PYROLYSIS: AN ALTERNATIVE TECHNOLOGY FOR MUNICIPAL SOLID WASTE MANAGEMENT

Abstract

This paper reviews the process of pyrolysis with an aim of assessing its potential as an alternative technology formanaging municipal solid  waste in  Kenya. Pyrolysis is the thermo-chemical  decomposition  of organic  matter, at high temperatures, in the absence of oxygen. Organic matter simultaneously undergoes a change in chemical and physical phase, forming a gas, liquid and carbon-rich solid residue, which can be used as fuels. Pyrolysis is one of the  processes  involved  in charring  of  wood, burning  of  solid  fuels  and  volcanic  eruptions  which  bring  lava  into contact  with  vegetation. Pyrolysis  has  been  applied  widely  in  the  chemical  industry  for  production  of  charcoal, methanol, PVC, activated carbon and gasoline. The process has also been applied to convert solid waste into safelydisposable substances. In Kenya, pyrolysis has been widely applied in local production of charcoal. This continues to pose serious environmental challenges due to widespread deforestation and emission of greenhouse gases into the  atmosphere.  Meanwhile,  Kenya  continues  to  face  serious  municipal  solid  waste  management challenges associated with urbanization and population pressure. Pyrolysis energy recovery from MSW has been successfully practiced in countries such as the UK, Turkey and Japan, where used tetra pak is now being used as a source of fuel,  reducing  its  presence  in  Municipal  Solid  Waste  by over  80%. Pyrolysis  can also  be  used  to  convert  plasticwaste and  waste  rubber,  which  pose a  great  environmental  problem  in  Kenya,  into  useful  energy. Pyrolysis  is relatively insensitive to input material and prevents formation of dioxins and combustion materials associated with burnt  waste. This  guarantees  my  strong  recommendation  to  Kenyan  environmental  management  agencies  to adopt  pyrolysis  to  help  manage  plastics  and  tetra  pak  in  Municipal  solid  waste  and  as  an  alternative  source  of energy.  

Key words: pyrolysis, thermochemical decomposition, municipal solid waste, energy recovery