Coming Full Circle: Moving Wastewater Treatment Plants Towards Energy Neutrality

Rising energy prices and increasingly stringent effluent requirements have amplified operating costs for many wastewater treatment plants (WWTP) throughout the country. The ability to accurately track the energy consumption and recovery throughout the wastewater treatment process from influent to discharge is critical to optimizing the operating costs associated with these facilities. A quantitative model that integrates each facet of the wastewater treatment process and their associated impacts on overall plant energy use was developed to provide wastewater treatment facilities a decision-making tool to evaluate how changes to WWTP operations and processes can impact the overall plant energy balance. The Hazen Energy Efficiency Tool (HEET) is this model. The HEET model provides a platform to integrate the results of BioWin™ process modeling into a comprehensive assessment of the energy use at the treatment facility. This paper will review three case studies of the model and the related conclusions.