Outline of Water Quality Control at Treatment Plants of Water Quality Control at Treatment Plants...

Outline of Water Quality Control at Treatment Plants

Kitakyushu City Water and Sewer Bureau - Sewer System Department Water Quality Control Division

August 2015

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

2 Daily monitoring at treatment plants • Visual inspections • Reaction tank SV measurements • Automatic monitoring using industrial instruments

3 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

5 Introduction to work standards documents, etc.

4 Characteristics of water quality control system in Kitakyushu City

1 2 3 4 5

6 7 8 9

10 11 18 22 24 37

40

43

1 Water quality control work

P1

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.

Importance of water quality control work

P2

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

The following measures are required:

◆ Importance of water quality control work

Legal system related to water quality control

P3

• Regulation of the wastewater flowing from factories and businesses,

etc., into sewage facilities • Regulation of the final effluent flowing from purification centers

Basic Environment Law

Water Pollution Prevention Act

Sewerage Law

<Others> • Bad smells ⇒ Offensive Odor Control Law • Sludge properties ⇒ Waste Disposal and Public Cleansing 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

• Regulation of the wastewater flowing from factories and businesses,

etc., into public water bodies (rivers, wetlands, sea areas, etc.)

Before inflow into the treatment plant ⇒ Management of the conformity of the business wastewater, etc., to the water

quality standards for sewers (Guidance staff)

Water quality control system in Kitakyushu City

Water quality management in Kitakyushu City is performed in the system below!

Purification center

Pumping station

House Factory

River

Sea

Purification center

Industrial pretreatment facility

Sewage pipe

Facilities to treat the wastewater from factories, etc., to within the standard values for acceptance into sewers

P4

The part to be discussed in the lecture today

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!

Sludge treatment facility

Settling basin

Reaction tank

Final sedimentation tank

Sterilization tank

Primary sedimentati

on tank

Air blower

• 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!

• Implement inspections periodically for the items defined in the laws, etc.!

Goals of water quality control work at treatment plants

Observance of regulation values for treatment water quality, etc.

P5

Check of functioning of each treatment process

P6

2 Daily monitoring at treatment plants

<Primary sedimentation tank> <Reaction tank>

<Final sedimentation tank> <Final effluent (Sterilization tank exit)> P7

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

Left for 30 minutes (2)

(1)

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.

Reaction tank SV measurements

The simplest method for the estimation of sludge properties inside the reaction tank!

P8

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)

<Monitoring point> Primary sedimentation tank influent and effluent <Automatic monitoring items> Total nitrogen, total phosphorus, COD, pH * Measure pH on primary sedimentation tank influent only

Automatic monitoring using industrial instruments

Automatic monitoring continuously for 24 hours to deal with abnormalities rapidly

P9

<Overall view of automatic measurement tools>

<Total nitrogen, total phosphorus and COD measurement tool>

<pH meter>

• Total nitrogen and total phosphorus are printed • COD is displayed on the screen

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

P10

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

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!

<Main measurement items, final effluent standard values and measurement frequency>

<Analysis method> Analysis is performed based on Sewage Test Method.

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.

<Wastewater treatment>

Water quality tests

P12

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 5.8~8.6 40 15 20 20 100 2 5 3,000

Measurement frequency Twice per month

<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

Water quality tests

P13

Target values/Standard

values

<Water quality testing results report (Calculation formulas)>

P14

Water quality tests

<Water quality testing results report (Calculation formulas)>

P15

Water quality tests

<Water quality testing results>

Measurement item

Treatment plant influent

(a)

Primary sedimentation tank

effluent

Final sedimentation tank treated water

(Deep vessel)

Final effluent

(b)

SS 145 32 1 2

BOD 120 51 4.5 2.3

COD 74 35 7.1 7.0

T-N 26 19 12 13

T-P 2.9 2.1 1.1 0.95

Units:mg/L

Removal rate

(a - b)/a

99%

98%

91%

50%

67%

* Annual average (FY2012) : Hiagari purification center

P16

Water quality tests

Good water quality is realized for each treatment process throughout the year!

<Effluent water quality at each purification center>

Purification center SS BOD COD T-N T-P

Shinmachi 2 1.9 8.1 9.1 0.25

Hiagari 2 2.3 7.0 13 0.95

Sone 2 1.2 8.0 10 0.16

Kitaminato 3 2.1 12 11 0.37

Kougasaki 1 1 ND 6.3 8.9 0.20

Kougasaki 2 2 ND 7.4 10 0.14

* Standard values 40 15 20 20 2

Units:mg/L

Annual average (FY2012)

Water quality tests

P17

Standard values sufficiently cleared throughout the year!

<Points to be checked>

<Test method>

Use an optical microscope and count the number of organisms

Number of organisms, biota, comparison with previous test, etc.

<Scene of observations using an optical microscope>

<Count the number of organisms with a counter>

P18

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!

