Landfill demand and allocation for municipal solid waste disposal in Dhaka city—an assessment in a GIS environment

Site selection of new landfills for municipal solid waste (MSW) disposal is a great concern of urban governments around the world as old landfill sites are being filled-up and demand for new sites is increasing. Finding a suitable MSW disposal site of adequate size meeting all the regulations is a costly endeavor. With the advent of geographic information systems (GIS) and its decision support tools, preliminary screening and prospective site selection can be done effectively with high degree of accuracy. In this paper landfill demand for disposal of MSW of Dhaka, the capital of Bangladesh is assessed by projecting population and waste generation for the period 2007-2025. A spreadsheet modeling is done for the assessment of area requirement for landfill demand using waste generation rate and population growth rate. Several waste management scenarios is considered in assessing of waste generation and landfill demand. For finding suitable landfill sites, a multi-criteria evaluation (MCE) on various raster map layers is done in GIS environment. Various map layers of Dhaka city (1734 km) is prepared using standard exclusionary criteria. Map layers are then overlaid and combined using weighted linear combination (WLC) method. In the suitability analysis for weighting of factors a pair-wise comparison method provided by the analytic hierarchy process (AHP) is used which is built-in the GIS environment. Suitable areas further masked out for being small size or discontinuity of land parcel. Finally suitable land parcel is ranked with size in descending order as larger sizes are more suitable than smaller sizes for landfill development. The paper presents three scenarios for available suitable lands by changing relative importance factors. © 2009 Institution of Engineers, Bangladesh. All rights reserved.