WASTE WATER TREATMENT SYSTEM DESCRIPTION THUYẾT MINH HỆ THỐNG XỬ LÝ NƯỚC THẢI

Normal waste water : • Demi Water Plant • Chemical Dosing System • Sampling System Abnormal waste water: • Boiler Chemicla Cleaning(Rinse) • EP Washing Water • AH Washing Water • Blowdown Quenching Water • SCR Waste Water • CPP Waste Water • Electro Chlorination Plant • Plant Area Sump • Coal Runoff Pond • Ash Waste Water Oily waste water: • Unit1 Turbine building oily sump • Unit2 Turbine building oily sump • Unit1 Transformer area oily sump • Unit2 Transformer area oily sump • Fire Fighting Pump House Area Sump • Aux Boiler Area Oily Sump • Unit1 Boiler area oily sump • Unit2 Boiler area oily sump • Fly ash transfer compresser shelter oily sump • LDO area Oily Sump • Workshop Wareahouse area oily sump • Vehicle repair shop area oily sump The purpose of waste water treatment plant is to collect normal, abnormal and oily waste water generated in the power plant, treat them and then dispose as per requirement.

0INT1 30.06.2020 H.J.KIM Y.H.PARK S.K.LEE FOR CONSTRUCTION

0 21.10.2019 H.J.KIM Y.H.PARK S.K.LEE FOR CONSTRUCTION

Rev Date Prepared Checked Approved Details of Revision

SYSTEM DESCRIPTION FOR WASTE WATER TREATMENT PLANT

FOR CONSTRUCTION

RECORD OF REVISION Rev Date Page Affected Description of Revision

NS2-XS00-P0GN-120001 Table of Contents

3 Chemicals Handling for Waste Water Treatment Plant 17 3.1 Filling of Chemical Storage Tank 17 3.2 Responsibilities and Duties during Chemical Filling 18

5 Code & Standard 20

6 References & Abbreviation 22

7 Operation Philosophy for Waste Water Treatment 23

2 SYSTEM / COMPONENT DESCRIPTION

Normal waste water :

• Demi Water Plant

• Chemical Dosing System

• Sampling System

Abnormal waste water:

• Boiler Chemicla Cleaning(Rinse)

• Electro Chlorination Plant

• Plant Area Sump

• Coal Run-off Pond

• Ash Waste Water

Oily waste water:

• Unit#1 Turbine building oily sump

• Unit#2 Turbine building oily sump

• Unit#1 Transformer area oily sump

• Unit#2 Transformer area oily sump

• Fire Fighting Pump House Area Sump

• Aux Boiler Area Oily Sump

• Unit#1 Boiler area oily sump

• Unit#2 Boiler area oily sump

• Fly ash transfer compresser shelter oily sump

• LDO area Oily Sump

• Workshop & Wareahouse area oily sump

• Vehicle repair shop area oily sump

The purpose of waste water treatment plant is to collect normal, abnormal and oily waste water generated in the power plant, treat them and then dispose as per requirement

NS2-XS00-P0GN-120001 2.1 MAIN EQUIPEMNT

Industrial waste water treatment system

Normal Waste Water Pond

8hr RCC + Painting Normal Waste Water Feed Pump

15m Abnormal Waste Water Pond

50hr RCC + Painting AIR-BLOWER(COMMON)

Abnormal Waste Water Feed

20min RCC + Painting Agitator for pH Adjustment Pond

(P0GNK08AM001) - Quantity - Type (Impeller)

- Speed

- Material (Impeller)

One (1×100%) Propeller / 2stage 153RPM

CS + R/L Coagulation Pond

10min RCC + Painting Agitator for Coagulation Pond

STS316 Flocculation Pond

20min RCC + Painting Agitator for Flocculation Pond

STS316 Clarifier (P0GNS01BB001) - Quantity

- Dimension

- Effective Depth

- Retention Time

One (1×100%) 17.0mΦ x 3.8mH 3.3mH

4hr

Denomination Specification

- Material RCC + Painting Clarifier Scraper

20m Clarified Water Pond

1hr RCC + Painting Clarified Water Pump A/B

30m Air Blower A/B for DMF

A516-70 + Epoxy painting Activated Carbon Filter (ACF) A/B

A516-70 + Epoxy painting Final pH Adjustment Pond

15min RCC + Painting Agitator for Final pH

A240-304 Final Effluent Pond

2hr RCC + Painting Final Backwash Pump A/B

20m Final Effluent Pump A/B

40m

4.5hr RCC + Painting Sludge Thickener Scraper

(P0GNS05AM001) - Quantity - Type (Motor/Reducer)

