Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea; Department of Environmental Biotechnology, KRIBB School of Biotechnology, University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, South Korea.
Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea.
Chemosphere. 2021 Jan;263:127934. doi: 10.1016/j.chemosphere.2020.127934. Epub 2020 Aug 10.
A high ammonia concentration and chemical oxygen demand (COD) in piggery wastewater force it to be diluted before conventional microalgal treatment to reduce ammonia toxicity. Incomplete treatment of ammonia and COD in piggery wastewater may cause eutrophication, resulting in algal blooms. This study tried to treat raw piggery wastewater without dilution, using three strains of microalgae (Chlorella sorokiniana, Coelastrella sp. and Acutodesmus nygaardii) that outcompeted other algae under heterotrophic, mixotrophic, and autotrophic conditions, respectively, through adaptive evolution at high ammonia concentration. The three stepwise processes were designed to remove (1) small particles, COD, and phosphorus in the 1st heterotrophic C. sorokiniana cultivation, (2) ammonia and COD in the 2nd mixotrophic Coelastrella sp. cultivation, and (3) the remaining ammonia in the 3rd photoautotrophic A. nygaardii cultivation. To enhance ammonia uptake rate, each algal species were inoculated after 2-day nitrogen starvation. When the N-starved three species were inoculated at each step sequentially at 7 g/L for 2 days, the final phosphorus, COD, and ammonia removal efficiencies were 100% (16.4-0 mg/L), 92% (6820-545 mg/L), 90% (850-81 mg/L) and turbidity (99%) after total 6 days.
养猪废水中高浓度的氨氮和化学需氧量（COD）要求其在进行传统微藻处理之前先进行稀释，以降低氨毒性。养猪废水中氨氮和 COD 处理不完全可能会导致富营养化，从而引发藻类大量繁殖。本研究试图在不稀释的情况下处理原始养猪废水，使用三种微藻（绿球藻、Coelastrella sp. 和钝顶螺旋藻），通过在高氨浓度下的适应性进化，分别在异养、混养和自养条件下竞争其他藻类。设计了三个逐步过程来去除（1）第 1 步异养绿球藻培养中的小颗粒、COD 和磷，（2）第 2 步混养 Coelastrella sp. 培养中的氨氮和 COD，以及（3）第 3 步光自养钝顶螺旋藻培养中的剩余氨氮。为了提高氨氮吸收速率，每种藻类在氮饥饿 2 天后进行接种。当饥饿 2 天的三种藻类分别在每一步以 7 g/L 接种 2 天时，在 6 天的总时间内，最终磷、COD 和氨氮去除效率分别达到 100%（16.4-0 mg/L）、92%（6820-545 mg/L）、90%（850-81 mg/L）和浊度（99%）。
