The below videos showcase our lab facilities at USC (including the Water Lab) and include testimonials from our students. Yamrot Amha, a fourth year PhD student in the Smith Research Group is featured!
Anaerobic biotechnologies, such as anaerobic membrane bioreactors (AnMBRs), are emerging as an approach to domestic wastewater treatment. Unlike aerobic activated sludge systems, AnMBRs produce energy directly in the form of methane-rich biogas. We have demonstrated that AnMBRs are capable of matching the treatment performance of activated sludge systems even at low psychrophilic temperatures (see figure to the right). We found supporting biofilm development on the membrane surface to be a key strategy in maintaining effluent quality at such low temperatures. Microbial characterization of the biofilm showed that we were able to enrich for a community with highly active methanogens and syntrophic bacteria. However, methane generation in the biofilm resulted in significant dissolved methane oversaturation in the effluent, a potential concern for energy recovery and greenhouse gas emissions of treatment. Read the full paper here.
Evaluating new biotechnologies such as AnMBRs requires systems level thinking. We used process modeling and sustainability assessment methodology to perform a life cycle assessment of AnMBRs compared to conventional treatment approaches. Because AnMBRs are still in the early phases of development, we evaluated uncertainty at two levels: "today" based on reported values from bench- and pilot-scale systems and "future" based on developments that are likely to occur as AnMBR technology moves to full-scale implementation. We found that for AnMBRs to be competitive with conventional treatment systems, energy demands for fouling control need to be significantly reduced and effluent dissolved methane must be managed to reduce global warming potential (see figure to the left). Outputs of this work (e.g., design and operational targets) are being used to guide future experimental research to develop strategies to improve AnMBR energy recovery and limit greenhouse gas emissions. Read the full paper here.
Our research team is exploring strategies to improve the energy balance of AnMBR treatment through co-digestion of high-strength waste streams and reducing energy use for fouling control. We are also evaluating methods that limit dependence on the biofilm for treatment to reduce dissolved methane oversaturation and downstream systems for dissolved methane recovery. Our research is expanding beyond AnMBR to consider compatible technologies needed to recover nutrients and reuse water for potable and non-potable applications.