From the ashes, emerges a green idea at Brahmapuram

On the evening of March 2, 2023, an inferno erupted in the mountains of plastic waste piled high at the Kochi Corporation’s waste treatment yard at Brahmapuram, located on the outskirts of the city.

For nearly a fortnight, flames devoured the sprawling dump, which mostly consisted of tonnes of plastic and non-biodegradable waste accumulated over a decade, along the banks of Kadamprayar, a critical freshwater source, sending plumes of smoke across Kochi’s skyline. The fire that released huge quantities of noxious gases and soot lasted for almost a fortnight lowered the air quality of the city to alarming levels. Hundreds sought medical assistance following respiratory issues.

When the fire was finally doused, a large area of the 110-acre plot at Brahmapuram in the Vadavucode-Puthencruz panchayat on the suburbs of Kochi city resembled a wasteland ravaged by war, leaving behind smouldering embers, acrid smoke and scorched earth so lifeless that it seemed even a blade of grass may never take root again.

Less than three years after the blaze, a 10-acre plot at the yard’s epicentre stands transformed beyond recognition, housing a Compressed Biogas plant, funded by BPCL-Kochi Refinery. It will be formally inaugurated by Chief Minister Pinarayi Vijayan on Friday (February 26, 2026).

Rising from the once-charred wasteland are three green domes. Two of them are, in fact, double-layered balloons mounted atop digesters, each with the capacity to treat 75 tonnes of municipal solid waste a day. The inner balloon inflates as raw biogas is generated, while the outer shell holds its form against inclement weather, ensuring the anaerobic functioning of the digesters with the help of a water column controlled by a blower. The third structure is a ground-mounted balloon — a specialised, collapsible storage membrane designed exclusively for biogas — with a capacity of 1,500 cubic metres.

Before the waste reaches the digesters — the heart of the gas generation segment — it undergoes an elaborate cycle of pre-treatment and feed preparation. Biodegradable waste collected from 177 centres across the city is first transported to the plant, where it is weighed on a 60-tonne electronic weighing machine. From there, the waste is tipped into a bunker in the pre-treatment area and carried forward on conveyors, passing through vibrators that separate non-biodegradable rejects. The segregated material is then channelled into a shredder and a bio grinder, which pulverises the waste into a fine slurry of 5 mm thickness. The slurry proceeds to the feed preparation stage where it is emptied into an unloading pit and mixed with an equal quantity of water. From there, it passes through intermediate tanks for further segregation, with fibrous content carefully removed. The slurry is then channelled into a hydrolyser tank, where the accelerated breakdown of organic matter takes place. Finally, it is fed into two digesters operating on a Continuous Stirred Tank Reactor system. Together, the digesters generate 5.6 tonnes of biogas each day.

Manure marketed by FACT

The digesters discharge 290 tonnes of Liquid Fermented Organic Manure (LFOM) and 28 tonnes of Solid Fermented Organic Manure (FOM) each day, which are channelled to a dedicated fertilizer shed for separation. Of this, 190 tonnes of LFOM are recycled within the plant itself, while the remaining 100 tonnes, along with the 28 tonnes of FOM produced daily, are marketed through Fertilisers and Chemicals Travancore (FACT).

“We have entered into a Memorandum of Understanding to market FOM through our distribution network. The application of such manure enriches the soil, facilitating better absorption of nitrogen and phosphorus, which in turn benefits crop yield. That is why petroleum companies have begun producing FOM products, and fertilizer companies are supporting them,” says Jeetendra Kumar, General Manager (Marketing), FACT.

Raw biogas generated by the digesters is stored in the ground-mounted balloon before being channelled to the purification unit. In its raw form, the gas contains 45–50% methane, 35–45% carbon dioxide (CO₂), and 0.1–0.4% hydrogen sulphide (H₂S). A water-scrubbing system is employed to purify the biogas, removing CO₂ and H₂S by feeding pressurised gas into a packed column while water is sprayed from above. This process enhances methane purity to 97%. The refined gas is then compressed to a higher pressure and transferred to the refinery at Ambalamedu, where it is converted into green hydrogen, explains the engineer.