- Speed

- Material

One (1×100%) Vertical / Cycloid 0.13 RPM SS400 + Painting Thickened Sludge Transfer Pump

20m Sludge Mixing Tank

A240-304 Sludge Lift Pump

A36 + Epoxy Painting Cake Hopper 1set Control Panel 1set Caustic Storage Tank

12m Caustic Dosing Tank

(For pH Adjustment Pond)

70ℓ/hr 20m Caustic Dosing Pump A/B

(For Final pH Adjustment Pond)

70ℓ/hr 20m Agitator for Caustic Dosing Tank

A240-304

12m Acid Dosing Tank

(For pH Adjustment Pond)

(For Final pH Adjustment Pond)

SS400 + Rubber Lining Coagulant Storage Tank

12m Coagulant Dosing Tank

122ℓ/hr 20m Agitator for Coagulant

Dosing Tank (P0GNN28AM001)

A240-304 A-Polymer Auto Dissolving Unit

(P0GNN21BB001) - Quantity - Type

- Size

One (1×100%) 3-Stage Tank 1.84mL x 0.75mW x0.75mH A-Polymer Dosing Pump A/B

360ℓ/hr 20m Fume Absorber

1hr RCC + Painting Air Receiver Tank for Instrument

0.55mΦ x 1.2mH A240 Gr 304Air Receiver Tank for Service Air

0.55mΦ x 1.2mH A240 Gr 304 Eye washer & Safety shower

(P0GNK26AZ001/002/003/004)

- Quantity

- Type

Four (4×100%) Hand & Foot Control

2 day RCC + Painting WWT Transfer Pump A/B for

30m

Oily waste water treatment system

Oily Waste Water Pond

12hr RCC + Painting Oil Skimmer A/B

90l/hr x 2set A240TP304 / A283Gr.C, A194 Gr2H

Oily Waste Water Feed Pump A/B

15m Oil Separator

25m3/hr SS400 + Epoxy painting

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RCC + Painting Oil Sludge & Skimmed Oil Pump

Oily Waste Water

Normal Waste Water

Abnormal Waste Water

2.2.2 INDUSTRIAL WASTE WATER TREATMENT PLANT

Normal Waste Water Pond

pH Adjustment Pond

Coagulation Pond

Flocculation Pond

Clarifier

Clarified Water Pond

Dual Media Filter A/B Sludge Thickener

Filter press / Cake Hopper

Final pH Adjustment Pond

Air Blower

WWT Retention Pond

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NS2-XS00-P0GN-120001 2.3 INDUSTRIAL WASTE WATER TREATMENT PROCESS

In this section a detailed description of duty of all major units will be provided Whole of the waste water treatment plant is divided into two major sub categories

• Industrial Waste Water Treatment Process

• Oily Waste Water Treatment Process

2.3.1 INDUSTRIAL WASTE WATER TREATMENT PROCESS

- Equalization

The equalized waste water being transferred from the normal waste water pond will be first pH corrected in a pH adjustment pond by dosing acid (15% HCl), caustic (15% NaOH) depending

on the incoming pH

- Coagulation and Flocculation

The pH corrected waste water will gravitate to the downstream coagulation pond, flocculation pond and clarifier Coagulant 10% (Alum) will be dosed in the coagulation pond for cohesion the particles in the waste water whereas A-polymer will be dosed in the flocculation pond for enlarging floc formation

- Clarification and Filteration

The flocs would then be settled in the downstream conventional clarifier And clarified water will be transferred to clarified water pond The clarified water transferred and treated in the dual media filter & activated carbon filter Finally the filtered water will be transferred to the final

pH adjustment pond If the Backwash process,Treated waste water is backwashed in Dual Media Filter (DMF) & Activated Carbon Filter (ACF) by the filter backwash pump

