Scientists from Abylkas Saginov Karaganda Technical University in Kazakhstan jointly with their colleagues from the AGH University of Krakow have discovered that landfills can be used as a source of energy. After studying waste composition, climatic conditions and landfill gas production at a landfill in the Karaganda Region, the researchers came to the conclusion that methane released during waste decomposition could be used instead of natural gas.
Landfills are the third-largest anthropogenic source of methane. Its ability to trap heat in the atmosphere is roughly 25 times greater than that of CO₂. Landfills also account for about 90% of greenhouse gas emissions in the waste sector. On the flip side, methane formed during the decomposition of organic matter can be a useful fuel. One cubic meter of landfill gas has the energy value of about half a cubic meter of natural gas. It can be used for heating, power generation and even as a vehicle fuel after additional purification.
Seeking to evaluate this potential, the researchers studied a landfill that has been operating on the site of a disused quarry since 2015. The landfill receives up to 4,000 tons of waste per year, with about 57% of this waste being organic matter, i.e., food waste, paper and cardboard. These materials decompose without oxygen, becoming the main source of biogas.
This process is significantly affected by the region’s climate. The Karaganda Region has a sharply continental climate: temperatures can rise to 43°C in summer and drop to –48°C in winter. Because of this, waste freezes in winter and often dries out in summer, resulting in uneven methane production with major seasonal variations. The calculation methodology approved by a Kazakh environmental agency takes this into account via a coefficient with an error margin of ±30%.
Using data on waste composition, climate and accumulated waste volumes for 2020–2024, the scientists calculated biogas production through 2030. Their estimates show that about 53% of landfill gas is methane, some 45% is carbon dioxide, and the rest is made up of various impurities, including toluene, ammonia, hydrogen sulfide, formaldehyde and organic compounds.
Calculations indicate that gross methane emissions rose more than fivefold from 2021 to 2025, from 7.2 tons per year to 38.4 tons per year. By the end of the decade, this figure could reach 81.7–92.6 tons per year. Moreover, emissions begin not immediately after waste is disposed of, but about two years later, when stable anaerobic conditions are developed within the waste.
In addition to methane, the researchers recorded a fivefold increase in hydrogen sulfide emissions, from 0.0036 tons per year to 0.0189 tons per year. This indicates a high proportion of decomposing organic matter and also signifies the risk of unpleasant odors and spontaneous waste combustion.
To solve these issues, the scientists proposed a degassing and monitoring system with special gas collection pipes and a network of sensors to continuously monitor its concentration. They also simulated methane distribution around the landfill, taking into account terrain, temperature, humidity and wind direction.
The researchers emphasize that their method is generally ready for practical application in designing new landfills and reclaiming old ones. This approach makes it possible to transform a landfill from a source of emissions into a source of energy. This can be achieved not only in Kazakhstan, but also in other countries where remote communities and industrial facilities experience difficulties in accessing natural gas.
