Chapter

CHAPTER 2 2.0 introduction LITERATURE REVIEW Municipal solid waste is defined as, a material for which the primary generator or user abandoning the material within the urban area requires no compensation upon abandonment. This definition covers all urban solid wastes if it is generally perceived by society as being with in the responsibility of the municipality to collect and dispose off (Cointreau, 1982). Some authors also define municipal solid waste (MSW) as material which is useless or unwanted material discarded as a result of human or animal activity. Most commonly, it is solids, semisolids or liquids in containers thrown out of houses, commercial or industrial premises (ESI Africa, 2004). The major type and source of municipal solid waste are food, paper, plastic, glass, metals and various other households’ items including street sweepings and general refuse from households, commercial, institutional establishments and non-hazardous solid wastes from industries (Tchobanoglous et al., 1977: Bilitewski et al., 1977). 2.1 Sources and components of solid waste The sources of solid wastes are residential, commercial, institutional, construction and demolish, municipal services, industrial, treatment plants sites and agricultural wastes (Tchobanoglous et al., 1977). Various industrial plants generate wastes, which are mainly hazardous wastes during their raw material preparation, production or transportation processes. The waste generated from such sources is not only hazardous but also inorganic requiring special treatment before final disposal (Bilitewski et al., 1977). In this regard, in Jimma small scale manufacturing activities are found and produce significant amounts of wastes. Solid waste sources are mainly municipal services in the town Jimma. In Jimma the length of Asphalted road is very small where street cleaning is under taken. From observations, cleaning of the drainage lines is not frequently conducted, thus the lines are almost full with solid wastes most of the time (Lem Ethiopia, 2006). 2.3 Physical Composition of Residential Solid Waste The composition of a municipal solid waste stream is important for designing material recovery facilities and developing other waste minimization programs. Successful characterization depends on obtaining representative samples of the collected solid waste and making statistically precise and accurate estimates of components weights (Zeng et al., 2005) The percentage of RSW components vary with location, season, economic condition and many other factors (Tchobanoglous et al., 1977). Components that typically make up most MSW include food wastes, paper, ash, plastic, metals, textiles, glass and ceramics, etc. Different sources express physical properties of municipal solid waste by its density, particle size, moisture content, etc. (Holmes, 1981; Tchobanoglous et al., 1977). According to these sources, density-specific weight (weight per unit volume) is managed by assessing total mass and volume of waste. It has major role in determining compaction, decomposition and incineration. Other physical properties of municipal solid waste are particle size and porosity (permeability), which are important in managing material recovery and governing movements of liquid and gases in a landfill. 2.4 Solid Waste Generation Rate Solid waste quantities should always be expressed in terms of weight not volume, since the latter varies with compaction (Vesiline and Rimer, 1981). Significant variations in composition and quantity also depend on economic status, geographical characteristics of land, rainfall, climate, habits of people what they eat and drink, the package material they purchase, etc. The reason for measuring solid waste generation rate is to obtain data to determine the total amount of wastes to be managed (Tchobanoglous et al., 1981). According to Gordon’s estimations referred to in a report documented by AACSBPDA in 2003, the solid waste generation rate in Addis Ababa is estimated to be 0.15-0.252kg/GNP/day (Bjerkli, 2005). 2.5 Solid Waste Management Municipal solid waste management (MSWM) is the generation, separation, collection, transfer, transportation and disposal of waste in a way that takes in to account public health, economics, conservation, aesthetics, and the environment, and is responsive to public demands (WWF, 2005). According to the World Bank, overall goal of solid waste management should be to collect, treat and dispose of solid wastes generated by all population groups in an environmentally and socially satisfactory manner using the most economical means available. Solid waste management is in crisis in many of the world’s largest urban areas as population attracted to cities continues to grow and this has lead to ever increasing quantity of domestic waste while space for disposal decreases (world Bank, 1999). Historically, the aim of waste management has been to prevent or to reduce the impact of waste materials on health or local amenity. Over the last 30 years, however, the focus of waste management has shifted to reducing impact of environment and to recover resources from waste materials. Waste management can involve solid, liquid or gaseous wastes, with different methods and fields of expertise for each (Lemma, 2007) There is a need for a complete rethinking of “waste” – to analyze if waste is waste. A thinking that calls for waste to become wealth, refuse to become resource, trash to become cash (Lem Ethiopia, 2006). 