Grant: Discovery Grants Program - Individual

Most wastewater treatment plants (WWTP) in North America, are approaching their design life and facing challenges such as increased energy costs, space constraints, and heightened needs for economic and environmental sustainability, necessitating significant capital investment. Biosolids processing and disposal costs account for 50%-60% of overall wastewater treatment costs. Conventional anaerobic digestion (CAD) is a well-established technology, especially in large WWTP (> 10 MGD) for biosolids minimization and energy recovery. Despite the development of few intensification strategies to enhance resource recovery through fermentation and anaerobic digestion, very few have been commercialized. The presence of hydrogen sulfide in biogas, devalues the financial benefit of biogas. Most hydrogen sulfide control technologies are ex-situ technologies that are not always cost effective. Micro-aeration of anaerobic digesters is an emerging in-line desulfurization technology that may have other benefits including digester performance stabilization, improved process kinetics, and enhanced product yields. The long-term objective of this research program is to develop innovative approaches to reduce the carbon footprint of wastewater treatment by: a) enhancing the recovery of valuable products from wastewater biosolids including, ammonia, volatile fatty acids, and phosphorous; b) improving biomethane production and overall biogas quality; c) decreasing anaerobic digester size and cost to facilitate adoption in small plants and; d) minimizing biosolids disposal. The 2 key short-term programs to support the long-term objective are: (1) advance a novel vacuum-assisted anaerobic technology to enhance the anaerobic digestion performance and product recovery, (2) investigate micro-aeration for biogas desulfurization and improved hydrolysis of lignocellulosic wastes. In the first program, a novel vacuum-based anaerobic digestion technology, which significantly enhances solubilization of primary and waste activated sludges, will be further developed for anaerobic digestion intensification by using ex-situ vacuum instead of the in-situ vacuum to minimize vacuum-induced stress on the microbial ecology, and enhancing product recovery through alkaline fermentation as opposed to conventional acidic fermentation. The second program will focus on micro-aeration. The role of important process parameters in various microbial processes, which facilitate chemical and bioenergy recovery from wastewater biosolids and lignocellulosic wastes have largely been unexplored. The impact of micro-aeration on fermentation of municipal wastewater biosolids and lignocellulosic wastes will be explored, both with respect to process performance and biogas quality. This work improves environmental sustainability through enhancement of resource recovery, reduction of carbon footprint, and growth of the Canadian circular economy