Cement plants can process a large quantum of segregated combustible waste through a mechanism called co-processing, write Kaushik Chandrasekhar and Suneel Pandey
With increasing accumulationin urban spaces, rapidly decreasing landfill space and fire and slippage incidents like in Ghazipur landfill, urban local bodies (ULBs) are looking for alternatives to treat waste efficiently and limit the wasteflow to dumpsites.
As options run out in the social sphere, the science arena has environmentally acceptable alternatives to offer. The cement plants, for instance, can process a large quantum of segregated combustible waste through a mechanism called co-processing. Co-processing refers to the use of waste resources in industrial processes as Alternate Fuel and Raw material (AFR). The Government, through solid waste rules 2016, has endorsed co-processing by proposing the use of municipal solid waste for preparation of Refuse Derived Fuel (RDF)for use in cement plants.
According to 2016 estimates by the Central Pollution Control Board, urban India generates close to 141,064 Metric tonnes per day with only 27 per cent treated. Further, it also estimates that only about 4,515 TPD was disposed to landfills, the rest ending up in dumpsites. Comprehending all the factors,a substitution of mere 10 per cent of available MSW in the cement industry could lead to savings of about 18,62,045 MT of coal per year.
As per the CII, the present Thermal substitution rate (TSR) of the cement industry is about 1 per cent. However, with projections for the year 2025 leading to 25 per cent TSR and RDF forming 57.07 per cent of the AFR share, the need to assess reasons leading to the slow progress of the mechanism becomes vital.
RDF is manufactured throughsegregating, shredding and dehydration of MSW. However, as the efficacy of source segregation is poor, quality of RDF manufacturedhas shown proportional results and may not be within the acceptable limits for commercial use in cement plants. Levels of chlorine,particle size, ash, moisture and calorific value are some indicators that dictate the acceptability of the fuel into cement plants. This SCF may need to be further pre-processed by the cement kilns by incurring a cost, in order to meet the acceptable quality standards before use in their facilities. Geocycle India in one thetechnical papers quote “Presently, Refuse Derived Fuel (RDF) presented for use by RDF manufacturing facilities in WTE and Cement plants is a misnomer for this material as it does not have the desired quality or consistency in it for using it as a source of fuel”.
There are very few RDF facilities located strategically located around to cement kilns in the country. Cost of transportation of RDF from the MSW processing facility to cement kilns is to be incurred either by the urban local body or cement plant. Since the quality of RDF delivered by MSW processing facilities is low, the cost behind transportation of the same projects itself asa ‘major cost’. Considering coal being transported between continents owing to its use and quality, there needs to be an impetus on improving the quality of RDF that is being manufactured. On similar lines, The Energy Resources Institute (TERI), in a recent study, suggested that co-processing of RDF made from waste within 100km around cement plants in India may lead to a TSR of only 0.43%. The report further suggests that areas greater that 100km may need to be explored to increase the levels of TSR substitution in cement plants.
With low quality RDF and its associated transportation costs, it is an uphill task for the ULBs to implement this mechanism. Lack of a nationally acceptable quality standard for RDF is an added stumbling block for all stakeholders. A standard would set a benchmark for compliance by stakeholders and ensure RDF is utilized benefitting both the waste management sphere and fuel substitution at a cement plant level. However, a committee has recently been formulated by the central government to understand these issues so as to suggest a solution for the same.
ULBs are often seen grappling with lack of funds to deal with MSW-related activities. With waste generators in today's scenario increasing waste output and not adhering to segregation standards, ULB’s must ensure formulation of a mechanism to collect user fees from residential and commercial waste generators. It may be done with due consideration to income levels/standards of living/existing BPL recommendations. This would ensure an uninterrupted waste management service to citizens and healthy cash flow to ensure timely payments to service providers.
RDF co-processing mechanism calls for an overarching consensus between different industries to arrive at a cost-sharing model to facilitate successful implementation. The mechanism also calls for a sound business model to ensure no entity is functioning at a negative IRR. While quality of the manufactured RDF needs a serious look, formulation of national standards for the same may be seen as a major breakthrough.While the concerns around transportation costs remain, situation also demands for improvedspatial planning to ensure MSW processing plants cater their finished products to industries.
(Writers are associated with TERI)