Carbon emission down by 85,000 tonnes

When operating at full capacity, the plant will reduce carbon emissions by 85,000 tonnes a year, which is equivalent to planting 3.5 million trees and nurturing them for a decade, a BPCL official says.

Similar biogas plants are in the pipeline across several districts in Kerala. Projects being developed under the public-private partnership (PPP) model are nearing completion in Palakkad and Thrissur. “In other districts, the government will hand over the land, and the BPCL will establish the plant. A Memorandum of Understanding has already been signed for Kollam, and the foundation stone is set to be laid in Kozhikode, while similar facilities are under consideration in Thiruvananthapuram and Changanassery. We are pursuing a mix of centralised and decentralised waste treatment facilities. There will not be a complete shift to this model, but it will be advanced alongside the strengthening of decentralised systems,” remarks M.B. Rajesh, Minister for Local Self-Governments.

The Kochi plant, which entails an annual operational expenditure of ₹7.5 crore, is equipped with both in-built and external safety systems, including a dedicated fire-water network to tackle potential outbreaks. Company officials claim that this feature is unmatched.

Controlled burning of gas

The system, say the engineers, is supported by a four-lakh-litre capacity tank, a bore well capable of supplying 5,000 litres an hour, and a conventional well, with the Kadamprayar also serving as an additional water source. A flare mechanism ensures that gas is burnt in a controlled manner even if pressure rises beyond the prescribed threshold, he explains.

However, the Corporation had initially proposed a windrow composting plant at an investment of ₹150 crore under BPCL’s corporate social responsibility (CSR) initiative. “The proposal changed in the aftermath of the Brahmapuram fire. While hearing cases related to the incident, the Kerala High Court asked why the Corporation could not establish a facility modelled on the plant in Indore. Though the company behind the Indore project held consultations, it eventually withdrew, citing feasibility concerns. It was at this juncture that the BPCL entered into discussions with the State government, and Ministers M.B. Rajesh and P. Rajeeve broached the possibility of a CBG plant,” recalls former mayor M. Anilkumar.

Subsequently, Prime Minister Narendra Modi performed the ground-breaking ceremony for the proposed plant online in October 2023. The State Cabinet approved the CBG project the following month, and the Corporation handed over the land in December. CEID Consultants and Engineering was awarded the contract to set up the facility, while the FACT Engineering & Design Organisation (FEDO) was appointed as the Project Management Consultant.

Reasons for delay

The original deadline of March 2025 for the project’s completion could not be met. The trial run of the plant, beginning with dung and later extended to actual municipal solid waste, commenced in December 2025. This delay was primarily due to the soil structure and the prolonged monsoon. “We received the land in March 2024 and began filling two months later. However, the extended rains triggered a soil collapse, forcing us to resort to piling for all structures except two. To ensure stability, we waited through two monsoon cycles before proceeding. Hence, the soil had time to settle,” explains R. Ugesh Raja, Project Manager at CEID, which has been entrusted with the operation and maintenance of the plant for the next decade.

Meanwhile, FEDO is preparing to conclude its association with the project, its first in Kerala. “We are in the process of carrying out a Performance Guarantee Test Run, the completion of which will mark the culmination of our role in the project,” says Sarath Santhosh, Senior Manager (Projects and Constructions), FEDO.

The treatment of ‘rejects’

In its 2026-27 Budget, the Kochi Corporation has earmarked ₹15 crore for the operation of the CBG plant. “It’s our responsibility to handle the rejects from the waste during segregation. Since the actual cost of handling this remains uncertain, we have set aside a token allocation. The company engaged in bio-mining of legacy waste at Brahmapuram has expressed interest in treating the rejects, and we have asked them to submit a project proposal. While the CBG plant is undoubtedly a blessing for the city, we do not want the treatment of rejects to become an additional burden. We are also concerned about whether the quality of waste supplied will affect the plant’s operations in the long run, as we have been told that the feedstock must be ‘pure’, free of any acidic content,” says Kochi Mayor V.K. Minimol.

From the ashes of Brahmapuram’s inferno has risen a facility that not only addresses the city’s mounting waste crisis but also feeds directly into the country’s green energy ambitions. As Kochi takes this pioneering step, the challenge ahead lies in ensuring consistent waste quality, managing rejects, and sustaining operations through monsoon cycles and fiscal realities.