)
Operations Overview Key Operational Improvements 7 day timer added to Biosolids Decant Pump Station to optimize when and how much supernatant is returned to the headworks Found optimal to pump every 3 hours for 30 minutes Has improved effluent phosphorus and TSS performance AddedhighlevelfloatinPrimaryAnoxicBasinandaddedtoalarm call out list Installed 1.5 inch air ports with shut off/quick disconnect on main air header to allow PM task for air blasting media screens in each cell
Treatment Performance Groundwater Discharge Permit (Venting to Surface Water) Effluent Limits Total Phosphorus 0.3 mg/l Monthly Avg. 0.5 mg/l Daily Max. BOD 5 30mg/LMonthlyAvg. 45 mg/l Daily Max. ph 6.5 9.0 s.u. TIN Report (8 mg/l Treatment Goal) D.O., Cl, Na Report
Treatment Performance Results Phosphorus Average 0.17 mg/l, >97% removal
35 30 25 20 15 10 5 0 Treatment Performance Results BOD5 Average 3.4 mg/l, Effluent Limit 30 mg/l Monthly Average Effluent BOD5 Average of BOD5 (mg/l) January February March April May June July August September October November December January February March April May June July August September October November December January February March April May June July August September October November December January February March April May June July August September 2009 2010 2011 2012 Concentration (mg/l)
Treatment Performance Results Total Inorganic Nitrogen (TIN) Ammonia N: 1.4 mg/l average Nitrate N: 5.2 mg/l average Nitrite N: 0.1 mg/l average TIN: 6.8 mg/l average effluent Influent TIN average 38.5 mg/l (range 28 50 mg/l) 82% Total Inorganic Nitrogen Removal
120 100 80 60 40 20 COMPARISON EXAMPLE Broomfield Colorado MBBR Nitrogen Performance % N reduction (total) % nitrification % Denit Temperature 60% Total Inorganic Nitrogen Removal 0 Reduction 1/3/2006 1/17/2006 1/31/2006 2/14/2006 2/28/2006 3/14/2006 3/28/2006 4/11/2006 4/25/2006 5/9/2006 5/23/2006 6/6/2006 6/20/2006 7/4/2006 7/18/2006 8/1/2006 8/15/2006 8/29/2006 9/12/2006 9/26/2006 10/10/2006 10/24/2006 11/7/2006 11/21/2006 12/5/2006 12/19/2006 Date
Approaching Limit of Technology Northport MBBR Performance Pollutant Parameter Biological Nutrient Rem. Enhanced Nutrient Rem. Limit of Technology Total 1 mg/l 0.1 to 0.3 mg/l <0.1 mg/l Phosphorus Total Nitrogen 8 mg/l 4 to 8 mg/l 3 mg/l WERF Striking the Balance Between Wastewater Treatment Nutrient Removal & Sustainability, Nov. 2010
Questions/Comments Contact Info Fleis & VandenBrink Engineering, Inc. 800 494 5202 Rich Grant P.E. Carey Bond P.E.
Treatment Performance Results Influent Flow Average 44,500 gpd 80,000 70,000 60,000 50,000 40,000 30,000 20,000 10,000 0 January February March April May June July August September October November December January February March April May June July August September October November December January February March April May June July August September October November December January February March April May June July August September Flow (gpd) 2009 2010 2011 2012