PLANT WATER SYSTEM REVERSE OSMOSIS PLANT

Scope of Work

The scope of work shall include the design, manufacture, supply and delivery to site, erection and integration with existing unit, commissioning and testing of the Reverse Osmosis (RO) plant with all components, instrumentation and complete accessories including but not limited to the following:

· 1 x 100% RO feed pump

· 1 x 100% filter feed pumps

· 1 x 100% Roughing and Polishing Multi Media Filters including coagulant and chemical injection

· 1 x 100% Reverse Osmosis plant for removal of dissolved solid

· 2 x 100% Cartridge Filters

· 2 x 50% High pressure pumps (HPP) for SWRO

· 3 x 50% High pressure for BWRO

· 2 x 50% River water Reverse Osmosis (RWRO) and Brackish Water Reverse Osmosis skids (BWRO) including auxiliary system

· Dosing pump chemicals

· Valves`

· Piping and accessories

· Instrumentations and control

· Spare parts

Note :

i) The Bidder shall provide any and all equipment, materials and accessories as required for a complete set for the system. Although not clearly specified in the above, any embedded materials for foundation, base plates, grounding materials, support, electric motors, accessory piping, valves, instruments and panels as well as the belt conveyor and piping support foundations related to the system shall be included in the scope of work.

ii) All necessary structures shall be provided.

Codes and Standards

The reverse osmosis plant and its accessories shall be designed manufactured, constructed and tested in accordance with the latest applicable codes and standards as specified in Part 4 Subsection 3A.5 and other reputable international codes and standards. The codes and standards of the following organization are specifically applicable to the work involved in these specifications.

Design and Operating Conditions

REVERSE OSMOSIS UNITS

· River water is pumped from a river water intake through roughing & polishing multi-media filters, after injecting coagulant and polymer.

· Incorporated in the pre-treatment system is the sulfuric acid and the antiscalant dosing. These two chemicals will control scaling by reducing the potential of calcium sulfate and strontium sulfate from precipitating and eventually clogging the micron filter and the membranes.

· Sulfuric acid is dosed to ensure that calcium carbonate is not precipitated within the membranes. This converts carbonates to carbon dioxide gas thereby reducing the carbonate concentration and the likelihood of precipitation of calcium carbonate.

· Provisions shall be made for the addition of antiscalant to inhibit residual carbonate and non-carbonate scaling on the membranes.

· Since scaling control is required based on the water analysis, the injection of sulfuric acid and antiscalant will be needed to ensure continuity of the membrane performance.

· The filtered water from the multi-media filters will have enough residual pressure to pass through the cartridge filters and to the high pressure pumps. The purpose of the cartridge filters is to remove particles greater than 5 micron.

· Prior to the riverwater high pressure pumps, the feed water is dechlorinated by the addition of sodium bisulfate, thus preventing chlorine attack on the membranes. For this purpose, a chlorine residual and redox potential monitors are located upstream of the riverwater high pressure pumps to shut down the units upon a preset high level of residual chlorine.

· In the event of an “Off Specification Feed Water”, the units are automatically shut down and the off-specification feed water is dumped to waste until stable operation of pre-treatment plant produces feed water of acceptable quality.

· The water is then boosted by two high pressure pumps (one for each stream) and is divided inside the RO pressure vessels into permeate and reject streams by Reverse Osmosis pressure.

· The brine water from the RO units will be collected in a common manifold and then discharged by gravity.

· First stage product water is then collected in a GRP suck-back / break tank.

· This tank performs two functions: first to allow osmotic effect on stage shutdown and, second to give buffer capacity between SWRO module and BWRO stack, thus avoiding shut-down of the BWRO module due to low suction pressure and most importantly avoiding a very complex control system which would require skilled personnel.

· With the design envisaged, there is no need for a complex control system with soft starting of the second stage, thus making operation easier for plant personnel.

· The first stage product water is then boosted by 2nd stage HPP and is passed to the two pass RO Block. The second stage RO membrane equipment has been designed to treat 100% of the full first stage output.

· The final product water is partly diverted to a Glass Reinforced Plastic (GRP) holding tank, which has been sized to provide adequate volume for cleaning of the riverwater and brackish water membranes.

· The desalinated water shall be collected in the 2 x 200 m3 service water reservoir to be further used as service water, portable water and as feed to demineralization plant.

FLUSHING SYSTEM

· The system shall be designed to produce a continuous, steady stream of high purity desalinated water. If one of the stream is used intermittently, the 1st stage product water is automatically flushed back through the BWRO high pressure pump, high pressure pipe work and membranes during shut-down to replace the riverwater and to avoid corrosion of Suspended Solid (SS) components.

