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Spatial effect of new municipal solid waste landfill siting using different guidelines Siti Zubaidah Ahmad, Mohd Sanusi S Ahamad and Mohd Suffian Yusoff Waste Manag Res 2014 32: 24 originally published online 15 November 2013 DOI: 10.1177/0734242X13507313 The online version of this article can be found at: http://wmr.sagepub.com/content/32/1/24
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WMR32110.1177/0734242X13507313Waste Management & ResearchAhmad et al
Original Article Waste Management & Research 2014, Vol 32(1) 24–33 © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0734242X13507313 wmr.sagepub.com
Spatial effect of new municipal solid waste landfill siting using different guidelines Siti Zubaidah Ahmad, Mohd Sanusi S Ahamad and Mohd Suffian Yusoff
Abstract Proper implementation of landfill siting with the right regulations and constraints can prevent undesirable long-term effects. Different countries have respective guidelines on criteria for new landfill sites. In this article, we perform a comparative study of municipal solid waste landfill siting criteria stated in the policies and guidelines of eight different constitutional bodies from Malaysia, Australia, India, USA, Europe, China and the Middle East, and the World Bank. Subsequently, a geographic information system (GIS) multicriteria evaluation model was applied to determine new suitable landfill sites using different criterion parameters using a constraint mapping technique and weighted linear combination. Application of Macro Modeler provided in the GIS-IDRISI Andes software helps in building and executing multi-step models. In addition, the analytic hierarchy process technique was included to determine the criterion weight of the decision maker’s preferences as part of the weighted linear combination procedure. The differences in spatial results of suitable sites obtained signifies that dissimilarity in guideline specifications and requirements will have an effect on the decision-making process. Keywords Municipal solid waste (MSW), landfill siting, landfill guideline, geographical information system (GIS), multi-criteria evaluation (MCE), constraint mapping technique (CMT), weighted linear combination (WLC), Malaysia
Introduction The new solid waste management plan introduced in Malaysia has enhanced the social, economic and environmental efficiency that promotes sustainable development. It has also helped resolve the dual crisis of non-renewable resources depletion and environmental degradation (Manaf et al., 2009). The government has being trying to ensure the quality of life among citizens so as to achieve the Vision 2020 of becoming fully developed country: ‘By the year 2020, Malaysia can be a nation that is united, with a confident society, infused by strong moral and ethical values, living in a society that is democratic, liberal and tolerant, caring, economically just and equitable, progressive and prosperous, and in full possession of an economy that is competitive, dynamic, robust and resilient’ (Mahathir, 2008). This statement, given by the exPrime Minister of Malaysia, relates to waste management issues. Waste management is realized as one of the factors that measures the achievement of a country toward the Vision 2020. Waste management is not only about the techniques of waste collection, transportation and disposing by the responsible party or agencies. Good waste management practices actually start at the sources of the waste. In Malaysia, the sources of solid waste within the community are residential, commercial, institutional, construction and demolition, and municipal facilities. By infusing strong moral and ethical values, as stated in the Vision 2020, proper waste management is achievable and, together with the serious concerns of the public, waste generation will reduce. Local
government in Malaysia has implemented numerous awareness campaigns and programs with the intention that the public will adhere to the efforts of reducing waste in the community. They introduced the ‘3R’ (recycle, reuse, reduce) concept for waste minimization purposes. The public should be aware that the environmental pollution (air pollution, water pollution and ground pollution) are happening as a result of the waste dumping process. The community itself is self-exposed to hazards and threats without proper management. Therefore, public concern is very important in ensuring the public health and prosperity in order to achieve the Vision 2020. Most countries in the world, including Malaysia, are having problems dealing with their municipal solid waste (MSW). Landfilling is the cheapest method used for the disposal of MSW in Malaysia, and most of the landfill sites are open dumping areas. However, disposal of wastes through landfilling has become complicated, with the landfill sites filling up at a very fast rate (they will be full in 5–10 years). At the same time, construction of new School of Civil Engineering, Universiti Sains Malaysia, Pulau Pinang, Malaysia Corresponding author: Siti Zubaidah Ahmad, School of Civil Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang, Malaysia. Email: [email protected]
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Ahmad et al. landfill sites is more difficult owing to land scarcity, an increase of land prices and high demand, especially in urban areas with the increasing population (Manaf et al., 2009). Locational criteria are important in the problem of where to site a landfill. Bagchi (1990) and Tchobanoglous (1993) state that landfills should be located a certain distance from the features such as lakes, ponds, rivers, wetlands, flood plain, highway, critical habitat areas, water supply, well and airports. Currently, landfill siting is prohibited in areas where potential contamination of groundwater or surface water bodies exists. Generally, special approval from local authorities will be required when the proposed landfill site does not meet the locational criteria. Nevertheless, there will be no issue when the proper site selection process has taken into consideration all constraints and statutory regulations. A proper revision of all restrictions during the preliminary siting process is significant to avoid wasting time and money in evaluating sites that will not conform to the standard requirements. At present, researchers are exploiting spatial information technology, such as geographic information systems (GIS). GIS tools and capability are applicable for site suitability assessment and provide results in a good manner with high accuracy (Ersoy and Bulut, 2009; Zamorano et al., 2008). GIS has a high capability of managing a large amount of data, as well as changes in the data (Siddiqui et al., 1996; Vatalis and Manoliadis, 2002). The GIS analytical tool is useful in checking spatial parameters (criterion attributes) imposed in site selection process. Landfill site selection is the fundamental step in an ideal waste disposal practice in protecting the environment, public health and ensuring the quality of life for a sustainable future. A proper landfill site selection determines the successive steps in the preliminary landfill process. Proper implementation of landfill siting is important to avoid the undesirable long-term effects. A suitable landfill site should be selected carefully by considering criteria (regulations and constraints) issued by environmental agencies or local authorities (Ahmad et al., 2011). In general, the criteria for landfill site selection consider the environmental, social, economic and physical aspects. With different countries having their specific guidelines for landfill site selection, the problem of finding the appropriate landfill site therefore requires a very complete and sustainable site selection model. The major setback of landfill waste disposal method is their short lifecycle and shortage of suitable land for landfills especially in urban areas. In addition, the ‘not in my back yard’ phenomenon has created a negative impression toward landfill by the local community. Landfill operations are blamed for causing external costs to nearby residents who perceive risks associated with traffic, noise, dust, litter, unattractive neighborhoods, groundwater contamination and hazardous waste pollution, etc., to be associated with landfill. There are also other non-market costs not borne by waste disposal firms and producers of garbage. These external costs will result in an incompetent allocation of resources (too much garbage and exposure to it) (Roberts et al., 1991). Hence, proper landfill site selection must be the basis of the preliminary landfill process to avoid undesirable
long-term effects. The selection procedure must refer to authorized guidelines that consider social, environmental and technical aspects in ensuring the sustainability of the livelihood process. The guidelines and policy will help to restrict and reduce the landfill effect on the external costs, but only if the decisionmakers strictly follow the stated site selection criteria. Externalities, sometimes known as spillover effects or offsite impacts, impose costs or benefits on the community that are not priced into market exchanges (BDA Group, 2009). Disposal of waste to landfill can result in externalities, including the effect of releasing methane and greenhouse gases from the decomposition of organic wastes. There is also the potential for effects from leaching of toxic metals and compounds into the surrounding soil structure. Other externalities include the impact of noise and odors on local amenities, and the effect of air emissions. Different materials and products disposed to landfill will contribute differently to externality costs. For example, inert materials are likely to have few external impacts, while biodegradable materials will present additional problems associated with greenhouse gas emissions and odors, while other materials may contain hazardous substances that pose potential risks to human health through air and water emissions. Landfill is currently the cheapest waste disposal option. Most would agree that all of the costs and externalities are known and internalized into the landfill gate price. Companies will make a commercial decision to build resources recovery infrastructure where they can make profit while competing against landfill disposal. It is recommended that landfill should be regulated and a set of minimum environmental standards should be agreed upon, the effect of which will be to push up the costs of landfill operations. The government, through their guidelines, must emphasize and control this because in a landfill siting the maximum environmental standards are required to ensure sustainability in the future. DEFRA (2003) states that it is widely accepted that externalities can be conceptually split into fixed (independent of the quantity of waste) or variable (depending on the quantity of waste) costs and benefits. The term ‘fixed externality’ refers to the externalities that arise from the mere existence of a landfill. Such fixed costs should be calculated as per site and should relate to the existing distribution of households around a site. In the context of landfills, such costs should therefore be independent of the size of the landfill (area or stock capacity), the amount of waste it receives (flow volume) and, possibly, the type of waste it receives (inert, biodegradable or hazardous). The term ‘variable externality’, however, refers to the externalities that depend on the type and amount of waste going to a landfill. Emissions to air and water are clear examples of variable externalities. Externalities arise, in an unconstrained market, as they convey external costs or benefits to others, and these effects are not captured in the price mechanism. Externalities are a form of market failure, and, where these are present, correction may lead to a more efficient outcome in terms of resource allocation. Site selection, when viewed as multi-criteria evaluation (MCE) problem, implies the assignment of values to alternatives
