IIT alumnus shows natural way to process waste water

It is a simple technology that ranks high on sustainability. Soil Bio Technology, a recycling technology featured at the Municipalika 2012 exhibition uses fundamental natural processes such as photosynthesis, soil respiration and mineral weathering to purify waste water.

Avinash Kadam, who holds a PhD in waste water treatment from IIT-Bombay, came up with the technology which has been patented by the institute and is marketed by his company Sugam Paryavaram Vikalp.

His system consists of a waste water tank, bioreactor containment and a treated water tank along with the associated piping and pumping mechanisms. "The system is sustainable as it uses locally available geological materials to purify water. This means the construction of a recycling plant will differ from state to state," says Kadam. "In Tamil Nadu, we would probably use laterite blocks to build the plant as laterite soil is naturally a good filter," he says. The water is not potable but can be used for gardening, construction and washing.

The system pumps the waste water over the bioreactor which consists of layers of geological media and microbial culture. When it trickles through the layers, it gets purified and treated water gets collected in the clean water tank. Typically, a garden can be grown over the bioreactor. Kadam says he has installed the Soil Bio Technology plant in more than 60 projects all over the country, including in university campuses, government buildings and airports. "This technology is being used in Bangalore to clean sewage water before it is discharged into lakes. We are setting up plants at seven lakes," he says.

Initial costs are high and a plant with a capacity of purifying 10 lakh litres a day will cost `1.2 crore to `1.5 crore. However, maintenance and operating costs are low. "It costs approximately `4 to purify 1,000 litres," said Kadam.