Assessing the impacts of a novel dissolved oxygen infusion system on wastewater treatment plant performance

Wastewater treatment plants rely on complex biological, chemical, and physical processes to transform pollutants, and innovations in operational systems are crucial for optimizing performance. This study investigates the efficacy of a novel high-concentration dissolved oxygen infusion system installed in a wastewater treatment facility in Greenleaf, Idaho. The system was designed to deliver return activated sludge infused with elevated levels of dissolved oxygen (>20.0 mg l⁻¹) to enhance microbial activity and improve nutrient removal processes. Seasonal monitoring of key parameters, including dissolved oxygen, temperature, pH, biochemical oxygen demand, chemical oxygen demand, and nutrient concentrations, revealed significant operational benefits. Specifically, total nitrogen concentrations in the effluent decreased from 28.3 to 12.8 mg l⁻¹ as N, while total phosphorus levels also declined, dropping from 9.62 to 7.08 mg l⁻¹ as P. The system facilitated improved removal of key nutrients without requiring major infrastructure modifications. However, the elevated dissolved oxygen environment also led to an increase in sludge volume index, likely due to shifts in microbial community dynamics within the oxidation ditch. Comprehensive correlation analyses revealed significant relationships between operational parameters, underscoring the dual impact of the system—improving nutrient removal while introducing operational challenges such as increased sludge settleability concerns. These findings highlight the potential of dissolved oxygen infusion systems as a transformative tool for wastewater treatment, advancing sustainability and performance. This research contributes to the understanding of how such systems can be integrated into existing facilities while managing associated trade-offs.