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Waste Management & Research 32(1)
Table 1. Benefits and costs of alternative waste management practices (BDA Group, 2009). Waste management practice
Benefits
Costs
Recycling/reuse
Potential to reduce use of virgin materials, energy and generation of pollution in industrial processes
Recyclate collection, sorting and processing costs, and associated environmental impacts
Composting
Potential to reduce use of virgin materials
Organic waste collection and processing costs and associated environmental impacts
Advanced waste technologies
Energy recovery Potential to reduce use of virgin materials, energy and generation of pollution in industrial processes
Processing costs and associated environmental impacts Environmental impacts with landfilling of residuals
Landfill
No further processing required Gas can be captured for conversion to electricity
Land consumption Environmental risks from gas emissions and leachate Long-term post-closure management
Incineration
No further processing required
Environmental risks from air pollution
Illegal disposal
–
Heightened environmental risks Amenity impacts
that been evaluated along with multiple dimension or criteria. In general, the MCE process applies decision rules to meet specific objectives, frequently in the cases of evaluating several criteria together. The main task in MCE is concerned with the process of combining information from several criteria to form a single index of evaluation. The landfill siting process is possible by integrating the GIS spatial analytical tool with MCE, which then becomes a decision-making tool for solving complex multiple criteria problems either in qualitative and/or quantitative aspects of the problem (Mendoza et al., 1999). There are various algorithms embedded in GIS–MCE for site selection modeling. Among them are analytical hierarchy process (AHP), ranking and rating, fuzzy, weighted linear combination (WLC), and ordered weighted averaging. MCE has many advantages, but it also has disadvantages. MCE can incorporate a diverse range of information, can be subcontracted and is easily communicated. It provides an audit trail, which is especially useful in situations where decision-making is required to follow rules and to be justified in explicit terms. The most extraordinary strength of MCE is the flexibility of this analysis in handling large amounts of complex information and various dimensions, i.e. choice of options, criteria and weighting in a consistent way. Unfortunately, MCE becomes poor because of the difficulty in deriving the weight, it lacks methodological strictness and is less inclusive. Cost–benefit analysis (CBA) is a conceptual framework for the evaluation of projects in the government sector that tries to consider all gains and losses from the project. This framework analysis takes a long and wide view that includes all relevant future dates and the effects on all relevant parties. CBA usually express costs and benefits in the common metric of today’s money. CBA can recognize that each choice has a cost and force more detailed consideration of what is meant by the adjectives placed in front of the word ‘value’. It also makes explicit hidden costs and benefits. However, some costs and benefits cannot be
monetized (qualitative costs and benefits), i.e. quality of life, equity, ensuring public health and safety, reducing crime, protecting human rights, employment, education, etc. The best way to handle the qualitative costs and benefits are to exclude the nonmeasurable costs and benefits from strict CBA. The decisionmakers can include it in final decision-making through other analyses, i.e. social impact analysis, and specify qualitative pros and cons or MCE. CBA is not competent enough because the valuation techniques are imperfect and loaded with assumptions. It is difficult to balance qualitative costs and benefits against quantitative costs and benefits in CBA framework terms. The private costs of landfilling vary depending on the size of the landfill, type of waste handled and management measures in place (BDA Group, 2009). The private costs of landfill include land purchase, the approvals process, the capital cost of equipment and buildings, and the cost of lining landfill bases to prevent leaching. Costs of on-site gas recovery and flaring, fencing and other measures to prevent waste from being blown into adjoining properties and operational costs, including labor, are also taken into account. Moreover, fuel and materials, the cost of capping landfills and landscaping, and the cost of rehabilitation and aftercare also need to be taken care of. A number of different waste management practices are available, and their associated costs and environmental impacts vary widely. Table 1 highlights the key benefits and costs of the major alternatives. In general, MCE been seen as subsuming a CBA, while CBA is one criterion for assessing options. MCE can define a narrow set of options then subjected to CBA. MCE can work together with CBA, where one handles the quantitative costs and benefits, and the other handles the qualitative costs and benefits. Landfill siting is a complex process involving social, environmental and technical parameters, including government regulations. Increased perception of health and other risks associated with solid waste disposal facilities has made the siting of new
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Ahmad et al.
MODEL BUILDING - IDRISI macro-modeler module LITERATURE REVIEW Comparative study - Land ill guideline review - Land ill siting criteria - Waste policy and guideline of each country (World Bank standard speci ication and seven areas, i.e. Malaysia, India, Australia, USA, Europe, China and Middle East)
GIS MAPPING - Constraint and factor map layers - IDRISI macromodeler for model building
MCE ANALYSIS - Constraint mapping technique CMT) - Weighted linear combination
RESULT AND DISCUSSION
SUMMARY OF FINDINGS WEIGHT DETERMINATION - AHP pair-wise weight derivation
Figure 1. Research study flowchart. MCE: multi-criteria evaluation.
municipal landfills technically difficult and, in some cases, socially and politically unacceptable (Roberts et al., 1991). This will indirectly increase the social costs of the siting process. The habitant acceptance, population distribution, habitant lifestyle, sensitive areas, region planning, public safety and road safety are the examples of non-measurable costs and benefits that measure the overall social costs in landfill siting. In reality, when a project is proposed for any selected areas, the population will act and favor projects or not. Therefore, the government of any country plays a role in reducing the social complains by enforcing a policy and guidelines. If the requirements and guiding principals are followed, any project will benefit society. This article focuses on the comparative study of guideline policies and criteria pertaining to the siting of a MSW landfill issued by eight different geographic regions (Malaysia, Australia, India, USA), Europe, China, the Middle East) and the World Bank Group. Subsequently, spatial comparisons between various landfill site selections criteria from the above-mentioned entities was carried out using a GIS–MCE-based constraint and weighted linear mapping to study the differences among the suitable sites selected.
performed to determine the weight of each criterion to complete the analytical procedure. The study area is located in Seberang Perai District, Pulau Pinang, Malaysia. It has three sub-districts—North, Central and South Seberang Perai—with an estimated area of 73,737 ha (737.37 km2). The rapid development in this region has led to higher solid waste generation. This area is best depicted through the various kinds of human activities and land utilization. It is very rich in culture and is very popular with tourists. Figure 2 shows the study area. In general, the waste generation rate per capita is about 1 kg/day, varying from 0.45 to 1.44 kg/day (CAP, 2001). The 2010 census showed that about 856,800 people live in Seberang Perai with a density of 1086 people per km2. The local authority, Seberang Perai Municipality, reports an estimated amount of waste disposal of 2000 tonnes per day and 0.7 million tonnes per year at the only existing waste disposal site available—Pulau Burung Landfill, which is located in Nibong Tebal, Southern Seberang Perai District (MPSP, 2011). It states that an integrated solid waste system in Penang is a major challenge for local authorities, and the proper implementation of domestic waste collection, transferring, recycling and disposal in the landfill remains a complex issue.
Materials and methods
Result and discussion Landfill siting guidelines
Figure 1 shows the flowchart of the model that links the comparative study of various landfill policies with GIS–MCE constraint mapping technique (CMT) and WLC. Comparisons are based on the parameters of criterion as specified in each of the guidelines. The guideline parameters are important in performing the site selection process as it provides the basis of spatial presentation through GIS map layers (spatial criteria). Application of Macro Modeler provided in IDRISI Andes helps in building the model for site selection process. In addition, AHP weight derivation was
Different countries have to comply with their respective guidelines for landfill site selection. Malaysia, for instance, has had landfill site selection guidelines—the National Strategic Plan for Solid Waste Management (MHLG, 2005)—set up by the Local Government Department Ministry of Housing and Local Government Malaysia since 2005. Table 2 describes the general summary of landfill guidelines compiled from seven geographic areas and the World Bank. The USA, through their Environmental
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Waste Management & Research 32(1)
Figure 2. The study area.
