A research team from Indian Institute of Technology (IIT)-Kharagpur has adapted a process called Hydro Thermal Carbonization (HTC) for Indian conditions, which can effectively manage mixed Municipal Solid Waste (MSW) with high moisture content. Through the process most of the mixed MSW can be converted into biofuel, soil amendment and absorbents.
The current waste incineration processes adopted from the developed nations are primarily focused on treating drier waste content. These processes require high energy input to combust municipal solid waste generated in India which has high moisture content due to tropical weather, open collection systems and mixed waste.
As per the Professor B K Dubey from the Department of Civil Engineering at IIT Kharagpur, “Using the existing processes, only 20-30 per cent of organic fraction of municipal solid waste is being recycled to biofuel. This led us to develop a technology which can address the challenge indigenously.”
Explaining how the technology works, Dubey said: “The technology converts organic fraction of MSW into hydrochar by using a batch reactor. The moisture in the waste is used to the advantage of the process which uses water for the reaction. The process has increased the resource recovery yield to 50-65 per cent of urban organic waste.”
The key to the success of the technology lies in designing proper industrial scale HTC reactor with improved heat integration system.“The process novelty lies in the use of water for the reaction. Thus, the moisture in MSW gets used during the recycling process without requiring any removal of moisture from segregated wet waste or high energy intake,” said researcher H B Sharma.
For example, 1 gm yard waste and 4 gm water is being used in the laboratory reactor. The waste output is 1 gm of biofuel with a calorific value of upto 24.59 MJ per kg, while the water remains available for reuse. Through this innovation process, the government’s waste-to-energy mandate could also be met.