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

我的总体研究计划侧重于先进的废水和污泥处理技术的开发，并受到我的工业合作者/合作伙伴目前面临的许多挑战的激励。特别是，城市废水处理厂因废水中的危险物质日益增多而日益捉襟见肘，这些物质成为“城市污泥”的一部分。“这种污泥的处理成本很高，以便有效地中和其中包含的病原体，重金属和各种新出现的关注的痕量污染物（TCECs）。我最近的研究调查了几种有前途的方法来处理这种废物，包括通过水热液化（HTL）的热化学污泥转化。HTL是一个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。迄今为止，我们已经发现脱水的城市污泥可以分别在350 ℃和220巴的温度和压力下有效地转化为生物原油和水热炭。此外，在这些升高的温度和压力下，城市污泥中的许多类别的TCEC（药物、激素、抗菌剂）被破坏。由于这种有前途的技术有可能通过产生可用于运输的燃料来对城市废水污泥中的有害物质进行灭菌，因此它具有降低与许多其他废水处理解决方案相关的成本的双重优势，并在几个方面提供环境效益。然而，HTL会产生一种副产品，即HTL水溶液，如果不进行额外的处理，会危及该技术在废水处理厂的未来规模扩大前景。HTL水溶液中的污染物水平显著超过环境排放法规，并且将其返回到渠首工程的风险未知。HTL水溶液也是一种未开发的营养/生物能源资源，由于其高浓度的有机酸，具有为处理厂创收的潜力。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，据报道对生物处理过程中的关键微生物培养物具有抑制作用，特别是具有生物能回收潜力的厌氧消化器。因此，HTL水溶液的生物能源潜力是未知的。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，由分析化学家指导，将开发和评估各种解毒方法的性能，用于从城市污泥中提取HTL水溶液，以稳定高浓度的有机酸，从而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污泥转化工艺无缝地整合到污水处理厂。通过与整个不列颠哥伦比亚省的市政当局的持续伙伴关系，这项研究的成果将立即产生影响。

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.