The Hindu         02.03.2011

Corporation sewage treatment plant inaugurated at Ukkadam

For cleaner environs: Rural Industries Minister Pongalur N. Palanisamy (third right) inaugurating the sewage treatment plant at Ukkadam in Coimbatore recently. Collector P. Umanath (fourth right), Mayor R. Venkatachalam (left) and Corporation Commissioner Anshul Mishra (second left) are in the picture. - Photo: M. Periasamy

The Coimbatore Corporation's sewage treatment plant at Ukkadam, which was inaugurated on Saturday, has achieved standards that are much higher than those prescribed by the Tamil Nadu Pollution Control Board, according to Commissioner Anshul Mishra.

State Minister for Animal Husbandry and Rural Industries Pongalur N. Palanisamy inaugurated the plant in the presence of Collector P. Umanath, Mayor R. Venkatachalam, Mr. Mishra, Superintending Engineer K. Boopathy, Chairman, South Zone, Pynthamil Pari, Assistant Commissioner, South Zone, Lakshmanan among others.

The plant, built at Rs. 55 crore under the Jawaharlal Nehru National Urban Renewal Mission scheme, has a capacity to treat 70 mld (million litres a day) sewage.

At present, the plant treats only about 20 mld of waste water which flows into it from the areas that already have underground drainage system.

Mr. Mishra said the sewage treatment plant had been constructed based on the ‘Sequential Batch Reactor' (SBR) process, which was the most advanced method for sewage treatment. The technology required very less land vis-à-vis other technologies. And, the treated sewage had very low fecal Coliform and turbidity levels, meeting very stringent quality standards.

Mr. Boopathy said compared to conventional sewage treatment technology, the plant would treat sewage to a very high degree.

Gharpure Engineering and Construction Private Limited, Pune, had built the plant with technological input by SFC Environmental Technologies Private Limited.

M. Kumaraguru of SFC Environmental Technologies Private Limited said the sewage that flowed beneath the ground into the plant was first filtered using a 20-mm screen, pumped to ground, and then filtered using a 6-mm screen for removing grit. The filtered water was then pumped simultaneously in to four C-Tech basins for aeration.

Bacteria, during the process, would break down the compounds for about an hour-and-a-half. The treated sewage was then allowed to settle down for 45 minutes, by which time the heavy waste would settle down at the bottom of the tank and the fresh, treated water rose to the top. The water was then decanted and pumped to another tank.

The sludge from the bottom was then taken to centrifuges for removing water and turning it into cakes, which could be used as manure. The water could be used for non-drinking purposes – agriculture, gardening, construction, washing, etc.

The Coimbatore Corporation has designed the tank for 70 mld, for lasting up to 15 years. It has decided to adopt the very same technology at the Nanjundapuram sewage treatment plant, yet to become operational.