Memoire Online - Landfill sites selection for municipal solid waste using multi criteria evaluation techniques. Case of Rusizi town, Rwanda

LANDFILL SITES SELECTION FOR MUNICIPAL SOLID WASTE USING MULTI CRITERIA EVALUATION

Individual Case Study done in the partial fulfillment for the award of the Post Graduate Diploma in Applied Geo-Information Science

I declare that the dissertation hereby submitted in the partial fulfillment for the award of the Post Graduate Diploma in Applied Geo-Information Science at the National University of Rwanda/ Centre for Geographical Information System and Remote Sensing, is original and has not been published and/or submitted for any other degree award to any other University before.

Firstly, I give thanks and praise to GOD for everything that happened in my life.

Much of the work for this project as well as for my study programme could not have been completed without the help and support of many people. I would like to thank my supervisor, Mr. Theodomir MUGIRANEZA, I am so deeply grateful to his help, support, and valuable guidance throughout this research and my study programme that I do not have enough words to express my gratitude.

My incredible recognition goes out to my fellow students for their moral and collaboration during this research.

Finally, special thanks are extended to all institutions and individuals that supported me in different manner.

My sincere gratitude is expressed to each and every one who supported me in one way or another to accomplish this research.

ABSTRACT

Siting a landfill is an extremely complex task mainly due to the fact that the identification and selection process involves many factors and strict regulations. For proper identification and selection of appropriate sites for landfills careful systematic procedures need to be adopted and followed. Wrong siting of landfill may have negative environmental, economic and ecological impacts. In this study, attempts have been made to determine sites that are appropriate for landfill siting in Rusizi Town of Rusizi District, Western Province in Rwanda. This was achieved by combining geographic information system (GIS) and a multi-criteria evaluation technique. For this purpose, ten input map layers including Roads network, Rivers, Kivu Lake, wetlands, forests, airport, markets, health facilities, schools and slope were prepared. A constrained area was created with respect to 100m buffer from the roads, 300m buffer from rivers, forest, wetlands and Kivu Lake, 1000m buffer from schools, health facilities and market and 3000m buffer from Kamembe airport. The final map was produced after spatial overlay of permissible area and suitable slope of between 8 and 12%. The final output was produced where 133 sites were identified to fulfill the required criteria; among them five met the land size criteria requirement of 2 hectares and above for a potential landfill site. 04 potential sites were identified in Mururu Sector while 01 potential site was identified in Gihundwe Sector. However, during this research, the lack of some of the required data such as ground water levels and geologic data that may improve the quality of the final result was among the problem faced due to time and budget constraints. The results showed the efficacy of GIS and multi-criteria evaluation technique in decision making, while dealing with complex and conflicting criteria.

Keyword: Landfill, Site selection, Municipal Solid Waste, Multi Criteria Evaluation Technique

CHAPTER 4: WASTE GENERATION AND MANAGEMENT IN RUSIZI: BOTLENECKS' ANALYSIS AND SUITABLE

Table 4-3 : Proportions (in %) of dwelling units according to mode of disposal of household

This study aimed at finding out potential landfill sites for Municipal solid waste in the town of Rusizi. This chapter presents the background of the study, problem statement, research objectives and research questions, scope of the research and research contributions.

1.1. Background of the study

Municipal solid waste (MSW) collection and disposal is a major problem associated with the urban development in different countries. It has also been recognized as one of the major problems confronting governments and city planners the world over (Rahman & Hoque, 2006). It is estimated that the United kingdom produces 35 million tones of municipal solid waste annually(Koshy, Emma, Sarah, Tim, & Kelly, 2007) and in the United states of America, more than 140 million tones of municipal waste is generated annually, while Japan and Germany generates 50.2 million and 43.5 million tones of municipal wastes in 1993 respectively(Sakai et al., 1996). In Africa, the situation appears to be the same as other parts of the world (Babalola & Busu, 2011).

In the developing countries, municipal solid waste management system is either not efficient or still at the rudimentary stage and as such solid waste generated has become a threat to the environment (Babalola & Busu, 2011). According to (Weigand, Fripan, Przybilla, & Marb, 2003) the «Lack of MSW management leads to significant soil, water, air aesthetic pollution associated human health problems, as well as an increase in greenhouse gases emission».

In urban areas of developing countries massive wastes generally consist of domestic garbage, organic litter, plant leaves, branches, logs, spoiled agric produce, crop residues, bad food materials, pieces of paper, polythene bags, rags, vehicle scraps, used tires, dusts, mire, plastics, glass, blood, bones, animal skins, hides, leather, urinary and fecal materials. When these wastes are improperly disposed-which is generally the case; they constitute a threat to air, water, land, vegetable, wildlife and man. Sickness and disease epidemics often occur when sewage, garbage wastes and unwanted substances are not properly disposed of and well managed (Awomeso, Taiwo, Gbadebo, & Arimoro, 2010).

