A Study of Municipal Solid Waste Management with Emphasis on Material Flows and Potential Parameters in Environmental System Analysis

Abstract

In this research, the author has studied the entire system of municipal solid waste (MSW) for designing an Integrated Municipal Solid Waste Management System (ISWMS) in Shalimar Town (ST) Lahore, Pakistan. The first part of the study deals with the composition and the quantities of MSW generated in different seasons of the year by three different socio-economic strata of ST. The total amount of MSW generated in ST is estimated to be 927 ton/day in 2013. The average per capita rate of MSW generated in ST is 0.69 kg day-1 in all four seasons. Statistical analyses shows the significant difference for food waste, paper and plastic (p < 0.001) was found among socio-economic groups and seasons. The results show that the lowest income group produces 0.39 kg capita -1day-1 during winter months which is the minimum MSW generated compared to high (1.1 kg capita -1 day-1) and middle (0.56 kg capita -1 day-1) income groups in the same season. It is also concluded that the low income group produces the minimum of waste in each of the four seasons. In terms of breakdown of the MSW, organic waste is in the highest percentage (82.2%) followed by paper and cardboard (PAC) (5.5%), plastic (5%), glass (1.8%), metal (0.5%) and others (5%). The second part of this study focuses on the recycling of MSW with main emphasis on material flows. In ST and other areas of Lahore, sorting of waste is carried out by informal sector which comprises junkyards, household waste collectors, street hawkers and scavengers. This part of the study explains the role of informal sector in recycling of waste in Eastern Lahore. People working in the informal sector belong to different socio-demographic and socio-economic groups. Recyclables are collected by males and females of all age groups, migrants, minorities and poor refugees. Purchased and collected recyclables are later sold at slightly higher price to junkyards located at different places of the town. The total estimated amount of recyclable material recovered by all junkyards working in Shalimar Town is about 15.30 tons/day which is worth 681.8€/day. People comprising the informal sector suffer from both health and safety problems because they are ignorant, illiterate, and poor and cannot afford medical facilities. Even then the people of informal sector are not only helpful in reducing the waste from highly populated urban areas of a third world country like Pakistan but also make important economic contribution. Better results could be obtained if local government authorities improve the working environment for people working in the informal sector by providing better facilities for health care and environmental safety. The third and final part of the study evaluates the environmental impacts of existing municipal solid waste management (MSWM) in ST using EASEWASTE by taking waste generation, collection, transportation, disposal technologies and material recovery into account. The management of recyclable fractions as well as organic waste has never been taken seriously in Pakistan. Different scenarios using Life cycle assessment (LCA) approach have been developed to find an appropriate municipal solid waste solution. The purpose of this specific study is to find out an economically viable as well as environment friendly solution of generated MSW. Both short term and long term scenarios have been defined and modeled with a LCA approach to find the best option for managing MSW. Short term scenarios include baseline scenario (BS) representing the existing MSW management system as well as scenario for transporting recyclable fractions (STR) to specific large scale recycling industries located far from Lahore across the province of Punjab, scenario for composting (CS) where emphasis in on using 32% of organic waste for composting before final disposal and scenario for using 32% of the organic waste for anaerobic digestion (AD) (SAD) respectively. The long term scenario incorporates the transportation of recyclable fractions from STR and represents the long term solution by using organic fractions (food waste, yard waste and diapers) for composting and anaerobic digestion (SRCA). The baseline scenario (BS) represents the existing MSW management system with a total of 338,656 ton/year (t/y) generated waste including glass 6,090.4 t/y (1.8%), metal 1,691.7 t/y (0.5%), paper and card board (PAC) 18,609.5 t/y (5.5%), plastic 16,917.8 t/y (5%), reuse 16,917.8 t/y (5%) and the remaining 278,127.8 t/y (82.2%) is treated as residual waste (organic waste mainly food waste, yard waste and diapers). A series of potential improvements in the waste management system have been introduced. SRCA explains the alternate strategies for organic waste management. Substituting open dumping with composting and AD has proved to be environmentally significant as overall impacts on environment are minimum compared to other short term scenarios. Results of the study clearly suggest that managing waste through SRCA shows savings on impact potentials like global warming potential (GWP), human toxicity (HT), photochemical ozone (PCO) with low and high NOx of the life cycle impact assessment (LCIA) categories. The total global warming potential (GWP) is 7.93E+06 (kg CO2-eq) in SRCA which is remarkably lower as compared to GWP in BS, STR, CS, SAD 3.02E+08, 3.04E+08, 1.60E+08 and 1.18E+08 (kg CO2-eq) respectively. Similar trend is observed in case of human toxicity and photochemical ozone formation. Therefore, SRCA suggests the best option for an aproperiate management of MSW in ST Lahore, Pakistan