Upgrading a Waste Stabilization Pond and Estimation of Biogas Production: Case of University of Abomey-Calavi, Benin

Abstract

Population growth affects land area availability as well as wastewater generation. In Africa, the treatment of wastewater relies mostly on the Waste Stabilization Pond system. These ponds are adapted to the warm climate of the continent. However, with time, they need to be renovated because they are subjected to overload causing therefore groundwater and water bodies pollution. WSPs also emit Biogas into the atmosphere. This study aims to upgrade a Waste Stabilization Pond constructed in 2011, on the University of Abomey-Calavi, in Benin and to evaluate the evolution of biogas producible over the years by the plant. To achieve this goal two scenarios vi were developed: The first one focuses on resizing the different ponds of the WSP with an estimation of the evolution of the biogas produced from 2011 to 2050. In the second scenario, a Sewage Treatment System is used instead of a Waste Stabilization Pond to reduce the amount of pond needed reducing the area required for the new system. The upgraded Waste Stabilization Pond requires a total surface area of 39939 m2 meanwhile for the same quantity of wastewater, a Sewage Treatment Plant requires only a total surface area of 3690.45 m2. The Sewage Treatment Plant suggested is not only advantageous in terms of space but also in the circular economy that can be developed to sustain the plant. The total amount methane produced or emitted from the WSP is estimated to increase from 5.7 Kg CH4/day in 2011 to 144.29 kg CH4/ day in 2050.