Outline of Water Quality Control at Treatment Plants

Transcription

1 Outline of Water Quality Control at Treatment Plants Kitakyushu City Water and Sewer Bureau - Sewer System Department Water Quality Control Division August 2015

2 Contents 1 Water quality control work Importance of water quality control work Legal system related to water quality control Water quality control system in Kitakyushu City Goals of water quality control work at treatment plants Daily monitoring at treatment plants Visual inspections Reaction tank SV measurements Automatic monitoring using industrial instruments Tests of water quality, etc., at treatment plants Water quality tests Biological analysis Sludge tests Water quality test procedures (Water sampling to analysis) Utilization of test results Characteristics of water quality control system in Kitakyushu City 5 Introduction to work standards documents, etc

3 1 Water quality control work P1

4 Importance of water quality control work Importance of water quality control work The preparation of sewers is essential for the achievement of the environmental standards for water quality in public water bodies. However, the current sewerage system is designed for domestic wastewater and it cannot completely treat business wastewater from places such as factories. The following measures are required: Management of the conformity of the business wastewater to water quality standard for sewers for the protection of the facilities such as the sewage facilities Management of the conformity of final effluent from treatment plants to water quality standards P2

5 Legal system related to water quality control Basic Environment Law Basic laws related to environmental conservation in Japan Established Environmental Quality Standards on Water Quality Water quality regulation with the laws shown below to observe these standards Water Pollution Prevention Act Regulation of the wastewater flowing from factories and businesses, etc., into public water bodies (rivers, wetlands, sea areas, etc.) Sewerage Law Regulation of the wastewater flowing from factories and businesses, etc., into sewage facilities Regulation of the final effluent flowing from purification centers <Others> Bad smells Offensive Odor Control Law Sludge properties Waste Disposal and Public Cleansing Law P3

6 Water quality control system in Kitakyushu City Water quality management in Kitakyushu City is performed in the system below! Before inflow into the treatment plant Management of the conformity of the business wastewater, etc., to the water quality standards for sewers (Guidance staff) After inflow into the treatment plant Management of the conformity of final effluent from treatment plants to the water quality standards (Inspection staff) The dirtied water goes along the sewer pipes and is collected at something called a purification center! River Purification center Pumping station Factory House Sludge treatment facility Sea Industrial pretreatment facility Reaction tank Settling basin Primary sedimentati on tank Final sedimentation tank Sterilizat ion tank Air blower Sewage pipe Purification center Facilities to treat the wastewater from factories, etc., to within the standard values for acceptance into sewers The part to be discussed in the lecture today P4

7 Goals of water quality control work at treatment plants Observance of regulation values for treatment water quality, etc. Implement inspections periodically for the items defined in the laws, etc.! Check of functioning of each treatment process Daily monitoring (Visual observation inspections, SV measurements, continuous monitoring using industrial instruments, etc.) Testing of water quality, etc., for each treatment process <Types of test> Water quality tests : Tests to check water quality at each treatment process Biological analysis : Tests to check the organism counts and biota inside the reaction tank Sludge tests : Tests to check the properties of the sludge generated at each treatment process <Test procedures> Sample collection Analysis Test results report production Gain an understanding of the treatment situation and adjust the operation management accordingly! P5

8 2 Daily monitoring at treatment plants P6

9 Visual inspections Check for abnormalities using the five senses, especially sight! <Inspection points and details> Primary sedimentation tank : Check the situation of scum occurrence and the scum color Reaction tank : Check the situation of scum occurrence and foaming Final sedimentation tank : Color of water surface, sedimentation status of activated sludge, occurrence situation of bubbles and scum Final effluent : Color of water surface, occurrence situation of bubbles and scum <Primary sedimentation tank> <Reaction tank> <Final sedimentation tank> <Final effluent (Sterilization tank exit)> P7

10 Reaction tank SV measurements The simplest method for the estimation of sludge properties inside the reaction tank! What is SV (Sludge Volume)? An index showing the settleability and concentration, etc., of the activated sludge The index shows the proportion of sludge that has settled ((2)/(1)) as a percentage when activated sludge is placed in a 1 liter measuring cylinder and then left to rest for 30 minutes. When there is a big change in the SV Check for an increase or decrease in filamentous bacteria, change in sludge properties, etc. When SV is high Respond by increasing the excess sludge withdrawal volume, etc. When SV is low Check the settleability (settling velocity) (1) Left for 30 minutes (2) P8