2.5.1 History of Solid Waste Management in Jimma Town In 1943 Sanitation rules /legal Notice No.25/ with regard to wells, food, vaccination and refuse was proclaimed. In 1950, legal Notice No. 148 was proclaimed with regard to refuse proclamation No.147 which established Ministry of Public health in Ethiopia, defines ‘Sanitation” as the surveillance of food stuffs, and beverages, buildings and factories, and of the methods employed for the water wells, drainage and sewerage systems (Lem Ethiopia, 2006). When the Jimma city was built as an administrative center there was hardly any thought of waste a potential threat. Rural tradition of disposing waste in the open air was instantly transferred to the emerging city to perpetuate to these days. In the early days of the problem of sanitation in Jimma may not have a significant impact. Because there was no over population and the houses were easier to dispose rubbish and other generated wastes, but latter when population increased the problem became worse and the government tried to minimize the problem by establishing municipality. The municipality was established in 1942 according to decree number 1/1942. At this time to make its management easier the town was divided in to four Sefers ( Quarters), which were named Bosa, Hirmata, Mendera and Jiren. Later the municipality was entitled to look after sanitary condition of the town. Hence, solid waste collection started using wooden trunk and barrels put at different places in the town. In 1952 the municipality bought one dump truck and two vacuum trucks. The dump truck used to collect and dispose the solid waste out side the town and the vacuum truck used for liquid waste collection. Although the history shows that the municipality started to manage the wastes of the town more than four decades ago but still the service is found to be at rudimentary stage (Lem Ethiopia, 2006). 2.5.2 Existing Solid Waste Management System in Jimma One of the most important problems of Jimma town is the solid waste management. The core problem is the pollution of the environment, especially streets, rivers and ditches. The pollution increases the health risks of the population and reduces the value of the environment. The municipality has only limited data on the rate of generation and composition. But some studies show that the daily solid waste generation rate is 0.0014m3 and the composition is 8.45% garbage, 79.42% combustible and 2.13% non-combustible. The types of solid wastes produced in the residential areas consist of mainly organic which consists of materials such as food waste, paper of all types, card board, textiles, rubber, leather, wood and yard wastes. While the inorganic fraction consists of items such as glass, metals of different types etc. The disposal site that is currently in use for the total of Jimma town is open field located at a distance of about 5 km form the town on Seka road in kofe kebele. This is an agricultural area where no extra preparation done to make it proper disposal site. The worst thing in relation to waste disposal is that most of the time dumping is done starting from 500 meters out of the town along the road with out even reaching the so called disposal site. These can be clearly seen by any traveler along the road to Seka. From the observations of the researcher, liquid waste is also dumped there. Jimma due to its transportation center and junction point to other most towns of the western part of the country, the economic activity is strong and serves large population that generates large volume of waste. Chat chewing is popularly known and widely practiced in the town, which produces large amount of waste and thus increasing the amount of waste generated in the town. The use and discarding of plastic bags, commonly called ‘’festal’’ is observed everywhere in the town and the trend seems to be increasing. Not only is the festal pollution unpleasant to look at but it also blocks natural and manmade drainage lines, decreases the rate of decomposition of organic wastes. Inadequate waste collection compounded with inappropriate final disposal system has increased the probability of ‘’festal’’ consumption by livestock, which has endangered their health and their produce. On top of this, it has adverse long-term effect on the environment. 2.6 EFFECTS AND IMPACTS OF SOLID WASTES If solid wastes are not managed properly there are many negative impacts that may result. In order to give more emphasis for the management work, one must have a good understanding about the effects and risks that may arise from improperly managed solid wastes. The following are lists found to be the most important effects associated with uncontrolled solid wastes.  