On the evening of March 2, 2023, a fire broke out in a pile of plastic waste piled high at the Kochi Corporation’s waste treatment yard in Brahmapuram, located on the outskirts of the city.
For nearly a fortnight, flames consumed the huge dump that had accumulated over a decade on the banks of Kadamprayar, an important freshwater source, consisting mostly of tonnes of plastic and non-biodegradable waste, sending plumes of smoke over the Kochi skyline. The fire, releasing huge amounts of noxious gases and soot, lasted for about a fortnight, causing the city’s air quality to fall to dangerous levels. Hundreds of people sought medical attention after suffering respiratory problems.
When the fire was finally extinguished, a large area of the 110-acre plot in Brahmapuram of Vadavukode-Puthencruz panchayat in the suburbs of Kochi city looked like a war-ravaged wasteland, leaving behind smoldering embers, acrid smoke and scorched earth so lifeless that it seemed as if not even a blade of grass would ever take root again.
Less than three years after the fire, a 10-acre plot at the epicenter of the yard has been transformed beyond recognition, housing a compressed biogas plant funded by the BPCL-Kochi Refinery. It will be formally inaugurated by Chief Minister Pinarayi Vijayan on Friday (February 26, 2026).
Three green domes rise from the once charred barren land. Two of them are, in fact, double-layered balloons mounted on top of the digester, each with the capacity to treat 75 tons of municipal solid waste a day. The inner balloon inflates as raw biogas is generated, while the outer shell maintains its shape against inclement weather, ensuring anaerobic functioning of the digester with the help of a water column controlled by the blower. The third structure is a ground-mounted balloon – a special, collapsible storage membrane designed specifically for biogas – with a capacity of 1,500 cubic metres.
Old waste treatment plant in Brahmapuram. | Photo Courtesy: H. Vibhu
Before the waste reaches the digester – the heart of the gas production section – it goes through an extensive cycle of pre-treatment and feed preparation. Biodegradable waste collected from 177 centers across the city is first taken to the plant, where it is weighed on a 60-tonne electronic weighing machine. From there, the waste is put into a bunker in the pre-treatment area and moved forward on conveyors, passing through vibrators that separate non-biodegradable rejects. The separated material is then fed into a shredder and a bio grinder, which turns the waste into a fine slurry of 5 mm thickness. The slurry proceeds to the feed preparation stage where it is emptied into a unloading pit and mixed with an equal amount of water. From there, it passes through intermediate tanks for further separation, in which the fibrous material is carefully removed. The solution is then put into a hydrolyzer tank, where rapid decomposition of the organic matter occurs. Finally, it is fed into two digesters operating on a Continuous Stirred Tank Reactor system. In total, the digesters produce 5.6 tonnes of biogas per day.
The fertilizer is 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 sent to a dedicated fertilizer shed for separation. Of this, 190 tonnes of LFOM is recycled within the plant, while the remaining 100 tonnes, along with 28 tonnes of FOM produced daily, is marketed through Fertilizers and Chemicals Travancore (FACT).
Jitendra Kumar, general manager (marketing), FACT, says, “We have signed an MoU to market FOM through our distribution network. The use of such manure enriches the soil, facilitating better absorption of nitrogen and phosphorus, thereby benefiting crop yield. That is why petroleum companies have started producing FOM products and fertilizer companies are supporting them.”
The raw biogas produced by the digester is stored in ground-mounted balloons before being sent to the purification unit. In its raw form, the gas consists of 45–50% methane, 35–45% carbon dioxide (CO₂), and 0.1–0.4% hydrogen sulfide (H₂S). A water-scrubbing system is used to purify biogas, which removes CO₂ and H₂S by forcing pressurized gas into a packed column while spraying water on top. This process increases the purity of methane to 97%. Engineers explain that the refined gas is then compressed under high pressure and transferred to the refinery in Ambalamedu, where it is converted into green hydrogen.