· Flushing is achieved using 1st stage product water from the flushing / break storage tank boosted by one flushing / cleaning pump.

· The flushing system is common to both streams and it has been sized to allow both, riverwater RO stacks to be flushed in sequence using the permanently installed facilities.

· Following the initial automatic flush of one RO stack, the automatic flushing sequence for the second module will be manually initiated from the control panel in the event that both streams are shut down.

CHEMICAL CLEANING SYSTEM

· During normal operation and with proper pre-treatment, deposits of mineral scale, biological matter, silt and insoluble organic constituents will build up on the membrane surface at a very slow rate.

· A common central chemical cleaning facility which makes use of the cleaning tank and flushing pumps and serving all modules is provided which enables the membranes to be cleaned readily on a routine basis.

· Cleaning connections are provided on the membrane’s modules for quick coupling of flexible hoses when cleaning is required. The number of modules makes it cumbersome to install permanent connection from the centrally located cleaning system.

CHEMICAL HANDLING FACILITIES

Chemical dosing units are provided for the following purposes:

Chemical Dosed	Point of Dosing	Chemical Form Packing	Dilution
Sulfuric Acid Scale Inhibitor M50 Sodium Bisulfate	Feed-water before micron filters Feed-water before micron filters Feed-water before HP pumps	Liquid / Drum Liquid/ Drum Power / Bag	100% 100% 10%

Detailed Requirements

a. The first stage of Reverse Osmosis plant offered is designed to operate on river water with a total dissolved solids (TDS) content on approx. 40,000 mg/l (tentative) and the second stage RO unit is designed to operate with a TDS of approx. 300 mg/l.

b. Quality of river water

Referring to preliminary data as specified in Part 4 Section 2.18, the bidder is to satisfy himself of the true conditions by mean of his own survey especially for sludge conditions.

c. Temperature of River water

Design at 34.8⁰ C

d. The Bidder is required to calculate approximately the RO plant

capacity necessary for the plant, but no less than 2 x 25 m³/day of

average net desalinated water production.

e. Design Limitations

Feedwater Design Limitations prior to the First Stage RO Unit.

- Iron, manganese, aluminum, tin : Not more than 0.05 mg/l

which could cause metal oxides

or hydroxides precipitation

- Chlorine, KmnO₄ or other : <0.1mg/l

oxidants which could react with

the membrane resulting in the loss

of productivity

- Silt Density Index (SDI) after : Less than 5mg/l

filtration which could cause

colloidal deposition

- Organic content (TOC, BOD, : <3mg/l

COD)

- Hydrocarbon, oils and greases : Zero

which could adversely effect

productivity of membranes

- Hydrogen sulfide, which could : Zero

form colloidal sulfur as an

oxidation product and deposit on

the membranes

- Barium (Ba), Strontium (Sr) and : Traces

Fluoride (F), which could form

sparingly soluble salts and cause

precipitation

Performance Testing And Guarantee

SHOP TESTING

According to the Standard Specification for Pumps.

SITE TESTS

In Particular the following plant properties shall be tested:

· Plant Performance (on automatic and manual control)

· Required Desalinated Water Quality according to US Standard Methods for Water Analysis or International recognized codes for Water Analysis or equivalent.

· Plant Capacity measuring flow in main pipes and/or water levels in the treated water storage reservoir.

PERFORMANCE GUARANTEE

The following guarantees shall be given by the Bidder

· Plant Performance shall be guaranteed and specified in “Bidder Data Sheet”.

· Plant capacity as indicated in clause 4.5.5.1.4

· Minimum lifetime of RO Modules and maximum exchange rate in percent of RO Modules per year.

· Maximum average specific consumption per net m3 of desalinated water, including treated raw water supply to the prefilter, and RO Plant. Guarantees to be stated by the Bidder in the Schedule of Functional Guarantees.

Notes : RO = Reverse Osmosis

GRP = Glass Reinforced Plastic

BWRO = Brackish Water Reverse Osmosis

SWRO = Sea Water Reverse Osmosis

SS = Suspended Solid

SDI = Silt Density Index

TOC = Total Organic Carbon

BOD = Biological Oxygen Demand

COD = Chemical Oxygen Demand

DEMINERALIZED WATER TANK

To store demineralized water from water treatment system, a demineralized water tank with capacity to store three (3) days of required demineralized water shall be provided

The tank shall be made of carbon steel plate JIS G3101 (SS400). The Bidder shall provide the complete accessories such as nozzles, level control, manholes, spiral stairway, ladder and handrail, valves, piping/flexible piping, foundation bolts and nuts, instruments, cables and grounding wire, air vent, motor pump, instrument and control equipment and painting. The Bidder shall design and construction with the equipments of internationally accepted standard, e.g. API 650 standard, etc.