Uncollected wastes cause blockage of drains, which result in flooding and unsanitary conditions,  Flies and Mosquitoes breed in some constituents of solid wastes, and flies are very effective vectors that spread disease,  Waste dumps are good shelter for rats. Rats consume and spoil food, spread disease, damage electrical cables and other materials,  Uncollected wastes degrade the urban environment, discouraging efforts to keep the streets and open places in a clean and attractive conditions,  Dangerous items (such as broken glass, razor blades, needles and other healthcare wastes, aerosol cans and potentially explosive containers) may pose risks of injury or poisoning, particularly to children and people who sort through waste,  Waste items that are recycled without being cleaned effectively or sterilized can transmit infection to later users,  Polluted water (leachate) flowing from waste dumps and disposal sites can cause serious pollution of water supplies.  Waste that is treated or disposed of in unsatisfactory ways can cause a severe aesthetic nuisance in terms of smell and appearance.  Fires on disposal sites can cause major air pollution, causing illness and reducing visibility, making disposal sites dangerously unstable, causing explosions of cans, and possibly spreading to adjacent property and etc. As described by Tchobanoglous et al 1977, public health, aesthetic and ecological concerns are the major impacts associated with the solid waste generation. 2.6.1 Public health concerns The concerns of public health are related primarily to the infestation of areas used for the storage of solid wastes with vermin and insects that often serve as potential reservoirs of disease. The practice of throwing wastes into unpaved streets, road ways and vacant land led to the breeding of rats, with their attendant fleas carrying the germs of disease that result in disease outbreak. The lack of any plan for the management of solid wastes led to the epidemic of various diseases. The most effective control measure for both fleas and rats is proper sanitation. This involves the use of containers with tight lids, the periodic washing of containers, storage areas and periodic removal of biodegradable materials, which is especially important in areas with warm climates. 2.6.2 Aesthetic concerns Aesthetic considerations are related to the production of odors and the unsightly conditions that can develop when adequate attention is not given to the maintenance of sanitary conditions. Most odors can be controlled through the use of containers with tight lids and with the maintenance of a reasonable collection frequency. If odor persists, the container can be sprayed as a temporary expedient. To maintain aesthetic conditions the container should be scrubbed and washed periodically. 2.6.3 Ecological Concerns Ecological impacts, such as water and air pollutions, also have been attributed to improper management of solid wastes. For instance, leachate from dumps and poorly engineered landfills contaminate surface waters and ground waters as it may contain toxic elements such as copper, arsenic etc. 2.7 Collection of Solid Waste The term collection includes not only the gathering or picking up of solid wastes from the various sources, but also the hauling of these wastes to the location where the contents of the collection vehicles are emptied (Tchobanoglous, 1993). There are three basic types of collection equipments: Human powered, Animal powered, and Engine powered. (According to Nurconsult, 1982 and AAHB, 1997) they are described as follows.  Human-powered collection equipment: These include pushcarts, pedal tricycles, wheelbarrows, and two wheeled dollies with baskets. In general, these equipments require some sort of smooth surface on the lanes to be effective.  Animal-powered collection equipment: Animal powered collection equipment either takes the form of drawn carts or the animal may be directly backed with containers such as basket. This type of collection is applicable in the cities where there is no much traffic.  Engine-powered collection equipment: These includes all motorized vehicles, like tricycles with hydraulic tipping containers mounted on the back, tractors pulling wheel containers, and trucks with mobile containers. This mode of collection system is used in the cities where road accessibility is not a limiting factor. In the case of Jimma town, both human, animal and motorized collection equipment have been used. There exists three broad types of refuse collection systems namely door-to-door, block, and communal collections that are facilitated by only one collection vehicle, i.e., container lift truck and these ways of collections are used in Jimma town solid waste collection systems (Lem Ethiopia, 2006). 2.8 Waste Disposal and alternative waste management options Solid waste disposal (the disposal of solid or semi-solid materials) resulting from human and animal activities that are useless, unwanted, or hazardous. Most of the municipal solid waste (MSW) in developing countries is dumped on land in a more or less uncontrolled manner. These dumps make very uneconomical use of the available space, allow free access to waste pickers, animals and flies and often produce unpleasant and hazardous smoke from slow burning fires. The safe and reliable long-term disposal of solid waste residues is an important component of integrated waste management (Tchobanoglous et al., 1977). Disposal is the ultimate fate of all solid wastes collected and transported to landfill site, incinerator, compost or other substances from the various solid waste processing plants that are of no further use to society. There is currently one open landfill dumping site known as Seka located 5 km away from Jimma town, which is found in Kofe kebele. This site has been given service since 2003. 