Researchers have designed a community-level waste management system that could solve three problems at once in rural India.
The system employs a heat-based biomass recycling method called pyrolysis to produce three different types of fuel. By running on waste such as manure, straw, and grain husks, the technology could cut indoor air pollution, improve soil health, and produce clean power for villagers.
“Scaled across a nation the size of India, even a modest uptake of the system could have a big impact on climate emissions and public health,” said Siming You, an engineering professor at the University of Glasgow, UK, in a press release.
In a new paper published in the journal Science of the Total Environment, You and his colleagues from the University of Glasgow and the University of Queensland, Australia, present a detailed analysis of their pyrolysis system. And they outline recommendations to maximize the system’s economic viability.
Air pollution, both indoor and outdoor, is a serious issue in India. Millions of rural residents use traditional cookstoves that burn fuels such as cow dung and coal, releasing carbon dioxide and methane. Cookstoves also produces soot and other indoor air pollutants, which can cause lung cancer and heart disease.
Crop residues are another source of harmful, climate-warming emissions. Farmers usually burn agricultural waste in the open, creating harmful air pollution that every year brings life to a standstill in some parts of the country.
Access to reliable electricity and degradation of arable land from unsustainable farming practices are also an ongoing challenge in rural India.
To address these issues, the UK-Australia research team designed a pyrolysis-based “bioenergy trigeneration” system. Pyrolysis works by sealing organic waste in an oxygen-deprived chamber and heating it to high temperatures of over 400°C. The process is typically used to produce a charcoal-like black residue called biochar that can be mixed into soil as a fertilizer, where it also stores carbon.
The researchers’ new system produces biochar, but also bio-oil and syngas, which is a mixture of carbon monoxide and hydrogen. Syngas and bio-oil could produce heat and power for the pyrolysis system, the researchers say. Surplus electricity could be used in homes and businesses. The bio-oil could also be a clean-burning replacement for dirty cooking fuels.
Computer simulations showed that the trigeneration system could help drop greenhouse gas emissions from communities by nearly 350 kg of carbon dioxide equivalent per capita a year.
The researchers designed their system after surveying nearly 1,200 rural households across the Indian state of Odisha. Around 90 percent of respondents said they would be willing to sell agricultural waste to support bioenergy. And over 80 percent wanted to switch from cookstoves to cleaner options. Almost all participants said reliable grid electricity was a priority.
The technology would be expensive, the team writes. But two business models could help with widespread adoption. A private sector partner could provide seed funding to set up the pyrolysis units in exchange for social benefits. Or villagers could be asked to contribute waste feedstocks for free, in return for free biochar and discounted bio-oil that saves them money.
Source: Simon Ascher et al, Trigeneration based on the pyrolysis of rural waste in India: Environmental impact, economic feasibility and business model innovation, Science of The Total Environment, 2024.
Image by Arun kumar from Pixabay
