Retrieving material for composting from open dumps across the developing world could reduce the environmental impact of growing mountains of waste, according to researchers in India.

People in the developing world are encouraged to compost garden waste or dispose of it in "green" garbage bins for collection and processing. In the developing world, the problems are very different. Open dumps are prevalent and have a poor environmental record, according to environmental engineer Kurian Joseph and colleagues at Anna University in Chennai, India.

Joseph's team is proposing landfill mining as a viable means of rehabilitating these open dumps. An earlier analysis of decomposed waste from the Deonar dumpsite, in Mumbai, India, revealed that almost a third of the mass was organic matter, while moisture accounted for 14 percent of the sieved material and inert matter the same. Soft plastics, textiles, glass, ceramics, metals, rubber, leather, and other substance accounted for the remainder of the sieved mass.

"Landfill mining can recover recyclable materials, landfill space and compost," explains Joseph. He suggests that mining of compost from open stabilized dumpsites and the application of the bioreactor landfill concept across the developing world could make dumps much more sustainable and reduce their environmental impact.

The current study as part of the “Asian Regional Research Programme on Sustainable Landfill Management in Asia” funded by the Swedish International Development cooperation Agency (Sida) indicates that up to half of material dumped at such sites could be recovered and re-used as compost for non-edible plants or as daily cover material for landfills.

Over the last two decades, experimental testing and field pilot studies have been conducted to develop and improve landfill techniques and designs with the aim of reducing their negative impact on the environment. The researchers suggest that by encouraging microbial degradation of solid waste in landfill bioreactors it should be possible to improve the overall efficiency of the landfill mining process. This, they explain, needs to be demonstrated at the pilot scale to complement the ongoing research in this area.

"Landfill may no longer be viewed as a final disposal system," adds Joseph, "rather it should be viewed as a method for large-scale processing of waste that combines recovery and recycling processes."

- International Journal of Environmental Technology and Management