Attached
Solid waste is a growing problem in Sri Lanka in the absence of proper management
measures. Development and implementation of a National strategy for municipal
management is essential in order to reduce environmental, social and the economic
problem associated with the present disposal practices. Such strategies however, need
to be subjected to proper economic analysis in order to arrive at informed decisions.
The present study presents an extended cost benefit analysis of a biogas generation
plant that uses munipal solid waste as the raw material.
To dispose vegetable market garbage available in Wattala, Kandana and Ja-ela areas
productively, the 640 Mt capacity biogas/ bio fertilizer project has been housed at
Muthurajawela (along Hamilton canal, Elakanda), by the National Engineering
Research & Development Center of Sri Lanka (NERDC), which uses Dry Batch
Anaerobic Digester Technology. Among the other biological treatment options,
anaerobic digestion is the most cost effective, due to the high-energy recovery linked
to the process and its limited environmental impacts.
Economic analysis has been carried out to identify costs and benefits associated with
the above project. Several environmental valuation methods have been applied to
value the identified costs and benefits. The main benefit of reduction of municipal
solid waste has been estimated as Rs 1,093,444 per year. Contingent valuation
method (CVM) was used to estimate this benefit using samples from Wattal-Matnla,
Ja-ela, and Peliyagoda local authorities. Green house gas (methane) emission from
solid waste was estimated through Scholl Canyon model and valued using avoided
global damage cost approach. Benefits of biogas as an energy source, organic
fertilizers and employment benefits were estimated by market based approach.
The project is viable from economy and environment point of view with net present
value of Rs. 249.43 million for 20-year period with 10% discount rate. This analysis
provides a justification for undertaking solid waste management strategies in a
technologically environmentally and economically viable manner.
