CHAPTER TWO
2.0 Literature Review
Several works have been done on different dumpsites in Nigeria and many parts of the world, that show how water qualities and human are affected.
The end of each product being a discard, the production process of any product is considered as a primitive source of solid waste. This is considered as being an important portion of the solid waste stream (Li et al., 2008). Eddy et al., (2006) study on the elemental composition of soils at dumpsites was conducted by analysing samples of soil at different dumpsites located within Ikot Ekpene, South Eastern Nigeria. The samples were analysed for the concentration of Na, Ca, Pb, Ni, Mn, Mg, Fe, P, N, Cu and Zn. Control soil samples were taken at 10km away from the dumpsites and were also analysed for the significant of these elements. The dumpsites were found to contain significant amount of toxic and essential elements hence remediation processes were suggested.
Waste is the direct consequence of many types of human activity, and has been a burden to deal with across the world and throughout history. Landfilling has emerged as the simplest and most economical method of disposing with this waste.
The United States Environmental Protection Agency (EPA) (2005), defined solid waste as “ any useless, unwanted or discarded materials with insufficient liquid content to be free flowing. According to Federal Environmental Protection Agency (FEPA) (1995), solid wastes are useless, unwanted or discarded materials that arise from man’s activities and cannot be discarded through sewer pipe.
2.1 Historical background of landfill
Landfills are the old form of waste treatment and are used in many places around the world. Since the advent of agriculture, humans have had to deal with garbage disposal. Yesterday’s dump was a pit or hill on the outskirts of town that played host to disease-carrying rodents, insects, and dangerous objects. Before the advent of modern landfills, Americans also burned their garbage. Due to environmental safety concerns, most municipalities have banned unregulated garbage dumps and burning due to the contamination of groundwater supplies, streams, and airways.
Landfills are now the only sanctioned garbage disposal sites for most municipalities, and only qualified personnel are allowed to bury or burn waste. Most people see the end of household garbage when they leave it on the curbside for the garbage haulers. When garbage is taken away, it is routed to the landfill where it becomes part of the unending cycle of waste disposal.
Once the garbage truck finishes a route, it arrives at a collection site or landfill where it is weighed and inspected for content. At the landfill, garbage is unloaded onto the tipping face and compacted by bulldozers and other machinery. Each day’s garbage is referred to as a cell, and when a cell is filled, soil, foam spray, wood chips, and/or temporary blankets are used to cover the area. This covering keeps rain and wind from dispersing the garbage and controls insects, birds, and rodents. Once a landfill section is capped, the area is planted with grasses.
Modern landfills are located in areas where clay deposits and/or other natural features can buffer the environment from contamination. Landfills are required to use liners made of plastic, clay, or other non-porous materials to keep garbage from leaking into the soil. Landfill operators employ a system of drainage pipes to route any liquid waste (leachate) into nearby ponds or wells where it is tested and treated. Groundwater around landfill sites is quality tested for many years after a landfill is full. To ensure safety, the Environmental Protection Agency (EPA) has developed strict regulations governing the operation of landfills to ensure the prevention of leachate breaks and methane leaks.
Garbage in landfills does not break down - a landfill is more like an airtight storage container. Even biodegradable items such as grass clippings and paper break down very slowly in a traditional landfill, making the space unrenewable. Though landfills cannot be used over and over, they are often put to good use. Closed landfills are turned into parks, golf courses, ski slopes, and parks. Homes and other buildings are not usually built on closed landfills due to settling.
Newer types of landfills, called a bioreactor, use leachate and/or air to create biodegrading inside the landfill. In these types of landfills, leachate is used on site and does not require disposal. Bioreactors are able to store much more garbage, due to biodegrading, than traditional landfills. Another benefit to bioreactors is the production of methane gas from the decomposition of organic waste. Methane has similar properties to natural gas and can be used as an energy source for fuel or by burning to generate steam and electricity.