Protection Agency (US EPA, 1993), was first to introduce guidelines for landfill site selection in 1993, followed by Europe (Germany) in 1994 (Oeltzschner and Mutz, 1994) and Australia (DUAP, 1996; NSW EPA, 1996). The World Bank Group first published landfill siting policies in 1996 and then updated them in 2004. Consequently, the Government of India introduced its own guideline (MEF, 2000) in 2000. A thorough review of Iranian and Chinese policies on solid waste management law can be found in Akbari et al. (2008) and Wang et al. (2009), respectively.
Landfill siting criteria The management of solid waste requires accurate guidelines pertaining to right selection of landfill sites. The guidelines are rules or criteria to follow in the process of allocating suitable landfill sites. In general, they include criteria such as the proximity to residential areas; water bodies, groundwater or aquifer potential; location of solid waste transfer stations; prohibited forest reserve area; airports, road or transportation routes; and physical factors, namely slope, soil and geological fault (Cointreau, 2004; Daly, 1995; JICA, 2004; Nakakawa, 2006; US EPA, 2010). Detail
characteristics of these criteria are described in Table 3, while the distinguishing perspective of different countries in quantifying common criteria is shown in Table 4. This study does not concentrate on determining the most appropriate guidelines, but is more concerned with the outcomes of the location when applying different criteria parameters to the site selection process. In addition, landfill-siting parameters pertaining to policies and guidelines must comply with their respective federal and state regulations. Furthermore, restriction on location criterion varies and is dependent on the environmental and climatic conditions of a region. Hasan et al. (2009) stress that most municipalities laid down their own location restriction parameters to meet the local environment conditions. In other words, their local respective interests is in place to protect the environment and public health, and to ensure the quality of life for a sustainable future.
Landfill siting model The landfill siting model was developed based on the information obtained from the review of different criteria from eight
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Ahmad et al. Table 2. Summary of landfill guidelines of various countries and the World Bank. Country
Department
Year issued
Guideline title
Malaysia
Ministry of Housing and Local Government Ministry of Environment and Forest Department Of Urban Affairs and Planning United States Environmental Protection Agency
Updated 2005
Europe (Germany)
Federal Republic of Germany
1994
China
Ministry of Environmental Protection (Republic of China) Iranian Management and Planning Organization The World Bank Group
After Wang et al. (2009) After Akbari et al. (2008) Published 1996 (updated 2004)
National Strategic Plan for Solid Waste Management Specification for Landfill Sites [Rules 6(1) and (3), 7(2)] Environment Impact Statement (EIS) Practice Guideline: Land Filling, Site Selection Procedures Solid Waste Disposal Facility Criteria: Technical Manual (Sub-B: Location Criteria Chapter 2 EPA/530-R-93-017.) Guidelines for an Appropriate Management of Domestic Sanitary Landfill Sites China Solid Waste Management Law
India Australia USA
Middle East (Iran) World Bank
2000 1996 1993
Criteria and Standard Used for Defining Unacceptable Areas An Asian Urban Structure Note
Table 3. Characteristics of landfill siting criteria (Akbari et al., 2008; Cointreau, 2004; DUAP, 1996; JICA, 2004; MEF, 2000; NSEL, 2004; NSW EPA, 1996; Oeltzschner and Mutz, 1994; US EPA, 1993; Vatalis and Manoliadis, 2002; Wang et al., 2009). Criteria
Detailed characteristics
Nearest residential area
Residential factor is the criteria that opposes landfill siting near residential areas. This criterion is regarded as an important factor as it answers the ‘not in my backyard’ or ‘not in anyone’s backyard’ issues. This syndrome expresses public objections towards siting of an urban waste management facility (such as a landfill or composting facility) in, or near, their community This criteria stops landfills being situated close to water bodies, including river networks, lakes and ponds, to protecting water body ecosystems and avoid flood plains. Consideration of preventing leachate or other pollutants from contaminating the area is made. Discharge to surface water is only acceptable when effluent is treated and diluted to a level where there is no significant adverse affect on the water quality requirements of the receiving water Groundwater takes into account the aquifer potential around the landfill site to prevent groundwater pollution. A landfill site must not be adjacent to any groundwater source, such as springs or groundwater wells. Any landfill directive requires prevention of groundwater pollution, but the engineering measures taken prior to set up cannot always guarantee this Transfer stations are facilities where municipal solid waste is unloaded from collection vehicles and briefly held while it reloaded onto larger, long-distance transport vehicles for shipment to landfills or other treatment or disposal facilities The law prohibits new landfill sites on forestland. In land use planning and decision-making processes, this land category is usually assigned as less suitable or not suitable for any development Airport safety factor is to restrict MSW landfill units in areas where sensitive natural environments, as well as the public, may be adversely affected. The landfill site is not to be located near to airport area to prevent disturbance of birds and rising dust from landfill Road or transportation route is an aesthetic consideration of the transportation issue and management of landfill to optimize travelling time and cost. The area must be easily accessible by the waste collection vehicles and all landfill machinery, at all times. It is also important to consider accessibility for emergency response services in the case of accidents or fire at the site. In reality, additional costs for road construction in areas far away from existing roads make them less favorable. However, the guideline states that the road must be as far away as it can be. Therefore, in the practice of siting process, the decision-makers must first create a buffer of a certain number of meters specified as the restriction distance and then reduce the range to an agreed distance for the cost–benefit issue Slope criteria deal with the appropriate terrain conditions suitable for the construction of a landfill site. Construction of landfill on hilly areas is economically not suitable and it may encounter the risk of soil erosion. The operation and maintenance cost of the landfill may increase periodically Soil permeability is important to prevent groundwater pollution from landfill leachate. Soil with good drainage (high permeability soil) is considered as undesirable for a landfill. The water infiltration through this soil is higher and the possibility of groundwater pollution may increase. To protect the groundwater, it is preferable that the soil content is silt or clay that has very low permeability. This does not include marshland and swamp The presence of a geological fault area may cause restriction to conditions, will have unpleasant effect on landfill performance, and could lead to leachate discharge to the environment or disruption of natural function
Nearest water bodies
Nearest groundwater line Nearest distance from sources Nearest protected forest Nearest airport location Nearest road line
Maximum Slope Soil Permeability
Nearest fault line
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Table 4. Landfill siting guidelines of World Bank and seven selected geographic areas. Parameter
Country
Malaysia World Bank (an India Asian urban infrastructure note)
Australia USA
Nearest residential area (m) Nearest water bodies (m) Nearest groundwater line (m) Nearest distance from sources (km) Nearest protected forest (m) Nearest airport location (km) Nearest road line (m) Maximum slope (%) or height (m) Soil permeability (cm/s) Nearest fault line (m)
1000 100 1000 25 100 3 500 10 < 10-6 100
250 100 100 15–20 500 8 100 20 < 10-6 100
1000 500 1500 25 500 3 3000 20 < 10-6 500
500 100 1000 20–25 100 20 200 15 < 10-7 500
Europe China Middle East
500–2000 500 300–500 500 1000 1000 25–40 25 50–100 100 4 3 50–100 500 15–20 10–20 < 10-6 < 10-7 100 100
500 300 500 200 1500 50 25 30 100 1600 3 3 100 300 10 20 < 10-7 < 10-6 100 100
Figure 3. Example of macro-modeler for landfill site selection.
different constitutional bodies (Malaysia, Australia, India, USA, Europe, China, the Middle East and the World Bank). The analytical comparative study applies MCE using the CMT and WLC. Both techniques were applied to investigate the differences among the suitable landfill sites selected. The model was tested using digital maps of Seberang Perai, Penang, Malaysia, with the criteria of the eight selected countries. Maps pertaining to the landfill site selection criteria were prepared for the GIS analytical procedure, such as buffer zoning of roads and residential settlement, classification of soil and geological properties, and constraint mapping to slope, protected forest, fault lines, etc. The GIS IDRISI macro-modeler is a graphical environment for building and executing multi-step models for batch processing and dynamic modeling (Eastman, 2006a, 2006b). Models were built from three basic types of element: (1) data elements, (2) command elements and (3) links. Data elements include raster and vector layers, attribute values files and groups. Command elements include
modules such as overlay and buffer, and sub-models are usercreated models. Links establish the sequence of processing between data and command elements. Figure 3 describes the example of the macro-model used in the landfill siting process.
