Eco-energetic feasibility study of using grid-connected photovoltaic system in wastewater treatment plant

Highlights: • Wastewater treatment plants can serve as dispersed photovoltaic generators. • Use photovoltaic energy to treat wastewater. • Optimal photovoltaic system is proposed for Algerian region wastewater treatment plants. • Eco-energetic analysis and environmental impact of designed photovoltaic system are discussed. The industrial activities intensification has inevitably caused an excessive use of underground waters and fossils energies, and severe environmental pollution with dire consequences for water resources. This situation intensifies in populated arid regions. In this context, wastewater treatment is a reliable source of water and nutrients for agricultural production. This study aims at treating wastewater using photovoltaic energy, to reduce conventional electricity demand. This paper studies energy and economic feasibility of grid-connected photovoltaic systems (GCPVS) in wastewater treatment plants (WWTPs). The optimization is based on: energy balance, installation surface area and levelized cost of energy (LCOE). Results show GCPVS installed in the northwest of Algeria, can cover 53% of WWTP electrical load and inject 510 MWh/year into grid representing 65% of the load. The regional energy consumption can be reduced by 2% in daytime. LCOE is estimated around 09.14 centUS$/kWh, which is lower than conventional electricity cost 10.17 centUS$/kWh. The benefit-cost ratio is estimated around 0.69 Million US$ (33%). This plant provides 4800 m³/day of agricultural irrigation, where treatment energy cost is decreased from 3.4 centUS$/m³ to 2.3 centUS$/m³. The WWTP fertilize 300 ha of soil per year. This work highlights the efficiency of self-sufficient WWTPs in northern Africa region.