Metaheuristic based device rating for energy harvest in sewage plant

Electricity consumption of wastewater treatment plants is considerable and afflicts the power system loading, in particular in developing countries such as Vietnam; on the other hand, organic content of sewage allows for local energy recovery by, e.g., anaerobic digestion of sludge and subsequent use of resulting biogas. Supplementary incineration of dehydrated sludge in a local small steam power unit can provide another quantity of electricity and, at the same time, exonerates from further treatment/deposition of infectious sludge. Waste heat from both steam circuit and combustion engine can contribute to sludge drying, thus significantly increasing its heating value. Furthermore, large expanse and usual location remote of residential areas make sewage plants eligible for harvesting renewable energy. For proper sizing of the particular system components under minimization of the Life Cycle Cost (LCC), the metaheuristic computational method of the Mean-Variance Mapping Optimization Algorithm (MVMO) was successfully applied to three different scenarios, showing that sewage plants can be widely brought towards independence of external energy supply.