Weight determination Weight, well known as ‘degree of importance’, is a value assigned to a criterion that indicates its importance relative to the other criteria under consideration. The derivation of weights is a central step in attaining decision-makers’ preference. Pair-wise comparison was done via a questionnaire survey where each candidate or alternative was compared (one-on-one) with each other using the AHP preference scale made available by the GIS IDRISI software (Ahamad et al., 2003). The weights were developed based on the relative importance of factors to the suitability of pixels for the activity evaluated. The weight derived from group
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Ahmad et al. decision-making where the geometric mean of the combined judgment was determined (Liberatore and Nydick, 2003) and used as the input parameter for the MCE. Table 5 describes the geometric mean of nine-criterion weight judged by 20 decision-makers.
considered suitable in all criteria (Eastman, 2006a, 2006b). The result shows that common criteria (from seven geographic areas) with different parameters produce different suitable sites, as shown in Figure 4. The total area of new landfill sites obtained is further listed in Table 6.
CMT
WLC
In CMT, all criteria are assumed to be constraints and the mathematical overlay (Boolean multiplication) is applied. This justified the combination procedure, which brings the lowest possible risk as the only areas considered suitable in the result are those
WLC combines both weighted factors and constraints. The factors are multiplied with weight and combined by means of linear summation of results to yield a suitability map. Factor weights are important in this model as they determine how individual factors will exchange relative to each other. The higher the factor weight the more influence that factor has on the final suitability map (Eastman, 2006a, 2006b). Figure 5 describes the result of the analysis. The suitability area has five classes: (1) most suitable site, (2) suitable site, (3) less suitable, (4) not suitable and (5) other sites. The classes are decided according to the required vastness of 300 ha of land area that equals to 4800 cells (625 m2 for each cell). The percentage similarity of the new landfill sites when compared with guidelines from Malaysia is shown in Table 7 and Figure 6. The Malaysian landfill guidelines has the highest spatial location similarity to the European guidelines (26.96%) and differs substantially from the World Bank guidelines (1.61%).
Table 5. Geometric mean of criterion weight. Criteria
Weight
Road Water body Groundwater (aquifer) Residential Soil permeability Land use Geological fault Slope Airport
0.2576 0.1678 0.1549 0.0843 0.0838 0.0786 0.0633 0.0584 0.0334
Figure 4. Multi-criteria evaluation (constraint mapping technique) site suitability based on guidelines from (a) Malaysia; (b) Australia; (c) China; (d) Europe; (e) India; (f) Iran; (g) USA; and (h) the World Bank.
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Table 6. Total area of new landfill sites. Country
Area (ha)
Malaysia Australia China Europe India Middle East USA The World Bank
1241 5156 2690 2407 3628 2767 2526 438
Figure 5. Multi-criteria evaluation (weighted linear combination) site suitability based on guidelines from (a) Malaysia; (b) Australia; (c) China; (d) Europe; (e) India; (f) Iran; (g) USA; and (h) the World Bank. Table 7. Percentage spatial similarity of the new landfill sites compared to Malaysian guideline. First map
Second image
Malaysia
Australia
China
Europe
India
US
World Bank
Middle East
14.58%
12.08%
26.96%
13.14%
12.71%
1.61%
18.92%
30.00 20.00 15.00
Conclusion
26.96
25.00
18.92 14.58
13.14
12.08
12.71
10.00 5.00
1.61
0.00 Australia China
Europe
India
US
World Middle Bank East
Figure 6. Histogram chart of spatial similarity (%) of new landfill sites of different countries.
The variations of criterion parameters in guidelines and policies will have an effect on spatial site selection. This signifies that dissimilarity in specification and requirement will have an effect on the location of new landfill sites. The World Bank guidelines were found to be strict and firm with respect to setting out policies for new landfill siting requirements. It produced a suitable area of only 438 ha. More surprisingly, Malaysian guidelines produced the second smallest size of suitable area (1241 ha) compared with other countries. This gives an indication that Malaysia is very firm with respect to setting out policies for new landfill
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Ahmad et al. sites so as to protect the environment and public health, and to ensure a good quality of life. From the research, we conclude that a comparative site selection process can be performed straightforwardly using GIS analytical procedures. It helps local authorities in detecting specific work on landfill site selection and to ensure that policies and guidelines of site selection criteria are strictly followed.
Declaration of conflicting interests The authors do not have any potential conflicts of interest to declare.
Funding The authors wish to thank the Universiti Sains Malaysia (USM) for the provision of the Research University Funding (RU Grant No. 814102) for the completion of this research.
References Ahamad MSS, Wan Hussin WMA and Ahmad S (2003) Comparison of normal AHP and multiplicative AHP for criterion weighting in GIS based land suitability analysis. In: International symposium and exhibition on geoinformation (ISG’03), Shah Alam, Malaysia, 13–15 October 2003. Ahmad SZ, Ahamad MSS and Wan Hussin WMA (2011) Comparative site selection process based on different policies and guidelines for municipal solid waste landfill site. In: 10th International symposium & exhibition on geoinformation 2011 (ISG 2011), Selangor, Malaysia, 27–29 September 2011. Akbari V, Rajabi MA, Chavoshi SH and Shams R (2008) Landfill site selection by combining GIS and fuzzy multi criteria decision analysis, case study: Bandar Abbas, Iran. World Applied Sciences Journal 3 (Suppl. 1): 39–47. Bagchi A (1990) Design, Construction, and Monitoring of Sanitary Landfill. New York, USA: John Wiley & Sons. BDA Group (2009) The full cost of landfill disposal in Australia. A report prepared for the Department of the Environment, Water, Heritage and the Arts, Melbourne, Australia. CAP (2001) Malaysia Country Report. Report, Consumers Association of Penang. Available at: http://www.jaringmetal.com/resource/wastemalaysia.pdf (accessed 25 July 2012). Cointreau S (2004) Sanitary Landfill Design and Siting Criteria. Washington, DC: World Bank. Daly D (1995) The location of landfills on regionally important (major) aquifers. The GSI Groundwater Newsletter 28: 2–5. DEFRA (Department for Environment, Food and Rural Affairs) (2003) A study to estimate the disamenity costs of landfill in Great Britain. Final report, DEFRA, UK. DUAP (Department of Urban Affairs and planning) (1996) EIS Practice Guideline: Landfilling, Site Selection Procedures. New South Wales: Crown Publication. Eastman JR (2006a) IDRISI Andes Guide to GIS and Image Processing Manual Version 15.00. Worcester, Massachusetts: Clark University. Eastman JR (2006b) IDRISI Andes Tutorial Manual Version 15.00. Worcester, Massachusetts: Clark University. Ersoy H and Bulut F (2009) Spatial and Multi-criteria Decision Analysisbased methodology for landfill site selection in growing urban regions. Journal of Waste Management and Research 27: 489–500. Hasan MR, Tetsuo K and Islam SA (2009) Landfill demand and allocation for municipal solid waste disposal in Dhaka City – an assessment in a GIS environment. Journal of Civil Engineering (IEB) 37: 133–149. JICA (Japan International Coorperation Agency) (2004) The study on the safe closure and rehabilitation of landfill sites in Malaysia, final report:
Technical guideline for sanitary landfill, design and operation, revised draft, volume 5. Tokyo, Japan: JICA. Liberatore MJ and Nydick RL (2003) Decision Technology: Modeling, Software, and Applications. New York: John Wiley & Sons. Mahathir M (2008) Malaysia as a full developed country – one definition. Report. Available at: http://www.wawasan2020.com/vision/p2.html (accessed 2 February 2012). Manaf LA, Samah MAA and Zukki NIM (2009) Municipal solid waste management in Malaysia: practices and challenges. Waste Management 29: 2902–2906. MEF (Ministry of Environment and Forests Notification) (2000) Schedule 3; Rule 6(1) and (3), 7(2): Specification for Landfill Sites. New Dehli: MEF. Mendoza GA, Macoun P, Prabhu R, Sukadri D, Purnomo H and Hartanto H (1999) Guidelines for Applying Multi-Criteria Analysis to the Assessment of Criteria and Indicators. Jakarta: Center for International Forestry Research. MHLG (Ministry of Housing and Local Government, Malaysia) (2005) Criteria for Siting Sanitary Landfills: National Strategic Plan for Solid Waste Management, Appendix 6B, Vol. 3. Kuala Lumpur, Malaysia: MHLG. MPSP (Majlis Perbandaran Seberang Perai) (2011) Laporan Tahunan Majlis. Pulau Pinang: MPSP. Nakakawa A (2006) A spatial decision support tool for landfill site selection for municipal solid waste management. Masters Dissertation, Uganda Scholarly Digital Library, Uganda. NSEL (Nova Scotia Environment and Labour) (2004) Municipal Solid Waste Landfill Guidelines, Environmental Monitoring and Compliance: Guideline under the Environment Act. Halifax, Nova Scotia: Department of the Environment. NSW EPA (New South Wales Environment Protection Authority) (1996) Environmental Guidelines: Solid Waste Landfills, Locational Criteria, EPA 95/85 Chatswood, New South Wales: NSW