The Hindu 25.04.2013
State’s first tertiary treatment plant for sewage at Koyambedu soon
Chennai Metrowater will soon own the first-of-its-kind
tertiary treatment plant in the State. The agency is in the process of
finalising the design and treatment process of the facility that will
reduce the amount of treated sewage let into waterways and also improve
supply to industries.
The six-acre facility will be
added to the existing sewage treatment plant in Koyambedu to treat the
sewage another time to make it fit for industrial use.
The
consultant, Engineers India Limited, is collecting data on the process
to treat the sewage and also finalising the route to take the treated
water from the plant to the industrial belt in Irungattukottai,
Sriperumbudur and Oragadam.
Metrowater sources said
the plant would reduce biochemical oxygen demand (BOD) and chemical
oxygen demand in sewage to almost nil, a requisite for it to be used in
industries. In the secondary treatment plants in Koyambedu, the BOD is
reduced to 20 mg per litre from the nearly 350 mg/l found in the raw
sewage.
The consultant is preparing a detailed
project report for the plant a capacity to treat 45 million litres of
sewage a day. “The design will be such that 60 mld of sewage can be
treated in the future,” said an official.
The
Koyambedu sewage treatment complex has two units that treat 94 mld. At
present, the water agency supplies 37 mld to industrial units in Manali
belt. Nearly Rs. 20 crore is generated through this. In order to meet
the growing industrial demand, it was decided to recycle the water and
provide it to the industries. The treated sewage will be conveyed
through a 60 km pipeline to the industrial parks.
The
consultant must also come up with project cost estimate and plans for
funding pattern. The production cost of the treated water is estimated
to be Rs.60 per kilo litre. The detailed project report and preparation
of bids are expected to be completed in five months. Work on the
tertiary treatment plant may start early next year.