Arrangements for sewage treatment to ensure the greenery

CHENNAI: Four parks under Smart Cities that have a water requirement of 10,000 litres for daily maintenance will be getting sewage treatment plants (STPs) to reduce dependency on external water supply, especially during the summer months.
Four STPs of 40,000 litres, 20,000 litres and 10,000 litres have been planned for Natesan Park, Jeeva Park, Kodambakkam Park and CIT Nagar Park, tenders for which have been floated by the city corporation, according to officials. “The STP plants will tap the underwater sewerage system for daily water requirements. The process to convert raw sewage into treated water will remove floating material and oil from the water in the sewers and it will undergo anaerobic breakdown,” said a senior official.

A Moving Bed Biofilm Reactor (MBBR) uses multiple conveyors to change suspended organics to dissolved organics, and also begins the decay latter. The suspended solids will be removed using a secondary clarifier in the next stage. Secondary treated sewage will be further treated using chlorine. The settled sludge is sent for recirculation to the equalisation tank. The dry sludge coming out of the system can be used as manure.

According to officials, this will be rolled out to other parks in a phased manner, so that the dependency on water supply for gardening and park maintenance can be reduced. Anna Nagar Bougainvillea Park and Herbal Park in Otteri already have such STPs in place with the latter making use of sewage water from the OtteriNullah. The 10KL, 20KL and 40KL plants will be set up at a cost of Rs 29lakh, Rs 35 lakh and Rs 40 lakh respectively.