EPA. Oeltzschner H and Mutz D (1994) Guidelines for an Appropriate Management of Domestic Sanitary Landfill Sites. Eschborn, Germany: Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH Publication. Roberts RK, Douglas PG and Park WM (1991) Estimating external costs of municipal landfill siting through contingent valuation analysis: A case study. Southern Journal of Agricultural Economics 23: 155–166. Siddiqui MZ, Everett JW and Vieux BE (1996) Landfill siting using geographic information systems: a demonstration. Journal of Environmental Engineering 122: 515–522. Tchobanoglous G, Theisen H and Vigil SA (1993) Integrated Solid Waste Management: Engineering Principles and Management Issues. McGrawHill International Editions: Civil Engineering Series. New York: McGraw-Hill. US EPA (US Environmental Protection Agency) (1993) Subpart B: Location Criteria Chapter, Chapter 2, EPA/530-R-93-017. In Solid Waste Disposal Facility Criteria: Technical Manual. Washington, DC: US EPA. US EPA (2010) Wastes: non-harzardous waste: municipal solid waste: transfer stations. Available at: http://www.epa.gov/osw/nonhaz/municipal/ transfer.htm (accessed 24 December 2011). Vatalis K and Manoliadis O (2002) A two-level multicriteria DSS for landfill site selection using GIS: case study in Western Macedonia, Greece. Journal of Geographic Information and Decision Analysis 6: 49–56. Wang G, Li Q, Guoxue L and Lijun C (2009) Landfill site selection using spatial information technologies and AHP: a case study in Beijing, China. Journal of Environmental Management 90: 2414–2421. Zamorano M, Molero E, Hurtado A, Grindlay A and Ramos A (2008) Evaluation of a municipal landfill site in southern Spain with GIS-aided technology. Journal of Hazardous Material 160: 473–481.
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Spatial effect of new municipal solid waste landfill siting using different guidelines Siti Zubaidah Ahmad, Mohd Sanusi S Ahamad and Mohd Suffian Yusoff Waste Manag Res 2014 32: 24 originally published online 15 November 2013 DOI: 10.1177/0734242X13507313 The online version of this article can be found at: http://wmr.sagepub.com/content/32/1/24
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WMR32110.1177/0734242X13507313Waste Management & ResearchAhmad et al
Original Article Waste Management & Research 2014, Vol 32(1) 24–33 © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0734242X13507313 wmr.sagepub.com
Spatial effect of new municipal solid waste landfill siting using different guidelines Siti Zubaidah Ahmad, Mohd Sanusi S Ahamad and Mohd Suffian Yusoff
Abstract Proper implementation of landfill siting with the right regulations and constraints can prevent undesirable long-term effects. Different countries have respective guidelines on criteria for new landfill sites. In this article, we perform a comparative study of municipal solid waste landfill siting criteria stated in the policies and guidelines of eight different constitutional bodies from Malaysia, Australia, India, USA, Europe, China and the Middle East, and the World Bank. Subsequently, a geographic information system (GIS) multicriteria evaluation model was applied to determine new suitable landfill sites using different criterion parameters using a constraint mapping technique and weighted linear combination. Application of Macro Modeler provided in the GIS-IDRISI Andes software helps in building and executing multi-step models. In addition, the analytic hierarchy process technique was included to determine the criterion weight of the decision maker’s preferences as part of the weighted linear combination procedure. The differences in spatial results of suitable sites obtained signifies that dissimilarity in guideline specifications and requirements will have an effect on the decision-making process. Keywords Municipal solid waste (MSW), landfill siting, landfill guideline, geographical information system (GIS), multi-criteria evaluation (MCE), constraint mapping technique (CMT), weighted linear combination (WLC), Malaysia
Introduction The new solid waste management plan introduced in Malaysia has enhanced the social, economic and environmental efficiency that promotes sustainable development. It has also helped resolve the dual crisis of non-renewable resources depletion and environmental degradation (Manaf et al., 2009). The government has being trying to ensure the quality of life among citizens so as to achieve the Vision 2020 of becoming fully developed country: ‘By the year 2020, Malaysia can be a nation that is united, with a confident society, infused by strong moral and ethical values, living in a society that is democratic, liberal and tolerant, caring, economically just and equitable, progressive and prosperous, and in full possession of an economy that is competitive, dynamic, robust and resilient’ (Mahathir, 2008). This statement, given by the exPrime Minister of Malaysia, relates to waste management issues. Waste management is realized as one of the factors that measures the achievement of a country toward the Vision 2020. Waste management is not only about the techniques of waste collection, transportation and disposing by the responsible party or agencies. Good waste management practices actually start at the sources of the waste. In Malaysia, the sources of solid waste within the community are residential, commercial, institutional, construction and demolition, and municipal facilities. By infusing strong moral and ethical values, as stated in the Vision 2020, proper waste management is achievable and, together with the serious concerns of the public, waste generation will reduce. Local
government in Malaysia has implemented numerous awareness campaigns and programs with the intention that the public will adhere to the efforts of reducing waste in the community. They introduced the ‘3R’ (recycle, reuse, reduce) concept for waste minimization purposes. The public should be aware that the environmental pollution (air pollution, water pollution and ground pollution) are happening as a result of the waste dumping process. The community itself is self-exposed to hazards and threats without proper management. Therefore, public concern is very important in ensuring the public health and prosperity in order to achieve the Vision 2020. Most countries in the world, including Malaysia, are having problems dealing with their municipal solid waste (MSW). Landfilling is the cheapest method used for the disposal of MSW in Malaysia, and most of the landfill sites are open dumping areas. However, disposal of wastes through landfilling has become complicated, with the landfill sites filling up at a very fast rate (they will be full in 5–10 years). At the same time, construction of new School of Civil Engineering, Universiti Sains Malaysia, Pulau Pinang, Malaysia Corresponding author: Siti Zubaidah Ahmad, School of Civil Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang, Malaysia. Email: [email protected]
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Ahmad et al. landfill sites is more difficult owing to land scarcity, an increase of land prices and high demand, especially in urban areas with the increasing population (Manaf et al., 2009). Locational criteria are important in the problem of where to site a landfill. Bagchi (1990) and Tchobanoglous (1993) state that landfills should be located a certain distance from the features such as lakes, ponds, rivers, wetlands, flood plain, highway, critical habitat areas, water supply, well and airports. Currently, landfill siting is prohibited in areas where potential contamination of groundwater or surface water bodies exists. Generally, special approval from local authorities will be required when the proposed landfill site does not meet the locational criteria. Nevertheless, there will be no issue when the proper site selection process has taken into consideration all constraints and statutory regulations. A proper revision of all restrictions during the preliminary siting process is significant to avoid wasting time and money in evaluating sites that will not conform to the standard requirements. At present, researchers are exploiting spatial information technology, such as geographic information systems (GIS). GIS tools and capability are applicable for site suitability assessment and provide results in a good manner with high accuracy (Ersoy and Bulut, 2009; Zamorano et al., 2008). GIS has a high capability of managing a large amount of data, as well as changes in the data (Siddiqui et al., 1996; Vatalis and Manoliadis, 2002). The GIS analytical tool is useful in checking spatial parameters (criterion attributes) imposed in site selection process. Landfill site selection is the fundamental step in an ideal waste disposal practice in protecting the environment, public health and ensuring the quality of life for a sustainable future. A proper landfill site selection determines the successive steps in the preliminary landfill process. Proper implementation of landfill siting is important to avoid the undesirable long-term effects. A suitable landfill site should be selected carefully by considering criteria (regulations and constraints) issued by environmental agencies or local authorities (Ahmad et al., 2011). In general, the criteria for landfill site selection consider the environmental, social, economic and physical aspects. With different countries having their specific guidelines for landfill site selection, the problem of finding the appropriate landfill site therefore requires a very complete and sustainable site selection model. The major setback of landfill waste disposal method is their short lifecycle and shortage of suitable land for landfills especially in urban areas. In addition, the ‘not in my back yard’ phenomenon has created a negative impression toward landfill by the local community. Landfill operations are blamed for causing external costs to nearby residents who perceive risks associated with traffic, noise, dust, litter, unattractive neighborhoods, groundwater contamination and hazardous waste pollution, etc., to be associated with landfill. There are also other non-market costs not borne by waste disposal firms and producers of garbage. These external costs will result in an incompetent allocation of resources (too much garbage and exposure to it) (Roberts et al., 1991). Hence, proper landfill site selection must be the basis of the preliminary landfill process to avoid undesirable
