Dr. Hossain Azam, P.E. gave a talk on “Sustainable Wastewater Treatment: Resources Recovery as Methane and Struvite from Next Generation Anaerobic Digestion Systems“ on April 28th, 2022. The talk was presented via a WebEx Virtual Meeting.
Speaker Biography: Hossain Azam, Ph.D.,PE is currently working as an Assistant Professor of Environmental Engineering at the Department of Civil Engineering of the University of the District Columbia (UDC) in Washington, DC. Dr. Azam completed his PhD degree in Environmental Engineering from University of Illinois at Urbana Champaign (UIUC), MSc degree in Water Resources and Environmental Engineering from North Carolina State University (NCSU) and BSc degree in Civil Engineering from Bangladesh University of Engineering and Technology (BUET). Currently, he teaches different undergraduate and graduate environmental engineering courses. He is leading different applied and fundamental research projects in the field of water and wastewater as well as water-energy-food-climate nexus at UDC. Professionally, he is actively engaged with Water Environment Federation (WEF) and its different national and regional committees as well as leading a book on PFAS as Editor and authors of several chapters.
Presentation Topic: Traditional wastewater treatment processes require significant amount of energy input and have limited resources recovery systems. Therefore, sustainable wastewater treatment systems focus on resources recovery and efficient energy utilization in addition to reduction of global warming gases, wastewater reuse and treatment of emerging contaminants. Anaerobic digestion systems can provide significant support to achieve those goals by recovering energy as methane as well as phosphorus and nitrogen as struvite. One major drawback observed in the anaerobic digestion systems is uncontrolled phosphorus mineral struvite precipitation. Although struvite is a problem when left uncontrolled and unmonitored; it has different benefits (e.g. slow release fertilizer) when recovered in a controlled environment. Therefore, we (a) investigated effective ways of energy recovery as methane and (b) explored effective strategies to prevent uncontrolled precipitation of struvite to recover it in a controlled environment. First, we utilized several substrates (waste activated sludge, cheese whey, grease interceptor waste, and pulped food waste) for methane recovery from anaerobic co-digestion in both lab-scale anaerobic digesters and biochemical methane potential (BMP) assays. The results showed that using fat, oil and grease (FOG) significantly increased the methane production in both settings compared to traditional anaerobic digestion systems (using primary sludge and waste activated sludge). Second, we utilized biodegradable chelating agents (e.g. GLDA, MGDA etc) to ensure dissolution of struvite in lab scale anaerobic systems. We found that biodegradable chelating agents was successful to prevent uncontrolled precipitation and ensure dissolution of struvite. In addition, we reported the evidence of microbial degradation of Mg-chelant complex with no adverse effects of chelating agents on anaerobic digestion systems. We are further conducting experiments to recover struvite from the released Mg+2 from the Mg-chelant complex in a controlled system. Thus, our research provided major guidelines for different effective resources recovery techniques from next generation anaerobic digestion systems.