The backwash water from DMF & ACF will be transferred to normal waste water sump

- Discharge and Monitoring

The treated waste water will be transfer to Final Effluent Pond and will be discharged into CW discharge canal or Reuse(Dust Suppression System(CHS), Make Up Water Pond(AHS)) Before discharge, flow and pH value will be monitored And also The waste water monitoring system located before CW discharge canal will be monitored the environment parameters (pH, COD and TSS) and then DCS will be send the signal to WWT

- Sludge Treatment

The sludge from the clarifier will be periodically transferred to a sludge thickener via sludge transfer pump Overflowed water from the sludge thickener is again treated to the normal waste water pond The thickened sludge from the sludge thickener will be dewatered in a filter press

The filtered water from filter press will be transferred to the normal waste water pond

The sludge cake generated from the cake hopper can be disposed of by truck

Note: 15% HCl, 15% NaOH and 8% (Alum), 0.2% A-Polymer will be applied for this project

2.3.2 OILY WASTE WATER TREATMENT PROCESS

Oily waste water pond is used to collect oily waste water from turbine area drains, boiler area drains, transformer area drains and drains other oil contaminated area of the plant Remove oil from the oil skimmer first And then from the oily waste water pond, oily waste water is transferred to the oil simmer and oil separator, where oil and water must be separated

The separated water from the oil separator is transferred to the normal waste water pond The separated oil and oil sludge of the sludge chamber are collected in the oil sludge pond by gravity The oil sludge are disposed of tank lorry by a tank truck own pump

The flushing water which washed plate by service water will return to oily waste water pond All piping associated with the oily waste water treatment system will be oil resistant pipe Oil

sludge pump and skimmed oil pump & supplied flexible hose will be used if a pump & hose of tank lorry is not possible to use

2.4 EQUIPMENT DESCRIPTION

2.4.1 Normal Waste Water Pond

Industrial waste water (MBP regeneration waste water, Sampling system) from the various process on the power plant site will be collected and transferred to the normal waste water pond

Air-Blower(Conmmon) will keep liquid to prevent settling of suspended solid inside the pond The contents of the normal waste water pond will be aerated Two (2) normal waste water feed pumps will transfer the contents of the normal waste water pond to the clarifier

2.4.2 Abnormal Waste Water Pond

Abnormal waste water (CPP regeneration waste water, Boiler chemical cleaning waste, Boiler blowdown quenching water, Cleaning water for ESP, Cleaning water for air heater, Coal runoff pond, Electro chlorination plant, Ash handling system) is generated at abnormal intervals in the plant like blow down water etc will be stored in the Abnormal waste water pond Coal and ash contaminated waste water after settling is transferred to abnormal waste water pond heavy rain season

Air-Blower(Conmmon) will be used to prevent contents of abnormal waste water pond from

settling inside the pond Three (3) abnormal waste water feed pumps will transfer the contents

of the abnormal waste water pond to normal waste water pond which will be treated in the waste water treatment system

In case of normal, the one(1) abnormal waste water pump operates If it is abnormal, two(2) operate at the same time

2.4.3 pH Adjustment Pond

pH of the waste water from the normal waste water pond will be adjusted in the pH adjustment pond for reacting coagulation and flocculation efficiently Provision is made to dose acid and caustic to this unit One agitator will be used to mix the contents of the pH adjustment pond

2.4.4 Coagulation Pond

pH corrected waste water is moved to the coagulation pond where the lighter particle coagulate

by overflows from pH adjustment pond Alum is added to the coagulation pond from the coagulant dosing system Two (2) coagulant dosing pumps will transfer coagulant from the coagulant doing system to coagulation pond 1 No agitator will be used to mix the contents of the coagulation pond

The debris and dense material is removed by means of chemical cohesion

Commonly Alum is used and the coagulation reaction of cohesion is as following

Al2(SO4)3 ∙18 H2O + 3 Ca(HCO3)2 → 2Al(OH)3↓ + 3CaSO4 + 6CO2 + 18H2O

2.4.5 Flocculation Pond

In the Flocculation pond lighter colloidal particles are made in to dense floc with the help of adding of Flocculant Flocculant (Anionic Polymer) is added to the flocculation pond from the Flocculant dosing system Two (2) A-polymer dosing pumps will transfer Flocculant from the Flocculant doing system to flocculation pond One agitator will be used to mix the contents of the flocculation pond

