IMPACT OF SOLID WASTE DISPOSAL ON ENGINEERING PROPERTIES OF SOIL WITHIN ADO-ODO OTA LOCAL GOVERNMENT OF OGUN STATE, NIGERIA.

Abstract

The disposal of solid wastes has been a big environmental challenge in Nigeria. The rapid growth of population leads to the increased in Urbanization and Industrialization which in turn increases the rate of generation of solid wastes. As leachates infiltrate into the soil, contaminated liquid substances are migrated into the soil, thereby affecting soil stability and strength. Hence, unscientific dumping pollutes the environment to a large extent. This paper presents the impact of open dumping of Municipal Solid Wastes (MSW) disposal on Soils in Ado-Odo Ota Local Government Area of Ogun State, Nigeria. The study based on the geotechnical investigation comparison of dump soil samples and the natural soil samples collected from outside the accessibility of dumpsites. The soil samples were taken from four trial pits in and outside the dumpsites at a depth of 1m. Three of the trial pits were located within the dumpsites to serve as contaminated soils, while the other trial pits was collected from natural soils to serve as control or uncontaminated soils for the investigation. Samples collected were subjected to Natural Moisture Contents (NMC), Specific Gravity (SG), Consistency Limit, Particles Size Distribution (PSD), Compaction and California Bearing Ratio (CBR) tests. The results indicated that municipal solids wastes (MSW) reduced the CBR (4.5-6.7%), SG (1.8-2.24), Consistency limit (6.2-10.5%), Maximum Dry Density (MDD) (1.59-1.63mg/m³) and increased the NMC (13.5-15.1%) and the fine particles contents (43.5-52.8% fine sand fraction.) as compared to the natural (uncontaminated) soils. This indicated that geotechnical characteristics of the soils at all the three dumpsites have been affected as a result of the contamination by the leachates from MSW.