Evaluation of the purification capacity of soils: case of the Kouogouo and Djeleng V quarters in Bafoussam City (West Cameroon)

This work aimed at evaluating the purification capacity of the Kouogouo and Djeleng V quarters’ soils (West Cameroon). Soil mapping was carried out, from which representative soil samples were collected, followed by their physical, chemical, and hydrodynamic characterization. Two types of effluents were identified, characterized, and subjected thereafter to filtration into these soil samples. The filtrates were then analyzed, in view of evaluating the performance of these soils through influent-effluent indicator level (physico-chemical parameters and fecal coliforms). The main results show four soil units in the study area, among which the indurated red brown clay soils and red clay loam soils with rock fragments were dominant, with 51.8% and 35.4%, respectively. The clayey texture was dominant (94.7%). These soils were classified as neutral to slightly acidic (5.83 to 7.19), while the permeability values ranged from 25.59 to 0.014 cm/h. Moreover, the hydrologic balance indicated a surplus of about 989.3 mm, which can contribute to the recharge of the water table at low depth, traditionally supplying wells and sources of drinking water, but also potentially to their pollution by the influx of organic and mineral matter. Two types of effluents were identified: these are latrines and domestic waste. They had contrasted physico-chemical and bacteriological pollution potentials, but sufficient to have a harmful effect on the population, compared to the WHO standards. The persistence of coliforms in some filtrates confirmed that water was exposed to pollution by the previous effluents and argued in favor of the installation of a safety distance between potential sources of pollution and water supply on the other hand.