<Organism testing results report>

P19

Biological analysis

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

Carnivorous

Disp

erse

d ba

ct.-

pred

ator

y

Fila

men

tous

ba

ct.-p

reda

tory

Floc

bac

teria

-pr

edat

ory

Dis

pers

ed

bact

eria

Fila

men

tous

ba

cter

ia

Adh

esio

n to

floc

su

rfac

e

Floc

form

atio

n Low-molecular, dissolved Solid

Nitr

ifyin

g ba

cter

ia

NH4

Inflow sewage

Organic matter (Producers)

Bacteria (Primary consumers)

Protozoa (Higher-level consumers)

Effluent

Treated water turbid in white

Bulking, scum, foam formation

Vorticella

Aspidisca

Biological analysis <Pyramid of organisms inside reaction tanks> Key point:The balance of the biota is extremely important

Biological analysis

<Biological transitions in sewage purification>

Biological analysis

P21

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.

Mic

robi

al c

ount

(rel

ativ

e)

Bacteria

Time

Ciliates

Flagellates

Rotifers (multicellular)

http://www.city.kitakyushu.jp/contents/0/4/9140/4.jpg

<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.

Sludge tests

P22

Check the sludge properties, etc., occurring at the treatment process

⇒ Adjust the operating conditions according to the results to realize good water treatment

<Sludge testing results report and dehydrated cake results report>

<Sludge testing results report> <Dehydrated cake results report>

Check whether the solid content is equal to or greater than the treatment target value

Enter comments if there are any abnormalities, etc. P23

Sludge tests

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

<Sample collection>

(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

Water quality test procedures (Water sampling to analysis)

[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.

Take extreme care to ensure that the sample is a representative sample

<Sampling method> • Manual sampling • Sampling using an automatic collection device

Check the advantages and disadvantages then decide.

<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. • The storage methods and possible storage periods will vary depending upon the test items, so

check these in advance.

• 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

P25


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

• 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.

<Types of water sampling apparatus>

<Hyroht water sampler> * Apparatus to sample water from an arbitrary depth

<Thermometer> <Polyethylene buckets>

<Polyethylene bottles (small, medium, large)>

P27


<ORP meter> <pH meter>

<Glass bottles>

<Influent outside site>

Install the water sampling bottle on the Hyroht water sampler and collect the water

<Primary sedimentation tank influent>


P28

<Water sampling apparatus> • Hyroht water sampler : Influent outside site • Dipper : Primary sedimentation tank, reaction tank, return sludge • Polyethylene bucket : Treated water, final effluent

<Reaction tank>

<Return sludge> <Treated water> <Final effluent>

<Water sampling>

<Cooler for keeping cool>


Record the time of sampling and the temperature, etc. Keep cool for testing for the number of coliform bacilli

<Water sampling>

P29

<Notes of caution for water sampling>

<SS> Suspended Solid: Insoluble substances

<Filtration> <Filter paper> <Drying (110°C, 2 hours)>

<Allowing to cool (30 minutes inside desiccator)> <Weighing>

P31


⇒ ⇒

⇒ ⇒

<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

<COD> Chemical Oxygen Demand: Chemical oxygen demand

<Sample collection> <Heating at 100°C for 30 minutes>

<Dripping in of potassium permanganate) ⇒ (Until the solution becomes a light pink color)

<Sample after dripping in>

<Addition of the reagents in the red frame> (From left: Sulfuric acid, silver nitrate and potassium permanganate)

<Addition of sodium oxalate> ⇒ (Reagent in the blue frame)


⇒ ⇒

P33

<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


⇒

⇒ ⇒

<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.

<Count the colonies> Reddish violet, 0.5 mm or larger

<After cultivation> <Cultivation in thermostatic chamber> (37°C),18~20h

P36


<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.

Utilization of test results

P37

(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

• 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

<Examples of results being useful for operation management (1)>


P38

• 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 re-elution of phosphorus from the final sedimentation tank.

• Adjustments were made to the telescopic valve and excess sludge withdrawal volume.

<Examples of results being useful for operation management (2)>

• It was confirmed in regular testing, etc., that the phosphorus treatment had improved.


P39

4 Characteristics of water quality control system in Kitakyushu City

P40

⇒ 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.

Characteristics of water quality control system in Kitakyushu City

P41

Automatic monitoring continuously for 24 hours to deal with abnormalities rapidly

<Goal> To understand the indices during normal operation and adjust the appropriate operation accordingly.

Type Shinmachi Hiagari Sone Kitaminato Kougasaki 1 Kougasaki 2 Regulation value

COD 11 8.5 8.4 15 8.8 8.0 20

Total nitrogen 10 15 11 12 11 13 20

Total phosphorus 0.3 1.6 0.2 0.6 0.2 0.2 2

Number of coliform bacilli (Quantity/mL)

300 3,000

Characteristics of water quality control system in Kitakyushu City

Kitakyushu City has set water quality objectives independently!

• 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

<Target water quality>

<List of water quality targets> P42

Units :mg/L

5 Introduction to work standards documents, etc.

P43

Work is implemented according to a manual that was produced independently!

• 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 (Common manual)

Introduction to work standards documents, etc.

<Water quality control work manual>

P44

<Other documents>

<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.

• National standards established by the Industrial Standardization Act

<JIS> (Japanese Industrial Standards)

Introduction to work standards documents, etc.

P45

Outline of Water Quality Control at Treatment Plants of Water Quality Control at Treatment Plants...

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