For a sustainable solid waste management, system policies and techniques such as waste recycling, reuse, waste reduction, thermal treatment, landfilling must be in place. The landfill

method has been widely recognized as the most used of all the waste management techniques and sanitary landfill is the most cost-effective system of solid waste disposal for most urban areas in developing countries (Nas, Cay, Iscan, & Berktay, 2010).

Several studies have been conducted on different scales to find the optimum locations for solid waste disposal sites. The selection of their ultimate site is complex. It must combine social, environmental, technical and economical parameters. Also, the location must comply with the requirements of the governmental regulations in order to be acceptable (Al-Hanbali, Alsaaideh, & Kondoh, 2011).

According to (RURA, 2011) no landfill site shall be located in any area where it is likely to have a significant negative impact on existing land uses, the location of the landfill should not give rise to any adverse effects or a significant risk of any adverse effects occurring». For a sustainable urban development, it is imperative not only to set up an effective system for waste collection and transport but also a selection of a suitable site for waste deposition.

To do so, a Multi-criteria evaluation (MCE) technique 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).

1.2. Problem statement

Rwanda cities are growing day by day. Due to the population growth and the improvement of life standards, there is a growing concern associated with waste generation. Some efforts were made to handle the urban waste, but there are still some weaknesses related to the selection of suitable sites for waste disposal. According to (REMA, 2010) waste disposal facilities remain inadequate in resettlements (imidugudu), small towns and cities throughout Rwanda.

In rural areas, organic waste is composted and mixed in fields. Other types of waste are reused or put underlay. In urban areas, the local administration usually manages solid waste collection and disposes waste in open dumpsites.

Research has been done in the field of landfill site selection for municipal solid waste in different countries and particularly in Rwanda, in the City of Kigali, using GIS overlay analyses. While ideal for performing spatial searches on nominally mapped criteria, these GIS overlay analyses are limited in use when multiple and conflicting criteria and objectives are concerned. MCE techniques offer means for making and supporting complex siting decisions, involving multiple criteria (STEPHEN, 1991).

In addition, their results cannot be efficiently and effectively used for the case of Rusizi Town without any modifications due to the heterogeneity of economical, environmental, political and social parameters that were used in other countries and cities. Therefore, this research is a contribution to the site selection and determination in secondary city of Rwanda such as Rusizi using state-of-art-technology like MCET.

1.3. Research objectives and Research questions

The main objective of this study is to identify/ show sites for municipal solid waste in Rusizi Town using MCET. In order to achieve the main research objective, the following specific objectives and research questions were answered in this research.

1.4. Scope of the Research

The study only covers the municipal solid waste in the Town of Rusizi that is made of Kamembe, Gihundwe and Mururu Sectors. The design, operations and maintenance of a landfill is out of the scope of this project.

1.5. Research contributions

This research makes a contribution to the literature in terms of landfill site selection. The result will always help city management officials to quickly identify and select suitable landfills for municipal solid waste disposal. In addition, it will help managers to cut down the time spent debating location based problems as well as reduce costs.

This chapter is about the review of literature on solid waste management. The first part of this chapter discussed solid waste categories, the second parts identifies different technologies that are used in solid waste management, the third part identifies various criteria that are taken into consideration in landfill siting, while the fourth part presents the role of GIS and MCE in site selection.

2.1. Solid waste categories

Rubin and Davidson (2001), created two classes of solid wastes: hazardous and nonhazardous. A hazardous waste was defined as « a solid waste or combination of solid wastes which because of quantity, concentration, or physical, chemical, or infectious characteristics may (1) cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible , or incapacitating reversible illness; (2) pose a substantial present or potential hazard to human health or to the environment when improperly treated, stored, transported, or disposed of, or otherwise managed.»

On the other hand, wastes that are not designed as hazardous are said to be non-hazardous. The most familiar type of nonhazardous waste is what we commonly call trash or garbage. These are components of municipal solid waste (MSW) which includes all of wastes commonly generated in residences, commercial buildings ( like shopping smalls, restaurants, and corporate offices), and institutional buildings (such as universities and government offices). MSW consists of such things as paper, packaging, plastics, food wastes, wood and discarded appliances. Similar kinds of wastes generated by industrial facilities also are part of MSW. The additional wastes generated by manufacturing processes, construction activities; mining and drilling operations, agriculture, and electric power production are distinct from MSW and are referred to as industrial wastes.

Household solid waste where household solid materials are collected locally and the amount depends upon the size and consumption habits of the population. Commercial wastes that are generated by commercial establishments but are usually disposed off by public facilities.

2.2. Solid waste management

Solid waste management may be defined as the discipline associated with the control of generation, storage, collection, transfer and transport, processing and disposal of solid wastes. Integrated solid waste management includes the selection and application of suitable techniques, technologies and management programs to achieve specific waste management objectives and goals (G. Tchobanoglous & Kreith, 2002). However, current solid waste management technologies can be summarized as:

2.2.1. Source reduction

It involves diminishing waste amount, volume and toxicity at the source of waste generation (Kreith, 1994). Source reduction is the most effective way which reduces the quantity of waste, the cost of associated with its handling, and its environmental impacts. Waste reduction may occur through the design, manufacture, and packaging of products with minimum toxic content, minimum volume of material, or a longer life and also at the household, commercial, or industrial facility through selective buying patterns and the reuse of products and material (G Tchobanoglous & 1993).

