Chemical, Biological and Environmental Engineering Department, Escola d'Enginyeria, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain.
Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Girona, Spain.
Sci Total Environ. 2017 Aug 15;592:1-11. doi: 10.1016/j.scitotenv.2017.02.224. Epub 2017 Mar 11.
In this study, a 1200L outdoor pilot scale microalgal photobioreactor (PBR) was used for toilet wastewater (WW) treatment and evaluate its ability to remove pharmaceutically active compounds (PhACs). The PBR was operated at two different hydraulic retention times (HRTs), which were 8 and 12days, during Period I (September-October) and Period II (October-December), respectively. Algal biomass concentrations varied by operating period because of seasonal changes. Nutrients (ammonia, nitrogen and total phosphorous) and chemical oxygen demand (COD) were monitored and efficiently removed in both periods (>80%), attaining the legislation limits. At the theoretical hydraulic steady state in both periods, pharmaceutical removal reached high levels (>48%). Two harvesting techniques were applied to the PBR microalgae effluent. Gravity sedimentation was efficient for biomass removal (>99% in 7min) in Period I when large particles, flocs and aggregates were present. In contrast, a longer sedimentation time was required when biomass was mainly composed of single cells (88% clarification in a 24h in Period II). The second harvesting technique investigated was the co-pelletization of algal biomass with the ligninolytic fungus Trametes versicolor, attaining >98% clarification for Period II biomass once pellets were formed. The novel technology of co-pelletization enabled the complete harvesting of single algae cells from the liquid medium in a sustainable way, which benefits the subsequent use of both biomass and the clarified effluent.
在这项研究中，我们使用了一个 1200L 的户外中试规模微藻光生物反应器（PBR）来处理厕所废水（WW），并评估其去除药用活性化合物（PhACs）的能力。PBR 在两个不同的水力停留时间（HRT）下运行，分别为 8 天和 12 天，分别在第一阶段（9 月至 10 月）和第二阶段（10 月至 12 月）进行。由于季节性变化，藻类生物量浓度在不同的运行阶段有所不同。在两个阶段中，营养物质（氨、氮和总磷）和化学需氧量（COD）都得到了监测并得到了有效去除（>80%），达到了法规限制。在两个阶段的理论水力稳定状态下，药物去除率达到了较高水平（>48%）。我们应用了两种收获技术来收获 PBR 微藻培养液中的藻类。重力沉降在第一阶段（当存在大颗粒、絮体和聚集体时）对于生物量去除非常有效（>99%，7 分钟内）。相比之下，当生物量主要由单细胞组成时（第二阶段 24 小时内 88%澄清），需要更长的沉降时间。我们研究的第二种收获技术是将藻类生物质与木质素分解真菌白腐菌（Trametes versicolor）共絮凝，一旦形成颗粒，就可以达到第二阶段生物质>98%的澄清度。共絮凝的新技术可以以可持续的方式从液体培养基中完全收获单细胞藻类，这有利于随后对生物质和澄清后的废水的利用。
