Advanced Water Treatment Technologies – Chennai

Initiatives

Workshop conducted by MoUD, New Delhi

11.03.2011

Chennai Metropolitan Water Supply and

Sewerage Board

Conventional Water Treatment

270 MLD WTP at Kilpauk (1914 – Slow sand Filters 60 MLD) /

(1959 – Rapid sand filters 45 MLD) / (1973 – Rapid sand filters

135 MLD) / (1990 – Rapid sand filters 90 MLD)

300 MLD WTP at Puzhal (1996)

180 MLD WTP at Vadakuthu (2004)

Pulsator Technology based Water Treatment

530 MLD WTP at Chembarambakkam (2007)

Brackish water (R.O. based) Water Treatment

Sea water Desalination

100 MLD Plant at Kattupalli, Minjur (2010)

100 MLD Plant at Nemmeli – Ongoing and completed by 2012

Sewage Renovation (TT / RO based) for Industrial use

Collaboration with Industries (CPCL / MFL / GMR Vasavi) – 41 MLD

WATER TREATMENT TECHNOLOGIES ADOPTED

NEED TO GO IN FOR LATEST WATER TREATMENT

TECHNOLOGIES

Slow sand filters

occupies more space – limitations in expansion

Low filtration rates – limitations in meeting the

demands

Replacement of media due to clogging / Time

consuming

Danger of flooding during Monsoon due to open

to air construction

WATER TREATMENT PLANT AT RED HILLS ( BOT) - 1996

The Operation & Maintenance of the Plant is done by

Private Contractor except the major repairs and

replacement which are being carried out by the Board

Capacity 300 MLD

Work completed &

Commissioned

1996

Cost Rs.50.43 Crore

300 MLD WATER TREATMENT PLANT AT PUZHAL - PROCESS FLOW CHART

300 MLD Water Treatment Plant at Puzhal

• Year of Construction - 1996

• Capacity - 300 MLD

• Operation & Maintenance - M/s VA Tech Wabag Ltd

• Period of contract - 3 Years

• Date of commencement - 16.12.2007

• Contract Value - Rs 7,37,55,068/- for 3 years.

NEW VEERANAM PROJECT INFRASTRUCTRES -2004

• Raw water pumping, Treatment Plant, Treated water pumping, 228 km pipeline and WDS

• Capacity - 180 MLD

Work completed &

commissioned - 2004

• Project Cost - Rs. 720 Cr.

After the completion of the construction and commissioning the same contractor are entrusted with O&M including all major repairs and replacements for 5 years

180 MLD WATER TREATMENT PLANT AT VADAKUTHU - PROCESS FLOW CHART

180 MLD Water Treatment Plant at Vadakuthhu

• Year of Construction - 2004

• Capacity - 180 MLD

• Operation & Maintenance - M/s. TMP Manoharan & Co- M/s. VA Tech Wabag Ltd – 2 Packages

- M/s. IVRCL Ltd – 2 Packages

• Period of contract - 5 Years

• Date of commencement - 08.09.2010

• Contract Value - Rs 23.11 Crore for 5 years.

530 MLD CHEMBARAMBAKKAM WATER TREATMENT PLANT

TREATMENT PROCESS

Total Cost Rs.134.9 Crore (French Assistance = Rs.33.5 Crore + CMWSSB Rs.107.0 Crore

O&M Cost = Rs.45 Crore for 7 yrs

THE PULSATOR TECHNOLOGY

Raw water

+

Aluminium

sulphate

Raw

water + Alum

sulphate

Air inlet

Valve closed

Top surface

sludge blanket

Vacuum

blower

High level

Low level water surface

clarification

area

sludge draw down pipe to

sludge channel

baffle plates

Sludge

concentrator

Sludge blanket

with downward

motion

Small raw water

flow rate at

lateral

distribution pipe

Raw water

+ Aluminium

sulphate

ADVANTAGES OF PULSATOR TECHNOLOGY

Low chemical consumption

Low water losses on sludge extraction

Low power consumption

Low maintenance

Low operator input

Excellent treated water quality

- SS (Low load on filters)