2.2.2. Recycling

It involves (1) the separation and collection of waste materials; (2) the preparation of these materials for reuse, reprocessing, and remanufacture; and (3) the reuse, reprocessing, and remanufacture of these materials. Recycling is an important factor in helping to reduce the demand on resources and the amount of waste require disposal by landfilling (G Tchobanoglous & 1993). Reusing waste products can be simply made by the public by returning drink containers to bottling manufacturers and the donation of used clothes, shoes, furniture, and electrical products to charities and retailers. Product recycling primarily involves melting glass and metals, pulping of paper waste so that the end product is useful as a raw material to manufacturers. Benefits of waste recovery include conserving finite

resources, lowering the need for mining or harvesting virgin material, reducing inert residues from incinerators, and fewer demands on landfills (Kreith, 1994).

2.2.3. Waste transformation

It involves the physical, chemical, or biological alteration of wastes. Typically, the physical, chemical, and biological transformations that can be applied to municipal solid wastes are; (1) to improve the efficiency of solid waste management operations and system, (2) to recover reusable and recyclable materials, and (3) to recover conversion products and energy in the form of heat and combustible biogas. The transformation of waste materials usually results in the reduced use of landfill capacity (Tchobanoglous, 1993).

Transformation examples include mechanical clipping, shredding, and grinding, thermal combustion, and composting organic food and yard waste (Kreith, 1994). A benefit of thermal incineration is the potential for energy generation while reducing waste volume up to 90% (Tchobanoglous, 1993).

2.2.4. Landfilling

It is the process by which the solid wastes that cannot be recycled nor further used; the residual matter remaining after the recovery facility and after the recovery of conversion products and energy is placed in a landfill. Although there is a public opposition to landfills, it is necessary and there is no combination of waste management technique that does not require landfilling to make them work. Landfilling includes monitoring of the incoming waste stream, placement and the compaction of waste, and installation of landfill environmental monitoring and control facilities. Disposing of waste in a landfill involves burying the waste. A properly-designed and well-managed landfill can be a hygienic and relatively inexpensive method of disposing of waste materials. However, poorly-designed or poorly-managed landfills can create a number of adverse environmental impacts such as wind-blown litter, attraction of vermin, and generation of liquid leachate (REMA 2010).

Moreover, waste management is the collection, transport, processing, recycling or disposal, and monitoring of waste materials. The term usually relates to materials produced by human activity, and is generally undertaken to reduce their effect on health, the environment or aesthetics. Waste management is also carried out to recover resources from it. Waste management can involve solid, liquid, and gaseous substances, with different methods and

fields of expertise for each. Waste management practices differ for rural, small town, urban or industrial producers (REMA, 2010).

Nevertheless, landfill technique and incinerators are two methods commonly used for solid waste management (Pandey & Carney, 2005). Incineration is a disposal method that involves combustion of waste material. Incineration and other high temperature waste treatment systems are sometimes described as "thermal treatment". Incinerators convert waste materials into heat, gas, steam, and ash. Incineration is carried out both on a small scale by individuals and on a large scale by industry. It is used to dispose of solid, liquid and gaseous waste. It is recognized as a practical method of disposing of certain hazardous waste materials (such as biological medical waste). Incineration is a controversial method of waste disposal, due to issues such as emission of gaseous pollutants (REMA, 2010).

To summarize, solid waste management techniques vary from country to country depending on physical geography, demographics and level of economic development. Most industrialized countries have regular solid waste collection and disposal services, waste disposal sites that are by law required to have at least some environmental prevention and control techniques (Nakakawa, 2006).

2.3. Criteria for Landfill siting

Landfill siting is a difficult, complex, tedious, and protracted process requiring evaluation of many different criteria (Chang, Parvathinathanb, & Breden, 2008) since it has to combine social, environmental, technical, and financial factors. Environmental factors are very important because the landfill may affect the biophysical environment and the ecology of the surrounding area ; (Kontos, Komilis, & Halvadakis, 2003);. Economic factors must be considered in the siting of landfills, which include the costs associated with the acquisition, development, and operation of the site (Delgado, Mendoza, Granados, E. L., & Geneletti, 2008).

Social and political opposition to landfill siting have been indicated as the greatest obstacle for successfully locating waste disposal facilities (Lober, 1995) . The «not in my backyard» (NIMBY) and «not in anyone's backyard» (NIABY) phenomena (Chang et al., 2008);(Kao & Lin, 1996); (Erkut & Moran, 1991); (Kontos, Komilis, & Halvadakis, 2003); (Lin & Kao, 2005) are becoming popular nowadays creating a tremendous pressure on the decision makers involved in the selection of a landfill site.

According to ENER, B. (2004), there are a number of criteria for landfill site selection. These are environmental criteria, political criteria, economical criteria, hydrologic and hydrogeological criteria, topographical criteria, geological criteria, availability of construction material and other criteria. Each criterion will be discussed briefly in the next sections.

