Experimental Investigation of the Migration of Organic Pollution in the Underlying Soils of Household Waste Dumpsites: A Case Study in Abomey Calavi, Benin

Abstract

The aim of this study was to develop a database for numerical simulations of the migration of the biodegradable organic pollution in soils. An experimental investigation of leachate migration in soils was implemented and experimental device designed for the study took into account the conditions prevailing in household waste dumpsites and those likely to influence the nature of the soil. The permeability of the soil used in the device was 2.36 10-6 m/s and the injected leachate had a high composition in biodegradable organic constituents (as its COD and BOD5 were 13128.19 mg O2/l, and 5822 mg O2/l, with biodegradability rate of 6.17 10-7 s-1, respectively). Leachate infiltration tests revealed that the pollutants retention by soils was a time function that decreased continuously and irreversibly once the maximum retention capacity of the soil was reached. The study showed also that the thickness of the soil layer had no influence on the hydrodynamic behaviour of the pollutants. The analysis of the concentrations in the infiltrated leachates showed that the reduction of organic pollution by the studied soil was not enough to ensure the protection of groundwater.