Residents raise concerns of sewage pollution in clean stretch of the Cooum river near Putlur check dam

A clean stretch of Cooum river near Putlur check dam in Tiruvallur district, located about 40 km from Chennai, is at risk of degradation due to sewage inflow. Residents charge that the pollution could undermine efforts to store freshwater in check dams and restore the river downstream.

Urbanisation and the absence of a proper sewage disposal system in Tiruvallur have been plaguing the clear stretch of the river for the past few years. The dysfunctional Periyakuppam sewage treatment plant (STP) compounded the issue of raw sewage polluting the river near the check dam, said residents of Manavalan Nagar in Tiruvallur.

D. Anandhakrishnan, a resident of Manavalan Nagar, said sewage was released into the river through stormwater drains and inlets linked to the STP from areas such as Bagirathiammal Street.

The check dam in Putlur helps areas abutting the river to tide over water crisis.
| Photo Credit:
B. JOTHI RAMALINGAM

“The check dam in Putlur helps areas abutting the river to tide over water crisis. Groundwater is available at a depth of 10 feet in these areas. But its quality is steadily declining as the river is choked with sewage,” he said, pointing out that the river was also an important source of irrigation.

Members of Manavalan Nagar Residents’ Welfare Association have submitted petitions stressing the need to treat sewage before releasing it into the river and prevent groundwater contamination.

Residents pointed out that the sewage treated in the STP was initially released into Putlur lake, and the surplus water flowed into the Cooum. The Tiruvallur municipality is now laying a pipeline to directly discharge treated wastewater into the river.

Aravind Chandramohan, a resident living near the riverbank, said several areas around the waterway were still dependent on groundwater. With raw sewage entering the river from areas upstream, groundwater has become coloured in areas such as Pillaiyar Koil Street. The local body has sunk borewells along the riverbed in the same stretch to supply water to various areas in Tiruvallur.

Residents demanded that the deficiencies in the STP be rectified and quality standards strictly monitored to arrest the discharge of untreated sewage and protect the river from becoming a sewage carrier. The downstream stretch between Sorancheri and Avadi are choked with water hyacinth.

With raw sewage entering the river from areas upstream, groundwater has become coloured in areas such as Pillaiyar Koil Street.
| Photo Credit:
B. JOTHI RAMALINGAM

Responding to the complaints, Tiruvallur municipality chairperson P. Udhayamalar said measures were being taken to control odour in the existing STP and incorporate advanced treatment technology. Another STP, being built at a cost of ₹10 crore near Putlur, would be commissioned in one or two months.

Pointing out various measures to safeguard the river, Poonamallee MLA A. Krishnaswamy said Bacillus bacteria-based chemicals were added to the treatment system to breakdown the pollutants, control odour, and improve wastewater quality. Efforts are under way to improve the performance of the existing STP.

Moreover, advanced soil biotechnology would be deployed to treat sewage and ensure quality of wastewater discharged into the river. A proposal is pending with the Water Resources Department to provide shutters in the check dam, he said.

Noting that the river has shown improvement in the past three months, officials of the WRD said the local body had been instructed to ensure quality of treated sewage remains within permissible limit.

The ₹13 crore project to install shutters in Putlur check dam, which will reduce siltation and help store more water, is under consideration, they said.