For performance and guarantee, the Bidder shall perform the entire test as minimum, as the following:

- leak testing

- radiography

- liquid penetration examination

WATER TREATMENT SYSTEM

The duty of the water treatment plant shall be to provided treated water of specified qualities and daily volume throughput to meet the requirement of the power plant. The system shall serve to remove suspended remaining salt from the raw water by means of filtration and mixed bed exchange. The result shall be very clean demineralized water, which complies with the standard for high pressure boiler feed water.

The Bidder shall provide the complete water treatment system. The water treatment system shall provide one (1) demineralized train, consisting of mixed bed vessels with prefilter complete with internals and initial charges of resin including all required piping, controls and instrumentation for efficient and safe operation of the plant. The Bidder shall calculate approximately the train’s capacity per hour, with 20 hours service time and 4 hours regeneration time.

The demineralized water system shall be furnished complete with all required equipment, filters, injection systems, motor drives, pumps, tanks, internal controls, appurtenances and accessories. The Bidder also shall design the sump pit for water treatment equipment to store the regenerative waste water.

The quality of demineralized water (treated water) shall be automatically checked and recorded. The product shall be stored at demineralized water tanks. The demineralized water produced shall meet these characteristics:

(1) conductivity level shall less than 0.5 micro-mho/cm at 25°C,

(2) dissolved silica amount shall less than 0.015 ppm,

(3) pH level shall be 6.5 - 7.0,

(4) dissolved oxygen (DO₂) amount shall less than 0.3 ppm at degassing tower outlet.

The product shall be stored at demineralized water tanks.

The Bidder shall provide all chemicals until commercial operation and also the building for all the equipment for the system.

The acid injection system shall use 30% to 35% HCl. The alkaline injection system shall use 45% NaOH. The storages capacity for each injection system shall capable to store a minimum of one (1) month solution required.

The conductivity and silica content of demineralized water shall be continuously and automatically recorded at the discharge of water treatment plant.

Make up water supply for Units 3&4 cooling towers will be assured by 2x100% pumping lines. Pumps will be placed inside of extension of actual pump room where there are two make up pumps Units 1&2 (near TRWB).

Make up water installation for Units 3&4 will include from upstream following components:

- Two suction lines butterfly valves on each one to isolate pumps, connected to existing suction collector

- Two axially split single stage double suction volute horizontal centrifugal type pumps with Q=580 m³/h and H=20 m

- Two discharge lines with check valve and butterfly valve on each one to isolate pumps

- Discharge collector

- Transportation pipe between pump discharge collector and cooling water intake channel, placed underground

- Flow meter for make up water flow with isolation valve upstream and control valve downstream to adjust flow

Expansion joints, pumps, valves will be by manufacturing sea water resistant

DOMESTIC AND SERVICE WATER SYSTEM

DOMESTIC WATER SYSTEM

The drinking water system provides treated drinking water at the plant site for the operating personnel. A common drinking water system shall receive the water from raw water tank where it will be chlorinated and blended with river water at a controlled ratio.

The Bidder shall provide a complete drinking water system. The system shall consist of supply pumps, blending system, injection system, pipings, equipment, accessories, control and instrumentation. Supply pumps shall use to suck distillate water from raw water tank to a head tank system located on the upper level of the power house. Sodium hypochlorite shall be injected up stream of the head tank.

All pipings values and associated equipment of river/raw water blended system from river water/raw water source up to drinking water storage tank shall be made from stainless steel 316.SS material.

The drinking water system is provided with 2 x 100% supply water pumps (1 unit as standby) to meet 100% of the water consumption of the operating personnel. Operating personnel for unit 1 and 2 shall consist of approximately 50 permanent employees, with 200 liter per person per day drinking water demand, resulting in a total drinking water consumption of 10.000 l/day. The drinking water will be stored within 3 days it means, the Bidder shall provide head tanks of 30 ton capacity. The head tanks shall make of fiber reinforce plastic (FRP) or equivalent. The tank shall be outdoor type, and provided complete with its injection system, control, valves, accessories and pipings. The water is distributed throughout the plant from the head tank by gravity.

