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.

废水处理厂在环境保护中起着至关重要的作用。在美国，市政废水处理厂（WWTPS）每天处理数十亿加仑的废水，以去除悬浮的固体，有机物和多余的养分，包括氮和磷。曝气是市政WWTP的关键单位操作，因为它为有氧生物学废水处理中使用的活性污泥过程提供了所需的氧气，以去除有机物和养分。但是，充气需要大量能量，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促进创新解决方案的开发，以减少运行活性污泥废水处理过程所需的曝气能量。为了促进这一目标，主要研究者建议执行一项集成的实验和建模程序，以表征和揭示控制活化污泥生物反应器混合酒中氧转移的物理化学和生物学过程和参数。该项目的成功完成将通过产生新的基本知识和创新解决方案来使社会受益，从而减少市政WWTS的能源消耗和温室气体（GHG）排放。将通过外展和教育活动来实现社会的其他好处，包括密苏里科学技术大学的两名研究生的指导。该项目的主要研究者（PI）的初步研究确定，活性污泥的生物学和物理化学特性对曝气过程中的氧气转移有重大影响。在这项初步工作的结果基础上，PI和他的研究小组建议对激活的污泥生物反应器混合酒中的氧气转移过程进行深入研究，包括在气体，液体溶液和气体液体溶液界面上。研究的具体目标是：1）评估污泥物理特性（例如形态，沉降性，粘度和疏水性）对气体液体界面上氧气转移的影响； 2）评估污泥物理特性（上面列出）和污泥生物学参数（例如，微生物种群和细胞外聚合物物质的浓度）对液体微生物界面上的氧转移的影响； 3）评估在空气界面上微生物增强氧气转移的机制； 4）开发和验证无量纲的过程参数，可用于表征活性污泥生物反应器的混合酒的内在氧转移特性。该项目的成功完成通过产生的基本知识和过程设计工具有可能降低充气和运行活性污泥废水过程所需的能量。为了实施该项目的教育和外展活动，PI计划利用密苏里科学技术大学的本科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的法定任务，并通过评估该基金会的智力功能和广泛的影响来审查CRITERIA。