A GIS based transportation model for solid waste disposal – A case study on Asansol municipality

Abstract

Uncontrolled growth of the urban population in developing countries in recent years has made solid waste management an important issue. Very often, a substantial amount of total expenditures is spent on the collection of solid waste by city authorities. Optimization of the routing system for collection and transport of solid waste thus constitutes an important component of an effective solid waste management system. This paper describes an attempt to design and develop an appropriate storage, collection and disposal plan for the Asansol Municipality Corporation (AMC) of West Bengal State (India).

A GIS optimal routing model is proposed to determine the minimum cost/distance efficient collection paths for transporting the solid wastes to the landfill. The model uses information on population density, waste generation capacity, road network and the types of road, storage bins and collection vehicles, etc. The proposed model can be used as a decision support tool by municipal authorities for efficient management of the daily operations for transporting solid wastes, load balancing within vehicles, managing fuel consumption and generating work schedules for the workers and vehicles.

The total cost of the proposed collection systems is estimated to be around 80 million rupees for the fixed cost of storage bins, collection vehicles and a sanitary landfill and around 8.4 million rupees for the annual operating cost of crews, vehicles and landfill maintenance. A substantial amount (25 million rupees/yr) is currently being spent by AMC on waste collection alone without any proper storage/collection system and sanitary landfill. Over a projected period of 15 yr, the overall savings is thus very significant.

Introduction

Technological development, globalization and population growth have accelerated the dynamics of the urbanization process in developing countries. In India alone, the urban population has increased from 11% in 1901 to 26% in 2001. The rapid growth rates of many cities, combined with their huge population base, has left many Indian cities deficient in infrastructure services like water supply, sewerage and solid waste management.

Due to a lack of serious efforts by town/city authorities, the management of garbage has become a tenacious problem, notwithstanding the fact that the largest part of any municipal expenditure is allotted to it. It is estimated that the urban local bodies spend about 500 rupees (1 US$ = 45 rupees approx.) per ton on solid waste collection, transport and disposal, which may rise to 1500 rupees per ton in some instances. A substantial amount of the total expenditure (85%) is spent on collection and as such improvement in the design of the collection systems could result in substantial savings, thereby saving a large proportion of the funds.

However just collecting the waste from different parts of city does not solve the problem, it requires disposing the waste in environmentally safe and economically sustainable manner. An effective solid waste management system is needed to ensure better human health and safety.

In general, an effective solid waste management system should include one or more of the following options: waste collection and transportation; resource recovery through waste processing; waste transportation without recovery of resources, i.e., reduction of volume, toxicity, or other physical/chemical properties of waste to make it suitable for final disposal; and disposal on land, i.e., environmentally safe and sustainable disposal in landfills (Tchobanoglous et al., 1993, Kreith, 1994, CPHEEO, 2000).

Most often, it appears difficult to minimize two variables – cost and environmental impact – simultaneously. Hence, the balance that needs to be struck is to reduce the overall environmental impact of the waste management system as far as possible within an acceptable cost limit.

In this paper, an attempt has been made to propose an efficient solid waste management system for municipal solid waste, excluding industrial, constructional and hospital waste. The framework of the proposed waste management plan is mainly based on the following considerations:

• Appropriate method of on-site storage.

• Appropriate method of bulk storage of waste.

• Appropriate method of primary collection of waste.

• Appropriate method of transportation of waste using Geographical Information System (GIS).

• Appropriate method of waste disposal.

• Financial expenditure on whole solid waste management plan.

Development of an optimal routing scheme for waste disposal involves determination of a number of selection criteria, which is a tedious job for a planner to do manually. Various optimization models are discussed in the literature. Pelms and Clark (1971) proposed a location model for optimal location allocation, while Male and Liebman (1978) used the districting and routing for solid waste collection. Clark and Gillean (1974) gave a system analytical approach, and Baetz (1990) adapted simulation modeling for optimal solid waste collection. In the present study, the principles of the Geographical Information System (Heywood et al., 1988) are mainly emphasized in planning an effective solid waste management system.