11 Automatic monitoring using industrial instruments Automatic monitoring continuously for 24 hours to deal with abnormalities rapidly <Monitoring point> Primary sedimentation tank influent and effluent <Automatic monitoring items> Total nitrogen, total phosphorus, COD, ph sedimentation tank influent only * Measure ph on primary <Total nitrogen, total phosphorus and COD measurement tool> Total nitrogen and total phosphorus are printed COD is displayed on the screen <Overall view of automatic measurement tools> <ph meter> P9

12 3 Tests of water quality, etc., at treatment plants P10

13 Water quality tests Check whether each treatment process and the effluent water quality conform to the standards and adjust the operating conditions according to the results! Tests for management (Check of the functioning of each treatment process) ests implemented for the appropriate operation and maintenance of water treatment facilities, sludge treatment facilities, etc. Daily tests : Simple tests performed at a fixed time each day Weekly tests : Tests to understand the water quality in each treatment process Legally-required tests (Observance of the regulation values for treated water quality, etc.) Tests required by the Sewerage Law, Water Pollution Prevention Act, etc. Judgment of whether the water quality of final effluent satisfies the defined standard values, etc. P11

14 Water quality tests <Main measurement items, final effluent standard values and measurement frequency> Measurement item ph SS (mg/l) BOD (mg/l) COD (mg/l) Total nitrogen (mg/l) Nitrogenous compounds (mg/l) Total phosphorus (mg/l) Normal hexane extracts (mg/l) Number of coliform bacilli (Quantity/mL) Standard values 5.8~ ,000 Measurement frequency Twice per month <Analysis method> Analysis is performed based on Sewage Test Method. <Wastewater treatment> Processing of the wastewater containing the heavy metals, etc., included in the reagents for the testing should be subcontracted to an industrial waste disposal contractor. P12

15 P13 Water quality tests <Water quality testing results report> State the target values and standard values for final effluent Implement water quality testing for each treatment process Enter comments on the evaluation of the test results, changes in water quality and future measures Inflow Effluent Target values/standard values

16 Water quality tests <Water quality testing results report (Calculation formulas)> P14

17 Water quality tests <Water quality testing results report (Calculation formulas)> P15

18 Water quality tests <Water quality testing results> Good water quality is realized for each treatment process throughout the year! * Annual average (FY2012) : Hiagari purification center Units:mg/L Measure ment item Treatment plant influent (a) Primary sedimentation tank effluent Removal rate (a - b)/a 99% Final sedimentation tank treated water (Deep vessel) Final effluent (b) SS % BOD % COD % T-N % T-P P16

19 Water quality tests <Effluent water quality at each purification center> Standard values sufficiently cleared throughout the year! Units:mg/L Purification center SS BOD COD T-N T-P Shinmachi Hiagari Sone Kitaminato Kougasaki 1 1 ND Kougasaki 2 2 ND * Standard values Annual average (FY2012) P17

20 Biological analysis Observe the organisms inside the reaction tank with a microscope (number of organisms and biota) and adjust the operating conditions according to the results! <Points to be checked> Number of organisms, biota, comparison with previous test, etc. <Test method> Use an optical microscope and count the number of organisms <Scene of observations using an optical microscope> <Count the number of organisms with a counter> P18

21 Biological analysis <Organism testing results report> Are the number of organisms and biota that of good water treatment? Is the flock size appropriate? Is there any deterioration from the results of the previous testing? Enter comments about the flock sizes and trends P19

22 Biological analysis <Pyramid of organisms inside reaction tanks> Key point:the balance of the biota is extremely important Aspidisca Carnivorous Vorticella Bulking, scum, foam formation Dispersed bact.- predatory Filamentous bact.-predatory Floc bacteriapredatory Protozoa (Higher-level consumers) Treated water turbid in white Inflow sewage Dispersed bacteria Filamentous bacteria Adhesion to floc surface Floc formation Nitrifying bacteria Bacteria (Primary consumers) Effluent Low-molecular, dissolved Solid Organic matter (Producers) NH 4

23 Biological analysis <Biological transitions in sewage purification> The structure of organisms changes as time elapses In piston flow incubators, slow-growing organisms cannot survive, but in the activated sludge method, flocks are formed, so a wide variety of organisms can be mixed together. Microbial count (relative) Bacteria Flagellates Ciliates Rotifers (multicellular) Time P21

24 Sludge tests Check the sludge properties, etc., occurring at the treatment process Adjust the operating conditions according to the results to realize good water treatment <Samples and measurement items> Samples) Sludge withdrawn from early sediment, gravity concentrated sludge, mixed sludge, dehydration separated liquid, etc. Measurement item ph, solid content (%), organic content (%), SS (mg/l), etc. P22

