Understanding the role of activated sludge in oxygen transfer to improve wastewater treatment sustainability

了解活性污泥在氧转移中的作用，以提高废水处理的可持续性

• 批准号: 2146781
• 负责人: Jianmin Wang
• 金额: $ 42万
• 依托单位: Missouri University of Science and Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2146781&HistoricalAwards=false
• 关键词: Understanding; role; activated; sludge; oxygen

Wastewater treatment plants play a critical role in environmental protection. In the United States, municipal wastewater treatment plants (WWTPs) process billions of gallons of wastewater every day to remove suspended solids, organic matter, and excess nutrients including nitrogen and phosphorus. Aeration is a critical unit operation in municipal WWTPs as it provides the required oxygen for the activated sludge process used in aerobic biological wastewater treatment to remove organic matter and nutrients. However, aeration requires a significant amount of energy and accounts for 70-80 % of the total energy used in an activated sludge wastewater treatment process. The overarching goal of this project is to advance the development of innovative solutions to reduce the aeration energy required to operate an activated sludge wastewater treatment process. To advance this goal, the Principal Investigator proposes to carry out an integrated experimental and modeling program to characterize and unravel the physicochemical and biological processes and parameters that control oxygen transfer in the mixed liquor of an activated sludge bioreactor. The successful completion of this project will benefit society through the generation of new fundamental knowledge and innovative solutions that could reduce the energy consumption and greenhouse gas (GHG) emissions of municipal WWTs. Additional benefits to society will be achieved through outreach and educational activities including the mentoring of two graduate students at the Missouri University of Science and Technology.In aerobic biological wastewater treatment, aeration accounts for approximately 50% of the total process energy consumption. Preliminary research by the Principal Investigator (PI) of this project has established that the biological and physicochemical properties of activated sludge have a significant impact on oxygen transfer during aeration. Building upon the results of this preliminary work, the PI and his research team propose to carry out an in-depth investigation of the oxygen transfer process in the mixed liquor of an activated sludge bioreactor including at the gas-liquid, liquid-solid, and gas-liquid-solid interfaces. The specific objectives of the research are to: 1) Evaluate the effects of sludge physical properties (e.g., morphology, settleability, viscosity, and hydrophobicity) on oxygen transfer at the gas-liquid interface; 2) Assess the effects of the sludge physical properties (listed above) and sludge biological parameters (e.g., microorganism population and concentration of extracellular polymeric substances) on oxygen transfer at the liquid-microorganism interface; 3) Evaluate the mechanisms of enhancement of oxygen transfer by microorganisms at the air-liquid interface; and 4) Develop and validate dimensionless process parameters that could be used to characterize the intrinsic oxygen transfer property of the mixed liquor of an activated sludge bioreactor. The successful completion of this project has the potential for transformative impact through the generation of fundamental knowledge and process design tools that could be leveraged to reduce the energy required to aerate and operate an activated sludge wastewater process. To implement the education and outreach activities of the project, the PI plans to leverage the Opportunities for Undergraduate Research Experiences program at the Missouri University of Science and Technology to provide research training opportunities to two undergraduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

污水处理厂在环境保护中起着至关重要的作用。在美国，城市污水处理厂（WWTPs）每天处理数十亿加仑的废水，以去除悬浮固体，有机物和多余的营养物质，包括氮和磷。曝气是城市污水处理厂的关键单元操作，因为它为好氧生物污水处理中使用的活性污泥工艺提供所需的氧气，以去除有机物和营养物。然而，曝气需要大量的能量，并且占活性污泥废水处理过程中使用的总能量的70- 80%。该项目的总体目标是推进创新解决方案的开发，以减少运行活性污泥废水处理工艺所需的曝气能量。为了推进这一目标，主要研究者建议进行一个综合的实验和建模计划，以表征和解开的物理化学和生物过程和参数，控制氧转移的活性污泥生物反应器的混合液。该项目的成功完成将通过产生新的基础知识和创新解决方案来造福社会，这些解决方案可以减少城市污水处理厂的能源消耗和温室气体（GHG）排放。通过推广和教育活动，包括对密苏里州科技大学两名研究生的指导，将为社会带来额外的好处。在好氧生物废水处理中，曝气约占总工艺能耗的50%。该项目的主要研究者（PI）的初步研究已经确定，活性污泥的生物和物理化学性质对曝气过程中的氧转移有重大影响。基于这一初步工作的结果，PI和他的研究团队建议对活性污泥生物反应器混合液中的氧传递过程进行深入研究，包括气-液，液-固和气-液-固界面。研究的具体目标是：1）评价污泥物理性质（例如，形态、沉降性、粘度和疏水性）对气-液界面处氧传递的影响; 2）评估污泥物理性质（上面列出的）和污泥生物参数（例如，微生物种群和胞外聚合物的浓度）对液体-微生物界面处氧传递的影响; 3）评价空气-液体界面处微生物增强氧传递的机制;以及4）开发和验证可用于表征活性污泥生物反应器的混合液的固有氧传递性质的无量纲工艺参数。该项目的成功完成有可能通过产生基础知识和工艺设计工具产生变革性影响，这些工具可以用来减少曝气和运行活性污泥废水工艺所需的能源。为了实施该项目的教育和外展活动，PI计划利用密苏里州科技大学的本科生研究经验计划的机会，为两名本科生提供研究培训机会。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。