2.4.6 Clarifier

Clarifier is provided to clarify the waste water Under the effect of gravity dense particles are settled at the bottom of the clarifier and passed to the sludge thickener by two (2) sludge transfer pumps Clarified water from the clarifier will be overflowed to the clarified water pond Operator should find out optimized operation time by using sampling points installed on clarifier

It has a cylindrical steel structure with conical bottom; central well, scraper arms at bottom and

a structural bridge

The waste water enters the clarifier at central well and flows to bottom of clarifier The waste water of central well rise from bottom to clarifier periphery While waste water rises to clarifier top, the solid particles settle at bottom cone and top rising water overflows to the Clarified water pond

NS2-XS00-P0GN-120001

The scraper arm rotates at a low speed at the clarifier bottom Due to the rotating movement of the scraper arm the sludge collected at bottom of clarifier is moved to the central cone of clarifier

The sludge is about 1% consistency and it is periodically taken out by two (2) sludge transfer pumps

The clarifier will remove turbidity, color and organic matter from the influent water

2.4.7 Clarified Water Pond

Clarified water from clarifier is stored in the clarified water pond Two clarified water pumps will feed clarified water to the dual media filter & activated carbon filter units

2.4.8 Dual Media Filter

Dual media filter with sand and anthracite beds is provided to remove suspended solids and turbidity present in clarified water

Suspended matters and turbidity gets removed when clarified water is passed in downward direction through this filter bed The unit should be backwashed whenever the pressure drop exceeds the preset value An air scour system has been provided to loosen the media before backwash for effective removal of settled solids This comes in handy if the impurities on the media bed are particularly difficult to breakup with a normal backwash

2.4.9 Activated Carbon Filter

Activated carbon filter with sand & Activated carbon beds is provided to remove odor, chromaticity

Suspended matters and turbidity gets removed when clarified water is passed in downward direction through this filter media

2.4.10 Sludge Thickener

Sludge from clarifier will be transferred sludge thickener Sludge is thickened under the effect

of gravity in the sludge thickener A slow moving sludge thickener scraper will be operated in the sludge thickening process Overflowed water from the sludge thickener is transferred to the normal waste water pond

It has a cylindrical steel structure with conical bottom; central well, scraper arms at bottom and

a structural bridge

Sludge thickener works on similar principle of clarifier The sludge enters the thickener at central well and flows to bottom of thickener The thickened sludge comes out of central well from bottom and rises to thickener periphery While sludge rises to thickener top, the solid particles settle at bottom cone and top rising water overflows to the normal waste water pond The scraper arm rotate with a low speed at the thickener bottom Due to the rotating movement of the scraper arm, the sludge collected at bottom of thickener is moved to the central cone of thickener

The sludge is about 2% consistency and it is periodically taken out by thickened sludge transfer pumps

2.4.11 Sludge Mixing Tank

Thickened sludge collected at the bottom of the sludge thickener is transferred to the sludge mixing tank by two (2) thickened sludge transfer pumps

2.4.12 Filter press

Filter press is a sludge dewatering device that applies mechanical pressure and operation mode is one batch type

One batch type process is as followings:

First, the filter press oil cylinder is moved to press the filter plate

From sludge mixing tank, conditioned sludge is fed to filter press by sludge lift pump

The sludge is trapped between filter plates and is passed through a filter clothes

Due to the pressure applied, the water is squeezed out of the sludge

When the operation time is over by the timer, the operator transfers the filter plate and drops the solid sludge between the filter plates to the cake hopper

Filter press receives sludge of about 2% consistency (from sludge mixing tank) and produces sludge cake of 20% consistency

Sludge discharged in the cake hoper will be taken out periodically to the disposal

The sludge cake is stored in the cake hopper and periodically disposed by owner using the

truck

2.4.13 Final pH Adjustment Pond

Before final discharge, the pH of the treated waste water has to be adjusted as per pH value

If the pH value does not meet the criteria, Acid and caustic will be dosed in this unit by dosing pumps

2.4.14 Final Effluent Pond

Treated waste water is stored in the final effluent pond Two (2) effluent pumps will be used to dispose the treated waste water

Normal Case : Reuse for CHS dust suppression

If coal runoff pond full, this case treated water flow to CW discharge canal

Note : Discharge through Waste water monitoring system before going to sea

2.4.15 Chemical Dosing System

The waste water treatment plant uses chemicals comprising of caustic soda, acid, alum and solid polymer (A-polymer)

