Carlsberg Research Laboratory, Bjerregaardsvej 5, 2500 Valby, Denmark.
National Food Institute, Technical University of Denmark, Kemitorvet Building 204, 2800 Kgs. Lyngby, Denmark.
Sci Total Environ. 2021 Sep 1;785:147337. doi: 10.1016/j.scitotenv.2021.147337. Epub 2021 Apr 24.
CIP wastewater is one of the major wastewater streams from the food industry, and its treatment is generally expensive, requiring a large effort to reduce its typically high nitrogen (N), and phosphorus (P) contents. Microalgae-based wastewater treatment is increasingly explored as a more sustainable alternative to the conventional methods, due to the added benefit of nutrient upcycling and value-added biomass production. For the first time, four microalgae species were used to treat CIP wastewater high in N (565.5 mg NO-N/l) and P (98.0 mg PO-P/l). An intermittent biomass harvesting strategy was adopted in this study to enhance the purification of CIP water and redirection of nutrients into algal biomass. Over 93 days operation, N removal efficiency was 52.1 ± 2.9%, 54.8 ± 2.5%, 50.0 ± 2.3% and 48.3 ± 0.5%, and P removal efficiency was 65.5 ± 10.0%, 79.4 ± 6.1%, 61.8 ± 2.5% and 69.1 ± 7.7% for Chlamydomonas reinhardtii, Chlorella vulgaris, Scenedesmus obliquus and wastewater borne microalgae, respectively. After the first (acclimatization) and second growth cycles, cell growth and nutrient removal slowed down but increased again after adding trace nutrients, indicating the lack of trace elements after the first two growth cycles. In the fourth and fifth batch runs, both algal growth rate and nutrient removal rate decreased despite adding trace nutrients and/or increasing light intensity, this being a consequence of the excreted soluble algal products accumulating during long-term operation. S. obliquus had the highest protein concentration of 44.5 ± 9.8% DW, while C. vulgaris accumulated the highest total lipid content (15.6 ± 0.9%, DW). In this proof-of-concept study, the cultivation of microalgae in CIP wastewater with an intermittent harvest of the accumulated algal biomass is demonstrated and it outlines the potential of microalgae to sustainably treat effluents with extremely high nutrients concentration while producing the food-grade algae biomass.
CIP 废水是食品工业的主要废水之一，其处理通常成本高昂，需要大量努力来降低其典型的高氮（N）和磷（P）含量。由于营养物质的再利用和增值生物量的生产带来了额外的好处，基于微藻的废水处理作为传统方法的替代方法越来越受到关注。 本研究首次使用四种微藻处理高氮（565.5 mg NO-N/l）和高磷（98.0 mg PO-P/l）的 CIP 废水。在这项研究中采用了间歇式生物质收获策略，以增强 CIP 水的净化效果，并将养分重新导向微藻生物质。在 93 天的运行过程中，N 去除效率分别为 52.1 ± 2.9%、54.8 ± 2.5%、50.0 ± 2.3%和 48.3 ± 0.5%，P 去除效率分别为 65.5 ± 10.0%、79.4 ± 6.1%、61.8 ± 2.5%和 69.1 ± 7.7%，分别为莱茵衣藻、普通小球藻、斜生栅藻和废水中的微藻。在第一个（驯化）和第二个生长周期后，细胞生长和养分去除速度减慢，但在添加痕量养分后又再次增加，表明在前两个生长周期后缺乏痕量元素。在第四和第五批运行中，尽管添加了痕量养分和/或增加了光强，但藻类生长率和养分去除率均下降，这是由于长期运行过程中积累的可溶藻产物的排泄所致。斜生栅藻的蛋白质浓度最高，为 44.5 ± 9.8%DW，而普通小球藻积累的总脂含量最高（15.6 ± 0.9%，DW）。在这个概念验证研究中，证明了在 CIP 废水中间歇式收获积累的藻生物质来培养微藻，并概述了微藻在可持续处理高浓度营养物质废水的同时生产食品级藻类生物质的潜力。
