FEASIBILITY STUDY OF TRANSFER STATIONS SITING: A CASE STUDY ON CITY OF NASHIK, INDIA

摘要

In India, a significant amount (~ 85 %) of total MSW management system is spent on waste collection; nonetheless, average collection efficiency in Indian urban centers is about 70%. Efficacy of collection system can be enhanced by using collection vehicles and staff members more efficiently with the help of transfer stations (TSs). TSs are linkages between waste generation sources and final disposal or processing facilities, and hence play a key role in efficient collection system. However, choosing best locations for TSs becomes extremely important for the urban centers willing to have TSs. In this study, a facility location based approach has been proposed to find the best sites in an economically optimal manner for TSs siting in the city of Nashik, Maharashtra, India. Nashik has got 45.91 marks out of maximum 100 marks in overall sanitation under the National Urban Sanitation Policy (2010), Government of India, which reflects the need of MSW management system ameliorations in the city. This approach has two elements: (i) a mixed integer non-linear facility location model; and (ii) a GIS based geo-spatial database for facility location model. For MSW management systems, GIS based geo-spatial data base provides a framework to analyze these problems spatially. On the basis of waste load estimation at waste generation sources and distance measurement methods, three distinct scenarios have been taken into consideration. The first scenario (scenario (a)) is a conventional approach and presumes waste generation sources as point sources situated at the centroid of each and every ward and Euclidean distances as measurement unit, whereas another scenarios (scenario (b) and (c)) presume generation point sources on road network and on-road distances as measurement unit. Furthermore, scenario (c) takes account of the population density of respective wards and therefore more accurate and realistic in nature. Facility location models for scenarios (a), (b) and (c) have 1005, 9186, 9186 constraints and 880, 8152, 8152 variables respectively. Also, to examine the economic feasibility of TSs, break-even point has been determined. Facility location model for the city of Nashik has been written in AMPL (a mathematical programming language), with KNITRO 5.2 (nonlinear interior-point trust region optimizer) and Gurobi Optimizer 6.0 as solvers. Model chooses three out of eight sites as best sites with the optimum capacity of 200 TPD.