Modeling of a Septic Tank Waste Treatment System for the Production of Biogas

Abstract

In developing countries, in general, especially in universities, the management of wastewater and excreta remains one of the major concerns. This uncontrolled practice can have negative im-pacts on the environment such as deforestation and global warming. The recovery of domestic wastewater through the production of biogas (methanization) is beneficial both on the environmental level and on the energy level (electricity, heat) and social, especially in universities where the increase of the students is accompanied by growth in energy consumption. This article delves into the physicochemical and biological processes involved in wastewater treatment, while also making predictions about the behavior of various variables such as methane, nitrogen, acetogenic microorganisms, and methanogenic biomasses. This approach allows knowing the variation of the biomass according to the type of bacteria. Indeed, it shows the relation, which exists between the biomass and the organic load. It is firstly noted in the results that the mean value of the biomass of acidogenesis and that of the biomass of methanogenesis are approximately equal to 0.67 d−1. Secondly, the nitric acid concentration is around 47.5 mgN/l/h and that of the viscosity is estimated to 0.046 Pa.s. Afterward, the temperature and the pH favor the activity of anaerobic bacteria. We finally conclude that an experimental device of 71m3 intended for the accumulation of sludge will be designed and built.