Disinfections system shall ensure complete removal of pathogenic bacteria, viruses and other harmful species. Storage and distribution facilities shall be designed to ensure no unacceptable contamination of the drinking water. The water shall treat to meet the minimum quality requirements issued by the Ministry of Health of the Republic of Indonesia. The latest revision of the applicable Indonesia water quality guidelines will be used.

All design fabrication installation and testing of the work to be done will be performed in accordance with last edition of internationally codes and standard.

WATER TREATMENT PLANT C & I SYSTEM

The normal mode of plant control shall be automatic changeover and regeneration, dosing, back-flushing or cleaning of the various treatment streams at either pre-determined intervals, volumetric throughput or when some control parameter is exceeded. In normal operation there shall be a minimum of operator intervention.

The control system shall have a single control panel for the whole treatment plant which shall include a diagrammatic representation of the plant on which the status of each plant item and treatment stage indicated together with volumetric flow, integrated flow, tank levels, treated water conductivities and any other relevant control parameters. This control system shall be located local to the water treatment plant. Selected alarm and operational parameters shall be displayed in the central control room to appraise the operator of water treatment plant operating status.

There shall be provision for manual override of the automatic control system activated from the local plant control panel.

The plant shall have adequate on-line chemical monitoring equipment to ensure its efficient and effective operation and to prevent detrimental effects on downstream treatment stages.

The demineralisation treatment stage shall have fully temperature compensated conductivity monitors, reading at 25⁰C, and dissolved silica monitors as a minimum of on line instrumentation for the treated water.

WATER TREATMENT SYSTEM PERFORMANCE TESTING

The Bidder shall provide details of the commissioning tests and performance test that will form part of the supply. A minimum requirement shall be that the water treatment plant produces water of the specified purity, as defined for the different end uses, at the normal maximum flow rating of the plant for a continuous period of seventy two (72) hours with the design consumption of treatment chemicals. A secondary requirement shall be that the make-up water treatment plant shall meet the purified water requirements of the power plant over a thirty (30) days operating period of normal power plant cycling.

SERVICE WATER

The Service water pumps shall be able to transfer service water from the service water reservoir to the system including but not be limited to the following:

1. Mobile garage

2. House

3. Lubrication Cooling for CWP (Cooling Water Pump)

4. Dust Suppresion Water

5. Ash Conditioning

6. Waste water Treatment

7. Washing water for coal conveyor system

8. Spray water for coal unloaded device

9. make up water coal unloaded boat

The service water pumps shall be horizontal outdoor centrifugal type pumps. The Bidder shall provide two (2) sets of pumps system complete with pipings, valves, accessories, controls, instrument and all required equipment.

All design fabrication installation and testing of the work to be done will be performed in accordance with last edition of internationally codes and standard.

RIVER WATER INTAKE AND RIVER WATER TREATMENT PLANT

RIVER WATER INTAKE

A river water intake system shall be provided that is capable of providing additional water for unit 1 and 2 and pumping line for unit 3 and 4 necessary to meet the rated plant performance requirements utilizing components proven elsewhere in service.

The principal criteria for the design of the system shall be to ensure a supply of water to the power plant during all possible conditions with maximum availability.

The Bidder is required to show by suitable analysis that his proposed design of system will meet the requirements of the power station and environmental requirements at all times.

The Bidder shall fully demonstrate the design as follows:

(a) The design intake and pumping equipment shall ensure adequate quantities of water are abstracted for continuous operation of the power station throughout the year. The system shall be able to work under the entire range of flows and levels that can occur in abstraction/receiving body of water at this site throughout the year.

(b) The Bidder demonstrates to the satisfaction of the Owner that the design of the system is suitable for the design life of the power station. This will include modeling to demonstrate the security of supply at the proposed intake position with the proposed design.

(c) The design and construction of any works associated with the make‑up or discharge arrangements shall be satisfactory to the relevant consenting statutory authorities (this shall involve modeling studies as and if required by the statutory authority).

(d) That adequate access exists for maintenance purposes.

(e) An economic optimization of the system and its performance, and its effects on condenser and steam turbine performance and their optimization.

(f) That provision has been made within the system design to limit in the event of mal‑operation of the system, the maximum transient pressures within the system and the reverse rotation of the pumps to within the limits by the pump manufacturers.

(g) That there is suitable provision within the design and scope of supply of all systems, to enable their reliable, safe and efficient operation throughout the design life of the power station, taking due account of all environmental conditions.

