BBMP is considering setting up mid-size biogas plants in every ward to process wet waste

Virulent protests against the waste processing units in the city seem to have forced the Bruhat Bengaluru Mahanagara Palike (BBMP) to change its strategy from large processing units to decentralised ward-level biogas plants. Mid-size biogas plants in every ward to process wet waste are likely to be the future of garbage processing in the city.

While Bengaluru has adopted a ‘no landfill’ policy and moved to a processing strategy, the combined capacity of the six processing plants in the city is 1,800 tonnes a day. The estimated generation of wet waste is 2,500 tonnes a day. The ward-level biogas plants are being planned to fill this gap locally.

Multiple studies have put the average wet waste generated by a ward at around 12 tonnes a day. According to BBMP sources, a biogas plant with a capacity of 12 tonnes will cost about Rs. 3.5 crore and require 12,000 sq ft of land.

BBMP is working on a model to provide the land, and has asked all the councillors to identify suitable plots in their wards. The private investors would have to put up the plant under the ‘Build, Own, Operate’ (BOO) model, and they will get to recover their investment by selling the biogas generated.

The biggest hurdle would be the limited availability of land, especially in the core parts of the city, BBMP officials concede.

“We will first begin with biogas plants in the outer zones, where earmarking land will be relatively easier. The core city is a challenge which we will try to handle later. Even if we manage to put up biogas plants in half the wards, we can effect a paradigm shift in waste processing in the city,” said N.S. Ramakanth, member, Expert Committee on Solid Waste Management, BBMP.

Though biogas plants run on anaerobic fermentation model (airtight) and don’t emanate foul smell, the officials are not discounting resistance towards setting up such plants in residential localities.

“This is being accounted for and a standard operating procedure is being drawn up. What needs to be standardised is how the streams of waste, including pineapple, that cannot go to a biogas plant are handled. Care needs to be taken to prevent dumping of garbage at these plants,” a BBMP official said.

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WHAT GOES WASTE

Total: 3,500 tonnes/day

Wet waste: 2,500 tonnes/day

Dry waste: 1,000 tonnes/day

Waste processing capacity

Plant Capacity per day (in tonnes) Lingadheeranahalli 200 Doddabidarakallu 200 Subbarayanapalya 200 Seegehalli 200 Kannenahalli 500 Chikkanagamangala 500 Total 1,800

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IN A NUTSHELL

* Most waste processing plants are facing opposition from locals

* There is a capacity deficiency of 700 tonnes of wet waste a day

* BBMP is moving towards biogas to fill the gap

* Average wet waste in each ward: 12 tonnes a day

* A biogas plant will need around 12,000 sq ft space

* BBMP will provide land, investors can sell biogas produced

* Biogas plants won’t emanate foul smell

* Biomethenation plants a big success in the city for handling waste from hotels and eateries

Subodh Yadav, Special Commissioner, Solid Waste Management, BBMP: We are working on the modalities of the scheme. The project, which will be taken up in collaboration with local RWAs (resident welfare associations) and others, will ensure no waste leaves the ward. It will make it a zero-waste ward.

N.S. Ramakanth, member, SWM Expert Committee, BBMP: The only efficient way to deal with waste is by decentralising management. Why should a village on the outskirts take the city’s waste? We need to take responsibility of our waste, process it in our ward itself. Biogas plants are our best bet.”

Taking care of leaf litter

The civic agency is also looking to set up leaf litter compost plants in all wards of the city. These units can be set up in smaller spaces, say around 400 sq ft. BBMP is likely to set them up within public parks.

The major technical infrastructure needed for these hyper-local compost plants is leaf shredders. Leaf litter is usually shred into a fine powder, which will speed up the process of composting. “A leaf shredder costs around Rs. 4 lakh. We are planning to buy a shredder for every three or four wards, and set up a cluster management system,” a BBMP official told The Hindu.

At present, leaf litter from across the city is being transported to the Karnataka Compost Development Corporation (KCDC) plant in H.S.R. Layout and the the MSGP plant in Chigarenahalli, Doddaballapur.