M4GHG: Integrating multi-Scale observations with wastewater process simulations for measuring, monitoring and modeling GHG emissions in Canadian sewers and WRRFs

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North American municipalities are recognized as major contributors to global green house gas (GHG) emissions, with water resource recovery facilities (WRRFs) and sewers responsible not only for the consumption of considerable amounts of non-renewable resources, but also major sources of methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O). For example, WRRFs and sewers are known to be a major contributor to GHGs mostly produced during their sub-optimal operations. With relation to WRRFs, biological treatment processes (which are mostly aerobic, thus requiring oxygen to support the growth of microorganisms that metabolize wastewater pollutants) require considerable electrical energy with aeration accounting for up to 50% of a plant's expenditure, often obtained from electricity production methods with significant CO2 contributions from fossil fuels. Moreover, emerging WRRFs processes such as short-cut denitrification, while crucial in achieving energy neutrality, have the potential of being strong contributors to N2O as intermediate formed during low dissolved oxygen operations. Furthermore, sewer processes are also major sources of GHGs, both for CH4 (for untreated sewer line with long retention time) and N2O (for sewer lines treated with nitrate).In 2015, the government of Ontario released its climate change strategy, with a goal of reducing GHG emissions to 15% below 1990 levels by 2020 and to 80% by 2050. Federal government "Net Zero" legislation mandating to achieve "Net Zero" by 2050. The goal of this project is to investigate and explore climate-friendly wastewater treatment processes, coupled with optimized sewer strategies, for accelerating the adoption of innovative solutions in Canadian municipalities. As regulations for WRRFs and sludge management become stricter, energy consumption and associated GHGs emissions are expected to further increase. While new treatment processes such as Anammox have been developed to tackle energy costs and nutrient removal, little attention has been given to optimizing treatment trains and plant layouts to mitigate climate change impacts. Thus, holistic solutions are needed to address this challenge. In addition, there is a need to establish baseline GHGs emissions and reliable methods for measuring, monitoring, modeling, and mitigating GHGs for WRRFs and sewers, together with protocols and accounting procedures for incorporating both in-boundary and transboundary GHG contributions.We believe that with the development of efficient and GHG-savvy treatment strategies, holistic solutions can be devised for the Canadian wastewater sector, thus leading to positive impact on both Ontario's water systems and the millions of people who rely on them. Currently, there are 68 anaerobic digestion wastewater treatment plants (AD WWTPs) in Ontario which are high energy intensive and flares biogas in atmosphere. More than 150 small and medium plants have energy cost as second highest operating expenses. In this project, multi-scale GHGs experiments will be carried out in several Canadian WWRFs, and associated sewer facilities, characterized by different operations, treatment processes, and plant configurations. In these sites, GHGs data will be collected using multiple measuring and monitoring techniques conducted at different scales, namely: with aircraft sensors operated at 3,000 m elevation for large-scale CH4 observations, with drones equipped with state-of-the-art sensors for WRRFs and sewer-scale CH4, CO2 and N2O observations, and with fixed sensors for their more local quantification. Collected data will be longitudinally integrated using machine-learning and AI-driven data fusion techniques, together with deterministic models for wastewater and sewer systems. In addition, deterministic models will be used in conjunction with pilots, operated in the state-of-the-art research and development (R&D) facilities of Greenway WRRF located in London Ontario, already equipped with advanced pilot systems able to simulate, in sequencing batch mode, several WRRF configurations and sewer conditions. Pilot experiments will be used to calibrate the mechanistic GHG models, which will be further verified against multi-scale data obtained with aircraft and drone sensors. Finally, the GHG-validated process models will be used to explore the most resilient sewer/WRRFs integration strategies, with the goal of identifying holistic solutions for climate-friendly WRRFs in Canada.The proposed study will be conducted highly collaboratively with North American WRRFs including Toronto, London, Calgary, Windsor and Detroit, highly specialized industries including USP Technologies, GHGSat, and Brown and Caldwell. The industry partnership will ensure the work is conducted according to state-of-the-art methods by providing in-kind contribution and actively participating to the site activities proposed in this project. Moreover, advanced training opportunities will be offered throughout this project in emerging technical fields including sewer process analysis, bioprocess simulations, data fusion and data analytics, model-based plant optimization, wastewater pilot operations and innovative wastewater treatment processes.