碳源对藻、菌及其共培养系统水处理效果的影响

Effect of Carbon Source on Nitrogen and Phosphorus Removal by a Bacterial-Algal Consortium

水体富营养化越来越严重影响水生态系统的结构和功能,甚至威胁人类健康,相比于传统的理化处理方法,利用藻菌共培养系统处理污水是一种绿色环保的水处理方式,合适的碳源可以提高藻菌共培养系统的污水处理效率。为探究不同碳源对藻、菌及其共培养系统污水处理效果的影响,分别使用葡萄糖、乙酸钠和柠檬酸三钠为碳源进行小球藻和地衣芽孢杆菌纯培养和藻菌共培养试验,每组试验设置3个平行,小球藻和地衣芽孢杆菌的初始接种量分别为2.0×10^(6)个/mL和1.0×10^(7)CFU/mL。结果显示,柠檬酸三钠是地衣芽孢杆菌纯培养时的适宜碳源,葡萄糖是藻菌共培养系统最适宜碳源,且地衣芽孢杆菌可促进小球藻生长。以葡萄糖为碳源,藻菌共培养系统的总氮、总磷和总有机碳去除率最高可达86.05%、93.71%和82.19%。研究表明,为提高污水处理效率并获得最大的微藻生物量,需要选择适合微藻生长并满足细菌代谢的碳源。

The use of symbiotic algal-bacterial consortia has great potential for advanced sewage treatment and resource regeneration,and the use of an appropriate supplemental carbon source improves treatment efficiency.In this study,Chlorella pyrenoidosa and Bacillus licheniformis FACHB-5 were selected for testing,based on previous research.The effects of different carbon sources on the treatment efficiency of C.pyrenoidosa and B.licheniformis acting alone,and symbiotically as a algal-bacterial consortium were investigated.The aim of the study was to identify the most suitable carbon source and provide technical support for using algal-bacterial consortia to sewage treatment.C.pyrenoidosa and B.licheniformis in the exponential growth phase were cultured alone or mix-cultured in artificially composed urban sewage,at initial concentrations of(1.0±0.5)×10^(7) CFU/mL for the bacteria and(2.0±0.3)×10^(6) cells/mL for the algae,and three carbon sources(glucose,sodium acetate and trisodium citrate)were used for the culture test.Each trial was run in triplicate with a control group,trials lasted 7 days and the culture was sampled each 24 h.Results show that B.licheniformis growth clearly depends on carbon source.Trisodium citrate gave the maximum biomass(NB max=1.13×10^(8) CFU/mL)of B.licheniformis and is the most suitable carbon source.The removal rates of TN,TP and TOC with trisodium citrate were,respectively,43.4%,33.70%and 56.21%.Glucose was the most suitable carbon source for C.pyrenoidosa,yielding a maximum cell count NU max=1.34×10^(7) cells/mL and respective TN,TP and TOC removal rates of 85.74%,89.52%and 68.64%,much higher than those of any B.licheniformis treatment.With the algal-bacterial consortium treatment,B.licheniformis promoted the growth of C.pyrenoidosa,and the TN,TP and TOC removal rates using the three carbon sources were all significantly higher than those in the B.licheniformis treatments.With glucose,the respective removal rates of TN,TP and TOC reached 86.05%,93.71%and 82.19%.In conclusion,glucose,sodium acetate and trisodium citrate could all be used as a carbon source for cultures or mix-cultures of C.pyrenoidosa and B.licheniformis.The most suitable carbon source is trisodium citrate for culturing B.licheniformis,while glucose is most suitable for culturing C.pyrenoidosa or the C.pyrenoidosa-B.licheniformis consortium.