Effect of solid waste landfill leachates on groundwater quality
1 Department of Civil Engineering, The Polytechnic Ibadan, Ibadan, Nigeria.
2 Department of Civil Engineering, Federal University, Oye Ekiti, Nigeria.
Research Article
Global Journal of Engineering and Technology Advances, 2023, 14(03), 205–216.
Article DOI: 10.30574/gjeta.2023.14.3.0058
Publication history:
Received on 14 February 2023; revised on 25 March 2023; accepted on 28 March 2023
Abstract:
Water is a universal solvent which is of inevitable use in our daily activities both domestic and industrial. It sources: ground and surface are indispensable to inhabitants of any community. Population increase over the years is directly proportional to the demand of water. And this has affected the composition and quality of waste generated. The need to dispose wastes result in the use of the simplest method, land filling, without due consideration to its effects on the environment. Land filling method is the breeding ground of leachate which contributes negatively to the quality of groundwater sources. This study aimed at assessing the effect of solid waste landfill leachate on ground water quality in the area. Water samples were collected from five different locations around the study dumpsite in Ajakanga, Ibadan. The samples were transported to the laboratory where the water tests on the physical, chemical, biological and bacteriological characteristics were carried out. The physicochemical parameters analyzed included colour, turbidity, pH, conductivity, TS, TDS, and total hardness while the bacteriological and biological parameters included biological oxygen demand (BOD), total viable count, total coliform count and total fungal count. The results observed varied from samples tested. The colour, turbidity, total hardness and total dissolved oxygen of the samples were within the WHO guideline. The pH samples of the two wells did not conform to WHO specification from 6.5 to 8.5. Both pH were acidic. Conductivity is temperature dependent. Higher conductivities recorded in samples 1, 2, 4 and 5 signified presences of contaminations. Total solids gave an idea of both suspended solids and total dissolved solids. Samples with more than 500mg/l TDS usually have disagreeably strong taste. In the bacteriological loading, only sample 2 showed the presence of Escherichia coli (E. coli). The presence of E. coli in the stream sample indicates feacal coliform contamination which is a potential health risk for individuals exposed to this water.
In conclusion, the proximity of wells and the exposure of surface steam to the dumpsite promote groundwater pollution due to leachate migration. This study recommended that wells should be cited at distance recharge area rather than the closed discharge side of the dumpsite. Sinking of borehole was recommended in the area rather than shallow well. The risks of leachate generation can be mitigated by properly designed and engineered landfill sites, such as sites that are constructed on geologically impermeable materials or sites that use impermeable liners made of geo membranes or engineered clay. This will prevent by gravity infiltration and percolation of leachate to the underground water thereby causing contamination. Periodic physicochemical and microbiological treatment of water is of essence.
Keywords:
Solid waste; Landfill; Leachates; Groundwater
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