LIFE CYCLE ASSESSMENT OF MUNICIPAL SOLID WASTE MANAGEMENT ALTERNATIVES FOR ISLAMABAD, PAKISTAN

Abstract

The growing population and rapid urbanization in developing countries like Pakistan are consequently giving rise to an increased level of municipal solid waste to be handled. Municipal solid waste management is important in order to reduce the environmental impacts of mismanagement. Selection of optimal municipal solid waste management technologies while taking environmental sustainability into account is a challenge for decision-makers and specialists. Several waste management and treatment options are available, however, due to the complexity of municipal solid waste management, it is necessary to employ tools like life cycle assessment (LCA) to evaluate how various treatment approaches would have an influence on the environment. The objective of the study is to provide insights into the environmental implications of the existing waste management system in Islamabad, Pakistan and demonstrate the potential benefits of transitioning to more sustainable practices such as recycling, composting, anaerobic digestion, and incineration along with sanitary landfilling of the rest of the waste. For achievement of the objectives, life cycle assessment of municipal solid waste management alternatives for Islamabad was conducted using SimaPro 9.4.1 version and Ecoinvent 3.0 database. Five scenarios namely, S1 (unsanitary landfill-BAU), S2 (sanitary landfill+recycling), S3 (anaerobic digestion+recycling+sanitary landfill), S4 (composting+recycling+sanitary landfill) and S5 (incineration + recycling) for assessing the potential environmental impacts against each other and to assess potentially viable options were modelled. The functional unit of the study is 700 tons. Literature review, and Ecoinvent datasets from the SimaPro libraries were used for collection of data.CML-1A baseline methodology was used to evaluate the modelled scenarios for 8 midpoint indicators namely, abiotic depletion (fossil fuels), global warming potential, ozone layer depletion, human toxicity, freshwater aquatic ecotoxicity, terrestrial ecotoxicity, acidification, and eutrophication. According to the results, S1 (unsanitary landfill) for municipal solid waste which is the business-as-usual scenario is the worst management approach with highest environmental impacts followed by the S2 (sanitary landfill). Biological treatment methods for organic fraction of waste such as anaerobic digestion and composting along with recycling and sanitary landfill for other fractions of waste performed better and demonstrated environmental savings. S3 (anaerobic digestion) performed best with upto 106% improvement in environmental savings for global warming potential followed by S5 (incineration) and S4 (composting). The sensitivity analysis showed that increasing the recycling rate from 50% to 85% leads to increased net environmental savings for all scenarios with 104% increased net environmental savings for freshwater ecotoxicity in case of S5. The study showed that current waste management option has the most environmental impacts while an integrated waste management system with energy, resource and material recovery will generate net environmental savings and have least environmental impacts.