- Colloids

- Algae

High Rate Gravity Sand FiltersMore filtering capacity

False Floor Fitted with NozzlesEffective floor usage

Uniform Sand media for filtrationIn-depth clogging longer filtration cycle

Constant Head & Constant Rate FiltrationBetter filter operation

Washing - Simultaneous Air & Water Scour

Effective cleaning of bed with less water

Washing - Simultaneous Air & Water Scour

FILTRATION

MODE

BACKWASH

MODE

B/W WATER

SCOUR AIR

B/W OUTLET

INLET CHANNEL

ADVANTAGES OF AQUAZUR FILTERS

BRACKISH WATER R.O.

DESALINATION PLANT

Metro water has taken a considered decision to focus on

Fishermen's Colonies and economically disadvantaged section to

supply them with good quality water for drinking and cooking

purposes. Since most of them are located close to the sea and in the

tail end of the city water supply distribution system, they suffer from

lack of potable water, resulting in major health related problems.

A conscious decision was taken to locate a battery of Reverse

Osmosis Plants to help these groups by supplying the potable water

by treating locally available brackish ground water through Reverse

Osmosis Process.

There are three Reverse Osmosis Plants located one at Velachery

(4.5 lakhs litres capacity) and the others at Nochikuppam

(1.5 lakh litres capacity) and Kasimedu (1.5 lakh litres capacity).

During the year 2001 drought, two new Reverse Osmosis Plants

were installed one at Ayothiakuppam (1.00 lakh litre capacity) and

another at Kasimedukuppam (Royapuram) serving a population of

about 5000 at each location.

The Reverse Osmosis Plants consists of open wells

and Bore wells to draw the required brackish water

for treatment through the Reverse Osmosis Plant.

The raw water drawn from the wells is stored in the

storage tanks and pumped to the Dual Media filters

consisting of quartz sand and anthracite wherein

suspended particles is removed.

The filtered water from the Dual Media filter is

pumped to a micron filter to remove the micron size

particles and then fed into the Reverse Osmosis

Process Unit by means of high pressure pumps.

The Reverse Osmosis process module consists of

a thin film composite of polyamide membrane.

When brackish water is pumped with high

pressure through this membrane, the dissolved

solids are removed and the output water is of

potable quality with dissolved solids content

below 500 ppm.

The rejects from the Reverse Osmosis modules

with high salt content is put into the nearby sewer

system for disposal since the quality is within the

permissible limit to dispose through the domestic

sewer.

INSIDE VIEW OF R.O.PLANT

VIEW OF R.O.PLANT

SEA WATER DESALINATION

Even after implementation of the various water supply

augmentation projects and water conservation measures,

there is still a shortfall in meeting the water demand of

Chennai City and adjoining areas.

Further all the existing sources are depend on monsoon

and subject to change in weather patterns and not 100%

reliable and assured supply.

Hence, it is necessary to examine the possibility of

identifying another reliable and assured source of water

supply to bridge the gap between demand and availability.

Need for Alternate Non-Rain dependent Sources

(Sea water Desalination Project)

Chennai - Sea water Desalination Project - Contd.,

Govt.of Tamil Nadu is determined to implement

a combination of schemes to make available

Sufficient quantity of water during normal years

Minimum lifeline supply during Critical drought years

Govt.of Tamil Nadu has therefore decided to

implement two Desalination Plants of 100 MLD

capacity each

This will ensure lifeline water supply to the

residents of Chennai during drought years

TECHNICAL ASPECTS OF THE PROJECT

Project Setting up of 100 MLD Seawater Plant on

DBOOT basis at Kattupalli, Minjur

Terms Bulk Water Purchase Agreement dated

13.09.2005

Operations Period 25 Years

Desalination Process Reverse Osmosis (RO)

