40 years of legacy waste treated in nine months
Assam’s North Lakhimpur shows the way
North Lakhimpur in Assam has treated a legacy waste of around 79,000 metric tonnes (MT) accumulated over 40 years in and near the river Sumdiri, which is not a designated dumping ground. The waste, cleared in less than a year, has been processed into refuse-derived fuel, sent to be used as fuel in a cement factory, and to 25 mm and 6 mm organic matter used as fertiliser.
The large mountains of municipal solid waste (MSW) were first excavated and broken into smaller piles, sprayed with an organic chemical called Bioculum, and left for 15 days to decompose. The decomposed waste was then passed through a Trommel machine comprising a cylindrical drum with several holes of predefined size that help segregate the waste material. It was used to obtain two by-products – 25 mm organic waste and the other refuse-derived fuel (RDF), which is largely plastic. The 25mm component is further processed through another Trommel machine, and the final product is six mm organic waste.
The total expense for treating 79,000Mt of legacy waste was `26.1 million, from the Tied funds of the North Lakhimpur Municipal Board (NLMB).
Part of the 25 mm and six mm organic waste is sold to farmers as fertilisers. The RDF is sent to a cement factory in the neighbouring state of Meghalaya to be used as fuel in the kilns. The NLMB so far does not derive a monetary benefit from this, instead transports truckloads of RDF at its own expense.
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