Zhao Yonggui, Fang Yang, Jin Yanling, Huang Jun, Bao Shu, He Zhiming, Wang Feng, Zhao Hai
Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences (CAS), Chengdu 610041, China E-mail:
Yunnan Light Industrial Academy of Science, Kunming 650034, China.
Water Sci Technol. 2014;70(7):1195-204. doi: 10.2166/wst.2014.334.
The effects of water depth, coverage rate and harvest regime on nutrient removal from wastewater and high-protein biomass production were assessed in a duckweed-based (Lemna aequinoctialis) pilot-scale wastewater treatment system (10 basins × 12 m(2)) that is located near Dianchi Lake in China. The results indicated that a water depth of 50 cm, a coverage rate of 150% and a harvest regime of 4 days were preferable conditions, under which excellent records of high-protein duckweed (dry matter production of 6.65 g/m(2)/d with crude protein content of 36.16% and phosphorus content of 1.46%) were obtained at a temperature of 12-21 °C. At the same time, the system achieved a removal efficiency of 66.16, 23.1, 48.3 and 76.52% for NH4(+)-N, TN, TP and turbidity, respectively, with the considerable removal rate of 0.465 g/m(2)/d for TN and 0.134 g/m(2)/d for TP at a hydraulic retention time of 6 days. In additionally, it was found that a lower duckweed density could lead to higher dissolved oxygen in the water and then a higher removal percentage of NH4(+)-N by nitrobacteria. This study obtains the preferable operation conditions for wastewater treatment and high-protein biomass production in a duckweed-based pilot-scale system, supplying an important reference for further large-scale applications of duckweed.
在中国滇池附近一个基于浮萍（细叶满江红）的中试规模废水处理系统（10个水池×12平方米）中，评估了水深、覆盖率和收获方式对废水养分去除和高蛋白生物质生产的影响。结果表明，水深50厘米、覆盖率150%和4天的收获方式是较为理想的条件，在此条件下，在12 - 21°C的温度下可获得高蛋白浮萍的优异记录（干物质产量为6.65克/平方米/天，粗蛋白含量为36.16%，磷含量为1.46%）。同时，该系统对NH4(+)-N、TN、TP和浊度的去除效率分别达到66.16%、23.1%、48.3%和76.52%，在水力停留时间为6天时，TN的去除率为0.465克/平方米/天，TP的去除率为0.134克/平方米/天。此外，还发现较低的浮萍密度会导致水中溶解氧升高，进而使硝化细菌对NH4(+)-N的去除率更高。本研究得出了基于浮萍的中试规模系统中废水处理和高蛋白生物质生产的优选运行条件，为浮萍的进一步大规模应用提供了重要参考。
