Department of Chemical Engineering, Qatar University, Qatar; Cranfield Water Science Institute, Cranfield University, UK.
Department of Chemical Engineering, Qatar University, Qatar.
Water Res. 2015 Dec 15;87:356-66. doi: 10.1016/j.watres.2015.08.021. Epub 2015 Aug 28.
The recent literature pertaining to the application of algal photobioreactors (PBRs) to both carbon dioxide mitigation and nutrient abatement is reviewed and the reported data analysed. The review appraises the influence of key system parameters on performance with reference to (a) the absorption and biological fixation of CO2 from gaseous effluent streams, and (b) the removal of nutrients from wastewaters. Key parameters appraised individually with reference to CO2 removal comprise algal speciation, light intensity, mass transfer, gas and hydraulic residence time, pollutant (CO2 and nutrient) loading, biochemical and chemical stoichiometry (including pH), and temperature. Nutrient removal has been assessed with reference to hydraulic residence time and reactor configuration, along with C:nutrient ratios and other factors affecting carbon fixation, and outcomes compared with those reported for classical biological nutrient removal (BNR). Outcomes of the review indicate there has been a disproportionate increase in algal PBR research outputs over the past 5-8 years, with a significant number of studies based on small, bench-scale systems. The quantitative impacts of light intensity and loading on CO2 uptake are highly dependent on the algal species, and also affected by solution chemical conditions such as temperature and pH. Calculations based on available data for biomass growth rates indicate that a reactor CO2 residence time of around 4 h is required for significant CO2 removal. Nutrient removal data indicate residence times of 2-5 days are required for significant nutrient removal, compared with <12 h for a BNR plant. Moreover, the shallow depth of the simplest PBR configuration (the high rate algal pond, HRAP) means that its footprint is at least two orders of magnitude greater than a classical BNR plant. It is concluded that the combined carbon capture/nutrient removal process relies on optimisation of a number of process parameters acting synergistically, principally microalgal strain, C:N:P load and balance, CO2 and liquid residence time, light intensity and quality, temperature, and reactor configuration. This imposes a significant challenge to the overall process control which has yet to be fully addressed.
对藻类光生物反应器（PBR）在二氧化碳减排和营养物去除方面的应用的近期文献进行了综述，并对报道的数据进行了分析。该综述评估了关键系统参数对（a）从气态废物流中吸收和生物固定 CO2，以及（b）从废水中去除营养物的性能的影响。单独参考 CO2 去除评估的关键参数包括藻类种类、光强、质量传递、气液停留时间、污染物（CO2 和营养物）负荷、生物化学和化学计量（包括 pH）以及温度。营养物去除是通过参考水力停留时间和反应器配置、C:营养物比以及影响碳固定的其他因素进行评估的，并与传统生物营养去除（BNR）的结果进行了比较。综述结果表明，过去 5-8 年藻类 PBR 研究产出呈不成比例的增长，其中相当数量的研究基于小型实验室规模系统。光强和负荷对 CO2 吸收的定量影响高度依赖于藻类种类，并且还受到溶液化学条件（如温度和 pH）的影响。基于现有数据计算的生物量增长率表明，需要大约 4 小时的反应器 CO2 停留时间才能显著去除 CO2。营养物去除数据表明，需要 2-5 天的停留时间才能显著去除营养物，而 BNR 工厂的停留时间<12 小时。此外，最简单的 PBR 配置（高效藻类塘，HRAP）的浅深度意味着其占地面积至少比传统 BNR 工厂大两个数量级。结论是，联合碳捕获/营养物去除过程依赖于许多协同作用的过程参数的优化，主要是微藻菌株、C:N:P 负荷和平衡、CO2 和液体停留时间、光强和质量、温度和反应器配置。这对尚未完全解决的整体过程控制提出了重大挑战。