Reduction of 85,000 tons in carbon emissions
A BPCL official says that when operating at full capacity, the plant will reduce carbon emissions by 85,000 tonnes per year, which is equivalent to planting 3.5 million trees and nurturing them for a decade.
Similar biogas plants are in the pipeline in several districts of Kerala. The projects being developed under the public-private partnership (PPP) model in Palakkad and Thrissur are nearing completion. “In other districts, the government will hand over the land, and BPCL will set up the plant. An MoU has already been signed for Kollam, and the foundation stone will be laid in Kozhikode, while similar facilities are being considered in Thiruvananthapuram and Changanassery. We are working on a mix of centralized and decentralized effluent treatment facilities. This model will not change completely, but will be taken forward along with strengthening the decentralized systems,” MB’s comment. Rajesh, Local Self Government Minister.
The Kochi plant, which has an annual operating expenditure of ₹7.5 crore, is equipped with in-built and external safety systems, including a dedicated fire-water network, to deal with a possible outbreak. Company officials claim that this feature is unmatched.
controlled combustion of gas
Engineers say the system is supported by a tank with a capacity of four lakh litres, a borewell capable of supplying 5,000 liters per hour and a conventional well, with Kadamprayar also acting as an additional water source. He explains that the flare mechanism ensures that the gas is burnt in a controlled manner even when the pressure increases beyond the prescribed limit.
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 after the Brahmapuram fire. Hearing cases related to the incident, the Kerala High Court asked why the corporation could not set up a facility on the lines of the plant in Indore. Although the company behind the Indore project held consultations, it ultimately withdrew it citing feasibility concerns. This was when BPCL held discussions with the state government, and ministers MB Rajesh and P. Rajeev stressed the possibility of a CBG plant,” the former mayor said. M. Anilkumar recalls.
Subsequently, Prime Minister Narendra Modi performed the ground-breaking ceremony online for the proposed plant in October 2023. The state cabinet approved the CBG project the following month, and the corporation handed over the land in December. CEID Consultants & Engineering was awarded the contract to set up the facility, while FACT Engineering and Design Organization (FEDO) was appointed as the project management consultant.
due to delay
The original deadline of March 2025 for completion of the project could not be met. Trials of the plant, starting with cow dung and later extended to actual municipal solid waste, began in December 2025. This delay was mainly due to soil composition and prolonged monsoon. “We got the land in March 2024 and filling began two months later. However, prolonged rains led to soil collapse, forcing us to resort to piling for all structures except two. To ensure stability, we waited for two monsoon cycles before proceeding. So, the soil got time to settle,” said R., project manager at CEID. explains Ugesh Raja, who has been entrusted with the responsibility of operating and maintaining the plant for the next decade.
Meanwhile, FEDO is preparing to end its association with the project, a first in Kerala. “We are in the process of running a performance guarantee test, the completion of which will mark the end of our role in the project,” says Sarath Santosh, senior manager (projects and construction), FEDO.
Treatment of ‘rejection’
In its 2026–27 budget, Kochi Corporation has earmarked ₹15 crore for the operation of the CBG plant. “It is our responsibility to handle the rejected materials from the waste during separation. Since the actual cost of handling it remains uncertain, we have set aside a token allocation. The company engaged in bio-mining of old waste in Brahmapuram has expressed interest in treating the rejected waste, and we have asked them to submit a project proposal. While the CBG plant is undoubtedly a boon for the city, we do not want the waste to be wasted. Treatment becomes an additional burden. We are also concerned about whether the quality of the waste supplied will affect the operation of the plant in the long run, as the feedstock should be ‘pure’, free from any acidic material,” says VK Minimol.
From the ashes of the Brahmapuram fire has emerged a facility that not only addresses the city’s growing waste crisis but also directly boosts the country’s green energy ambitions. As Kochi takes this pioneering step, the challenge ahead lies in ensuring consistent effluent quality, managing rejected materials and sustaining operations through monsoon cycles and fiscal realities.