2.4.15.1 Caustic Dosing System

The purpose of caustic dosing system is controlling pH value of pH adjustment pond and final pH adjustment pond

Cuastic System comprises of the following equipment:

- Caustic Storage Tank : 1 x 100%

- Caustic Dosing Tank : 1 x 100%

- Caustic Dosing Pump for pH adjustment pond : 2 x 100%

- Caustic Dosing Pump for final pH adjustment pond : 2 x 100%

Cuastic (45%, NaOH) is stored in Cuastic storage tank It is charged by tank lorry or drum Cuastic (45%, NaOH) are transferred and is diluted to 15% caustic solution in caustic dosing tank

Diluted Cuastic (15%, NaOH) is used to wastewater treatment system

2.4.15.2 Acid Dosing System

The purpose of acid dosing system is controlling pH value of pH adjustment pond and final

pH adjustment pond

Acid System comprises of the following equipment:

- Acid Storage Tank : 2 x 100%

- Acid Dosing Tank : 1 x 100%

- Fume Absorber : 1 x 100%

- Acid Dosing Pump for pH adjustment pond : 2 x 100%

- Acid Dosing Pump for final pH adjustment pond : 2 x 100%

Acid(35%, HCl) is stored in acid storage tank It is charged by tank lorry or drum

Acid (35%, HCl) are transferred and is diluted to 15% acid solution in acid dosing tank Diluted acid (15%, HCl) is used to wastewater treatment system

2.4.15.3 Coagulant Dosing System

Alum shall be used as the coagulant

Purpose of coagulant dosing system is to coagulate suspended solid in water

Coagulant System comprises of the following equipment:

- Coagulant Storage Tank : 1 x 100%

- Coagulant Dosing Tank : 1 x 100%

- Coagulant Dosing Pump : 2 x 100%

NS2-XS00-P0GN-120001

Coagulant (8%, Alum) is stored in Coagulant storage tank It is charged by tank lorry or drum

Coagulant (8%, Alum) are transferred in Coagulant dosing tank

Coagulant (8%, Alum) is used to wastewater treatment system

2.4.15.4 Flocculant Dosing System

Anionic Polyacrylamide will be used as the coagulant aid

Purpose of Flocculant dosing system is to increase a suspended solid to a larger floc Dissolving of this coagulant aid will be made easy to achieve uniform concentration

Flocculant System comprises of the following equipment:

- A-Polymer Auto dissolving unit : 1 x 100%

- A-Polymer Dosing Pump : 2 x 100%

A-Polymer auto disoolving unit is all in one type automatic dissolving unit which completes the storage, feeding, mixing, dissolving and matching in single system The concentration

of the solution is always maintained constantly as it emplys the constant proportional feeding principle

The Flocculant system is an equipment for inserting good quality solution after complete dilution polymer at fixed density continuously in order to supply fully maturated cohesion materials

2.4.15.5 Oily Waste Water Pond

Oily waste water pond is used to collect oily waste water from turbine area drains, boiler area drains, transformer area drains and drains other oil contaminated area of the plant Its function is to provide adequate /sufficient flow to compensate the daily fluctuation of oily waste water from varied sources Two(2) oily waste water feed pumps will pump the oily waste water to the oil separator

Once oil skimmers are started, it always works except for the case of shut down

2.4.17 Oil Separator

Oil separator is a device for separating oil and water by gravity or density difference

The oil separator is consist of several corrugated plate Egg plate shapes are stacked

horizontally at regular intervals

When the oily waste water passes between EPS, the oil drop rises up to the surface of the water by buoyancy and it can be removed by pipe skimmer Sludge is settled at the bottom of basin by specific gravity In the filtering basin, fine oil can be removed by oil absorbent The skimmed oil will be collected in the oil sludge pond for disposal by truck

The oil sludge is displaced to the oil slduge pond periodically by the operater

Waste water generated due to WWT not operating normally is supplied from the final effluent pump and stored for up to 2 days, then transferred to WWT normal waste water pond for re-treatment of waste water.Two (2) WWT Transfer pumps will transfer the contents of the normal waste water pond to the clarifier

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