Ahmed Abouhend
Ahmed Abouhend, UMass Amherst, USA
Title: The Oxygenic Photogranule (OPG) process as a novel technology for wastewater treatment
Biography
Biography: Ahmed Abouhend
Abstract
Wastewater treatment is an energy-intensive industry. About 2.16 MJ of energy is required for the treatment of 1 m3 of wastewater. Since 1912-1914, activated sludge process is the most common technology for wastewater treatment. In activated sludge system, mechanical aeration is required to provide oxygen to the biological flocs (bacteria). Then, the bacterial flocs use this oxygen to oxidize the organic matter and ammonia from wastewater. The process involves oxygen being introduced into the activated sludge system accounts for 25-60% of the overall operational costs. Besides, activated sludge does not settle very well so settling tanks are required to allow the biological flocs to settle. On the other hand, untreated wastewater holds more than 10 times the energy used to treat it. If we can capture this potential energy from wastewater, the wastewater treatment process might become an energy producer rather than a consumer. We propose the oxygenic photogranule (OPG) process for aeration-free wastewater treatment. OPG process is a light-driven wastewater treatment that eliminates the need for mechanical aeration to treat wastewater. These photogranules are enriched with a phototrophic community (cyanobacteria, microalgae) that produces O2 needed for oxidizing organic matter and treating wastewater. Under sunlight, the phototrophs autonomously produce O2 through photosynthesis, which in the activated sludge process should be provided by energy-intensive aeration. In turn, the heterotrophic bacteria within the OPG uses this oxygen to oxidize the organic matter in wastewater and produces CO2 for phototrophs. We evaluated the feasibility of these granules for wastewater treatment in bench and pilot scales. The OPG process can cut the wastewater treatment costs in half through sustaining self-aeration process. Besides, the easily harvested phototrophic biomass could be converted through various pathways to biofuels. This phototrophic biogranule technique would allow wastewater treatment plants to generate most of the energy needed for plant operation.