Optimization of energy consumptions of oxidation tanks in urban wastewater treatment plants with solar photovoltaic systems

Abstract

This paper combines solar photovoltaic (PV) to wastewater treatment plants (WWTPs). A new methodology is proposed to design solar PV to reduce energy consumptions of aeration thanks in WWTPs. New analytical equations and parameters, based on the air temperatures, solar irradiations, biological kinetics, dissolved oxygens, mechanical oxygenations, are introduced to obtain the peak power of PV that maximize the auto-consumptions of aeration blowers installed in the oxidation tanks of WWTPs. The method allows a direct preliminary design and a calibrated estimation for energy power. To justify this method, three aspect are mainly discussed: (i) the oxidation tanks consume up to 30% of the energy of a WWTP; (ii) the temperature of wastewater is variable during the year, in the smaller WWTPs; (iii) the dissolved oxygen reduces, increasing temperature of wastewater. This methodology will support the sector in making decision over PV investments, helping wastewater utilities to consider sustainable management practices. Therefore, a further contribute to develop the integration of renewable energy sources combined with wastewater sectors is activated.

Keywords: Energy consumption; Oxidation tanks; PVP; Self-consumptions systems; WWTP.