Wastewater Biorefinery: Treatment and Resource Mining

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Every year, over one billion people are affected by waterborne diseases (diarrhea, typhoid, etc.) caused by water pollution. According to the 2016 Environment and Climate Change Canada status report, 1.8 billion m3 of the total effluent discharged across Canada did not meet quality standards under Wastewater Systems Effluent Regulations (WSER), with more than 17 % of wastewater treatment (WWT) systems failing the acute lethality test. We are now facing new challenges beyond the management of WSER- regulated conventional contaminants. We must also reduce nutrients (nitrogen and phosphorus) and manage a growing list of non-conventional unregulated contaminants, collectively termed contaminants of emerging concern (CECs), such as pharmaceuticals and personal care products. Ineffective removal during WWT releases CECs into surface waters, threatening drinking water quality and adversely impacting human health and the environment. Aerobic granular sludge (AGS) is a novel technology that has shown significant advantages over conventional activated sludge (CAS). Aerobic granules are aggregates of microorganisms that are self-immobilized without carrier media in a matrix of extracellular polymeric substances (EPS). AGS offers simultaneous removal of organic matter and nutrients within one reactor, up to a 75 % space reduction, up to 50 % energy savings, superior effluent quality, and greater tolerance to toxins. However, lack of understanding of the fundamental mechanisms governing biofilm formation, the long granulation period, and disintegration of AGS are hindering the practical application and realization of the benefits offered by this technology. My research will address several key gaps in the academic literature. Finding the links among reactor operating conditions, wastewater (WW) composition, microbial community, and EPS production will provide an enhanced understanding of the fundamental mechanisms of granular biofilms and will open a new avenue of research that targets the recovery of value-added non-energy-carrier products from waste AGS. My program encompasses three main objectives: 1) Develop a biofilm process based on the selective enrichment of functional organisms and investigate the fundamental microbial interactions. 2) Explore the recovery of value-added extracellular polymers and phosphorus from waste AGS as well as the effects of EPS extraction on sludge digestibility. 3) Devise an integrated AGS-bioadsorption method for the removal of select CECs. These objectives will be addressed systematically through a multi-pronged approach based on systems engineering, microbiology, and analytical chemistry experimental methods. The proposed technological platform will revolutionize WWT through the development of a novel bioaugmentation treatment method and the recovery of high-value products, leading to the creation of next-generation WWT plants (WWTPs) driven by a cradle-to-cradle-based economy.