Methodology

The key feature of the proposed analysis is GIS technology. According to Ghose et al.

(2006) and Chalkias and Lasaridi (2009), GIS is an important tool for solving complex routing problems with regard to waste transport, from the collection spot to the waste landfill with the aim of minimising costs. The effectiveness of this tool is well documented in the literature; for example, Santos and Rodrigues (2003), Tarantilis et al.

(2004), Armstrong and Khan (2004), Ghose et al. (2006), Viana (2006), Ericsson et al.

(2006), Salhofer et al. (2007) and Taveres et al. (2009). The structure of the methodology that was followed in this work, shown in Figure 5-1, comprised of three general steps.

Step 1 established the spatial database of the study area as described previously. Step 2 was dedicated to the research for different optimisation versions with the use of GIS analysis functions. Finally, Step 3 consisted of the waste collection routing optimisation in terms of minimum time, distance and fuel consumption.

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Figure 5-1. Flow chart of the adopted methodology 5.3.2.1. FIELDWORK STUDY AND DATA COLLECTION

In order to analyse the spatial data for the optimisation of the waste collection scheme in the study areas, a spatial database (SDB) within a GIS framework was constructed. The description of this database is provided in section 3.1. The main sources of the SDB were (a) analogue maps from the municipalities involved, (b) digital data from various official providers (e.g. National Statistical Service) and (c) data derived from field work/on-site data capture with the use of GPS technology.

5.3.2.2. GISANALYSIS

For the purpose of efficiently managing the SW collection and transport system through a reduction in haul distance, time and cost, balancing the distribution of waste collection in all the zones, and ensuring equitable involvement of all assigned vehicles in waste hauling, GIS techniques were used to optimise the collection routes in the study areas involved. Since, by using ArcGIS, it is possible to plan routes for an entire fleet, calculate drive-times, locate facilities and solve other network related problems (Son, 2014), it was used together with the Network Analyst extension to develop an optimisation module to calculate the shortest distances.

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The GIS software took into account parameters in solid waste management such as the location of dumpsites, truck capacities and the road network, as well as the waste generation volumes of the area (Son, 2014; Kinobe et al., 2015).

In the identification of the existing practice with regard to municipal waste materials collection, where the main objective was to identify existing collection routes of bins, the receivers of the Global Positioning System (GPS) technology were used to collect data on dumpsites and routes. A Magellan® Triton 1500 model GPS was used to collect and store data that was later integrated into, and managed by, GIS software.

With the aim of mapping the current situation, the existence of a complete road network, satellite images of the area from the Google Earth application (Figure 5-2), descriptive information of roads such as one-way streets, average speeds, street names, street types and dead ends, were required.

Figure 5-2. Satellite image for one of the areas studied (Irbid city) using Google Earth application

Another very crucial point for the routing application development was the identification of the municipal solid waste vehicles’ routes, including landfill sites and garages, the positions and types of containers per sub-region, container density per route, and finally a set of additional information such as the number and type of bins, capacity, district they belong to, etc. After determining the itinerary’s start and end points, the route was determined. Finally, another category of primary data was created related to the existing routes of the waste trucks which are operated by the municipality. Figure 5-3 illustrates an example of one collection route tracked using GIS data.



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Tracking the overall operational cost of solid waste collection and transportation was one of the main goals of this study. The main objective was to optimise the cost of solid waste collection and transportation. Consequently, the costs of handling solid waste in the form of the cost of staff (staff type, amount and costs), vehicles (number of vehicles, capital costs, fuel costs, oil costs and maintenance) and containers (capital costs and maintenance) were input and analysed using Microsoft Excel. Detailed data were obtained from the three cities concerned.

The third phase was the main objective of this study because it had, as the final derivative, the development of a methodology to optimise the waste trucks’ routes utilising GIS technology. The routing application of the routing in the study area was undertaken using the Network Analyst tool, which is an extension of ArcGIS software that provides network-based spatial analysis including routing, travel directions, closest facility and service area analysis. The Network Analyst tool is able to identify efficient travel routes for the trucks during solid waste collection.

In order to solve the route optimisation problem, distance criteria and collection time by the truck (regardless of time spent in traffic) were generated and considered. By considering the speed formula (v = Δd/Δt), the duration taken for each truck travelled throughout the solid waste collection procedure was obtained. The final output was an optimal solution in terms of distance criteria. After setting the stop points, the optimised routes for solid waste collection were produced.

5.3.2.3. R^OUTE OPTIMISATION

The final stage of the implementation included the calculation of the optimal route which would be followed by the waste truck for the collection of bins in the study area, in order for the waste collection process to be undertaken in the most efficient way, and subsequently to compare the results of the implementation with the current waste collection situation in the municipalities under consideration. Next, the best possible scenarios for solid waste collection routes were identified based on the information obtained with the help of the GIS regarding the possible routes, and having taken into account the restrictions in terms of road conditions and topography. The routes were chosen in such a way that the resources used for collection, the length of the route and the time taken to complete the collection, is minimised.