2.3.1. Environmental Criteria

2.3.1.1. Ecological value of the flora and fauna

The direct and indirect spatial use of a landfill will destroy the actual vegetation and fauna. When making a decision, the ecological value of the actual vegetation and fauna should be evaluated carefully for the candidate area. Ecological value is based on diversity, naturalness and characteristic feature.

2.3.1.2. Odour and dust nuisance

A new landfill should not be located within a distance of a housing area because of the dust and odour emissions. Dependent of the local wind direction and speed, the safe distance necessary to locate a landfill site should be determined to prevent sensing dust and odour.

2.3.1.3. Nuisance by traffic generation

A new landfill will generate more traffic. How much more traffic depends of the distance to the collection area, the kind of transport and the use of transfer stations. Access roads passing through housing areas will cause more nuisance than access roads through the open country side. So, routing vehicle traffic through industrial, commercial or low density population areas decreases the noise impacts of landfill related vehicles.

Especially national parks and natural conservation areas and also historical areas are not suitable for the location of a landfill.

A new landfill should not be planned within an existing recreational area or adjacent to it. However, a landfill is possible in some kinds of recreation areas like car/motor racing. Also the final use of a landfill can be planned as a recreational area.

2.3.2. Political Criteria

2.3.2.1. Acceptance by the local municipalities

The political acceptance of a new landfill location can differ in each region and sometimes the potential sites are located in different regions. The level of political acceptance has influence on the willingness of the local municipalities to make their regional physical plans and to give permission for the construction of a landfill. The unwillingness will cause to a delay of the decision on the landfill location

2.3.2.2. Acceptance by the pressure groups involved

The acceptance by the public of a landfill in their own region or municipality is an important factor in the decision making process. The so-called NIMBY (not in my backyard) syndrome is becoming a common attitude. The influence of the public is significant if there are local groups which are well organized and having good relations with the local authorities and the media (papers, radio and television). The level of the public acceptance can be measured how far the local pressure groups are succeeding to delay the decision making process.

2.3.2.3. Property of the landfill area

The ownership of the needed land for the landfill is very important. Public ownership is easier than private ownership because the private ownership will give problems with the cost of the land. Sometimes, expropriation is needed.

2.3.3. Economic Criteria

Costs of the land depend on the land prices which can differ for each location. The actual use of the land is important for the price which influences the level of compensation for the owner or actual users. The potential landfill with the lowest costs is more preferable.

Costs for the access of the landfill depend on the condition and the presence of roads close to the landfill. If reconstruction of actual roads is needed, the costs will increase. Because of that road network is an important factor to locate a landfill site.

2.3.3.3. Transport costs

Transport costs are determined by the transport distances from the source of waste generation, the way of transport and the way of collection. The other factors affecting transport costs are the need for waste transfer stations and the possibility to use railways.

2.3.3.4. Costs for personnel, maintenance and environmental protection

The costs for personnel will not differ so much between the different potential landfill sites. Maintenance depends on the availability of soil needed for the daily or regular covering and for the stability of the landfill. If the soil is not available in the area, it should be imported which increases the maintenance costs. Extra technical provisions should be placed to prevent the pollution of the soil, groundwater and surface water at the landfill. Monitoring the drainage system and the quality of the leachate and surface water are also important factors in the maintenance costs. The potential landfill with the lowest maintenance costs is more suitable for a landfill.

3.3.3.5. Costs for the after-care

The costs for after-care is not only dependent on the kind of final use but also on provisions to monitor the groundwater quality, existence of gas, the winning of gas, the stability of the completed landfill. Needed provisions are depending on the characteristics of the filled waste, the kind of subsoil, the hydrogeological situation, and the kind of final use.

2.3.4. Hydrologic/Hydrogeologic Criteria 2.3.4.1. Surface water

The landfill site should not be placed within surface water or water resources protection areas to protect surface water from contamination by leachate. Safe distances from meandering and non-meandering rivers should be achieved to prevent waste from eroding into rivers and major streams. A landfill should not be located within 100 feet (30.48 m) of any non-meandering stream or river, and at least 300 feet (91.44 m) from any meandering stream or river. Large ponds, lakes, and reservoirs should have a buffer zone of land to prevent blown debris and runoff from harming aquatic habitats. Large bodies of water (greater than 20 acres (80937.45 m2) of surface area) should be at least 100 feet (30.48 m) from any landfill site.

2.3.4.2. Groundwater

To protect subsurface drinking water, landfills should not be situated over high quality groundwater resources. Fresh groundwater (total dissolved solids>1000 mg/l) should be avoided or protected with a compound liner system and monitoring wells (Bagchi, 1994). Since potential leachate leaks will travel down gradient, landfills should be placed greater than 304.8 m (1000 feet) up gradient from water wells.

2.3.5. Topographical Criteria

The topography of an area is an important factor on site selection, structural integrity, and the flow of fluids surrounding a landfill site because it has important implications for landfill capacity, drainage, ultimate land use, surface and groundwater pollution control, site access and related operations (Wilson, 1977). Deciding the type of landfill design (area-, trench-, and depression-type landfills) is directly related to topography of a site.

