Tamil Nadu government is planning to have underground sewage network
in all the 126 municipalities, nine corporations and 529 town panchayats
in the next five years, according to a senior engineer with
corporation.

A Vaitheesswaran, CADD engineer and a research
scholar with Madras University, presenting his finding during a brain
storming session on recent challenges and innovations in environmental
management organised by department of geology, said that currently only
20 municipalities have underground sewage network and the state
government plans to have a sewage network in all the municipalities and
town panchayats in a phased manner in next five years.

The study,
which was a result from findings from six municipalities including
Valasaravakkam and Alandur (now under Chennai Corporation) besides
Kancheepuram, Sathur, Periyakulum and Madurai, stated that the planning
of sewerage network was done with unrealistic population projection and
it does not match local condition of population growth.

The study
stated that currently each house is provided with independent water
storage tank by keeping one sump and one overhead tank. Hence minimum
two days demand of water is stored in each house.

As a result the concept of hourly water utilisation differs from the hourly water utilisation prescribed by the municipality.

As
a result this puts huge pressure on the sewerage network in the
municipalities, he added. To handle such a huge flow, the pipe needs to
be designed with proper peaking factor.

Dr Karthikeyan, joint chief environmental engineer of Tamil Nadu Pollution Control Board, also spoke on the occasion.