- Chennai MetroWater Supply and Sewage Board
Chennai Metropolitan Water Supply and Sewage Board Type Public Sector Undertaking Industry Water Supply, Sewage, Sewage Treatment, Desalination Founded 1978 Headquarters Chennai, Tamil Nadu, India Area served Tamil Nadu, India Products Water Website 
Chennai Metropolitan Water Supply and Sewage Board known as CMWSSB to provide Water supply and sewage treatment to the city of Chennai and around areas of Chennai.
Chennai is one of the metros in India which is dependent mostly on ground water supply. Ground water in Chennai is replenished by rain water and average rainfall in Chennai is 1276 mm. Chennai receives about 985 million liters per day (mld) from various sources against the required amount of 1200 mld and the demand is expected to rise to 2100 mld by 2031. The newly constructed Minjur desalination plant adds another 100 mlds to the city's growing demand.
The Veeranam Water Supply Project was implemented as additional source of water to Chennai City. The Project was commissioned in the year 2004 to supply 180 MLD of water to Chennai City by drawing water from Veeranam Lake. This lake receives water from Cauvery River system through Kollidam, Lower Anicut and Vadavar Canal besides rainwater from its own catchment area. The capacity of the lake is 1465 Mcft. The lake water is treated at Vadakuthu Water Treatment Plant by pumping raw water at a distance of 20 km. from Sethiathope to Vadakuthu through 1775 mm dia mild steel pipe. The treated water is then pumped at a distance of 8 km. to Break Pressure Tank at Kadampuliyur through 1750 mm dia mild steel pipe and from there the water is conveyed to a distance of about 200 km. through the mild steel pipe of 1875 mm and 1500 mm dia by gravity to Porur Water Distribution Station near Chennai. From this Distribution Station, water is pumped to a distance of 1.2 km. and distributed to Chennai City through Trunk mains and Water Distribution stations.
Reverse Osmosis & Desalination
Chennai has Reverse osmosis plants namely at Velachery,Nochikuppam,Kasimedu, Ayodha kuppam. It takes raw Brackish water from bore wells , stores in tanks and then it purifies before supply.
Desalination plant is located in at Kattupalli, Minjur.The Chennai Water Desalination Limited(CWDL)is setting the plant infrastructure and maintaining the plant for 25 years as per agreement between CWDL & CMWSSB. The CMWSSB purchase water from them and supplies to the city network through Madhavaram Booster Station.
In an effort to alleviate the woes of chennaiites, Tamil Nadu Government has forged into projects acquiring fresh water by desalinating sea water. The first such desalination plant located in Chembarambakkam has a capacity of 530 mld. The second plant was built in 60 acres (240,000 m2) in Kattupalli village near Minjur about 35 KM north of Chennai. Minjur desalination plant which supplies 100 million litres a day water to Chennai city was inaugurated on July 31, 2010. Chennai is constructing another water desalination plant at Nemmeli.
The Water Treatment Plants are:
- Kilpauk Water Treatment Plant: 270 MLD
- Puzhal Water Treatment Plant: 300 MLD
- Vadakuthu Water Treatment Plant (Veeranam Lake source): 180 MLD
- Chembarambakkam Water Treatment Plant: 530 MLD
Chennai City Sewage System was designed in 1910 for an estimated 1961 population of 6.6 lakhs. A comprehensive improvement to the city sewerage system was designed in 1958 for an estimated 1976 population of 25.5 lakhs and 1991 population of 27.2 lakhs at a sewage flow rate of 110 lpcd in 1976 and 180 lpcd in 1991; the city was also divided into five zones with proposals for five independent disposal works. It was planned to isolate the system of collection, transmission and disposal of sewage in each zone in order to obviate the difficulties of the relay system. Presently the sewerage network in Chennai city has covered 98% of its area. As the capacity of sewers was limited, during rainy days they became surcharged due to ingress of storm water. Any surplus of sewage in excess of pumping stations capacity was drained into the nearby natural water courses of the city viz. Cooum river, Adyar river, Buckingham canal and Otteri Nalla.
Rain Water Harvesting
The importance of conservation of water and rainwater harvesting can not be understated. While issuing Planning Permission for construction of major developments such as flats, residential developments, office, shopping and other commercial complexes, the condition to provide rain water-harvesting structures within the premises was put and ensured to be provided before issue of Completion Certificates. Provision of rainwater structures in all types of developments, irrespective of size or use was made mandatory by amending DCR and Building Byelaws in the year 2001, not only for the buildings proposed to be constructed but also for all the existing buildings. After implementation of this scheme widely in CMA, a significant increase in the ground water levels and also quality of ground water was noted.
The water quality in Chennai is a long way to reach International standards as outlined in this study published on April 2007. Researchers from National Environmental Engineering Research Institute, Chennai Zonal Laboratory, Chennai found Cryptosporidium oocytes in Chennai water. Cryptosporidium is an enteric parasitic protozoan capable of causing diarrhea.
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