2.3.6. Geological Criteria

The geology of an area will directly control the soil types created from the parent material, loading bearing capacity of the landfill's foundation soil, and the migration of leachate. Rock and its structure type will determine the nature of soils and the permeability of the bedrock. Geologic structure will influence the movement of leachate and potential rock-slope failure along joints and tilted bedding planes.

On the other hand, RURA states that a landfill site should meet the following criteria:

The site shall not be closer than three thousand (3,000) meters from an airport, airfield or site reserved for the construction of an airport or airfield;

The site shall be located and operated in such a manner that it does not create significant negative impacts on flora and fauna on adjoining land;

The site shall not be closer than four hundred (400) meters from an existing residential development;

The edge of the landfill shall not be closer than hundred (100) meters from an area to which the public have access, a national park, protected area or an area having national historical or archaeological significance;

There must be a buffer area around the landfill of at least twenty (20) meters to allow provision for visual screening from adjoining properties.

Landfill access roads shall be located and constructed so as to have a minimum impact on adjacent residents.

2.4. GIS and Multi Criteria Techniques in site selection

Site selection procedures can benefit from the appropriate use of GIS. Common benefits of GIS include its ability to: (a) capture, store, and manage spatially referenced data; (b) provide massive amounts of spatially referenced input data and perform analysis of the data; (c) perform sensitivity and optimization analysis easily; and (d) communicate model results (Vatalis & Manoliadis, 2002).

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, Suzen, & Doyuran, 2006).

(Higgs, 2006) reported the potential of integrating multi-criteria techniques with GIS in waste facility location and documented through a review of the existing literature to highlight the opportunities and challenges facing decision makers at different stages of the waste facility management process. Moreover, projects with numerous variables are best approached in GIS using a multi- criteria evaluation (MCE). The MCE is particularly effective as it allows for designation of suitability values to portions of the study area so as to determine which sites would be best suited to meet all criteria.

This chapter presents 4 different parts: Study area description, data and material, methods and techniques and data analysis and interpretation.

3.1. Study area description

The town of Rusizi is composed of Kamembe, Gihundwe and Mururu Sectors of Rusizi District. In the west, it shares borders with the Democratic Republic of Congo, separated by Rusizi River and Lake Kivu. It occupies a surface area of some 34.94 Km ² with 70345 populations.

3.2. Data and material

Data availability is of prime importance when using GIS. During this research, the main and specific objectives were achieved after using primary and secondary data. Field observation and interview with different District staffs in charge of environment, infrastructure and land officer land were used as techniques to obtain primary data that were used to complement spatial data that were used as secondary data. Systematic exploration of written documents such as books and others was used as documentation technique.

Spatial data for Rusizi town were collected from Rwanda Natural Resources Authority (RNRA/Department of Lands and Mapping) through CGIS-NUR were used to come up with a proposed suitability map for landfill site selection.

On the other hand, different materials were also used so as to come up with the expected result. They include:

3.3. Methods and techniques

The methods and techniques are research tools for data collection, adapted at the same time for investigation, adapted for analysis and above all from the point of view, guide the research. The methodology in this chapter provides evidence for analysis that is utilized to determine the optimal landfill sites. The technical approach was also employed to produce suitability maps emphasizing «suitable» geographic areas resulting from weighted and combined map layers based on established variables.

Methodologies used are normally based on a composite suitability analysis using map overlays and their extension to include statistical analysis. In this study, the approach was to utilize models that combine and integrate maps to determine an optimal landfill siting. There are a number of integration models in GIS.

Probably the simplest and best-known type of GIS model is based on Boolean operation. It involves the logical combination of binary maps resulting from applicable conditional operators. If the criteria and guidelines are to be established as a set of deterministic rules (Constraints), this method is a practical and easily applied approach (Dikshit, Padmavathi, & Das, 2000). The model consists of applying Boolean operators to a set of input maps. Each of the maps used as a condition can be thought of as a layer of evidence. The various layers of evidence are combined to support a hypothesis, or proposition. The output is a binary map, because each location is either satisfactory or is not (Bonham-Carter, 1994). The following figures show model builder that were used in this study.

This model builder was used to produce Constraints and Permissible Area Map (Fig 4-3).

This model builder was used to produce Distribution of Suitable and Potential sites Maps (Fig 4-4 and Fig 4-5).

3.4. Data Analysis and Interpretation

AGIS-based analysis was conducted using ArcGIS software, Spatial Analyst. Spatial Analyst is a raster or grid based software package that provides a platform for working with gridded data sets. It was used to produce suitability maps highlighting «suitable» geographic areas derived from weighted and combined map layers based on established criteria.

Analyzing spatial layers essentially involves setting the study area boundary, making slope map, buffer zone maps, find distance from water body and roads, reclassified maps and suitability maps that are presented in Chapter 4 of this study.

