The Indian Express             25.11.2013

Civic body to use recycled sewage water for gardens

The Ahmedabad Municipal Corporation, which had so far been maintaining its 200-odd gardens with bore well water, has come up with a pilot plan to recycle sewage water to meet their needs. A prototype plant has been operating in Naranpura area for the past one month.

According to Municipal Commissioner Guruprasad Mohapatra, the pilot plant, having a capacity to process 10,000 litres of waste water a day, was set up by a private firm free of cost. Once this plant is fully operational, it will do away with bore well water for watering its gardens and nurseries as well as roadside plantations across the city.

The plant, set up over a less than 40 sq m area, is located near Navdeep Hall in Naranpura. The quality of water after tertiary treatment is below 10 mg per litre.

Explaining the process, Mohapatra said that the raw sewage would be taken from manholes of main trunk line to the storage tank, where three zones have been formed in closed tanks. Of the three zones, solid particles would be removed in the first zone. On reaching the second zone, water would be aerated before removing dissolved oxygen and conducting biological process. Suspended particles are settled in the third zone and suspended particles are removed.

"The recycled water would be chlorinated and then disinfected. This water is odorless, nutritious and ready for use," he said. He said that use of this recycled water will save both ground water and an estimated 40 units of power (worth Rs 200 a day), which amounts to around Rs 73,000 per year. Most importantly, this water is nutritious for plants. Use of this water will also reduce movement of water and its pressure on the main drainage lines This will also reduce movement of the quantity of sewage water via pipelines.