MODELING OF ENERGY GENERATION FROM MUNICIPAL SOLID WASTE

This Thesis is aimed at modeling of energy generation from municipal solid waste. The area of study is a densely populated urban environment dotted with public structures and institutions resulting in the generation of very high volume of refuse, the quality of municipal solid generated are dependant to the social status and class of the individual households. Samples were randomly collected from 15 locations within the study area sorted and characterized. Moisture content of waste samples was 28.38%, density was 88.25 kg/m3 total energy content was 3075200 kJ giving unit energy content of waste as 30752 kJ/kg. Energy content on dry basis was 42937.37 kJ/kg while on ash-free dry basis, it gave 47588.37 kJ/kg. Chemical composition of the waste samples is carbon, hydrogen, nitrogen, oxygen and sulfur. Twenty years projected population of 354658 persons showed that 6.326 x 109 kJ of energy equivalent to 1.523109 x 109 Watt hour will be recovered from the waste generated by this population if it is effectively converted and managed. The very high quantity of energy generated by high volume of waste will also discourage indiscriminate dumping of refuse and associated environmental pollution It is therefore concluded that Municipal solid waste can be converted to useful energy for domestic and industrial usage.

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2.1 Generalized flow of materials and the generation of solid wastes, recovery and reuse of waste material. 22

 

 

Solid wastes are the waste arising from human, animal and industrial activities that are normally solids, discarded as unwanted and useless. They include the mass of throwaways from residence, commercials and industries. Because of recent developments in recycling and recovery technologies, the above definition may not be absolutely correct.

Solid waste management (SWM) is the control of solid waste generation, collection, storage, transport, processing and disposal activities based on engineering principles at minimum environmental impacts and cost published in American Federal Register 1980.

Many developing countries of the world are faced with the biggest challenge of solid waste management, mainly due to increase in solid waste generation (SWG), from homes which are a burden on the municipal budget ( Abdel-Shafy et al. , 2018). Global municipal solid waste (MSW) generation is estimated at about 1.3 billion tonnes per year, and is expected to increase to approximately 2.2 billion tonnes per year by 2025. (The World Bank., 2012). Solid waste generation in urban cities have serious impact on sanitation facilities like water supply, waste management and transport infrastructure(Liyala., 2011). Studies have shown that collection, storage, transportation and disposal of solid wastes are the major problems in many cities (Okot-Okumu, and Nyenje, 2011). Many African countries are economically unstable and as a result, cannot afford the huge cost of solid waste management (Okot- Okumu, and Nyenje, 2011). Factors affecting SWG include average family size, number of rooms, monthly income and employment status(Sankoh et al., 2013). It has been established that solid waste composition is directly propositional to the social class in any given community ( Gidarakos et al., 2006).For instance areas dominated by high income earners are more likely to generate more solid wastes than those with low income earners who live in unconducive environments (Gu et al., 2015). Wastes can be transmuted to energy by incineration, a system known as waste-to-energy (WTE) incineration in which energy is recovered from municipal solid waste (MSW) to produce electricity and/or steam for heating, being a renewable source of energy (Cheng and Hu, 2010).

Municipal solid wastes are an important part of any society, its management by land filling method is in order to prevent such problems like air, water and land pollution ( Abu-Qudis, and Abu-Qudis., 2000). Though, there are still problem associated with it, which includes hazardous gas emissions and production of leachate from land filled wastes ( Dong et al.

,2003) and (Shu et al., 2006). Municipal solid waste can be appropriately managed by recovery of its energy content through such processes like, combustion, pyrolysis, and refuse derived fuel. However, no matter which kind of MSW strategy is chosen, modeling from the empirical approach, three models are available for prediction based on physical composition, ultimate and proximate analytical methods respectively ( Liu and Backhurst, 1996). MSW generation according to influencing factors is very important in solid waste management, as it can provide more accurate predictions of future MSW generation.

(European Environmental Agency, 2013). Per capita data are widely used to compare the intensity of MSW generation among different places ( AbuQuadis et al., 1997) and (Gomez et al., 2008). MSW generation per capita ranged from 0.09 kg day-1 in Ghana to 5.50 kg day-1 in Antigua and Barbuda; the median was 0.94 kg day-1, and it was 0.58 kg day-1 in Nigeria ( Kawai and Tasaki, 2016). Population increase, rapid urbanization, booming economy, and the rise in the standard of living in developing countries have greatly accelerated the rate, amount and quality of the municipal solid waste generation (Minghua et al., 2009) and Sujauddin et al., 2008). This is essentially due to financial resources, lack of organization and complexity (Burntleyet and Waste Management, 2007). The composition of MSW varies significantly from one municipality to another and from country to country significantly.

 

Such variation depends mainly on the life style, economic situation, waste management regulations and industrial structure (IAEA., 1985). In this respect, the composition of the waste will provide valuable information on the utility of the material for either composting or for biogas production as fuel via biological conversion(Kumar et al., 2010).The EPA estimated the amount of MSW generation in the United States with 254 million tonnes( US EPA., 2013). Several studies reported that the municipal solid waste that are generated from the developing countries are mainly from households (55–80%), followed by market or commercial areas (10-30%). The later consists of variable quantities generated from industries, streets, institutions and many others (Hum.and Nabegu , 2010) .

Generally, solid waste from such sources is highly; heterogeneous in nature. Thus, they have variable physical and chemical characteristics depending on their original sources. Their composition are yard waste, food waste, plastics, wood, metals, papers, rubbers, leather, batteries, inert materials, textiles, paint containers, demolishing and construction materials as well as many others that would be difficult to classify.

Indiscriminate dumping of solid waste all over the environment, drainages and throwing away wastes while on transit has been a major occurrence within this area. This also degenerates into pollution of the environment resulting in spread of diseases with the associated sickness like typhoid, malaria, cholera and skin diseases. It reduces the aesthetic value of the environment, occupies available space and thereby increases the cost of future constructions.

 

To study solid waste production and determination of the energy content of the different component of solid waste in Umuahia North Municipal objectives.

The Objectives of the this research is to:

There exist so many types of wastes such as solid waste, hazardous waste, liquid waste, gasses waste etc. Because of the huge cost involved in research, these wastes cannot be studied. Also, for the fact that solid waste are more problematic in Umuahia North municipal, the scope of this work is limited to Modeling of Energy Generation from municipal solid waste in Umuahia North.

Upon completion of the study, it will give the following information on Umuahia North municipal waste management.