Consultant hired by Metrowater likely to complete study of Chennai’s sewerage network by November

Metrowater hires consultant to study, recommend improvements to decades-old sewerage infrastructure in Chennai. To tackle recurring issues of choked pipelines, water contamination and sewage overflows, consultant to identify affected areas and suggest upgrades. Metrowater to use machinery to desilt sewers before monsoon to reduce overflows.

To keep pace with the growing demand, Metrowater has hired a consultant to study the decades-old sewerage infrastructure in the city and recommend improvements, and this exercise is expected to be complete by November.

The city’s core areas face recurring issues of choked sewer pipelines, water contamination and sewage overflows, which peaks during the northeast monsoon. The water agency hired a consultant to assess the existing condition of its sewerage infrastructure. The consultant will have to identify chronically affected areas and recommend improvements to the infrastructure, be it the upgrade of pumping and lift stations or pipelines, an official said.

Currently, Metrowater operates a sewerage system comprising pipelines running for a length of 4,500 km, 302 pumping stations and 13 treatment plants. The agency will chalk out schemes, including increasing the capacity or building new pumping stations and enlarging the capacity of the old sewer lines, based on the detailed project report to be submitted by the consultant. “We will have to decide on a funding tie-up for the projects. Work will commence during the next fiscal after this is finalised,” an official said.

Earnest Paul, president, Royapuram Residents’ Welfare Association, said many areas in north Chennai, such as Royapuram, Parrys and Mint, still had pipeline networks laid during British rule. There was a dire need to replace the old pipes with more than double their present carrying capacity in densely-populated localities such as Aaduthotti and Meenakshiamman Pettai.

Some of the pipelines that burst in K.K. Nagar were over four to five decades old. Officials said nearly 590 million litres per day (mld) of sewage is treated at plants that have a total capacity of 745 mld. The pipeline network gets an additional 50-100 mld of rainwater pumped during the monsoon, which leads to more pressure and pipeline bursts.

The study will bring solutions to problems such as ageing infrastructure and inadequacies in the sewage collection network. The system, designed in 1914 to cater to a projected population of 6.5 lakh in 1961, has changed and expanded over the decades. The comprehensive study now looks to modernise the entire system. At present, 90% of the pipes are made of cast iron in the deep sewer network, officials said.

Metrowater plans to use machinery to desilt the sewers at night ahead of the northeast monsoon to minimise sewage overflow and blockage, officials said.