Eight waste water treatment systems will come up around Periyakulam, Selvachinthamani and Valankulam lakes in the city. These systems, to be set up under the first phase of the lake restoration project under the Smart city mission, will be eco-friendly and require minimal construction and space, as per the city corporation officials.
Approximately, 63.5MLD of waste water enters all the eight lakes of the city every day. There are 43 inlets in the eight lakes. Most of the contamination is from septic tank overflow, bathroom waste water and kitchen waste water.
As the second phase of discussions on the smart city projects commence, the corporation is all set to construct these sewage treatment plants. One treatment plant on Singanallur lake will also be set up under the second phase of the project.
Regional manager (Tamil Nadu) of Consortium for DEWATS Dissemination Society (CDD) Andrews Jacob said, “These waste water treatment systems does not necessarily mean concrete structures using space and electricity. We have only opted for eco-friendly techniques. Wherever the water contamination is higher, we will set up some underground structures using biological treatment methods. Various technologies have been developed by IIT and other institutions that only involve construction of an underground space. The top surface can be used as parking space. Decentralized waste water treatment system (DEWATS) is a passive system. It uses microorganisms which will disintegrate the organic content of waste water. It takes around 30-40 hours.”
In some inlets where water contamination is lesser, primary and tertiary treatment methods such as filtering drain water, setting up of floats, wetland based treatment, bio swales and other methods that naturally treat the contaminated water will be used.
The team members of Oasis Designs Inc and CDD, consultants for the project, said that they conducted field study over a period and found the pattern, quantity and quality of the water entering these lakes. “So based on this, we are using only the locations where space is available. Structures will only be set up at locations where the pollution level is comparatively higher,” said P G Ganapathy, senior advisor of CDD.
He added that the quality of water will improve once these interventions are carried out. “Growth of hyacinth will stop. They will not only ensure the water quality but the lake will also have water during the dry season of the years as well. The lakes will become a place where people can come for recreation. The treated water will be discharged into the lakes and this water will be further treated using floating wetlands. Good quality water will also ensure increased ground water tables,” said Ganapathy.
Corporation officials said that apart from these sewage treatment plants, the decentralized plants constructed in the apartments, gated communities and residential welfare associations will also be connected to them to ensure the drains carried only good quality water. The commissioner of municipal administration and the city corporation commissioner who attended the meeting said that once the financial aspects are worked out, the projects will receive technical sanction.