2.0 Literature Review

(cont. Musanna’s Part)

In addition, Landfill site selection is a difficult, complex process, which requires evaluation of many different criteria (Chang et al. 2008) such as social, environmental and economic factors. It is an important component of any waste management system. A good waste disposal area has few characteristics. One of which is that the area should be away from the regions in which there is a history of flooding. Otherwise, the wastes can be a serious source of water pollution which in turn threatens the environment and lives (Akbari et al., 2008). To get a good waste disposal in accordance with technical requirements, economical and environmentally friendly; the right method is needed such as placing the waste disposal with the appropriate geological formations so that pollution that happen can be prevented or reduced. (Leao et al., 2004).

In order to protect the those region from getting affected by the landfill, a buffer distances are provided to make the separation between the landfill and the sensitive land uses and act as the primary control of potential adverse impact. The buffer distance between the waste operations area and sensitive land uses should be incorporated into the licensed area to prevent future encroachment of incompatible activities and land uses (EPA Guidelines, 2007).

Landfill should not be seen from highway for aesthetical reason and yet it should be accessible, thus buffer zone should be added on both sides of the highways. As an example, a 500 m buffer zone was set on each side of highways for Beijing-China (Guiqin et al., 2009) and while 1000 m buffer zone was used in Kurdistan Province and Asansol cases (Ghose et al., 2007; Sharifi et al., 2009).

A minimum buffer distance of 500 m shall be maintained between areas dedicated for waste disposal and the nearest surface water (whether permanent or intermittent) and the ‘100 year flood plain’. The landfill also should be buffered about 500 m to residential development, rural townships and highways or arterial road networks. A lesser buffer may be acceptable where it is considered compatible with the surrounding area and land uses so that there will be an effective buffer of 500 m between the landfill and any sensitive or incompatible land use (EPA Guidelines, 2007)

Lin and Kao (2005) suggest that appropriate slope for landfill is about 8 -12 percent. While Akbari (2008) states that the best places for waste disposal are areas with medium altitude surrounded by hills and with less than 20 percent slopes. It also widely mention in the literature that landfill sites should be located on the remote areas from the surface water resources (Sharifi et al., 2009; Guiqin et al., 2009; Kontos et al., 2005; Senar et al., 2010). In

addition to that, the China, Turkey, Greece Regulation states that a 500 m buffer zone must be maintained around the surface of water bodies.

According to the Department of Environment (DOE), Malaysia (2012), the overall buffer of residential area (in meters) from landfill (disposal of solid or non solid, municipal, non-toxic and non-hazardous waste) is about 500 meters; not applicable for the disposal of transition radioactive waste from hospitals.

While in the Executive Summary of the EIA for the proposed Municipal Solid Waste Sanitary Landfill (2008) state that the minimum buffer zones from the waste disposal areas to the nearest privately owned property is set at 250 m. This reduces conflicts with surrounding sensitive receptors. Potential conflict on land use compatibility is the permanent loss of agricultural land (i.e. orchards at the southern section of the site) due to land acquisition and more difficult access to forest reserves by the Orang Asli from the nearby Kampung Orang Asli Kachau and Kampung Orang Asli Beroga. Potential conflict with current residential areas (i.e. Taman Tasik Semenyih) may result in a reduction in property values in the vicinity. In addition, the land use of the proposed site may conflict with future built developments (residential/institutional) that may be planned for the area. In future development in the vicinity of the Beroga Sanitary Landfill, BSL 1.5 km should be limited to low-density development such as waste recycling and supporting ancillaries, landscape plant nurseries, utilities, wood industries and forest conservation activities, cemeteries, and agricultural based industries.

Meanwhile, James Gough stated that, “In the initial stage to start the report of Ipoh’s Solid Waste Sanitary Landfill, Ipoh Echo approached Ipoh City Council for a copy of the site map and discovered that indeed the landfill location was within the 1.7 km Asian Rare Earth refinery (ARE) buffer zone. A subsequent check with the Director of Atomic Energy Licensing Board (AELB), Raja Dato’ Abdul Aziz, verified that the map in question was the same which the Board had based its objections on. Abdul Aziz also clarified that “the buffer zone is 2 km in radius. However, since it encroached onto the Lumut Highway, the Board reduced the buffer zone to 1.7 km”.

