Valorization of hydrothermal liquefaction aqueous stream towards commercial viability of municipal sludge to biocrude oil conversion

我的总体研究计划专注于开发先进的废水和污泥处理技术，并受到我的行业合作者/合作伙伴目前面临的许多挑战的推动。特别是，城市污水处理厂因废水中越来越多的有害物质而日益捉襟见肘，这些物质成为城市污泥的一部分。为了有效中和其中含有的病原体、重金属和一系列新出现的痕量污染物(TCECs)，这种污泥的处理成本很高。我最近的研究调查了几种处理这种废物的有前景的方法，包括通过水热液化(HTL)转化热化学污泥。HTL是一项改变游戏规则的进步，因为它可以将污泥转化为可用作燃料替代品的生物原油。到目前为止，我们已经发现，在350℃和220bar的温度和压力下，脱水的城市污泥可以有效地转化为生物油和加氢焦油。此外，在这些高温和压力下，城市污泥中的许多类别的TCEC(药物、激素、抗菌剂)都会被破坏。由于这项前景看好的技术有可能通过产生可用于运输的燃料来消毒城市废水污泥中的有害物质，它具有与许多其他废水处理解决方案相关的降低成本的双重优势，并在几个方面提供环境效益。然而，HTL会产生一种副产品HTL水，如果不进行额外处理，就会危及这项技术在废水处理厂的未来扩大前景。HTL水中的污染物水平大大超过了对环境的排放规定，将其返回到井口工程的风险尚不清楚。HTL水溶液也是一种未开发的营养/生物能源资源，由于其含有高浓度的有机酸，因此具有为处理厂创造收入的潜力。然而，也有许多种类的有机物，包括呋喃、酮、酚和N-杂环化合物，据报道在生物处理过程中对关键微生物的培养具有抑制作用，特别是具有生物能量回收潜力的厌氧消化器。因此，HTL水溶液的生物能潜力是未知的。为了解决这些差距，在接下来的5年里，3名研究生和2名本科生将在一名分析化学家的指导下，开发和评估从城市污泥中提取的HTL水的各种解毒方法的性能，以使高浓度的有机酸在先进的厌氧消化器中产生沼气。这些目标将使我们更接近于将HTL污泥转化过程无缝地整合到废水处理厂中。通过与不列颠哥伦比亚省各市的持续伙伴关系，这项研究的结果将产生立竿见影的效果。

My overarching research program focuses on the development of advanced wastewater and sludge treatment technologies, and is motivated by many of the challenges my industrial collaborators/partners currently face. In particular, municipal wastewater treatment plants are increasingly stretched by ever growing volumes of hazardous materials in wastewater that become part of `municipal sludge.' This sludge is costly to process in order to effectively neutralize the pathogens, heavy metals, and a wide range of trace contaminants of emerging concern (TCECs) that it contains. My recent research has investigated several promising approaches to process this waste product, including thermochemical sludge conversion through hydrothermal liquefaction (HTL). HTL is a game-changing advancement, since it can convert sludge into biocrude that can be used as a fuel replacement. To date we have found that dewatered municipal sludge can be efficiently converted to biocrude oil and hydrochar at temperature and pressure of 350 C and 220 bar, respectively. Furthermore, at these elevated temperatures and pressures, many classes of TCECs (pharmaceuticals, hormones, antimicrobials) in municipal sludge are destroyed. Since this promising technology has the potential to sterilize the hazardous materials in municipal wastewater sludge by generating fuel that can be used in transportation, it has the double advantage of reducing costs associated with many other wastewater treatment solutions, and provides environmental benefits on several fronts. However, HTL creates a by-product, HTL aqueous, that without additional treatment, jeopardizes the future scale-up prospects of this technology at wastewater treatment plants. The pollutant levels in HTL aqueous significantly exceed discharge regulations to the environment and the risks of returning it to headworks is unknown. The HTL aqueous is also an untapped nutrient/bioenergy resource that holds revenue-generating potential for treatment plants due to its high concentration of organic acids. However, there are also many classes of organics, including furans, ketones, phenols, and N-heterocyclic compounds, reported to be inhibitory to key microbial cultures in biological treatment processes, in particular anaerobic digesters with bioenergy recovery potential. Therefore, bioenergy potential of HTL aqueous is unknown. To address these gaps, over the next 5 years, 3 graduate and 2 undergraduate students, mentored by an analytical chemist, will develop and evaluate the performance of various detoxification methods for HTL aqueous derived from municipal sludge to valorize high concentrations of organic acids to generate biogas in advanced anaerobic digesters. These objectives will bring us one step closer to incorporating HTL sludge conversion processes to wastewater treatment plants seamlessly. Through ongoing partnerships with municipalities throughout British Columbia, outcomes of this research are poised to have immediate impact.