A Novel Membrane Biofilm Reactor for Microalgae Cultivation and Harvest and Wastewater Treatment

用于微藻培养、收获和废水处理的新型膜生物膜反应器

• 批准号: RGPIN-2019-05087
• 负责人: Liao, Baoqiang
• 金额: $ 2.04万
• 依托单位: Lakehead University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=747159
• 关键词: Novel; Membrane; Biofilm; Reactor; Microalgae

The algae industry is an important part of the global economy. In addition to bioproducts, algae are increasingly recognized for their use in the bioenergy and waste management sectors (nutrients removal from wastewater and abatement of greenhouse gas (CO2)). However, the cell concentration of suspended microalgae culture is very dilute and usually less than 0.5-2 g/L. Consequently, microalgae grown in open ponds or closed photobioreactors require large volumes of water and a significant amount of energy input for cultivation, harvest, and dewatering. It is estimated that 20-30% microalgae production cost and about 90% of the equipment cost are associated with the harvest and dewatering of algal biomass, respectively. Thus, novel technologies for microalgae cultivation, harvest, and dewatering are highly desirable to improve the economy of microalgae production. As an alternative to open ponds and closed photobioreactors, algal biofilm systems have drawn great attention in recent years, due to their unique features, such as high biomass density, easy biomass harvest, and increased biomass productivity. The key advantage of microalgal biofilm (MB) lies in the higher cell concentration (up to 100 times of suspended cell concentrations), which greatly reduces harvesting effort as the MB can simply be scraped or vacuumed off the surface and can be used without the need for further concentration. However, the high cell density in MB requires a larger amount and faster transfer rate of CO2 for biofilm growth. The traditional strategies of directly bubbling CO2 gas into photobioreactors or microalgae ponds have a low transfer and utilization efficiency with 50% to 90% CO2 existing back to atmosphere. Thus, novel CO2 delivery technologies are vital to increase CO2 transfer and utilization efficiencies and reduce energy cost, particularly for MB systems. The proposed research program focuses on the development of a novel membrane carbonated microalgal biofilm bioreactor (MCMBR) for microalgae cultivation, harvest, and wastewater treatment. This novel system utilizes hydrophobic gas permeable membranes to deliver molecular CO2 into MB grown on outside surfaces of the membrane, while nutrients (N and P) and photons are transported into the MB from an opposite direction. This novel bioreactor system combines the advantages of high cell density biofilm systems and a high CO2 transfer and utilization efficiency through membranes (via a synergistic effect) and has a low energy consumption and thus can achieve a much higher process efficiency that is not achievable with current microalgal technologies. The outcome of this research is the development of a novel MCMBR system for microalgae cultivation, harvest, wastewater treatment, and greenhouse gas (CO2) abatement. This research will benefit the Canadian environmental and energy industries and train highly qualified personnel (HQP) in areas that are critical to Canada.

藻类行业是全球经济的重要组成部分。除了生物生物产品外，藻类在生物能源和废物管理领域的使用越来越多（从废水中去除营养和消除温室气体（CO2））。然而，悬浮的微藻培养物的细胞浓度非常稀释，通常小于0.5-2 g/l。因此，在开放池或封闭的光生反应器中生长的微藻需要大量的水和大量的能量输入，以培养，收获和脱水。据估计，分别与藻类生物量的收获和脱水有关，微藻的生产成本和约90％的设备成本分别是相关的。这是非常需要微藻培养，收获和脱水的新技术，可以改善微藻生产的经济性。作为开放池塘和封闭光生反应器的替代方案，藻类生物膜系统近年来引起了人们的极大关注，因为它们的独特特征，例如高生物量密度，易于生物量收获和提高的生物量生产率。微藻生物膜（MB）的关键优势在于较高的细胞浓度（悬浮的细胞浓度高达100倍），因为可以简单地将MB刮掉或从表面上吸尘，可以大大降低收获的努力，并且无需进一步浓度就可以使用。但是，MB中的高细胞密度需要更大的二氧化碳生长二氧化碳速率和更快的转移速率。直接气泡二氧化碳气体进入光生反应器或微藻池的传统策略的传递效率低和利用效率，而有50％至90％的CO2现有回到大气。这是新颖的CO2输送技术对于提高二氧化碳转移和利用效率并降低能源成本至关重要，尤其是对于MB系统。拟议的研究计划着重于开发新型的膜碳酸微藻生物膜生物反应器（MCMBR），用于微藻培养，收获和废水处理。这个新型系统利用疏水气体可渗透的膜将分子二氧化碳输送到膜外表面生长的MB中，而营养（N和P）和照片从相反的方向运输到MB中。这种新型的生物反应器系统结合了高细胞密度生物膜系统的优势以及通过机制（通过协同效应）具有高二氧化碳转移和利用效率，并且具有低能消耗，因此可以实现更高的工艺效率，而在当前的微型技术技术中无法实现，而这是无法实现的。这项研究的结果是开发了一种新型的MCMBR系统，用于微藻种植，收获，废水处理和消除温室气体（CO2）。这项研究将使加拿大环境和能源行业受益，并在对加拿大至关重要的地区培训高素质的人员（HQP）。