Bengaluru: Roadblocks in trash-to-power push

Bengaluru has just begun its waste-to-energy journey, but poor segregation, logistical inefficiencies and lack of emission monitoring can hinder this transition

Bengaluru: Located off the Bengaluru-Mysuru highway in Medanahalli near Bidadi, Karnataka’s first waste-to-energy plant—and India’s 11th—spans a sprawling 160-acre site. The plant with an 11.5 MW capacity reached 11.3 MW, all emission parameters blinking in green, while the DH reporters on a guided tour of the premises watched the overall process.

The Rs 310 crore project is funded jointly by Karnataka Power Corporation Limited (KPCL) and the Bruhat Bengaluru Mahanagara Palike (BBMP). The BBMP has paid Rs 130 crores as of now, with Rs 25 crores pending. The BBMP also agreed to provide 600 tonnes of quality dry waste with good calorific value (burning capacity) to the plant. This is also called refuse-derived fuel (RDF), which consists of nonrecyclable plastic, paper, cloth and anything burnable. 

In the absence of solutions, this would go to a landfill, but finding land for landfills has been a challenge. Existing landfills have faced protests, disruptions and litigations now and then due to the environmental hazards they pose. The plant was conceptualised as a solution.

Inside the plant

Satish Kumar H, executive engineer of the plant, says the waste should have less than 25-30% moisture content—a condition the BBMP is meeting. He says the maintenance is more for this plant, due to too many variables in the refuse-derived fuel (RDF). Light diesel oil is used to start the fire when the plant is inevitably shut down for maintenance.

The waste is dumped into the waste pit, where it is allowed to stay for days, helping the waste get rid of its moisture content through leachate. A leachate treatment plant on the premises treats this leachate.

The waste from the waste pit is fed into the combustion zone and burned using the Great Incineration method, with the help of a Japanese firm. In this process, the waste is burned at a temperature exceeding 1000 degrees, thereby reducing the risk of dioxin and furan emissions that are common when plastics are burned at temperatures below 850 degrees.

The residual goes out as bottom ash, and fly ash is collected separately. The heat inside the furnace produces steam, which is used to generate power. The power goes to the nearby grid. “We can light up 25000 homes,” says Satish Kumar.

The emissions are filtered through activated carbon and cooled to 80-90 degrees before being released to the atmosphere, says Satishkumar. The emissions abide by the Central Pollution Control Board (CPCB) and the Swachh Bharat mission norms and are directly monitored by the CPCB through a live monitoring system, he says.

“We have burned 1,00,856 tonnes of waste until now, and have produced 14822 tonnes of bottom ash and 2061 tonnes of fly ash to date. This means we have saved that much landfill space,” says Satish Kumar. He says the KPCL plans to use the bottom ash and fly ash in road construction instead of sending it to the landfill.

“It’s not like other thermal power plants. It should be run in a disciplined way,” he says. The lessons were learned the hard way after the unfortunate accident on January 4.

Metal or hard, non-combustible materials in the waste can cause the bottom ash conveyor to jam, requiring regular manual clearing. During one such clearing operation, five workers were fatally injured when metal clinkers were ejected and struck them. “Even metal springs from beds can cause such jams,” says Satish Kumar, emphasising the importance of receiving clean RDF.

After an extensive review of the accident at multiple levels, standard operating procedures and processes have been established to prevent such accidents in the future, says Satish Kumar.

Issue of dry waste collection

Lokesh M, chief engineer of Bangalore Solid Waste Management Limited (BSWML), says the contractors drop the dry waste rejects in dry waste collection centres across Bengaluru. This is collected and transported to the WTE plant.

This system is not perfect as of now. Mansoor, a dry waste collection centre (DWCC) operator from Jayanagara working with an NGO, explains one side of the problem of the broken collection system. Multilayer plastic (MLP) collected by his DWCC, which is not recyclable, is being sent to the power plant.

However, “the BBMP is providing only open lorries (tippers) and not compactors equipped with excavators to transport the waste, the DWCC operators have to manually fill the material or hire a JCB excavator to do it. We have been asking the BBMP to provide us with JCBs or compactors to transport this waste,” says Mansoor. 

Out of the 165 DWCCs in the BBMP limits, Mansoor says that 79 operators recently gathered to discuss problems and submitted a letter to the BBMP, requesting payments and incentives for collecting rejected dry waste, such as MLP. 

DWCCs also await inclusion in extended producers’ responsibility, as they collect and sort the dry waste. “The BBMP used to pay DWCC operators Rs 37,051 per vehicle for collecting waste and managing it. After a few changes in the payment amount and conditions, they are no longer paying us to collect dry waste,” says Mansoor.

According to BSWML officials, the value for recyclables covers the cost of this work; hence, there is no payment. Mansoor argues that recyclables do not fully compensate for the job done, which is why DWCCs struggle to manage.

The larger picture

Mansoo says until now, about 90 tonnes of MLP have been sent to the plant. However, when the overall quantity of waste the plant needs is considered, the amount of multilayer plastic is relatively small.

As per Lokesh, the city produces 53% of wet waste, 40% of dry waste and 7% of rejects. Out of the approximate 5,000 tonnes of waste the city produces, 3,200 tonnes of mixed waste go to Bellahalli landfill every day. This is mud-capped and maintained, which will be open to biomining at a future date.

Waste getting shifted from waste pit to the incineration section inside waste-to-energy plant in Bidadi.

More than 1000 tonnes of what is supposed to be wet waste go to BBMP’s seven wet waste processing plants, which have a processing capacity of 1570 tonnes per day and can produce 471 tonnes of RDF per day if functioning optimally. Machinery breakdowns, local factors, and protests have halted the operation of these plants in the past, and can happen in future as well if not properly maintained.

The RDF produced here and the dry waste from DWCCs go to the WTE plant, while the rest of the 600 tonnes is managed with the legacy waste from Mandur, where biomining is taking place. 

Segregation is the key

The plant that began trial in July 2024 is yet to be formally inaugurated. All seemed well inside the plant, and everyone agreed so. Yet some things need attention. Bengaluru’s system for collecting, transporting, and processing waste has been evolving, yet it remains stuck in a loop. 

Satish Kumar says this is a solution to a larger problem and not a profitable project. A better segregation at source and a foolproof collection and transportation system from the BBMP would ensure better waste quality and less burden to the plant, he feels.

Power plant operators monitoring the waste incineration and power generation process.

Lokesh also seems unhappy about the quality of waste segregation. He suggests that better segregation at the source by citizens would alleviate the burden on waste collectors, who currently handle it or put it in the mixed waste and send it to the landfill.

Priyadarshini Karve, Convener of Pune-based Indian Network on Ethics and Climate Change (INECC), calls waste-to-energy a myth in most cases, when the energy spent on collecting and transporting the unsegregated waste, and the energy required for operating the incinerator, is accounted for.

“There are technologies where the incineration is genuinely clean, but both capital and operating costs are high. Even if such an incinerator is installed, there is a tendency to operate it at suboptimal conditions to save money on operations,” she points out.

“The lack of monitoring and corruption inside pollution control boards indirectly encourages malpractice. The only sustainable solution is to promote waste minimisation and waste segregation at all levels. Incinerators are technological fixes that appear to solve the problem, but are no substitute for the effort required for the systemic change,” she cautions.