When paper manufacturers in Vapi, Gujarat, were asked by the state pollution control board to find a solution for the large amounts of non-recyclable plastic waste that the industry generated, they were initially clueless. As things stood, the waste was either finding its way to the landfill or...
When paper manufacturers in Vapi, Gujarat, were asked by the state pollution control board to find a solution for the large amounts of non-recyclable plastic waste that the industry generated, they were initially clueless. As things stood, the waste was either finding its way to the landfill or piling up in the premises of the mills.
But after the release of guidelines from the Central Pollution Control Board (CPCB) in 2010 recommending the use of co-processing technology to utilise the waste, the paper mills decided to give it a try. They signed a memorandum of understanding with the Kodinar unit of Ambuja Cement and from then on, the plastic waste from the paper industry started being used in cement manufacture. From 2012 to 2016, around 1,54,018 MT of plastic waste was co-processed from the paper mills of Vapi, according to a May 2017 CPCB case study.
How exactly does this technology, which is used in energy-intensive industries like cement, work? As the name suggests, co-processing means using inorganic waste as part of the fuel to fire cement kilns. As a result, cement manufacture occurs parallel with safe destruction of the waste material, without emitting toxic fumes. The temperature in the cement kiln process varies from about 1,400 degrees centigrade to 2,000 degrees centigrade, leading to co-processing completely destroying the waste material without leaving a residue.
Vapi has not been alone in discovering the benefits of co-processing. Last year, Madukkarai panchayat in Coimbatore district of Tamil Nadu entered the Guinness Book of World Records as the “largest recycling lesson in the world”. Here, around 50 women collect waste from every household in the town, segregate it under eight heads and dispose it appropriately towards achieving a zero-landfill status.
Of the waste collected, the non-recyclable plastics and other materials under the non-recyclable Segregated Combustible Fraction (SCF) category are sent to the ACC cement kiln in the vicinity where they are co-processed as Alternative Fuels and Raw material (AFR) in the cement making process.
This has been a win-win for both Madukkarai panchayat and ACC. The company is able to reduce its coal consumption and greenhouse gas emissions from cement making, while the panchayat gets the much coveted clean and green status, with much less waste reaching the landfill.
More recently, Goa has experimented with co-processing, setting a trend that other municipalities are looking to emulate. When Panaji was selected for conversion into one of the country’s Smart Cities, the State government was enthused to give it ‘green’ status. It planned to establish four Municipal Solid Waste (MSW) plants with a daily capacity of 100 tonnes based on the mechanical biological treatment process. While these were being created, a petition was filed in the National Green Tribunal to ensure comprehensive waste management. This included the remediation or maintenance of the old MSW dump site.
Waste management services major Geocycle India took on the task of collaborating on the remediation efforts. It screened the waste from the dump site and lifted 1000 T of the inorganic waste to check on its efficacy for pre-process and co-processing at its Wadi facility. Geocycle managed to pre-process and co-process approximately 5000 T of SCF at Wadi.
The success has not only made Goa State identify other dump sites for remediation, but also officials from other cities have been visiting Goa to learn first-hand on how it was implemented. Following this, Chennai, Bengaluru, Mumbai, Nagpur and Visakhapatnam have also initiated similar projects.
What these examples go to show is the immense potential of co-processing as a means to both reduce inorganic waste as well as the cement industry’s dependency on traditional fuels and raw material. “Besides this, co-processing reduces CO2 emissions since the inherent heat value in certain wastes is utilised in the cement kiln and it replaces, to some extent, the fossil fuels utilised in the process. If these wastes had not been co-processed, they would have been incinerated or landfilled instead, it would have led to corresponding GHG emissions,” explains Berthold Kren, who heads Geocycle India, one of the largest waste management companies, which is part of global brand LafargeHolcim and Ambuja Cement in India.
However, not every waste material can be used for co-processing, hence there is great emphasis on the system of segregation and pre-processing before applying the technology. Wastes such as non-recyclable plastics, textiles, packaging material, tyres, liquid waste byproducts such as used oil, solvents or paint sludge can be safely co-processed, while electronic waste, explosives, asbestos, unsorted municipal waste and others are a strict no-no.
In fact, co-processing is not a new concept as a waste management option. It is known to have been in practice and evaluated for over 40 years globally. The technology has been approved by the Basel Convention for disposal of all kinds of hazardous and other wastes.
According to Geocycle India, more than 90 co-processing trials have been conducted in the country at different cement kilns and with different waste streams. During the trials, detailed emission monitoring and monitoring of the final product was carried out, with the results showing that there is no detrimental impact of co-processing. These extensive trials led to co-processing being recognised and mentioned as a sustainable technology option in the Hazardous and Other Wastes (Management and Transboundary Movement) Rules, 2016, the Plastic Waste Management Rules 2016 and the Solid Waste Management Rules, 2016.
“Building on the global experience of Geocycle in co-processing waste, Ambuja Cement has managed to significantly contribute to the Swachh Bharat Mission and fight plastic pollution,” says Bimlendra Jha, MD & CEO of Ambuja Cement.
However, there is still tremendous potential of co-processing that can be exploited by cement companies in the country. Geocycle India itself believes it can handle a total volume of 650,822 tonnes of refuse-derived fuel (RDF) from both landfill remediation and fresh sources by 2025.
For fresh sources of RDF, the company has begun tapping biomass from farmers in the country. As this organic waste is carbon-neutral, generated in massive quantities in rural India and a renewable source of energy, it helps cement plants reduce fossil fuel use in the production process. This, in turn, meets the target of cement companies in reducing net specific CO2 emissions by 40 per cent per tonne of cement. And while doing so, there is the very big benefit of avoiding field burning of biomass and the subsequent detrimental impact on air quality.
To take forward the biomass sustainability strategy, Ambuja Cement Foundation (ACF) started a partnership with the farming community and established a farmer-producer company which began to directly supply biomass to Geocycle India. Hence, the Ambuja cement plant in Rabriyawas, Rajasthan, has processed over 12,500 tonnes of biomass in 2018.
“More than 500 farmer families around the Rabriyawas plant benefit from this partnership, are able to share knowledge with each other more easily and have increased household revenues as a result,” says Kren. Going further, Geocycle plans to set up similar partnerships with farmers in Gujarat and Maharashtra and extend it across the country. This will expand the scope of co-processing even further.
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