Raster maps as constraints maps indicating areas, which are suitable and not suitable for the sitting of a landfill, will be provided. The non-suitable areas are known as buffers (Kontos, Komilis, & Halavdakis, 2003). These constraints maps include the surface water, towns, rivers, roads, and land-use. They will also be used as factor maps representing areas that range from low suitability to high suitability.

CHAPTER 4: WASTE GENERATION AND MANAGEMENT IN RUSIZI: BOTLENECKS' ANALYSIS AND SUITABLE LANDFILL SITES LOCATION

This chapter presents 4 different parts: Waste generation and management in Rusizi town, Gaps and challenges in waste management in Rusizi town, Site selection for landfill in Rusizi town, possibilities for landfill sites project implementation.

4.1. Waste generation and management in Rusizi Town

There are no major industries within the town of Rusizi and as such the solid waste generated within the CBD is largely biodegradable material from the municipal market mixed with polythene and paper products used in packaging.

4.2. Gaps and challenges in waste management in the town of Rusizi

According to REMA, the disposal of the following wastes with the rest of the municipal solid waste is prohibited:

? Hazardous Wastes other than those specifically authorized in the Hazardous Waste

? Automobiles, white goods, other large metallic objects and tires (except in the case of

Despite the separation of some kinds of municipal solid waste as requirement of REMA, Rusizi District Leaders have set up an open dumping site where all solid wastes are disposed. The following pictures show gaps in waste management of different municipal solid wastes that are disposed in an open waste dumping located in Ruganda Cell, Kamembe Sector, Rusizi District.

Table 4-3: Proportions (in %) of dwelling units according to mode of disposal of household waste in the town of Rusizi.

According to MINIFRA, Rusizi town is facing different solid waste management challenges

> Lack of designated dumping site / land fill where 50% of the population relies on

> There is no designed garbage dumping site and most of the garbage is deposited along

4.3. Site selection for landfill in Rusizi Town 4.3.1. Criteria for site selection

There are different criteria for landfill site selection, but given the availability of data, environmental, economic and social criteria were taken into consideration in this study.

4.3.1.1. Environmental criteria 4.3.1.1.1. Land slope

(Lin & Kao, 2005) have suggested that the appropriate slope for constructing a landfill is about 8-12% because too steep of a slope would make it difficult to construct and maintain while too flat of a slope would affect the runoff drainage. Slopes above 12% created high runoff rates for precipitation. With higher runoff rate and decreased infiltration, contaminants are able to travel greater distances from the containment area.

4.3.1.1.2. Proximity to wells and Forest

A landfill must not be located near any surface streams, lakes, rivers, wells, or wetlands. Proximity to wells was an important criterion to accessing the landfill site. Landfills create noxious gases and leachate that make them unsuitable to be in proximity to water wells (Dorhofer & Siebert, 1996). For this reason, a 300-m buffer would be placed using the function in GIS software, which will be used to generate the buffer around all wells and forests.

4.3.1.2. Social- economic criteria

4.3.1.2.1. Airports

Landfill sites attract variety of birds to be accumulated around. This issue may interfere with the operation of airplanes. So it is essential to consider suitable distance from landfill site according to airport and airplane types (Daneshvar, 2004). By considering this criterion as a constraint, for safety matters, 3 kilometer buffer around airport was omitted from the next investigation.

4.3.1.2.2. Roads network

Landfill location must be close to roads network in order to facilitate transportation and consequently to reduce relative costs. However, aesthetically and logically a buffer of 100 meter has been considered in this study. In other words, direct relationship between distance from roads and land suitability is started from the 100 meter distance of roads.

4.3.1.2.3. Schools, Hospitals and Markets

By considering this as a constraint, a buffer of 01 Km will be reserved to Primary and Secondary schools, health centers and District hospitals, and markets (REMA, 2010).

4.3.2. Landfill site determination

The site selection analysis involves three steps: preliminary analysis, multi-criteria evaluation, and identification of the most suitable site. The preliminary analysis stage involves creating a study area map to input the data layers, then creating permissible area map for landfill sites in Rusizi town.

The second step involves performing GIS overlaying, which is conducted by combining the non restricted area map and slope analysis map in order to get the suitable landfill sites in Rusizi town that would be located in the intersection of non restricted area and suitable slope. The final step relates the finding of suitable sites using the information in advanced GIS and REMA regulations regarding landfill site's size.

Non restricted area map, Slope analysis map, Potential landfill sites in Rusizi town, Potential landfill sites in Mururu Sector, Potential landfill sites in Gihundwe Sector and General Suitability maps were created and produced.

4.3.2.1. Slope analysis

That slope map was created based on the DEM of Rusizi Town. Using spatial analyst tools, the DEM was transformed into slope and after the slope was classified into 2 classes using raster calculator as shown in Fig 3-2 in order to come up with the appropriate slope for constructing a landfill which is about 8-12% because too steep of a slope would make it difficult to construct and maintain while too flat of a slope would affect the runoff drainage. Slopes above 12% created high runoff rates for precipitation. .

