Leachate Composition and Groundwater Pollution at Municipal Solid Waste Landfill of Ibb City, Yemen

Compositions of landfill leachate and groundwater pollution were studied at Ibb landfill, which is located at Al-Sahool area, north of Ibb City, Yemen. The leachate was sampled at three different locations at the landfill, i.e. at the landfill itself and at 15 and 20 m downstream of the landfill. Groundwater samples were collected from five boreholes to study the possible impact of leachate percolation into the groundwater. The leachate and groundwater samples were collected during wet season, due to the excessive generation of leachate during this season. The objective of this paper is to evaluate the groundwater pollution due to the landfill leachate. The leachate and groundwater were physically and chemically characterised. The parameters measured were pH, temperature, electrical conductivity (EC), total dissolved solids (TDS), dissolved oxygen (DO), fluoride (F(-)), chloride (Cl(-)), sulphate (SO(4)(2-)), nitrites (NO(2)(-)), nitrates (NO(3)(-)), ammonia-N (NH(3)(-)N), heavy metals (Pb, Zn, Ni, Cr, Cd and Cu), major cations (Na, Mg, Ca, K and Fe) and biological parameters (COD and BOD(5)). The leachate at this landfill is most likely in methanogenic phase, based on the alkaline pH value recorded (pH=8.2). The results show that four out of five boreholes are contaminated, where the concentration of physico-chemical parameters are above the standard acceptable levels which are required for drinking water adapted by Yemen's Ministry of Water and Environment (YMWE). Therefore, detailed study of the leachate and its effect to the groundwater in the study area is recommended.