(h) The system shall be designed to ensure that failure of any single plant component does not result in the shutdown of a steam turbine.

(i) The plant shall be included to minimize the entraintment of debris into, including suitable protection of pump intakes.

(j) The intake capacity will assure make up water supply of cooling towers including required surplus for treatment process

EXTENT OF SUPPLY

All plant equipment and works necessary to meet the circulating water requirement shall be provided;

The principal items shall be provided for each unit including but not limited to:

CDA No.: M-011

(a) Two (2 x 100%) river water intake pump (vertical, centrifugal, submersible type 2) complete with electric motors. With minimum Q = 780 m³/h.

(b) All associated electrical equipment and controls.

(d) All isolation, non return and control valves necessary to permit safe operation and maintenance

(e) Debris filter with Q = 780 m³/h

(f) All system pipework, valves and flexible connections associated with this scope.

(g) Pipe line from pump to RWTP to include butterfly valve. For pipes above ground will be made from carbon steel, with internal rubber lining and external epoxy coating. For pipes underground will be made from glass reinforced plastic.

(h) 1 x 100% portable submersible pump for maintenance and equipment washing

(i) Cathodic protection for all hydro mechanical equipment, screen and pump.

(j) Re-route of existing river water intake piping from existing river water intake pump to header.

RIVER WATER TREATMENT PLANT

General

The scope of work shall include the design, manufacture, supply and delivery to site, erection, commissioning of the River Water Treatment Plant (RWTP) according to the latest technology and good engineering practice, capable of continuous satisfactory operation, producing the design quantities and qualities from water specified. The RWTP will supply the treated water to the existing Treated River Water Basin (TRWB).

The RWTP system will include all related equipment, motor drives, pumps, tanks, integrated controls, appurtenances and accessories, including but not limited to :

- 1 x 100% concrete, Clarifier / Setting Basins equipment and accessories to give output of water under 10 NTU

- 1 lime milk preparing and feeding system

- 1 coagulant preparing and feeding system

- 1 flocculant preparing and distribution facility

- 1 chlorination plant with sodium hypochlorite tank and dosing system

- 1 used water reservoir and 2 used water pumps

- 1 thickening and 1 dewatering equipment of sludge including sludge loading equipment

- Auxiliary equipment within the RWTP

- All instrumentation and control including controls, valves and accessories, also the RWTP inlet control valve will be supplied

- All stairs, ladders, galleries and platforms for the equipment access and maintenance

- All chemicals and consumables required until one year after starting the commercial operation

- All piping, instrumentation and controls for chemical fill lines.

The existing RWTP service building had prepared space for future dosing unit. The sludge treatment plant will include all related equipment, motor drives, pumps, tanks, integrated controls, appurtenances and accessories, including but not limited to :

- 1 concentrate sludge thickener constructed from reinforced concrete including mechanical equipment for the sludge thickener (including scraper)

- 1 sludge dewatering filter press and 2 filter press feed pumps

- 1 flocculant feed pump

- 1 sludge cake conveyor system to truck. A sludge cake loader hopper with capacity of 12 tonne will be provided

- The fittings, accessories and other equipment which are necessary or usual for satisfactory operation will be included.

Design Conditions and Technical Requirements

General requirements

The river water treatment plant shall supply decarbonized and clarified water to the treated river basins and pump bay from where the water shall be transferred to the Cooling Tower 1 & 2 and the fire fighting system as well as in a later stage to the Cooling Tower 3 & 4. The plant shall be designed for chlorination, flocculation, decarbonization and sedimentation of the river water.

The production of decarbonized and clarified water shall be safe and continuous and the production rate adjustable to the river water demand of the power plant. The plant shall be designed in such a way that variation in the demand only requires little changes in the production rate.

The design of the plant shall conform to the plant descriptions with regard to the plant performance, and with respect to the standard and type of control, for example, automatic control or remote control from local control panel.

The detailed design of the plant and equipment shall be the proprietary design of the Contractor who is responsible for perfect plant performance according to the functional requirements of the Specification. The design and construction of the plant and the equipment shall meet the technical requirements given in this Specification.

Plant description

The following descriptions define the process :

Sodium Hypochlorite, Clarifier/lime, coagulant and flocculant preparation

and feeding

(1) Process

The river water shall flow to the clarifiers where Sodium Hypochlorite solution shall be added and rapidly mixed the river water to remove micro-organism and to enhance flocculation.

The Sodium Hypochlorite (NaOCl) supply will be supplied in drums, and transferred to the feed tank by barrel pump. Alternative to this feeding, the Contractor may provided 1t-containers (at least 15 containers).

