Friday, July 18, 2008


1. The root cause of failure of the entire range of technology options for treatment of mixed municipal solid waste is the fundamental law called the ‘Second Law of Thermodynamics’ which in simple words is called ‘The Law of Disorder’. The law says that ‘higher the disorder, the higher the need for external energy/resource input to get some thing useful out of any initiative’. If the cost of input is higher than the price or premium on the output, it is not worthwhile as an industrial venture.

2. Unlike any other industrial feedstock (e.g., iron ore, coal, etc.) the mixed municipal solid waste is characterised by a high degree of disorder – called ‘entropy’. For instance it has high moisture content, plastics, rags, soil, sand and stones, metal fines, and at times hazardous substances. Such variable and aggressive composition demands very advanced and robust equipment for pre-processing. Secondly the ‘degree of disorder’ is also not fixed – it keeps varies from batch to batch, day to day and season to season. For instance in summer there will be high silt/grit content while in Monsoon there will be high moisture levels. Therefore the pre-processing plant can not deliver a reliable and consistent output which could be guaranteed to be one hundred percent suitable round the year for feeding into a downstream ‘waste-to-energy’ plant or a ‘compost’ plant or an ‘RDF’ plant. Moreover, because of this ‘high disorder’, the equipment itself is subjected to high degree of corrosion, abrasion and therefore high wear and tear entailing frequent and costly repairs and replacements. Thus unlike an ore processing industrial plant, here the ‘feedstock’ is highly unreliable.

3. The society which generates the waste or let’s says the ‘feedstock’ for our processing plants is also characterised by a ‘high degree of disorder’. A large percentage of the population is either uneducated, unaware or unconcerned about segregation of waste. The waste is neither stored at home nor is it properly packed and disposed off in plastic bags. Efforts to bring about community awareness have not been able to bring about the desired response and the producers (householders) are not even prepared to pay a small price to the door collection service providers who helps in reducing the ‘disorder’. Further, open disposal at waste storage depots/ community collection point (or ‘Dalao’ as it is called in India) invites cattle to increase the disorder further and the monsoon adds an extra dose of moisture. Many towns are not able to control mixing of construction debris, drain silt, domestic hazardous waste, hospital waste, etc. at the Dalao’ . Thus the ‘disorder of feedstock’ starts from its place of generation/collection and continues all the way up to the dump yard and the processing plant.

4. On top of all this, we try to convince ourselves that this ‘highly disordered’ feedstock can be processed by a ‘low cost appropriate technology’. As a matter of fact, on the contrary the conventional wisdom says that it would require a much higher degree of robustness of the processing technology from the points of view equipment specifications, energy input, process control and environmental impact. Unfortunately the widely proclaimed ‘windrow’ technology for composting scores very low on all the four criterion.

5. In the backdrop of this ‘disorderliness’, it is not surprising to find a large number of failed initiatives for converting ‘waste-to-energy’ or ‘waste-to-wealth’ across the country. As a matter of fact, it needs to be emphasised and must be realised sooner than later that these initiatives are taking us nowhere but leading to ‘Waste-of-Energy’ and ‘Waste-of-Wealth’. Without harbouring any expectations of making gainful recovery (in financially viable terms as in an industrial enterprise) from the Indian mixed MSW (from where the rag pickers and the cows have taken out the last vestige of recoverables), it must be recognised that it is fit for only giving a ‘dignified burial’, i.e., safe disposal in a sanitary landfill, so as to protect environment and public health. Otherwise we will continue to experience not just the usual dysentery, viral and bacterial diarrhoea, typhoid and conjunctivitis, but more deadly versions of epidemics, e.g., gastro-enteritis, trachoma, laptospirosys, plague, typhus, salmonella, filariasis, malaria, tapeworm and trichonosis.

Asit Nema M.Tech. (Env. Engg., IIT Kanpur), M.Sc. (Sanitary Engg., Netherlands)
Foundation for Greentech Environmental Systems
K-12, Sarita Vihar
New Delhi 110 076
Ph 011 4105 4084 / 2697 4941

No comments: