1.1 Background of Study
In terms of Sustainability and environment, the natural elements play important roles for ecological preservation. Water is the most abundant environmental resource on earth but its accessibility is based on quality and quantity, as well as space and time. It may be available in various forms and quantity but its use for various purposes is the subject of quality. About 70% of the human body and about 60-70% of plant cells is made up of water (Smith and Edger, 2006). It is one of the determinants of human settlement, existence and activities on the earth. Its quantity is fixed but dynamic in formation and storage. Of all the environmental concerns that developing countries face, the lack of adequate, good quality water remains the most serious (Markandya, 2004). Once contaminated, groundwater may forever remain polluted without remedy or treatment. Water is one of the determinants of human earth system. Diseases may spring up through water pollution, especially groundwater contamination, and rapidly spread beyond human expectation because of its flow mechanism (Afolayan et al., 2012). One of the major factors that make the earth habitable for humans is the presence of water. Forming the major component of plant and animal cells, it is the basis of life and therefore the development of water resources is an important component in the integrated development of any area.
Water is critical to our daily lives and is an extraordinary compound in nature. It covers 71% of Earth (USGS, 2014). Water is the most important resource of a country, and of the entire society, since no life is possible without water. It has this unique position among other natural resources, because a country can survive in the absence of any other resource, except water (Garg, 2009). According to the National Water Policy (2002), in the planning and operation of systems, water allocation priorities should be broadly as follows: drinking, irrigation, hydropower, ecology, agro-industries and non-agricultural industries, navigation and other uses.
About 68.7% of the fresh water is tied up in polar ice caps and glaciers, and a further 30.1% is underground as groundwater, most of which is not available for use (Gleick, 1996). Rivers and lakes constitute a mere 0.32%, atmospheric moisture 0.03% and soil moisture 0.05%.The major sources of water are surface water (oceans, rivers, streams, seas and brooks), groundwater, snow and ice, and lakes. However their exploration and exploitation varies from place to place based on their state of existence. Groundwater plays a vital role for urban and agricultural water supply. It accounts for about 0.5% of total hydrosphere, approximately 6.73 x10km3 in volume (Ayoade, 2003). It constitutes a major portion of the earth’s water circulatory system known as hydrological cycle and occurs in permeable geologic formation known as aquifers i.e. formations having structure that can store and transmit water at rates fast enough to supply reasonable amounts to wells (Afolayan et al., 2012).
Wastes of different types, mostly solid wastes are the major input of dumpsites/landfills. With respect to the hydrological analysis of groundwater, it flows from areas of higher topography towards areas of lower topography, thereby bringing about the examination of the degradable material which form leachate and contaminate the groundwater of the study area.
Landfill practice is the disposal of solid wastes by infilling depressions on land. The depressions into which solid wastes are often dumped include valleys (abandoned) sites of quarries, excavations, or sometimes a selected portion within the residential and commercial areas in many urban settlements where the capacity to collect, process, dispose of, or re-use solid waste in a cost-efficient, safe manner is often limited. The practice of landfill system as a method of waste disposal in many developing countries is usually far from standard recommendations (Mull, 2005; Adewole, 2009; Eludoyin & Oyeku, 2010). A standardized landfill system involves carefully selected location, and is usually constructed and maintained by means of engineering techniques, ensuring minimized pollution of air, water and soil and risks to man and animals. It involves placing waste in lined pit or a mound (Sanitary landfills) with appropriate means of leachate and landfill gas control (Alloway & Ayres 1997; Eludoyin & Oyeku 2010). Land filling of municipal solid waste is a common waste management practice and one of the cheapest methods for organized waste management in many parts of the world (El-Fadel et al., 1997; Jhamanani et al., 2009; Longe & Balogun, 2010). Increasing urbanization results in an increased generation of waste materials and landfills become the most convenient way of disposal. Most of these landfills are mere ‘holes in the ground” do not qualify as sanitary means of solid waste disposal. Most of the areas around the Solous dumpsites depend either on dug-up wells or bore-holes which may likely be affected by the generated leachate through waste decomposition from the dumpsites despite the provision of pipe-borne water by government. According to Papadopoulou et al. 2007, as the natural environment can no longer digest the produced wastes, the development of solid waste management has contributed to their automated collection, treatment and disposal. One of the most common waste disposal methods is landfilling, a controlled method of disposing solid wastes on land with the dual purpose of eliminating public health and environmental hazards and minimizing nuisances without contaminating surface or subsurface water resource.
There are three major landfills and two temporary landfill sites serving the area of Lagos State. The Olushosun landfill site is the largest, situated in the Northern part of Lagos within Ikeja Local Government Area, and receives approximately 40% of total waste deposits from Lagos (LAWMA, 2011).
The Solous landfills, I, II and III, may be regarded as the second most functional landfill in Lagos State after the Olusosun landfill in Ketu. This is because of its location within the largest Local Government Area of the State. For the teeming population of the surrounding community, groundwater is the major source of water supply. Despite the provision of pipe-borne public water by Lagos State Water Cooperation mini water works, some households still prefer their personal wells and bore holes. Owing to this fact, the possibility of the generated leachate affecting the hydrology of the area deserves proper investigation through experimental analysis.
1.2 Statement of Problem
Landfills have served many years as ultimate disposal site for all types of waste; municipal solid waste, industrial sewage and hazardous waste. Physical, chemical and biological processes interact simultaneously to bring about the overall decomposition of the wastes. One of the by-products of this mechanism is chemically laden leachate. Leachate is produced by the action of rainwater aiding bacteria in the process of decomposition. Leachate is typically composed of dissolved organic matter, inorganic macro components (such as chlorides, iron, aluminum, zinc and ammonia), heavy metals and xenobiotic organic compounds such as halogenated organics. Other chemicals including pesticides, solvents and heavy metals may also be present. Leachates are a potential hazardous waste from landfill sites. If not dealt with properly they can cause pollution to groundwater, health problems and affect the environment. It is therefore important that leachates are treated and contained to prevent these occurrences (Kostova, 2006).
The city of Lagos with its teeming population has less than 50 Water Supply Boards to cater to it in terms of water treatment and distribution. It therefore relies rely mostly on bore holes and hand dug wells for its water needs. The major environmental problem experienced around the Solous landfill areas is the contamination of groundwater via discharged leachate. Areas near landfills have great possibility of groundwater contamination because of the potential pollution source of leachate originating from the nearby site. Such contamination of groundwater resource poses a substantial risk to local resource users and to the natural environment. The impact of landfill leachate on the surface and groundwater has given rise to a number of studies in recent years (Mor et al., 2006). It is therefore important to study the water quality in areas especially those around these landfill sites to examine its impact on groundwater quality.
1.3 Research Objectives
The aim of the research is to examine the impact of sanitary landfills towards sustainable development in Nigeria. The research also considers the effect of the location of dumpsites on the underground water quality in Lagos State. To this effect, the study will particularly:
Examine the effect of distance from dumpsite on the physical, chemical and heavy metal properties of sampled groundwater.
Determine the effect of soil physical properties on the ground water quality in the study area.
Examine if there is variation in water quality among sampled groundwater sources
Compare the difference in the quality of sampled water with WHO and NSDWQ water quality standards.
1.4 Research Questions
What is the effect of distance from dumpsite on the physical, chemical and heavy metal properties of sampled groundwater?
What is the effect of soil physical properties on the ground water quality in the study area?
Is there any variation in water quality among sampled groundwater sources?
What is the impact of sanitary landfill towards sustainable development in Nigeria?
1.5 Significance of the Study
Seasonality is the first criteria of the period of this research work because it plays prominent role in waste degradation and groundwater migration. Similar studies have also been carried out in the past during the rainy season and this study monitors the sites to compare results over time. This serves as the basis of the fieldwork being carried out in August, 2011 unlike either during the dry season when there is no water ingression or during the excess rainfall which can easily dilute and reduce parameter concentration. The study will also recommend measures with which local authorities can continue to reduce pollutant levels over time. The selected variables were based on their long life span and being the common pollutants within the landfill, as well as their degree of concentration in relation to groundwater migration. They have been regarded as being responsible for various health problems, being non-biodegradable, as well as their possibility of accumulation in the food web. Despite the provision of pipe borne water by state government in areas of the landfill, people still rely more on their dug-up wells which are easily contaminated through seepage. Low literacy levels may have influenced their choice of preference for dug-up wells. Some physical parameters like taste, colour and odour are the main indicators of water pollution to the people without taking into consideration the other physical, chemical and biological variables of water.
This will add to the body of existing literature on this research topic as well as be a reference point for other researchers who want to write on a related field or area in the nearest future.
1.6 Limitation of the Study
Assessing the variability in leachate composition and leachate migration from old landfills needs an integrated approach. Historical information (including old maps, aerial photographs, interviews, etc.) creates a valuable basis for understanding the variability. Also, information on the hydrology of the dumpsite and the adjacent part of the polluted aquifer is needed. Detailed information of the site like depth could not be extracted from the appropriate authority due to the fact that the sites were not originally planned and designed for the purpose of waste management. As a result of proximity of the examined dumpsites, there were problems of spatial boundary location. The Solous dumpsites are interconnected and to establish surface hydrological boundary in between them posed a very serious task. However, surface delineation of landfill areas may not coincide with the underground water basin. Most of the inhabitants refused to cooperate due to their suspicion that the researcher was an agent to State Government set out to expose their non-compliance with the instructions of the Lagos State Water Corporation.
The lack of standard laboratories as well as the high cost of testing each sample affected the number of samples tested. A long distance was travelled to avail the services of the Lagos State Environmental Protection Agency to test the water samples and soil samples were tested out of state resulting in additional transport costs. Period of observation, that is rainy season, might also checkmate the results from the parameters.
1.7 Definition of Terms
Sustainable Development: is the organizing principle for meeting human development goals while at the same time sustaining the ability of natural systems to provide the natural resources and ecosystem services upon which the economy and society depend. The desired result is a state of society where living conditions and resource use continue to meet human needs without undermining the integrity and stability of the natural system. Sustainable development can be classified as development that meet the needs of the present without compromising the ability of future generations
Dumpsites: Also known as traditional landfills are excavated pieces of land or pits where waste materials are stored.
Landfill: An old and easiest method of waste disposal that involves burying the waste in specially constructed sites.
Sanitary Landfill: A designed and engineered method of disposing of solid wastes to reduce groundwater pollution.IMPACT OF SANITARY LANDFILLS TOWARDS SUSTAINABLE DEVELOPMENT IN NIGERIA