Analysis of a wastewater treatment plant for energy consumption and greenhouse gas emissions

Abstract

This article presents an environmental and energy analysis of a wastewater treatment plant operating on sequential batch reactor technology. The analysis of energy consumption shows that the electrical, mechanical, chemical, and human energy consumption works out to 0.26 kW h/m3 of the treated wastewater. The overall share of electrical energy consumption is 84%, and 15% share is of mechanical energy. Nearly 78% of the electrical energy is consumed in the aeration process. The biological oxygen demand, chemical oxygen demand, total suspended solids, total nitrogen, and total phosphorous are measured for the influent and effluent of the treatment plant. A reduction of 76–97% occurs in these parameters due to wastewater treatment. The greenhouse gas emissions arising directly from the treatment processes and indirectly from the electricity and diesel usage are estimated. The direct and indirect emissions from the wastewater treatment plant amount to 105 tCO2e/year and 1316 tCO2e/year, respectively. A projection of methane accumulation in the atmosphere from this plant till the year 2041 is also made. The contribution of this plant to the atmospheric accumulation of CH4 is projected to reach 8679 kg in 2029. The projection for 2030 and thereafter is 9468 kg. Analysis of the energy, environment, and wastewater treatment nexus is of significance to have a holistic view for the sustainable development.