Integrated Process Modeling of Energy Consumption, Energy Recovery and Nutrient Management Strategies for Wastewater Treatment Plant Retrofits

The wastewater treatment (WWT) industry is attempting to meet two, seemingly contrary treatment objectives: 1) Minimizing energy usage for WWT; and 2) Improving nutrient removal. As energy costs rise, treatment schemes that reduce energy use and/or enhance energy recovery are preferred alternatives when new and retrofit applications for WWT are considered. Carbon management during treatment with the goal of maximizing biogas yield is emerging as an important strategy in this context. Our team is evaluating various energy reduction and recovery options for domestic wastewater treatment using both modeling and experimental approaches (Smith, Stadler et al.; Smith 2012). In support of this objective, we are integrating process and energy balance models to evaluate the impact of process configuration, hydraulic conditions and mass loadings on the effluent water quality and on the system's energy balance. This paper demonstrates the benefit of this integrated modeling approach in the analysis of a process called WASACTM.