Coagulant solution is added to river water for coagulation of the suspended solids. The solution is fed by metering pump to the river water, before it enters the clarified. The metering pump is provided by a preparation and feed tank of one day’s storage capacity.

It is the Contractor’s responsibility to select the most suitable chemicals, in particular the coagulant.

In case of dry Alum, the scope shall include two hoppers with 3 days capacity each and 2 preparation and feed tanks with motor driven agitator. The hoppers shall be fully eqipped in accordance with the P & I Diagram.

Lime milk and flocculant solution are fed to the clarifiers. The purpose of lime milk is for partial cold-lime softening.

The quantity of lime milk concentration is dependant on the river water flow inlet ratio. The concentration variation is achieved by the screw type feeders.

The lime milk is prepared continuously, and the solution surface level in the preparation tank is kept constant by level controlled addition of service water.

The main lime silo is refilled with hydrated lime on a daily basis.

The flocculant solution is prepared continuously by the automatic package system.

The flocculant solution is proportioned to the clarifier b y metering pump. In the clarifier part of the settling solids is recirculated by the impeller. The sludge produced in the clarifier is transferred to a sludge thickener.

(2) Main controls

The water flow through the clarifier is automatically controlled by a manual set point. If high level in the TRW Basins occurs the flow rate shall be reduced accordingly. A device shall be provided to avoid raw water flow increasing greater than 10%/hour. The inlet flow of river water shall be controlled by a modulating valve and measured by a flow indicator transmitter.

The feed rate of Sodium Hypochloride of coagulant and flocculant solution shall be automatically controlled proportionally to the water flow through the clarifier (closed-loop control) and by manual ratio adjustment, depending on the the river water composition. If dry alum is used, preparation of alum solution shall be fully automatic.

If Ferric Chloride is used, the transfer of Ferric Chloride solution from the storage tank to the feed tank shall be controlled automatically by the level switches of these tanks.

The feed rate of lime milk to the clarifier shall be constant. The concentration of lime milk shall be varied automatically and proportinally to the river water flow by adjustment of the vibratory be kept constant and lime milk feed rate from circulation line to clarifier may be varied. Adjustment of lime dosing to account for variations of water quality shall be performed by (remote) manual changing of the ratio feeder rate/river water flow.

The Service Water flow to the lime milk preparation vessel shall be automatically controlled by a float valve of the vessel. The transfer of hydrated lime from the storage silo to the metering hopper shall be automatically controlled by the level in the metering hopper.

The transfer of sludge from the clarifier to the sludge thickener shall be automatically controlled by an adjustable time program, controlling also Service Water flow for sludge fluidization and line flushing.

Treatment River Water Basins (TRWB)

From the clarifier the decarbonized and clarified water flows to the TRWB. From the TRWB the water is supplied to the pump bay, from where the water is transferred by pumps to the Cooling Tower and Fire Fighting Systems.

River water chlorination system

The river water shall flow to the clarifiers where Sodium Hypochlorite solution shall be added and rapidly mixed with the river water to remove micro-organism.

The Sodium Hypochlorite feed system shall have the following basic design parameters :

- the design dosage of Sodium Hypochlorite shall be determined by the Contractor.

- the minimum design dosage shall be determined by the Contractor

- the point of injection shall be provided at the inlet of the clarifiers

- Sodium Hypochlorite dose control shall be by manual adjustment of mg/l dose but automatically proportioned to flow.

Sodium Hypochlorite feed equipment shall include but not limited the following :

- One (1) Sodium Hypoclorite solution feed tank with agitators, gallery work, piping controls and instrumentation.

- All equipment overflow and drains shall be piped and routed to the drain sump.

- A complete Sodium Hypochlorite solution feed system for pumping Sodium Hypochlorite solution from the feed tank to the clarifiers shall be furnished. The shall include but not limited to the following equipment :

- One (1) Carbon Steel rubber lined Sodium Hypochlorite solution shop-fabricationed feed tank per M-302. The tank sahll be designed for automatic make – up and storage of a Sodium Hypochlorite solution. The tank shall be sized at the high tank level to store 3 days capacity of Sodium Hypochlorite solution at the design dosage rate and at the design gross river water flow rate to the clarifier. The tank shall have a minimum freeboard of 200 mm above the high tank level.

- Baffles, bolted to the tank wall for ease of removal during cleaning. The baffles shall be designed to promote adequate mixing.

PLANT WATER SYSTEM