2.8.1 Source Reduction, Reuse and Recycle Source Reduction means decreasing the amount or toxicity of the materials that we thrown away. Effective source reduction promotes the use of products that generate the smallest environmental impacts (USEPA, 1990). It includes  Purchasing of long lasting goods  Seeking products and packaging which are as free of toxics as possible.  Redesigning products to use fewer raw materials in production, have a longer life, or are used again after its original use. Reusing items- by repairing them, donating them to charity and community groups, or selling them – also reduces waste. Reusing products, when possible, is even better than recycling because the item does not need to be reprocessed before it can be used again. Whereas, recycling turns materials that would otherwise become waste into valuable resources. In addition, it generates a host of environmental, financial, and social benefits. Materials like glass, metal, plastics, and paper are collected, separated and sent to facilities that can process them into new materials or products. 2.8.2 Composting Composting has been defined (Haug, 1980) as the biological decomposition and stabilization of organic substrates under conditions that allow development of thermophilic temperatures as a result of biologically produced heat. Therefore, the final product is sufficiently stable for storage and application to land with out adverse environmental effects. Composting is usually applied to solid or semi-solid materials and can be carried out under either aerobic or anaerobic conditions. The aerobic products consist of carbon dioxide, water, ammonia, and heat, whereas methane and other volatile acids are produced by anaerobic composting (Martin, 1991) 2.8.3 Incineration Incineration (mass burning with a Temperature of 900-10000 c) is the term used for the combustion of solid wastes. In properly designed and operated incinerator, there is a substantial reduction in the volume of waste material. The residue (ash) is eventually disposed of by landfill or used for road construction in some countries. The process is extremely hygienic and many of the problems associated with landfill, such as windblown refuses, rodents and flies, are completely eliminated (Hall et al., 1993). Domestic waste is characterized by its heterogeneity and can range from an old refrigerator to a sackful of bones or a tea chest of old books. Thus, equipment for reducing the size of irregular objects is normally a prerequisite at most incinerator plants (WB, 1999). 2.8.4 Sanitary Landfill A sanitary landfill is a method of solid waste disposal that functions with out creating a nuisance or hazard to public health or safety. Engineering principles are used to confine the waste to the smallest practical area and volume, and cover it with a layer of compacted soil at the end of each day of operation, or more frequently if necessary. This covering of the waste makes the sanitary landfill “Sanitary”. The compacted layer effectively denies continued access to the waste by insects, rodents, and other animals. It also isolates the refuse from the air, thus minimizing the amount of surface water entering into and gas escaping from wastes. The most significant possible hazard from a sanitary landfill is ground water or surface water pollution by leachate. Landfilling is necessary for municipal solid waste disposal but every landfill has its own finite capacity. The most common approach to extending the life of landfills is to introduce recycling, composting, and incineration in to the solid waste disposal system (Chang and Nishat, 2005) 2.9 Integrated Solid Waste Management There is no single right way to manage municipal wastes responsibly as described by Tchobanoglous et al. (1977). Integrated waste management, or IWM, is a tool to determine the most energy efficient, least polluting ways to deal with the various components and items of a community’s solid waste stream (Stokoe and Teague, 1995). Therefore Integrated Solid Waste Management (ISWM) is a comprehensive waste prevention, recycling, composting and disposal program in ways that most effectively protect human health and the environment. ISWM involves evaluating local needs and conditions, and then selecting and combining the most appropriate waste management activities for those conditions. Each activity such as waste prevention, recycling, composting etc require careful planning, financing, collection and transport of solid waste. Life cycle assessment (LCA) which is used to assess the environmental impacts of products from cradle to grave, has to be applied for evaluation of waste starts when a material is discarded in to the waste stream and ends when the waste material has either been converted in to a resource (such as recycled material or recovered energy) or, when it has been finally disposed. Perhaps the most important requirement for an alternative is that it has to be quantifiable with respect to equipment, disposal site, economics, etc (Tchobanoglous et al., 1977).