Leachate Characterization and Assessment of Groundwater and Surface Water Qualities Near Municipal Solid Waste Dump Site in Effurun, Delta State, Nigeria

Abstract

Leachate, groundwater and surface water samples were collected from trenches dug into refuse dump site, hand dug water wells and borehole as well as surface water in the vicinity of the Effurun refuse dump site.  Some physico- chemical parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS) were determined in-situ. While other such as chloride (Cl^-), sulphate (SO₄), nitrates (No₃), ammonia-N (NH₃-N), Pb, Zn, Cu, Cr, K, Na, Mg and Ca, COD and BOD were analyzed in the laboratory in accordance with standard laboratory procedures. The ratio of BOD₅/ COD is less than 0.5mg/l for leachates from shallow trenches and 0.1mg/l from deeper trenches, an indication of the impact of depth on the landfill stabilization. The leachate has no significant impact on groundwater quality as all parameters analyzed were below the WHO and Nigerian standard for drinking water quality (NSDWQ), except the concentration of NH₃- N that is above the WHO standard but less than the NDWWQ, also the influence of landfill leachate on groundwater quality is dependent on the distance and depth of water wells. There was increase in the amount of the parameters analyzed for surface water, a reflection of pollution. The study concludes that in spite of absence of pollution, the Groundwater beneath the landfill has the tendency of being polluted in the distant future except the refuse dump site is upgraded to a well engineered standard landfill which is lacking in the whole of the delta state of Nigeria.

Key words: leachate, landfill, groundwater, surface water and pollution