Application of GIS in Landfill Selection Site:

One of the commonly used software to exploit huge amount of spatial data is Geographical Information System (GIS) and for choosing landfill site - GIS can be thought as one of the most suitable and competent software. The issue of landfill site selection was complicated and time consuming. During the last few decades and particularly when environmental planning emerged, this issue became systematic and technical. The evolution of GIS made this field much easier and manageable. GIS gave the ability and functionality to find

best location for certain purposes with many limitations. GIS has been found to play a significant role in the domain of sitting of waste disposal sites. Many factors must be incorporated into landfill sitting decisions and GIS is ideal for this kind of preliminary studies due to its ability to manage large volumes of spatial data from a variety of sources. (Sener et al. 2006)

A GIS-based constraint mapping was employed to eliminate the environmentally unsuitable site and to narrow down the number of sites for further considerations. Several important factors and criteria were considered to arrive at the optimum sitting decision including the pre-existing land use, location of sensitive sites, infiltration, water bodies, water supply sources, groundwater quality, air quality, fault line and geology. Thematic maps (map which designed to show the physical, social, political, cultural, economic, sociological, agricultural or any other aspect of the city, state, region, nation or continent) of the selected criteria were developed within the paradigm of standard GIS software. Subsequently, weightings were assigned to each criterion depending upon their relative importance, and ratings in accordance with the relative magnitude of impact. Geneletti (2010) proposed and implemented an approach by combining stakeholders view with spatial multi-criteria evaluation approach in the sitting and ranking of landfill site in south-western Trentino, Italy. Their approach used seven criteria (distance from settlement, elevation, slope, distance from water bodies, soil permeability, major farmlands and ecological values) to construct land suitability map. The involvement of stakeholders and experts in the analysis creates room for the handling of different inputs such as the views of the locals and neighbors thus lending credence to the technical nature of landfill site selection. Then, the GIS-based overlay analysis was performed to identify the optimum site for the landfill, one which fulfilled all of the desired attributes.

Other than that, GIS allows the users to integrate GIS data with the other sources of data such as satellite images, CAD drawings, and parcel maps to create a visual overview of a project and turn it into easily understood reports. It accepts CAD data without conversion and includes it as a layer in a geodatabase. The integration and interoperability capabilities of ArcGIS with many other products offer complete flexibility in workflow support. The data integration capabilities of ArcGIS make it a powerful tool for modeling and for visualizing results.

Many of the attributes involved in the process of selection of landfill sites have a spatial representation, which in the last few years has motivated the predominance of geographical approaches that allow for the integration of multiple attributes using geographic information systems (Kontos et al. 2003; Sarptas et al. 2005; Sener et al. 2006; Gomez-Delgado and Tarantola 2006; Delgado et al. 2008; Chang et al. 2008).

Multi-criteria evaluation (MCE) is used to deal with the difficulties that decision makers encounter in handling large amounts of complex information. The principle of the method is to divide the decision problems into more smaller understandable parts, analyze each part separately, and then integrate the parts in a logical manner (Malczewski 1997). The integration of GIS and MCE is a powerful tool to solve the landfill site selection problem because GIS provide efficient manipulation and presentation of the data and MCE supplies consistent ranking of the potential landfill areas based on a variety of criteria (Sener et al. 2006).

Other than that, Lin and Kao (1998) developed a model which was applicable for vector-based data. When the model integrated with a GIS, the model was capable of processing digital spatial data to facilitate landfill sitting analysis.

GIS-based MCDA is an intelligent system that utilizes and converts spatial and non-spatial data into valuable information which in addition to the judgment of the decision maker can be used to make critical decision (Chen, Yu, & Khan, 2010; Sumathi et al., 2008). GIS-based MCDA requires a variety of geographically referenced data and a set of alternatives with a series of evaluation criteria. It aggregates the criteria maps in accordance with attribute values and the preference of the decision maker (Malczewski, 2006). Sitting of a new landfill using a multi-criteria decision analysis (MCDA) and overlay analysis using GIS proposed a system that considered several factors in the sitting process, such as geology, water supply resources, land use, sensitive sites, air quality, and ground water quality. This system could help government bodies set guidelines and regulations, and evaluate prevailing strategies for handling and disposal of waste.