long-term effects. The selection procedure must refer to authorized guidelines that consider social, environmental and technical aspects in ensuring the sustainability of the livelihood process. The guidelines and policy will help to restrict and reduce the landfill effect on the external costs, but only if the decisionmakers strictly follow the stated site selection criteria. Externalities, sometimes known as spillover effects or offsite impacts, impose costs or benefits on the community that are not priced into market exchanges (BDA Group, 2009). Disposal of waste to landfill can result in externalities, including the effect of releasing methane and greenhouse gases from the decomposition of organic wastes. There is also the potential for effects from leaching of toxic metals and compounds into the surrounding soil structure. Other externalities include the impact of noise and odors on local amenities, and the effect of air emissions. Different materials and products disposed to landfill will contribute differently to externality costs. For example, inert materials are likely to have few external impacts, while biodegradable materials will present additional problems associated with greenhouse gas emissions and odors, while other materials may contain hazardous substances that pose potential risks to human health through air and water emissions. Landfill is currently the cheapest waste disposal option. Most would agree that all of the costs and externalities are known and internalized into the landfill gate price. Companies will make a commercial decision to build resources recovery infrastructure where they can make profit while competing against landfill disposal. It is recommended that landfill should be regulated and a set of minimum environmental standards should be agreed upon, the effect of which will be to push up the costs of landfill operations. The government, through their guidelines, must emphasize and control this because in a landfill siting the maximum environmental standards are required to ensure sustainability in the future. DEFRA (2003) states that it is widely accepted that externalities can be conceptually split into fixed (independent of the quantity of waste) or variable (depending on the quantity of waste) costs and benefits. The term ‘fixed externality’ refers to the externalities that arise from the mere existence of a landfill. Such fixed costs should be calculated as per site and should relate to the existing distribution of households around a site. In the context of landfills, such costs should therefore be independent of the size of the landfill (area or stock capacity), the amount of waste it receives (flow volume) and, possibly, the type of waste it receives (inert, biodegradable or hazardous). The term ‘variable externality’, however, refers to the externalities that depend on the type and amount of waste going to a landfill. Emissions to air and water are clear examples of variable externalities. Externalities arise, in an unconstrained market, as they convey external costs or benefits to others, and these effects are not captured in the price mechanism. Externalities are a form of market failure, and, where these are present, correction may lead to a more efficient outcome in terms of resource allocation. Site selection, when viewed as multi-criteria evaluation (MCE) problem, implies the assignment of values to alternatives
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Waste Management & Research 32(1)
Table 1. Benefits and costs of alternative waste management practices (BDA Group, 2009). Waste management practice
Benefits
Costs
Recycling/reuse
Potential to reduce use of virgin materials, energy and generation of pollution in industrial processes
Recyclate collection, sorting and processing costs, and associated environmental impacts
Composting
Potential to reduce use of virgin materials
Organic waste collection and processing costs and associated environmental impacts
Advanced waste technologies
Energy recovery Potential to reduce use of virgin materials, energy and generation of pollution in industrial processes
Processing costs and associated environmental impacts Environmental impacts with landfilling of residuals
Landfill
No further processing required Gas can be captured for conversion to electricity
Land consumption Environmental risks from gas emissions and leachate Long-term post-closure management
Incineration
No further processing required
Environmental risks from air pollution
Illegal disposal
–
Heightened environmental risks Amenity impacts
that been evaluated along with multiple dimension or criteria. In general, the MCE process applies decision rules to meet specific objectives, frequently in the cases of evaluating several criteria together. The main task in MCE is concerned with the process of combining information from several criteria to form a single index of evaluation. The landfill siting process is possible by integrating the GIS spatial analytical tool with MCE, which then becomes a decision-making tool for solving complex multiple criteria problems either in qualitative and/or quantitative aspects of the problem (Mendoza et al., 1999). There are various algorithms embedded in GIS–MCE for site selection modeling. Among them are analytical hierarchy process (AHP), ranking and rating, fuzzy, weighted linear combination (WLC), and ordered weighted averaging. MCE has many advantages, but it also has disadvantages. MCE can incorporate a diverse range of information, can be subcontracted and is easily communicated. It provides an audit trail, which is especially useful in situations where decision-making is required to follow rules and to be justified in explicit terms. The most extraordinary strength of MCE is the flexibility of this analysis in handling large amounts of complex information and various dimensions, i.e. choice of options, criteria and weighting in a consistent way. Unfortunately, MCE becomes poor because of the difficulty in deriving the weight, it lacks methodological strictness and is less inclusive. Cost–benefit analysis (CBA) is a conceptual framework for the evaluation of projects in the government sector that tries to consider all gains and losses from the project. This framework analysis takes a long and wide view that includes all relevant future dates and the effects on all relevant parties. CBA usually express costs and benefits in the common metric of today’s money. CBA can recognize that each choice has a cost and force more detailed consideration of what is meant by the adjectives placed in front of the word ‘value’. It also makes explicit hidden costs and benefits. However, some costs and benefits cannot be
monetized (qualitative costs and benefits), i.e. quality of life, equity, ensuring public health and safety, reducing crime, protecting human rights, employment, education, etc. The best way to handle the qualitative costs and benefits are to exclude the nonmeasurable costs and benefits from strict CBA. The decisionmakers can include it in final decision-making through other analyses, i.e. social impact analysis, and specify qualitative pros and cons or MCE. CBA is not competent enough because the valuation techniques are imperfect and loaded with assumptions. It is difficult to balance qualitative costs and benefits against quantitative costs and benefits in CBA framework terms. The private costs of landfilling vary depending on the size of the landfill, type of waste handled and management measures in place (BDA Group, 2009). The private costs of landfill include land purchase, the approvals process, the capital cost of equipment and buildings, and the cost of lining landfill bases to prevent leaching. Costs of on-site gas recovery and flaring, fencing and other measures to prevent waste from being blown into adjoining properties and operational costs, including labor, are also taken into account. Moreover, fuel and materials, the cost of capping landfills and landscaping, and the cost of rehabilitation and aftercare also need to be taken care of. A number of different waste management practices are available, and their associated costs and environmental impacts vary widely. Table 1 highlights the key benefits and costs of the major alternatives. In general, MCE been seen as subsuming a CBA, while CBA is one criterion for assessing options. MCE can define a narrow set of options then subjected to CBA. MCE can work together with CBA, where one handles the quantitative costs and benefits, and the other handles the qualitative costs and benefits. Landfill siting is a complex process involving social, environmental and technical parameters, including government regulations. Increased perception of health and other risks associated with solid waste disposal facilities has made the siting of new
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Ahmad et al.