25 Sludge tests <Sludge testing results report and dehydrated cake results report> Check that there are no abnormal values in the ph, solid content, organic content, etc. Check whether the solid content of the dehydrated cake is equal to or greater than the target value Check whether the solid content is equal to or greater than the treatment target value <Sludge testing results report> Enter comments if there are any abnormalities, etc. <Dehydrated cake results report> P23

26 Water quality test procedures (Water sampling to analysis) <Sample collection> Take extreme care to ensure that the sample is a representative sample [Cautions] Carefully consider the position and time of sampling. Sampling position A position where mixing is sufficient and where a sample can be taken safely Sampling time Collect the sample at a time presumed to be showing average values. (Because water quality varies throughout the day.) Select appropriate methods to suit the structures of each facility. (Example) Sampling of sewage influent Sampling position Before the settling basin inflow (at a point not affected by return water) If this is difficult, then at a manhole on the inlet pipe P24

27 Water quality test procedures (Water sampling to analysis) <Sampling method> Manual sampling Sampling using an automatic collection device Check the advantages and disadvantages then decide. Sampling method Advantages Disadvantages Manual It is possible to check the condition of the sample. It is possible to collect water samples at a different place to the usual point. The collection frequency and time of day are limited. It is not possible to always collect the sample under the same conditions. Automatic collection device In this city, the sample collection for testing is performed manually. Install (automatic) industrial instruments for the primary sedimentation tank influent and effluent and continuously measure COD, total nitrogen, total phosphorus and ph. * Measure ph on primary sedimentation tank influent only <Storage of samples for repeat testing> There may be doubts about the test results, or the testing may fail, so collect a greater amount of sample than is necessary. Store in a cool dark place. It is possible to always collect the sample under the same conditions. It is easy to increase the frequency of sample collection. It is possible to safely collect samples during the night hours. It is necessary to clean the equipment frequently. There is a risk of equipment failure or malfunction. There is a limit to where the equipment installation is possible. The storage methods and possible storage periods will vary depending upon the test items, so check these in advance. P25

28 Water quality test procedures (Water sampling to analysis) <Preparations for water sampling> <Prepare water sampling bottles for each separate purification center (Day before sampling day)> <Stick labels on the water sampling bottles> P26

29 Water quality test procedures (Water sampling to analysis) <Types of water sampling apparatus> <Polyethylene bottles (small, medium, large)> <Glass bottles> <Hyroht water sampler> * Apparatus to sample water from an arbitrary depth <Thermometer> <ORP meter> <ph meter> <Polyethylene buckets> P27

30 Water quality test procedures (Water sampling to analysis) <Water sampling apparatus> Hyroht water sampler : Influent outside site Dipper : Primary sedimentation tank, reaction tank, return sludge Polyethylene bucket : Treated water, final effluent <Water sampling> <Influent outside site> Install the water sampling bottle on the Hyroht water sampler and collect the water <Primary sedimentation tank influent> <Reaction tank> <Return sludge> <Treated water> <Final effluent> P28

31 Water quality test procedures (Water sampling to analysis) <Notes of caution for water sampling> Record the time of sampling and the temperature, etc. Keep cool for testing for the number of coliform bacilli <Water sampling> <Cooler for keeping cool> P29

32 Water quality test procedures (Water sampling to analysis) <Electrical conductivity, ph, turbidity> <Situation of analysis apparatus installation> <Electrical conductivity meter> <ph meter> <Turbidimeter> P30

33 Water quality test procedures (Water sampling to analysis) <SS> Suspended Solid: Insoluble substances <Filter paper> <Filtration> <Drying (110 C, 2 hours)> <Allowing to cool (30 minutes inside desiccator)> <Weighing> P31

34 Water quality test procedures (Water sampling to analysis) <BOD> Biochemical oxygen demand: Biochemical oxygen demand <Dilution of sample> <Transfer to incubator bottle> <Cultivation at 20 C for 5 days> <DO measurement (Before and after cultivation)> P32

35 Water quality test procedures (Water sampling to analysis) <COD> Chemical Oxygen Demand: Chemical oxygen demand <Sample collection> <Addition of the reagents in the red frame> (From left: Sulfuric acid, silver nitrate and potassium permanganate) <Heating at 100 C for 30 minutes> <Addition of sodium oxalate> (Reagent in the blue frame) <Dripping in of potassium permanganate) (Until the solution becomes a light pink color) <Sample after dripping in> P33