Conversion rate of drinking

water from sea water

45%

No.of RO trains 5

No.of Pressure Vessels 248 in each RO train

Number of Membranes 7 in each pressure vessels

Type of Membrane Composite polyamide spiral wound

membranes

TECHNICAL ASPECTS OF THE PROJECT

Pre-treatment Coagulation & Flocculation;

Clarifier; 2-stage media Filtration

Pressure Filtration & Cartridge Filtration

Energy Recovery System Energy Recovery System using the

principle of positive displacement and

isobaric chambers

Product Water Quality As per IS 10500 : 1991

SEAWATER INTAKE TRAVELLING SCREEN & FLUSHING PUMPS

• The raw sea water is drawn by gravity from an intake tower erected at

635 m away from the shoreline.

• High Density Poly Ethlene (HDPE) pipeline of 1600 mm dia is laid on the

seabed for the drawal of 237 MLD raw seawater.

• Bar screens and dual flow travelling band screens installed in the

seawater sump protect the pumps .

• Seawater from the sump is pumped to Pre-treatment Units

Chemical Dosing unit for Pre-Treatment

1. Sulphuric Acid is added to decrease pH of sea water in order to maxmize the

coagulation

2. Ferric Chroride is added to enhance coagulation of seawater required in the

plant.

3. Sodium Hypo chlorite solution is added to disinfect seawater.

Pre-treatment – Flocculation Chamber

• The seawater from seawater pump house is pumped to the first pretreatment

system namely, flocculation chamber.

• Here the suspended, dissolved and colloidal are removed by means of adding

chemicals thereby increasing the efficiency of decantation.

• Volume to be treated – 237 MLD

• Average volume per hour – 9,921 cum/hr.

Pre-treatment - Gravity Settlers

• The flocculated water is uniformly distributed in the Gravity Settlers.

• The Gravity Settlers have been designed with 4 lamellar decanters with pulsating

mire beds with a capacity to treat 237 MLD.

• The GRP lamella plates are installed with 60 degrees of inclination, each vase

contains 52 lamella plates

Intermediate Pumping Station

• The filtered water from the Dual Media Filters is pumped from the intermediate

sump cum pump house for the next stage of pressure filtration to obtain clear

seawater.

• Discharge – 945 cm/hr

Pressure Filter Vessels

• The water pumped from the intermediate sump cum pump house is passed

through pressure filters to improve the clarity of the seawater

• No.of Pressure Filters - 16

Cartridge Filters

• This is the last stage of pre-treatment by which the ultra fine particles, present in

the filtered seawater are removed.

• There are 10 No.of Cartridge Filters.

Reverse Osmosis Process Unit with pressure vessels

• Reverse Osmosis is diffusive mechanism wherein the feed water is highly

pressurized using High Pressure pumps before passing through a sequence of

membranes placed in a Pressure Vessel, to obtain permeate water or desalinated

water.

• The water is pressurized to 58 Bar pressure.

• The plant has a set of 5 Reverse Osmosis modules each producing 20 MLD of

desalinated water.

Energy Recovery System

• The pressure in the reject brine water system is nearly 56 Bar.

• The pressure energy in the reject brine water is recovered at the outlet of the

membrane by means of pressure exchangers.

• The high pressure brine exchanges pressure with the pre-treated feed water in

the energy recovery system and equally pressurized with Booster Pumps before

combining with the feed water from high pressure pumps for the desalination

process.

• The energy (Power) requirement is reduced by nearly 82%

Post Treatment Units

• The desalinate water flowing out of the Reverse Osmosis process unit is

rematerialized and pH correction is carried out by adding chemicals such as lime,

Carbon-di-oxide and Sodium hypo chlorite solution

Product Water Tank

• After the post treatment the product water is collected in a 20 Million litres

capacity Underground Tank.

