Low-cost maintenance, zero power consumption its advantages
CHENNAI: A residential apartment complex in Srinagar Colony, Saidapet, has been able to reduce its use of fresh water by adopting a low-cost waste water treatment process for six years now.
Like many other residential complexes in the city, it recycles grey water, but through a simple treatment system. The residents of the complex make use of a natural process involving canna (‘kalvazhai’) plants to filter grey water.
The row of canna plants in the backyard appears to be part of the garden. But, a closer look reveals the contribution of the plants to recycling of water used for kitchen and bathing purposes.
The grey water is passed through the canna bed, beneath which are layers of sand and blue metal. A polythene sheet at the surface prevents water from percolating to the ground. The roots of these plants help in decomposition of the suspended solids in the grey water and the sand bed further purifies the water. The clear water is then collected in a filter chamber and pumped to a separate overhead tank to be used for flushing toilets.
A resident V.H. Prasad said the complex that housed eight apartments recovers up to 700 litres of its total consumption of 1,200 litres of water daily using the system, which was devised along with Alacrity Foundation.
This has helped minimise use of groundwater and judicious use of water supplied by Chennai Metrowater.
Low cost maintenance and zero power consumption were the advantages of the waste water recycling process.
The investment cost would be less if the system is implemented when the building is constructed. Plantain and colocasia (yam) are the other plants suitable for such waste water treatment process, he said.
“Thanks to the process, a few years ago, we were able to tide over even a water crisis,” Mr.Prasad said.