MODEL BUILDING - IDRISI macro-modeler module LITERATURE REVIEW Comparative study - Land ill guideline review - Land ill siting criteria - Waste policy and guideline of each country (World Bank standard speci ication and seven areas, i.e. Malaysia, India, Australia, USA, Europe, China and Middle East)
GIS MAPPING - Constraint and factor map layers - IDRISI macromodeler for model building
MCE ANALYSIS - Constraint mapping technique CMT) - Weighted linear combination
RESULT AND DISCUSSION
SUMMARY OF FINDINGS WEIGHT DETERMINATION - AHP pair-wise weight derivation
Figure 1. Research study flowchart. MCE: multi-criteria evaluation.
municipal landfills technically difficult and, in some cases, socially and politically unacceptable (Roberts et al., 1991). This will indirectly increase the social costs of the siting process. The habitant acceptance, population distribution, habitant lifestyle, sensitive areas, region planning, public safety and road safety are the examples of non-measurable costs and benefits that measure the overall social costs in landfill siting. In reality, when a project is proposed for any selected areas, the population will act and favor projects or not. Therefore, the government of any country plays a role in reducing the social complains by enforcing a policy and guidelines. If the requirements and guiding principals are followed, any project will benefit society. This article focuses on the comparative study of guideline policies and criteria pertaining to the siting of a MSW landfill issued by eight different geographic regions (Malaysia, Australia, India, USA), Europe, China, the Middle East) and the World Bank Group. Subsequently, spatial comparisons between various landfill site selections criteria from the above-mentioned entities was carried out using a GIS–MCE-based constraint and weighted linear mapping to study the differences among the suitable sites selected.
performed to determine the weight of each criterion to complete the analytical procedure. The study area is located in Seberang Perai District, Pulau Pinang, Malaysia. It has three sub-districts—North, Central and South Seberang Perai—with an estimated area of 73,737 ha (737.37 km2). The rapid development in this region has led to higher solid waste generation. This area is best depicted through the various kinds of human activities and land utilization. It is very rich in culture and is very popular with tourists. Figure 2 shows the study area. In general, the waste generation rate per capita is about 1 kg/day, varying from 0.45 to 1.44 kg/day (CAP, 2001). The 2010 census showed that about 856,800 people live in Seberang Perai with a density of 1086 people per km2. The local authority, Seberang Perai Municipality, reports an estimated amount of waste disposal of 2000 tonnes per day and 0.7 million tonnes per year at the only existing waste disposal site available—Pulau Burung Landfill, which is located in Nibong Tebal, Southern Seberang Perai District (MPSP, 2011). It states that an integrated solid waste system in Penang is a major challenge for local authorities, and the proper implementation of domestic waste collection, transferring, recycling and disposal in the landfill remains a complex issue.
Materials and methods
Result and discussion Landfill siting guidelines
Figure 1 shows the flowchart of the model that links the comparative study of various landfill policies with GIS–MCE constraint mapping technique (CMT) and WLC. Comparisons are based on the parameters of criterion as specified in each of the guidelines. The guideline parameters are important in performing the site selection process as it provides the basis of spatial presentation through GIS map layers (spatial criteria). Application of Macro Modeler provided in IDRISI Andes helps in building the model for site selection process. In addition, AHP weight derivation was
Different countries have to comply with their respective guidelines for landfill site selection. Malaysia, for instance, has had landfill site selection guidelines—the National Strategic Plan for Solid Waste Management (MHLG, 2005)—set up by the Local Government Department Ministry of Housing and Local Government Malaysia since 2005. Table 2 describes the general summary of landfill guidelines compiled from seven geographic areas and the World Bank. The USA, through their Environmental
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Waste Management & Research 32(1)
Figure 2. The study area.
Protection Agency (US EPA, 1993), was first to introduce guidelines for landfill site selection in 1993, followed by Europe (Germany) in 1994 (Oeltzschner and Mutz, 1994) and Australia (DUAP, 1996; NSW EPA, 1996). The World Bank Group first published landfill siting policies in 1996 and then updated them in 2004. Consequently, the Government of India introduced its own guideline (MEF, 2000) in 2000. A thorough review of Iranian and Chinese policies on solid waste management law can be found in Akbari et al. (2008) and Wang et al. (2009), respectively.
Landfill siting criteria The management of solid waste requires accurate guidelines pertaining to right selection of landfill sites. The guidelines are rules or criteria to follow in the process of allocating suitable landfill sites. In general, they include criteria such as the proximity to residential areas; water bodies, groundwater or aquifer potential; location of solid waste transfer stations; prohibited forest reserve area; airports, road or transportation routes; and physical factors, namely slope, soil and geological fault (Cointreau, 2004; Daly, 1995; JICA, 2004; Nakakawa, 2006; US EPA, 2010). Detail
characteristics of these criteria are described in Table 3, while the distinguishing perspective of different countries in quantifying common criteria is shown in Table 4. This study does not concentrate on determining the most appropriate guidelines, but is more concerned with the outcomes of the location when applying different criteria parameters to the site selection process. In addition, landfill-siting parameters pertaining to policies and guidelines must comply with their respective federal and state regulations. Furthermore, restriction on location criterion varies and is dependent on the environmental and climatic conditions of a region. Hasan et al. (2009) stress that most municipalities laid down their own location restriction parameters to meet the local environment conditions. In other words, their local respective interests is in place to protect the environment and public health, and to ensure the quality of life for a sustainable future.
Landfill siting model The landfill siting model was developed based on the information obtained from the review of different criteria from eight
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Ahmad et al. Table 2. Summary of landfill guidelines of various countries and the World Bank. Country
Department
Year issued
Guideline title
Malaysia
Ministry of Housing and Local Government Ministry of Environment and Forest Department Of Urban Affairs and Planning United States Environmental Protection Agency
Updated 2005
Europe (Germany)
Federal Republic of Germany
1994
China
Ministry of Environmental Protection (Republic of China) Iranian Management and Planning Organization The World Bank Group
After Wang et al. (2009) After Akbari et al. (2008) Published 1996 (updated 2004)
National Strategic Plan for Solid Waste Management Specification for Landfill Sites [Rules 6(1) and (3), 7(2)] Environment Impact Statement (EIS) Practice Guideline: Land Filling, Site Selection Procedures Solid Waste Disposal Facility Criteria: Technical Manual (Sub-B: Location Criteria Chapter 2 EPA/530-R-93-017.) Guidelines for an Appropriate Management of Domestic Sanitary Landfill Sites China Solid Waste Management Law
India Australia USA
Middle East (Iran) World Bank
2000 1996 1993
Criteria and Standard Used for Defining Unacceptable Areas An Asian Urban Structure Note
Table 3. Characteristics of landfill siting criteria (Akbari et al., 2008; Cointreau, 2004; DUAP, 1996; JICA, 2004; MEF, 2000; NSEL, 2004; NSW EPA, 1996; Oeltzschner and Mutz, 1994; US EPA, 1993; Vatalis and Manoliadis, 2002; Wang et al., 2009). Criteria
Detailed characteristics
Nearest residential area
Residential factor is the criteria that opposes landfill siting near residential areas. This criterion is regarded as an important factor as it answers the ‘not in my backyard’ or ‘not in anyone’s backyard’ issues. This syndrome expresses public objections towards siting of an urban waste management facility (such as a landfill or composting facility) in, or near, their community This criteria stops landfills being situated close to water bodies, including river networks, lakes and ponds, to protecting water body ecosystems and avoid flood plains. Consideration of preventing leachate or other pollutants from contaminating the area is made. Discharge to surface water is only acceptable when effluent is treated and diluted to a level where there is no significant adverse affect on the water quality requirements of the receiving water Groundwater takes into account the aquifer potential around the landfill site to prevent groundwater pollution. A landfill site must not be adjacent to any groundwater source, such as springs or groundwater wells. Any landfill directive requires prevention of groundwater pollution, but the engineering measures taken prior to set up cannot always guarantee this Transfer stations are facilities where municipal solid waste is unloaded from collection vehicles and briefly held while it reloaded onto larger, long-distance transport vehicles for shipment to landfills or other treatment or disposal facilities The law prohibits new landfill sites on forestland. In land use planning and decision-making processes, this land category is usually assigned as less suitable or not suitable for any development Airport