The Oxygenic Photogranule (OPG) for Aeration-free and Energy-Recovery Wastewater Treatment Process

Wastewater treatment is energy intensive industry. Although the activated sludge process is effective for removing organic matter, it consumes high energy, particularly in the aeration process (25–60% of operation costs). However, untreated wastewater itself is actually a significant energy resource. lf we can capture and harness this potential energy from wastewater, wastewater treatment process might become an energy producer rather than a consumer. We developed oxygenic photogranule (OPG) as a novel wastewater treatment technology. The first-generation of the OPG-based wastewater treatment was successfully demonstrated by seeding and operating OPGs in flow-through reactors and effectively removing organic matter and ammonia without external aeration. The OPG process eliminates the need for external mechanical aeration, which is currently the most energy intensive part of wastewater treatment processes and allows recovery of chemical energy laden in wastewater in the form of bioenergy feedstock. OPGs are easily harvestable biomass; thus, overcoming the main challenge of algal-based wastewater treatment technologies.