4.3.2.2. Constrained and permissible areas

The constraint map was produced by merging each individual theme within the study area. This procedure created a constraint map for each theme containing only two classes (suitable land) and (unsuitable land). The 11 constraint maps (layers) namely, River, Lake, Wetland, forest, Roads, Airport, Market, Primary schools, Secondary schools, District hospitals and Health centers were used as shown by Fig 3-3.

That map was created by combining the non restricted area map and slope analysis map as shown in Fig3-4 in order to get the suitable landfill sites in Rusizi town that would be located in the intersection of non restricted area and suitable slope. 133 suitable landfill sites were identified in the town of Rusizi. Their shape length area and shape area are shown in the table 4-4 below.

OBJECT ID	Grid Cod	Shape Length	Shape Area	OBJECT ID	Grid Cod	Shape Length	Shape Area	OBJECT ID	Grid Cod	Shape Length	Shape Area
1	1	188.6	1711.6	45	1	355.0	5922.8	91	1	188.6	1711.6
2	1	200.0	2500.0	46	1	188.6	1711.6	92	1	187.5	1601.0
3	1	188.6	1711.6	47	1	283.7	3374.6	93	1	381.4	5010.8
4	1	200.0	2500.0	48	1	353.6	5867.0	94	1	188.6	1711.6
5	1	282.9	3413.5	49	1	188.6	1711.6	95	1	188.6	1711.6
6	1	188.6	1711.6	50	1	188.6	1711.6	96	1	355.0	5922.8
7	1	282.9	3413.5	51	1	188.6	1711.6	97	1	283.7	3374.6
8	1	188.6	1711.6	52	1	188.6	1711.6	98	1	188.6	1711.6
9	1	187.5	1601.0	53	1	188.6	1711.6	99	1	982.6	26915.3
10	1	282.9	3413.5	54	1	188.6	1711.6	100	1	188.6	1711.6
11	1	188.6	1711.6	55	1	188.6	1711.6	101	1	188.6	1711.6
12	1	841.2	29831.5	56	1	188.6	1711.6	102	1	433.8	11155.7
13	1	188.6	1711.6	57	1	188.6	1711.6	103	1	188.6	1711.6
14	1	282.9	3413.5	58	1	188.6	1711.6	104	1	188.6	1711.6
15	1	188.6	1711.6	59	1	188.6	1711.6	105	1	282.9	3413.5
16	1	188.6	1711.6	60	1	188.6	1711.6	106	1	188.6	1711.6
17	1	282.9	3413.5	61	1	188.6	1711.6	107	1	188.6	1711.6
18	1	379.4	5160.5	62	1	283.7	3374.6	108	1	188.6	1711.6
19	1	188.6	1711.6	63	1	188.6	1711.6	109	1	200.0	2500.0
20	1	353.6	5867.0	64	1	646.6	24024.8	110	1	282.9	3413.5
21	1	408.3	8280.5	65	1	282.9	3413.5	111	1	355.0	5922.8
22	1	282.9	3413.5	66	1	188.6	1711.6	112	1	400.0	7500.0
23	1	188.6	1711.6	67	1	188.6	1711.6	113	1	924.0	43540.0
24	1	188.6	1711.6	68	1	188.6	1711.6	114	1	187.5	1601.0
25	1	188.6	1711.6	69	1	282.9	3413.5	115	1	188.6	1711.7
26	1	188.6	1711.6	70	1	282.9	3413.5	116	1	200.0	2500.0
27	1	188.6	1711.6	71	1	188.6	1711.6	117	1	400.0	7500.0
28	1	188.6	1711.6	72	1	188.6	1711.6	118	1	200.0	2500.0
29	1	283.7	3374.6	73	1	188.6	1711.6	119	1	188.6	1711.7
30	1	188.6	1711.6	74	1	188.6	1711.6	120	1	188.6	1711.7
31	1	188.6	1711.6	75	1	188.6	1711.6	121	1	188.6	1711.7
32	1	188.6	1711.6	76	1	188.6	1711.6	122	1	200.0	2500.0
33	1	188.6	1711.6	77	1	188.6	1711.6	123	1	188.6	1711.7
34	1	188.6	1711.6	78	1	188.6	1711.6	124	1	282.9	3413.5
35	1	353.2	5791.9	79	1	188.6	1711.6	125	1	200.0	2500.0
36	1	188.6	1711.6	80	1	381.4	5010.8	126	1	188.6	1711.7
37	1	188.6	1711.6	81	1	282.9	3413.5	127	1	200.0	2500.0
38	1	188.6	1711.6	82	1	188.6	1711.6	128	1	271.7	3488.0
39	1	188.6	1711.6	83	1	188.6	1711.6	129	1	200.0	2500.0
40	1	188.6	1711.6	84	1	355.0	5922.8	130	1	1135.6	52633.1
41	1	282.9	3413.5	85	1	188.6	1711.6	131	1	188.6	1711.7
42	1	188.6	1711.6	86	1	188.6	1711.6	132	1	188.6	1711.7
43	1	188.6	1711.6	87	1	282.9	3413.5	133	1	379.4	5160.5

4.3.2.4. Potential landfill sites in Rusizi Town

That map was created based on Distribution of suitable sites in Rusizi Town map and REMA regulations regarding landfill site's size. According to REMA requirement related to the size of a suitable landfill site, 05 potential landfill sites were identified because their area is greater than 20000 Sqm (2 Ha) given that the site should provide at least 10 years of use in order to;

minimize costs for site establishment and closure, smooth running of operations, and provision of adequate time for acquiring the next site.

