Waste to watts: Green energy generated from food leftovers in Pune city
Biogas generators save power costs and waste collection fees
Until four years ago, garbage
disposal meant one thing to Savitri Bai Patil — stinking, putrefied heaps of trash spread around her neighbourhood in Pune, in western state of Maharashtra.
But now the streets of the Ashok Meadows housing complex where she lives are clear, with workers picking up garbage from residents’ doorsteps each day and turning some of it into electricity.
Since 2017, the complex has fed its food waste into a digester that converts it into biogas used to light the area’s street lights, park, social club and gym.
“Clean energy from our rancid food leftovers, vegetable peels and other such throwaways? It is unbelievable how the concept of waste management has changed in the past few years,” Bai Patil, 62, told the Thomson Reuters Foundation.
Biogas generators like the one used in Ashok Meadows are now installed in more than 75 locations across India.
Developed by Xeon Waste Managers (XWM), based in Pune, the EnergyBin systems let communities turn waste into free, renewable energy, said company president Jalaj Kumar Chaturvedi.
Piling up waste
“It is a common sight to find overburdened landfills with garbage that grows by the day. But since these EnergyBins dispose of the waste at the source itself, the landfills are spared,” he said.
According to Ashok Meadows resident Rishika Mahalley, the complex’s system — operated and maintained by residents — has helped solve the problem of how to dispose of the nearly a tonne of garbage produced each day by the complex’s 550 homes and common areas. Before the community bought the generator at the cost of Rs2.3 million ($31,000), it struggled with unreliable municipal garbage collection, which often left waste piling up, Mahalley noted.
But “we have now gotten rid of the buzzing flies, scourge of mosquitoes and other insects, besides of course the stink that came from the vats where the garbage would be left until the municipal vehicles arrived to collect them,” she said.
Food to fuel
Each day, waste pickers paid by the Ashok Meadows residents put between 550kg and 600kg of food waste into the biogas plant, Mahalley said. As the organic matter breaks down it produces a flammable gas made up mainly of methane and carbon dioxide.
The methane is then pressurised and piped into a power generator that burns the gas to convert it into 50 kilowatt-hours of electricity for the community each day.
Mahalley said before the plant was installed the complex spend about Rs550 a day on electricity for street lights and other common facilities — a cost that has now virtually disappeared. It also saves the residents up to Rs6,000 ($82) every month on municipal garbage disposal costs, she said.
It is a common sight to find overburdened landfills with garbage that grows by the day. But since these EnergyBins dispose of the waste at the source itself, the landfills are spared.”
Jalaj Kumar Chaturvedi | XWM manager
Climate change
The biggest benefit of biogas plants is their ability to reduce emissions, said Jitendra S. Sangwai, a chemical engineering professor at the Indian Institute of Technology Madras in Chennai.
In particular, such technology can curb emissions of methane gas, a potent shortterm driver of climate change.
While many small-scale biogas digesters are in operation around the globe, for now the costs and climate benefits of large biogas generators like EnergyBins are limited to communities that can afford them, Sangwai added.