Bengaluru: Waste processors need bio-filters to quell the stink

BENGALURU: While all the seven waste processing units commissioned to tackle the city's garbage are located close to residential localities, the civic corporation's plans to use bio-filters to quell the bad odour emanating from them are far from ready . Biofiltration is the process by which pollutants that are released into the atmosphere are made to pass through a layer of micro-organisms that break them up and eliminate the odour.

The state government, under pressure to deal with the garbage crisis, spent Rs 440 crore to set up municipal solid waste management units at seven locations -Sigehalli, Kanahalli, Doddabidarakallu, Subbarayanapalya, Chikkanagamangala, Lingadheeranahalli and an extension of the Karnataka Compost Development Corporation (KCDC) unit near HSR Layout. They have a combined capacity to handle 2,600 tonne of waste every day . A backlash from HSR Layout residents over the bad smell prompted authorities to announce in last November that bio-filter systems would be installed in the unit.

As a pilot, four bio-filters were installed at the KCDC unit but are of little use without ducting. The civic body has issued a show-cause notice to the contractor responsible for the ducting work.

The initial deadline to get this up and running was February 18 but was extended to February 29, March 15, March 30 and April 25. “While the filters are ready , ducts to suck the odour remain undone. We are tracking the progress every day,“ said Subodh Yadav , BBMP's special commissioner for solid waste management.

In fact, the BBMP's expert committee on solid waste management has distanced from the bio-filter pilot. “We weren't consulted about this,“ committee member NS Ramakanth said.

Authorities claim that this is the first time a civic body is using bio-filters in municipal solid waste management.“The filters have been designed by the Indian Institute of Science Education and Research in Thiruvananthapuram,“ Yadav said. “Once the KCDC pilot takes off successfully , bio-filters will be installed in the remaining six units.“

Bio-filters are widely used in Europe and other parts of the world primarily for odour control at wastewater treatment plants and composting units.“Bio-filters are compulsory wherever there is a biological odour,“ said Hoysala N Chanakya, chief research scientist at IISc's Centre for Sustainable Technologies. “I see no reason why they won't be successful in Bengaluru.“