safety factor is to restrict MSW landfill units in areas where sensitive natural environments, as well as the public, may be adversely affected. The landfill site is not to be located near to airport area to prevent disturbance of birds and rising dust from landfill Road or transportation route is an aesthetic consideration of the transportation issue and management of landfill to optimize travelling time and cost. The area must be easily accessible by the waste collection vehicles and all landfill machinery, at all times. It is also important to consider accessibility for emergency response services in the case of accidents or fire at the site. In reality, additional costs for road construction in areas far away from existing roads make them less favorable. However, the guideline states that the road must be as far away as it can be. Therefore, in the practice of siting process, the decision-makers must first create a buffer of a certain number of meters specified as the restriction distance and then reduce the range to an agreed distance for the cost–benefit issue Slope criteria deal with the appropriate terrain conditions suitable for the construction of a landfill site. Construction of landfill on hilly areas is economically not suitable and it may encounter the risk of soil erosion. The operation and maintenance cost of the landfill may increase periodically Soil permeability is important to prevent groundwater pollution from landfill leachate. Soil with good drainage (high permeability soil) is considered as undesirable for a landfill. The water infiltration through this soil is higher and the possibility of groundwater pollution may increase. To protect the groundwater, it is preferable that the soil content is silt or clay that has very low permeability. This does not include marshland and swamp The presence of a geological fault area may cause restriction to conditions, will have unpleasant effect on landfill performance, and could lead to leachate discharge to the environment or disruption of natural function
Nearest water bodies
Nearest groundwater line Nearest distance from sources Nearest protected forest Nearest airport location Nearest road line
Maximum Slope Soil Permeability
Nearest fault line
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Table 4. Landfill siting guidelines of World Bank and seven selected geographic areas. Parameter
Country
Malaysia World Bank (an India Asian urban infrastructure note)
Australia USA
Nearest residential area (m) Nearest water bodies (m) Nearest groundwater line (m) Nearest distance from sources (km) Nearest protected forest (m) Nearest airport location (km) Nearest road line (m) Maximum slope (%) or height (m) Soil permeability (cm/s) Nearest fault line (m)
1000 100 1000 25 100 3 500 10 < 10-6 100
250 100 100 15–20 500 8 100 20 < 10-6 100
1000 500 1500 25 500 3 3000 20 < 10-6 500
500 100 1000 20–25 100 20 200 15 < 10-7 500
Europe China Middle East
500–2000 500 300–500 500 1000 1000 25–40 25 50–100 100 4 3 50–100 500 15–20 10–20 < 10-6 < 10-7 100 100
500 300 500 200 1500 50 25 30 100 1600 3 3 100 300 10 20 < 10-7 < 10-6 100 100
Figure 3. Example of macro-modeler for landfill site selection.
different constitutional bodies (Malaysia, Australia, India, USA, Europe, China, the Middle East and the World Bank). The analytical comparative study applies MCE using the CMT and WLC. Both techniques were applied to investigate the differences among the suitable landfill sites selected. The model was tested using digital maps of Seberang Perai, Penang, Malaysia, with the criteria of the eight selected countries. Maps pertaining to the landfill site selection criteria were prepared for the GIS analytical procedure, such as buffer zoning of roads and residential settlement, classification of soil and geological properties, and constraint mapping to slope, protected forest, fault lines, etc. The GIS IDRISI macro-modeler is a graphical environment for building and executing multi-step models for batch processing and dynamic modeling (Eastman, 2006a, 2006b). Models were built from three basic types of element: (1) data elements, (2) command elements and (3) links. Data elements include raster and vector layers, attribute values files and groups. Command elements include
modules such as overlay and buffer, and sub-models are usercreated models. Links establish the sequence of processing between data and command elements. Figure 3 describes the example of the macro-model used in the landfill siting process.
Weight determination Weight, well known as ‘degree of importance’, is a value assigned to a criterion that indicates its importance relative to the other criteria under consideration. The derivation of weights is a central step in attaining decision-makers’ preference. Pair-wise comparison was done via a questionnaire survey where each candidate or alternative was compared (one-on-one) with each other using the AHP preference scale made available by the GIS IDRISI software (Ahamad et al., 2003). The weights were developed based on the relative importance of factors to the suitability of pixels for the activity evaluated. The weight derived from group
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Ahmad et al. decision-making where the geometric mean of the combined judgment was determined (Liberatore and Nydick, 2003) and used as the input parameter for the MCE. Table 5 describes the geometric mean of nine-criterion weight judged by 20 decision-makers.
considered suitable in all criteria (Eastman, 2006a, 2006b). The result shows that common criteria (from seven geographic areas) with different parameters produce different suitable sites, as shown in Figure 4. The total area of new landfill sites obtained is further listed in Table 6.
CMT
WLC
In CMT, all criteria are assumed to be constraints and the mathematical overlay (Boolean multiplication) is applied. This justified the combination procedure, which brings the lowest possible risk as the only areas considered suitable in the result are those
WLC combines both weighted factors and constraints. The factors are multiplied with weight and combined by means of linear summation of results to yield a suitability map. Factor weights are important in this model as they determine how individual factors will exchange relative to each other. The higher the factor weight the more influence that factor has on the final suitability map (Eastman, 2006a, 2006b). Figure 5 describes the result of the analysis. The suitability area has five classes: (1) most suitable site, (2) suitable site, (3) less suitable, (4) not suitable and (5) other sites. The classes are decided according to the required vastness of 300 ha of land area that equals to 4800 cells (625 m2 for each cell). The percentage similarity of the new landfill sites when compared with guidelines from Malaysia is shown in Table 7 and Figure 6. The Malaysian landfill guidelines has the highest spatial location similarity to the European guidelines (26.96%) and differs substantially from the World Bank guidelines (1.61%).
Table 5. Geometric mean of criterion weight. Criteria
Weight
Road Water body Groundwater (aquifer) Residential Soil permeability Land use Geological fault Slope Airport
0.2576 0.1678 0.1549 0.0843 0.0838 0.0786 0.0633 0.0584 0.0334
Figure 4. Multi-criteria evaluation (constraint mapping technique) site suitability based on guidelines from (a) Malaysia; (b) Australia; (c) China; (d) Europe; (e) India; (f) Iran; (g) USA; and (h) the World Bank.
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Waste Management & Research 32(1)
Table 6. Total area of new landfill sites. Country
Area (ha)
Malaysia Australia China Europe India Middle East USA The World Bank
1241 5156 2690 2407 3628 2767 2526 438
Figure 5. Multi-criteria evaluation (weighted linear combination) site suitability based on guidelines from (a) Malaysia; (b) Australia; (c) China; (d) Europe; (e) India; (f) Iran; (g) USA; and (h) the World Bank. Table 7. Percentage spatial similarity of the new landfill sites compared to Malaysian guideline. First map
Second image
Malaysia
Australia
China
Europe
India
US
World Bank
Middle East
14.58%
12.08%
26.96%
13.14%
12.71%
1.61%
18.92%
30.00 20.00 15.00
Conclusion
26.96
25.00
18.92 14.58
13.14
12.08
12.71
10.00 5.00
1.61
0.00 Australia China
Europe
India
US
World Middle Bank East
Figure 6. Histogram chart of spatial similarity (%) of new landfill sites of different countries.
The variations of criterion parameters in guidelines and policies will have an effect on spatial site selection. This signifies that dissimilarity in specification and requirement will have an effect on the location of new landfill sites. The World Bank guidelines were found to be strict and firm with respect to setting out policies for new landfill siting requirements. It produced a suitable area of only 438 ha. More surprisingly, Malaysian guidelines produced the second smallest size of suitable area (1241 ha) compared with other countries. This gives an indication that Malaysia is very firm with respect to setting out policies for new landfill
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Ahmad et al. sites so as to protect the environment and public health, and to ensure a good quality of life. From the research, we conclude that a comparative site selection process can be performed straightforwardly using GIS analytical procedures. It helps local authorities in detecting specific work on landfill site selection and to ensure that policies and guidelines of site selection criteria are strictly followed.
Declaration of conflicting interests The authors do not have any potential conflicts of interest to declare.
Funding The authors wish to thank the Universiti Sains Malaysia (USM) for the provision of the Research University Funding (RU Grant No. 814102) for the completion of this research.
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