• Under ground Tank water is supplied by the company to the CMWSS Board for

transmission and distribution to Chennai City

100 MLD DESALINATION PLANT - NEMMELI – Mass flow diagram

Location of the plant at Nemmeli

100 MLD DESALINATION PLANT AT NEMMELI

Sl.No

Name of work Name of the contractor

Construction Cost

(Rs. in Crore)

O & M cost for 7 years

(Rs. in Crore)

Contract Period

1

Construction of 100 mld capacity Desalination Plant

M/s V.A.Tech Wabag Limited in consortium with M/s IDE Technologies, Israel.

533.38 500.29 24 Months

2 PMC for Plant M/s Mecon Limited in Consortium with M/s ADECO Technologies Ltd/SOECO

13.46

-

24 Months

3 Conveyance System

M/s Larsen & Toubro Limited

121.47 1.02 20 Months

REASONS OF ADOPTING ULTRA FILTRATION FOR TSS REMOVAL IN

NEMMELI DESALINATION PLANT

Occupies less land area (From 40 Acres at Kattupalli

and 19 Acres at Nemmeli

Enhances R.O.Membrane life from 3 to 5 years at

Kattupalli and 5 to 7 years at Nemmeli

Ultra filtration is used for most of the plants

commissioned for the last 5 Years

SEWAGE RENOVATION FOR INDUSTRIAL USE

Screen chamber

Primary clarifier

Aeration Tank

Balancing tank

Parshall flumeA

Secondary clarifierChlorine contact tank

Treated Sewage

Screening Grit

Excess Return Sludge

Raw Sludge

BOD5 = <20 mg/lTSS = <30 mg/lFaecal coliform = <10000

MPN/100 ML

Primary Treatment

Biological treatment -chlorination

LEGEND

Inlet chamber

Grit chamber

BOD5 = 350 mg/lTSS = 400 mg/lFeacal coliform = 4.6 x 106

MPN/100 ML

Return Sludge

B

C

Discharge in Coovam river

1. PRIMARY AND SECONDARY TREATMENT

SEWAGE TREATMENT PLANT – ACTIVATED SLUDGE PROCESS FLOW DIAGRAM

48

DIGESTERCENTRIFUGE

GAS HOLDER

SCRUBBER UNIT

SLUDGE THICKENER

A

For Power Generation

Bio-Gas

Power For plantExcess Bio- Gas

Sludge for Disposal

Excess Return Sludge

Raw Sludge

Supernatant

Return to Primary clarifierSupernatant Centrate

GAS ENGINE

Methane

Gas Burner

SLUDGE TREATMENT AND POWER GENERATION

BC

Sludge treatment

Power generation

LEGEND

2. SLUDGE TREATMENT

TERTIARY TREATMENT PLANTS INSTALLED

BY CPCL AT MANALI

SEWAGE RECLAMATION PLANT-1

(capacity: 475 Cu.M/Hr)

• Installed with old lime process byM/s. Hindustan Dorr Oliver in 1991-92 anddebottlenecking with UF system was done byMs. Doshi Ion Exchange Limited in 2004-05.

• Consists four RO banks with each 110Cu.M/Hrfeed (3 banks operation and one standby)

ClarifiersSurface

Aeration

Tanks

Hydro-

treater

Intermediate

storage

pond

Multimedia

filter

Ultra-

Filtration

Pressure

sand filter

Reverse

OsmosisUF Product

tank

Degasser

FeCl3 & Anionic

Poly dosing

Refinery /

Canteen Sewage

Secondary

treated sewage

Cooling Tower make-up or

Additional RO feed ZDPII

Chemical dosing

SBS,HCl,Antiscalant

Rejects to RORR

Old permeate

tank (PT-1)

DM Plant

Sewage Reclamation Plant - I (SRP-I)

3.0MGR

Chlorine

1.5 MGR for CT makeup

Permeate

Reject

Cartridge

filter

SEWAGE RECLAMATION PLANT-2

(capacity: 475 Cu.M/Hr)

• Installed with state of the art technology of

Sequential Batch Reactor (SBR) by

M/s. VA Tech WABAG in the year 2006-07.

