Yang Liu

Yang Liu

Civil and Environmental Engineering
University of Alberta

Chair title

NSERC Industrial Research Chair in Sustainable Urban Water Development

Chair program

Industrial Research Chairs program


Associate Chair since 2017


With Canada's changing demographic profile and climate, there are growing challenges to our urban water systems and their expansion. Much of the current underground infrastructure was built 50–100 years ago. As of 2016, the cost of upgrading this infrastructure was estimated at $82 billion. Additionally, water and wastewater collection and treatment systems are energy-intensive and costly processes with significant financial and environmental health impacts. However, the evolving wastewater-to-resource-recovery paradigm offers an economic solution: municipal wastewater contains sufficient embedded energy (in the form of organics, nitrogen and phosphorous) that innovative treatment systems could be energy-neutral if not positive. Several academic and industry sources are pointing towards a shift from conventional, centralized water services to alternative strategies involving more decentralized reuse, source-diverted streams for enhanced energy/nutrient recovery, and adaptive management to control emerging issues. Fundamental to timing and action is that any new infrastructure will be in place for at least 50 years. Thus, sustainable, energy-efficient alternatives need to be critically evaluated before they can be seriously considered.

Given the context of current Canadian urban wastewater management, the overall objective of this associate IRC program is to evaluate and optimize engineered bioreactors that can carry out energy conservation and energy-efficient nutrient reduction, leading to resource-recovery-based wastewater treatment in urban water service systems. The IRC intends to take advantage of the unique opportunity to be involved in developing sustainable municipal wastewater services by providing fundamental research knowledge, pilot-scale process demonstration and optimization, training of highly qualified personnel, and effective industrial collaborations for research uptake. The first step is to evaluate process fundamentals in selected bioreactors representing known unit operations. Then, we plan to provide novel insights to improve the treatment-train configuration to enhance methane (energy) recovery and nutrient reduction, resulting in an overall reduction in greenhouse gas emissions. A key aspect of the research involves assessing factors affecting microbial population diversity and functional dynamics and stability in bioreactors utilizing different feedstocks. The goal is to link microbial members/activities to operational factors affecting energy conservation and nutrient reduction to enhance efficacy of resource recovery. With the knowledge gained on microbial members and their functional genes, optimized biological unit operations will provide improved treatment train integration. Finally, recommended bioreactor configurations and performance will be documented, and relative impacts of the different treatment processes will be assessed using life-cycle assessment (for environmental and health impacts). Key design, costing and operational information will be modelled using a system dynamics platform to address centralized and decentralized treatment systems – both domestic wastewater collected from existing sewers and novel source-diverted systems.

Today, a number of constraints limit the market uptake of energy-positive treatment solutions, including technical uncertainties, economies of scale, governance structures, lack of confidence and regulatory mechanisms. This IRC is expected to provide fundamental knowledge on bioreactor operation and optimization options for energy-positive wastewater treatment, alleviate technical concerns, generate confidence in overall treatment-system performance, and help to guide future urban wastewater management practices in Canada. Expected outcomes in the next five years include:

  • Providing the scientific/engineering foundation for energy-positive wastewater treatment that provides energy recovery, nutrient reduction/recovery, and polishing steps to maximize any remaining effluent quality before environmental release or water reuse.
  • Developing critical expertise for the transition to new wastewater management systems.
  • Training graduate students to obtain both academic and industrial knowledge and experience that will promote their transition from university to utility, regulatory or corporate positions. In addition, the Chair will provide a starting point for new training programs for operators to manage novel energy-positive treatment systems.

Over the medium- to long-term (more than five years), the research program is expected to lead in the integration of sustainable urban development options for regulatory-accepted and operational wastewater services, facilitating effective and safe urban wastewater treatment with reduced energy footprints across Canada. This effort will also lead to more cost-effective housing developments with lower carbon emissions, and reduced dependence on external energy sources and government infrastructure grants.


  • EPCOR Utilities Inc.
  • Alberta Innovates
  • WaterWerx

Contact information

Civil and Environmental Engineering
University of Alberta



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