Authors : Japo O.M. Amasuomo, Alexander U. Onyia and Nathaniel O. Imaah
Abstract: The study was aimed at selecting appropriate onsite system for effective domestic sewage disposal in Yenagoa, Nigeria. The various types of onsite systems considered were the soakaway pit, subsoil disposal bed and the Sand-Filter Systems. Field investigations and site tests carried out during the study revealed that Yenagoa had silty clay soil that had very low acceptance rate of 5.21 L/m2/day and a low percolation rate of 218 min/100 mm and the soil was of semi-impervious nature and had high ground water table of 3.0 m and <300 mm in the dry and wet seasons, respectively. The implication of findings was that the study area with very low acceptance and percolation rates was not suitable for soakaway pit system which was only suitable for soils with reasonably permeable and relative absorptive surface and the field disposal bed which only suitable for soil of semi-impervious nature with low ground water table both in dry and wet seasons. The sand-filter system was selected for onsite disposal of domestic sewage because it was found to provided the required treatment capacity and its operation do not depend on whether the soil has low acceptance and percolation rates or high ground water table. In comparing the cost between the two systems, sand-filter system cost about twice that of the soakaway pit system. However, the sand-filter system was still selected for the study area because it will protect public health and reduce environmental pollution that characterised the use of soakaway pit system.
Japo O.M. Amasuomo, Alexander U. Onyia and Nathaniel O. Imaah, 2013. Selecting Appropriate Onsite Systems for Effective Domestic Sewage Disposal in Yenagoa, Nigeria. Environmental Research Journal, 7: 48-60.