• Consists four RO banks with each 110Cu.M/Hr

feed (all four continuous operation) & Reverse

Osmosis Reject Recovery (RORR) two banks

each with 40 Cu.M/Hr feed

High Rate

ClarifierSequencing

Batch

Reactor

Pressure

sand &

Multi grade

filter

Flash

Mixer

Ultra-Filtration Break point

chlorination

Reverse Osmosis

FeCl3 & Anionic

Poly dosingSecondary treated sewage

Chemical dosing

SBS,HCl,Antiscallant

DM Plant

Degasser

Reverse Osmosis Reject

Recovery

New permeate

tank (PT-2)

Sewage Reclamation Plant - II (SRP-II)

Final Reject to MPL-II

2.5MGR

PermeateReject

Cartridge

filter

SEQUENCE OF SEWAGE TREATMENT PLANT

Sewage receipt (Equalisation)

Boilogical treatment (BOD /COD & Ammonia reduction)

Chemical treatment (Coagulation & Flocculation)

Filtration (SS & NTU reduction)

Ultra filtration (removal of colloidal of size 0.01microns)

Reverse Osmosis (Removal of dissolved particles of size 0.0001microns)

Storage / Export to Refinery

Cartridge Filtration ( Removal of chemical and other dusts of size upto 10 microns)

Chemicals

BIOLOGICAL TREATMENT

•Aerator : Continuous growth of MLSS (Livingmicro organism) and diffusion of oxygen.The micro organism consumes organicand inorganic load in feed water. (Resultsin BOD & COD reduction and alsoammonia reduction through nitrification).

•Clarifier: The sludge ( MLSS ) is settled. Ammoniaremoved through denitrification.

(Note : Sequential batch reactor combinesboth the operation in a single unit in SRP-2)

CHEMICAL TREATMENT

• Hydro Treater High rate clarifier : coagulation

of suspended particles and phosphates by addtion

of ferric chloride and flocculation by addition of

anionic poly electrolyte

• Chlorination Break point chloriantion:

Disinfection of bacteria and removal of residual

ammonia by conversion to chloroamines

FILTRATION

• Pressure Sand / Multimedia Multi grade filters :

Removal of particle size upto 0.45 microns and iron thereby

reducing Suspended Solids (SS) & Trubidity (NTU).

• Pressure sand filters loaded with grades of pebbles , coarse

and fine sand

• Multimedia filters have additional layer of Anthracite for

polishing

CARTRIDGE FILTRATION

• Removal of chemical dust due to addition of Hydrochloric

acid, Sodium Bi sulphite and Antiscalants and dust from

feed tanks (up to particle size 10 microns)

• The cartridge filter is of spiral wound and thread type and

the thread made of Poly propylene or polyethylene material.

ULTRA FILTRATION

• Removal of colloidal

particles up to 0.01 nm size

thereby reducing the Silt

Density Index (SDI) of RO

feed water.

• The Ultra filtration

membranes are made up of

Polysulfones material

• In SRP-1 alone the UF is of

Cross flow filtration type

(with reject) and in all other

units of Dead end filtration

(without reject)

COST FOR DIFFERENT SOURCE WATER

Sl.

No

Source of water Cost per Kilo litres

in Rs.

1 Surface Water (KPS – 270 MLD) 5.48/-

2 Surface Water (Red Hills – 300 MLD) 4.78/-

3 Surface Water (Veeranam – 180 MLD) 10.50/-

4 Surface Water (Chembarambakkam- 530 MLD) 8.04/-

5 Surface Water (Surapet – 14 MLD) 5.11/-

6 Ground Water (Well Fields – 15 MLD) 28.72/-

7 Desal Water (100 MLD) - DBOOT 48.66/-

8 Desal Water (100 MLD) – EPC

(To be on stream by 2012)

20.64/-

* Total Water Treatment Capacity available = 1400 MLD