CFD simulation of a novel mixing and aeration system for wastewater treatment

用于废水处理的新型混合曝气系统的 CFD 模拟

• 批准号: 469189-2014
• 负责人: Ray, Madhumita
• 金额: $ 1.82万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=563330
• 关键词: CFD; simulation; novel; mixing; aeration

Water and wastewater systems are significant energy consumers with an estimated 3%-4% of total U.S. electricity consumption. Wastewater treatment using activated sludge process is generally aided by aeration, supplying the required oxygen for degradation of organic materials. Current aeration systems account for 50% to 80% of wastewater treatment plant operating budgets. With rising energy costs and a growing focus on energy conservation and carbon footprint reduction, there is increasing demand for energy-efficient aeration technologies. Ekologix Earth-Friendly Solutions Inc. (Ekologix) is currently experimentally testing its new invention, Plunge-AspiroTM Mix (PAM) that can reduce energy use by up to 60%. Using a liquid pump and multiple vertical jet streams introduced from the top of the aeration reactor, PAM concurrently mixes and aerates while supplying tiny bubbles, resulting in improved performance and energy efficiency of the reactor. Although, performance of current design of PAM is being tested in full-scale, both hydraulic and process optimizations should be conducted for further improvement in the efficiency by simulating alternating hydraulic mixing levels without sacrificing process efficiency (i.e. organics destruction and nitrification efficiency). This can be achieved by computational fluid dynamics (CFD). The objective of this project is to establish a CFD simulation model for an aeration basin fitted with a basic design of PAM to determine the mixing pattern in the tank and to identify short-circuiting, dead and recirculation zones. The validated CFD model will be coupled with kinetic models to predict the organics removal for variable water and air flow rates, suspended solids, and dissolved organics concentration. The validated CFD model along with the bio-kinetic model will be a useful tool for the design of similar activated sludge aeration basins.

水和废水系统是重要的能源消耗者，估计占美国总电力消耗的3%-4%。使用活性污泥法的废水处理通常通过曝气辅助，提供降解有机材料所需的氧气。 目前的曝气系统占污水处理厂运营预算的50%至80%。 随着能源成本的上升以及人们对节能和减少碳足迹的日益关注，对节能曝气技术的需求越来越大。Ekologix地球友好解决方案公司（Ekologix）目前正在实验性地测试其新发明Plunge-AspiroTM Mix（PAM），该发明可将能源使用量减少高达60%。利用液体泵和从曝气反应器顶部引入的多股垂直射流，PAM在提供微小气泡的同时同时混合和曝气，从而提高反应器的性能和能量效率。 虽然目前PAM设计的性能正在全面测试中，但应通过模拟交替的水力混合水平进行水力和工艺优化，以进一步提高效率，而不牺牲工艺效率（即有机物破坏和硝化效率）。 这可以通过计算流体动力学（CFD）来实现。 本项目的目的是建立一个CFD模拟模型，曝气池配有一个基本的设计PAM，以确定在坦克的混合模式，并确定短路，死区和回流区。 经验证的CFD模型将与动力学模型相结合，以预测可变水和空气流速、悬浮固体和溶解有机物浓度的有机物去除。经过验证的计算流体力学模型沿着生物动力学模型将为类似活性污泥曝气池的设计提供有用的工具。