36 Water quality test procedures (Water sampling to analysis) <Total nitrogen, total phosphorus> <Addition of sodium hydroxide - potassium peroxodisulphate solution> <Autoclave disintegration (120 C, 30 minutes)> <Transfer to glass tube and dilute with distilled water> (Addition of HCl for nitrogen and coloring solution for phosphorus) <Absorbance measurement> P34

37 Water quality test procedures (Water sampling to analysis) <Number of coliform bacilli> <Put sample in sterilized Petri dish> <Transfer desoxycholate agar to Petri dish> <Leave until culture medium becomes solid> When solid, put culture medium in again. <Cultivation in thermostatic chamber> (37 C),18~20h <After cultivation> <Count the colonies> Reddish violet, 0.5 mm or larger P36

38 Utilization of test results <Water quality review meeting> (1) Goal The goal is to consider the water treatment situation at each purification center and exchange opinions, to share knowledge of water treatment and to make a contribution to the passing down of water treatment techniques and to the development of personnel. (2) Participants Staff responsible for water quality inspections (Water Quality Control Division) Facility managers (Facilities Construction Division) Operation managers (Eastern and western purification centers) Contractors * (Kitakyushu Water & Sewer Association) * Consignment of part of work for water quality inspections and operation management, etc. (3) Materials Water quality testing results report, Dehydrated cake results report, Organism testing results report, Comments on general situation of water treatment, etc. in the past month P37

39 Utilization of test results <Examples of results being useful for operation management (1)> In the water quality inspection at the Kitaminato purification center, it was found that the nitrification (from nitrous acid to nitric acid) was not proceeding in the standard tank *. It was judged that there was a problem in the activated sludge and sludge was transferred from the deep tank * to the standard tank. A special examination was performed and it was confirmed that the nitrification was proceeding. * Standard tank : Reaction tank with water depth of 4.5 m Deep tank : Reaction tank with water depth of 10 m P38

40 Utilization of test results <Examples of results being useful for operation management (2)> In the water quality inspection at the Shinmachi purification plant, it was found that the phosphorus treatment was deteriorating. When a special investigation was performed, it was found that the cause was the reelution of phosphorus from the final sedimentation tank. Adjustments were made to the telescopic valve and excess sludge withdrawal volume. It was confirmed in regular testing, etc., that the phosphorus treatment had improved. P39

41 4 Characteristics of water quality control system in Kitakyushu City P40

42 Characteristics of water quality control system in Kitakyushu City Automatic monitoring continuously for 24 hours to deal with abnormalities rapidly There are very few local governments constantly monitoring total nitrogen and total phosphorus in the influent. <Goal> To monitor the influent water quality to respond rapidly to any abnormalities that may occur. <Method> Implementation using industrial instruments <Measurement items> ph, COD, total nitrogen, total phosphorus <Action for emergencies> When a value greater than normal is produced, a sample of water is taken and a simplified water inspection product test is performed to check that there is no failure of the industrial instruments. If it is not a failure of the instruments, etc., then samples are taken to the Water Quality Control Division for analysis and emergency action is implemented according to the figures. P41

43 Characteristics of water quality control system in Kitakyushu City Kitakyushu City has set water quality objectives independently! <Goal> To understand the indices during normal operation and adjust the appropriate operation accordingly. <Target water quality> Water quality treatment possible at the current facilities Water quality on consideration of the characteristics and past results of each purification center Continuous measurement of the inflow water quality using industrial instruments Units :mg/l Type Shinmachi Hiagari Sone Kitaminato Kougasaki 1 Kougasaki 2 Regulation value COD Total nitrogen Total phosphorus Number of coliform bacilli (Quantity/mL) 300 3,000 <List of water quality targets> P42

44 5 Introduction to work standards documents, etc. P43

45 Introduction to work standards documents, etc. Work is implemented according to a manual that was produced independently! Water quality control work manual (Common manual) Produced with reference to JIS, Sewage Test Method, Guideline for Maintenance and Operation in Sewerage Systems, etc. It is a common manual, so staff transfers (movement roughly every 3 years) are dealt with. <Water quality control work manual> P44

46 <Other documents> Introduction to work standards documents, etc. <Guideline for Maintenance and Operation in Sewerage Systems> A practical technical book about sewage maintenance and control work. Many local governments use this as a reference for maintenance and control <Sewage Test Method> A document defining the test methods for water quality and sludge testing, legally-required inspections of effluent water quality and monitoring of business wastewater, etc. <JIS> (Japanese Industrial Standards) National standards established by the Industrial Standardization Act P45