Dynamic Energy Footprint Monitoring of Wastewater Aeration Systems via Full-Scale Deployment of Real-Time Off-Gas Analyzers

Wastewater aeration is a highly complex and dynamic process for which site-specific analysis and control are needed. Off-gas testing is a method that can determine the aeration process requirements and conditions in real-time, so that appropriate operational changes and control strategies can be implemented. For this research project, off-gas analyzers were installed at five wastewater treatment plants in Southern California to continuously measure standard oxygen transfer efficiency (SOTE) and off-gas flux and perform a subsequent energy analysis. The results were as expected and show that there is an inverse relationship between SOTE and off-gas flux that follows a distinct diurnal pattern. The energy analysis showed that the energy usage during peak demand is amplified due to compounding factors of increased COD and volumetric wastewater load. Utilizing off-gas monitoring to determine process requirements and performance, many energy saving strategies (e.g. blower type, variable frequency drives, control strategies) that can lower peak and overall energy demand are feasible and can be implemented in a energy rebate program.