American Water Resources Association
This presentation will show how the dual goals of energy self-sufficiency and optimum treatment processing can lead wastewater agencies to go beyond the goal of achieving net zero energy wastewater operations. The energy content of wastewater surpasses the energy required of treatment, reportedly be a factor of up to 10 times. Nevertheless, conventional activated sludge plants with advanced treatment purchase typically 1,800 kWh/MG of electricity, with facilities varying from 1,000 to 3,000 kWh/MG. Energy efficiency studies conclude that the potential for energy use reductions through efficient pumps and aerators are on the order of 30 to 50 percent, which is a range of about 400 to 700 kWh/MG. For plants with anaerobic digestion, a rule-of-thumb for electrical production from biogas-fueled generators is 500 kWh/MG. In the future, advances in treatment technologies will likely increase biogas yield from received BOD in wastewater or from delivered sources. Also, emerging tools for controlling energy production and demand in synchrony with real-time wholesale electricity pricing on the grid will incentivize WWTPs to manage operations for a significant financial return, going beyond the NZE goal to serving as a source of community power.