Environmental impact assessment of municipal solid waste management value chain: A case study from Pakistan.

Abstract

The present study quantified environmental impacts of the Rawalpindi Waste Management Company (RWMC) value chain in Pakistan for three consecutive years (2015-2018) using a cradle-to-grave life cycle assessment (LCA) approach. Energy potential from municipal solid wastes (MSW) was also predicted till the year 2050. Based on a functional unit of 1.0 tonne of MSW, the study analyzed inputs and outputs data through SimaPro v.8.3 applying CML 2000 methodology and cumulative exergy demand indicator (CExD). LCA revealed that operational activities of RWMC mainly contributed to marine aquatic ecotoxicity, i.e. 8962.83 kg1,4-DBeq t-1 MSW, indicating long-range transport of petrogenic hydrocarbons from the company's fleet gasoline combustion. Similarly, human toxicity potential, global warming potential and freshwater aquatic ecotoxicity potential were also found to be significant, i.e. 18.14 kg1,4-DBeq t-1 MSW, 15.79 kgCO2eq t-1 MSW and 6.22 kg1,4-DBeq t-1 MSW, respectively. The CExD showed that company activities consumed 827.14 MJ t-1 MSW exergy from nature, and gasoline used in MSW transport was the most exergy-intensive process, using 634.47 MJ exergy per tonne MSW disposed of. Projections for energy generation potential up to the year 2050 showed that MSW of Rawalpindi city will have the potential to produce 3901 megawatt of energy to fulfill the energy needs of the country. Possible stratagems to reduce environmental impacts from the municipal solid waste management (MSWM) value chain of RWMC include curtailing dependency on petrogenic and fossil fuels in mobile sources, optimization of waste collection methods and dumping routes, inclining attention toward suitable wastes-to-energy conversion technology and opting for a holistic approach of MSWM in Pakistan.