Govt mulls waste to Bio-CNG conversion plant near Dhapa

The state Urban Development and Municipal Affairs department has conceived a project of conversion of waste to Bio-CNG without any exposure to environmental release of carbon dioxide using a most efficient tool of controlling Biochemical Oxygen Demand (BOD).

The project will be implemented by the Kolkata Municipal Corporation (KMC) with a funding of Rs four crore from the Municipal Affairs department.

"We are consistently trying to explore all avenues to address the multi-faceted problems of management of solid waste as there is lack of space in dumping grounds. After movable and stationery compactors, we are now going for generation of energy out of waste," Firhad Hakim, state Municipal Affairs minister said.

A top official of the department said that significant amount of organic waste is generated everyday in the city from various fruits, vegetables and flower markets that results in creating unhygienic condition within and around the markets.

"Systematic treatment and disposal of this waste are essential while recovering energy and fertilizer from it. In this project, two to three markets with

capacity of five metric tonne per day have been identified for the pilot project," the official said adding that it will be further expanded to 25MT per day.

Vegetable market waste will be converted into raw biogas first and then will be purified into Bio-CNG and Bio Carbon Dioxide. Bio product carbon dioxide will be captured and used to grow algae to treat waste water by reducing the BOD.

According to the official, using algae to treat

waste water is a more efficient way of controlling BOD

than the conventional aeration system.

The algae will then be reused as a feed stock in the anaerobic digester to allow more carbonaceous feed stock which is otherwise difficult to process. Finally, the end product will be used as fertilizer. "Around 100 kg Bio-CNG per day will be produced by using five MT organic waste per day,"he added.

One acre land in Dhapa available with KMC has

been identified for carrying out the project.