New technologies for wastewater resource recovery by anoxigenic photoheterotrophic biological processes

收紧对生物固体处置的监管和不断增长的能源利用增加了污水处理厂的运营成本，并降低了市政基础设施的可持续性。作为回应，污水处理行业正在从只处理环保废水转向额外回收与水一起浪费的资源。在能量含量方面，可回收有机物和养分(氮、磷)约占人均用电量的15%；因此，回收将提高可持续性并减少二氧化碳足迹。然而，使用目前的好氧生物工艺进行回收是有限的。因此，目前的计划将有助于开发新的厌氧生物工艺，使之能够进行回收。这一结果将提高基础设施的效率，减轻纳税人的负担。厌氧工艺给加拿大带来了挑战，因为许多废水设施在12摄氏度以下运行长达6个月。事实上，厌氧微生物的最大生长率通常低于好氧微生物，导致工艺稳定性较低，在低温下满足排放法规的能力也较低。此外，城市污水对于养分回收来说是相对稀薄的，在进行物理化学提取之前必须进行生物浓缩。我们建议使用紫色非硫细菌(PNSB)来应对这些挑战。与其他厌氧菌相比，它们同时从光中获取能量和从有机物中获得碳的能力为它们提供了更高的生物量产量和更快的生长速度。因此，高的生物质产量使它们适合于浓缩生物质中的营养物质，并且高的生长速度降低了它们对较低的操作温度的敏感性。最后，由于它们是唯一利用红外线(&gt；800 nm)的光合作用生物，工程师将拥有强大的选择工具来控制混合开放培养物中的微生物群落。已发表的研究主要集中在纯培养PNSB废水处理和在20-35℃下的操作。这些条件不适用于加拿大全规模的市政污水处理设施；因此，在开发PNSB工艺方面仍然存在重大的知识差距。此外，需要严格控制反应器条件，使新陈代谢最大化生物质产量，而不是竞争氢气和聚羟基烷酸的合成。该提案将调查与加拿大有关的非无菌PNSB光生物反应器的运行条件，以实现废水资源回收。此外，将利用基因组规模的代谢模型和高通量的元基因组分子工具来开发PNSB代谢和微生物群落组成的控制策略。该项目将培养2名博士、4名孟加拉人和10名本科生。*

Tightening regulations on biosolids disposal and growing energy utilization increase the operational costs of wastewater treatment plants, and reduce the sustainability of municipal infrastructures. In response, the wastewater industry is converting from only treating wastewater for environmental protection to additionally recovering resources wasted with the water. In terms of energy content, recoverable organics and nutrients (nitrogen, phosphorus) account for ~15% of the per capita electricity consumption; accordingly, recovery will improve sustainability and reduce CO2 footprint. However, recovery using current aerobic biological processes is limited. Thus, the current program will contribute to the development of new anaerobic biological processes enabling recovery. The results will improve infrastructure efficiencies and reduce burden to tax payers.******Anaerobic processes pose challenges for Canada because many wastewater facilities operate below 12C for periods of up to 6 months. Indeed, anaerobic microbes typically have lower maximum growth rates than aerobic ones, resulting in lower process stability and capacity to meet discharge regulations at low temperatures. Additionally, municipal wastewater is relatively dilute for nutrient recovery, and biological concentration is necessary prior to physico-chemical extractions. We propose to use purple non-sulfur bacteria (PNSB) to address these challenges. Their ability to simultaneously obtain energy from light and carbon from organics provides them with higher biomass yields and faster growth rates than other anaerobes. Consequently, high biomass yields make them suitable for concentration of nutrients in biomass, and high growth rates reduce their sensitivity to colder operation temperatures. Finally, because they are the only photosynthetic organisms utilizing infrared light (>800 nm), engineers would possess powerful selection tools to control microbial communities in mixed open cultures.*******Published studies mainly focused on pure culture PNSB wastewater processes and operation at 20-35C. These conditions are inapplicable to full-scale Canadian municipal wastewater facilities; thus, significant knowledge gaps persist in developing PNSB processes. Additionally, reactor conditions need to be tightly controlled such that metabolism maximizes biomass yields instead of competing H2 and polyhydroxyalkanoate syntheses. This proposal will investigate operation conditions of non-sterile PNSB photobioreactors that are relevant to Canada for enabling implementation of wastewater resource recovery. Furthermore, control strategies for PNSB metabolism and microbial community composition will be developed by using genome-scale metabolic modeling and high-throughput metagenomic molecular tools. The program will train 2 PhD, 4 MEng and 10 undergraduate students.***