Assessment of Wastewater Discharge Impact from a Sewage Treatment Plant on Lagoon Water, Lagos, Nigeria

The aim of this study was to assess the wastewater discharge impact from the University of Lagos campus treatment plant on the lagoon system . In order to achieve this objective water samples were collected from nine sites and analyzed for different wastewater quality variables. The field survey was carried out between July and November in order to capture both the wet and dry seasons. Average removal efficiencies of measured parameters from treated effluents are 26% for Total Dissolved Solids (TDS), 73% for Biological Oxygen Demand (BOD), 65.8% for Chemical Oxygen Demand (COD) and 72% for Total Nitrogen (Total N) for the wet season campaign. During the dry season average rem oval efficiencies of measured parameters are 54% for TDS, 54% for BOD, 39% for COD and 42% for Total N. These values are lower than values obtained for the wet season except for TDS. Most parameters in effluents exceeded the National Environmental Protection Regulations, Effluent Limitation standards for discharge into river bodies. Average concentrations of TDS, BOD and COD in lagoon water show higher concentrations than in the treated effluent and are above the regulatory requirements. The research recommends further study on the possible influence of water dynamics and sampling methods on water quality of the lagoon. The overall results from this research conclude that the lagoon is being polluted by effluents discharge from the university treatment plant thereby exposing the health of local residents who use it for recreation and for food production purposes.