The general suitability map was created by combining potential landfill sites map and different constraint layers including proximity to roads (National roads, District roads, and other roads), proximity to river (Rusizi River and other rivers), Kivu lake, wetland, forest,

airport, schools (primary and secondary schools), healthy facilities (health centers and District hospitals) and markets layers.

4.4. Possibilities for landfill sites project implementation

Landfill sites project implementation in Rusizi town can involve different actors both private and public. After the identification of different landfill suitable sites in Rusizi town, the public authority can proceed on site location to find out whether there is no site that is located in the public land so as to reduce the cost of compensation of land owners. Given the budget constraint, landfill sites project in Rusizi town can be implemented once they decided to use a sanitary landfill among different landfill management techniques because sanitary landfill is the most cost-effective system of solid waste disposal for most urban areas compared to composting of solid waste that costs 2-3 times more than sanitary landfill, and incineration that costs 5-10 times more (REMA 2010).

Landfill sites project implementation requires Private Sector Involvement, if properly arranged, can increase the likelihood that landfill design and operation specifications will be followed. Ideally, the landfill would be designed, built, owned and operated by a private identity or NGO under a concession agreement.

Landfill sites project implementation should be based on environmental report that describes the site selected, outlines potential environmental impacts of sanitary landfill at the site, and proposes mitigative measures; public education and local consultations with residents in the vicinity of the proposed sanitary landfill, including an open forum where all interested parties have an opportunity to express their opinions concerning site selection; compensation and resettlement action plans for affected parties; and conceptual design and budgetary costing of the sanitary landfill, including mitigative measures identified in the environmental report and responsive to the local consultations.

5.1. General Conclusion

Locating suitable sites for any purpose (for example industrial, landfills, and road construction or Infrastructure development among others) is always a major challenge faced by both the government and the private sector due to NIMBY attitudes among the communities. Landfill site selection results are usually faced with NIMBY syndrome in every country, because people are concerned about their property. So in site selection, the problem is not to find sites which cause no opposition, but the goal is to find sites which should lead to minimum conflicts as a result of waste disposal.

The main objective of this research was to identify/ show different suitable landfill sites for municipal solid waste in Rusizi town. Three specific objectives have been formulated in order to achieve the main objective. The specific objectives are: to assess the current situation of waste generation and management in Rusizi town, to determine different criteria for selecting a landfill site in Rusizi town, and to determine suitable site (s) for landfill for waste dumping.

To respond to these specific objectives, multi source data and methods were used. These included the review of government rules and regulations regarding landfill sites selection, secondary data and primary data collected from the field. Several input data were also integrated in this analysis. These included Airport, Digital Elevation Model, rivers, slope, Kivu Lake, wetland, roads, schools, hospitals, markets and forests.

Objective 1: To assess the current situation of waste generation and management in Rusizi town

To respond this specific objective, the field study was conducted in Rusizi District and it was found out that about 26 tons of municipal solid waste are generated per day and a small part of it is deposited in open dumping landfill site located in Ruganda Cell, Kamembe Sector, in Rusizi Town given that 50% of the population relies on compost pits while 40% of ordinary households on the farms.

To achieve this specific objective, the necessary criteria including regulations and constraints were gathered through literature review. Regulations and constraints gathered from literature review were complemented by field study that found out that Ruganda open dumping site was not suitable for landfill site given that it did not fulfill the environmental, political, economic, hydrologic, topographical and geologic criteria. Furthermore, it is located in a forest.

To achieve this objective, GIS analysis was conducted with respect to slope, roads network, rivers, Kivu Lake, wetlands, forest, schools, healthy facilities, markets and airport, 131 suitable landfill sites were produced. With reference to REMA regulations regarding to suitable landfill size, 05 best landfill sites with more than 02 ha were identified in Rusizi town where 04 suitable landfill sites were identified in Mururu Sector and 01 suitable landfill site was identified in Gihundwe Sector.

5.2. Recommendations

The major problem encountered during this study was lack of some of the required data that may improve the quality of the final result. Ground water levels of the recommended suitable sites were not measured because of costs involved, lack of technical equipment required for that functionality, and time. Soil types map was missing while (Sadek, El Fadel, & El Hougeiri, 2001) emphasize that in the selection of a site for MSW land-filling, special care has to be given to the underlying foundation soil and bedrock characteristics: geologic structure, soil type, existing fractures, and so on. The starting point is a geologic map of the study area showing the geologic characteristics, the chronology of a bedrock formation and lithology.

The recommendations for future urban planning and further research are the following:

3. Launch public education and awareness campaign on safe waste handling and disposal methods given that 50% of the population relies on compost pits while 40% of ordinary households on the farms.

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