基于缓释固体碳源的好氧反硝化复合菌NF21+FX32脱氮特性研究

Denitrification performance of aerobic denitrification mix-cultured NF21+FX32 based on slow-release solid carbon source

从活性污泥中筛选两株好氧反硝化菌NF21和FX32,由16S rDNA基因序列分析,确定NF21为假单胞菌属(Pseudomonas),FX32为氏菌属(Bosea).以复合菌NF21+FX32为对象,通过测定菌株的生长状况和脱氮特性,研究了缓释固体碳源聚丁二酸丁二醇酯(PBS)、聚己内酯(PCL)和聚乳酸(PLA)对复合菌脱氮性能的影响.结果表明:PBS具有良好的释碳能力,60 h内的COD平均释放速率可达0.98 mg·L^(-1)·h^(-1);复合菌NF21+FX32均可用缓释固体碳源PBS、PCL和PLA降解废水中的NO_(3)^(-)-N,其中以PBS为缓释固体碳源时对NO_(3)^(-)-N的去除效果最好,去除率大于85%;NF21+FX32混合培养对废水中NO_(3)^(-)-N去除具有协同作用,脱氮效果好于单菌株;以PBS为缓释固体碳源时,复合菌NF21+FX32更适宜于低浓度NO_(3)^(-)-N废水脱氮,最适初始NO_(3)^(-)-N浓度为30 mg·L^(-1)、温度为30℃和pH为7.5.

Two aerobic denitrifying bacterial strains named NF21 and FX32 were isolated from activated sludge.Based on 16S rDNA gene sequence analysis,they were identified as Pseudomonas sp.NF21 and Bosea sp.FX32.By measuring the growth and denitrification characteristics of the cocultured strains NF21 and FX32,the effects of polybutylene succinate(PBS),polycaprolactone(PCL),and polylactic acid(PLA)as sustainedrelease solid carbon sources on the denitrification performance of the co-cultured strains were evaluated,respectively.The results showed that the PBS had good carbon release ability,of which its average release rate of COD could reach 0.98 mg·L^(-1)·h^(-1) within 60 h.The co-cultured NF21 and FX32 could utilize all the slow-release solid carbon sources(i.e.,PBS,PCL,and PLA)to degrade nitrogen in the wastewater.The removal efficiency of NO_(3)^(-)-N was the best when PBS was used as the carbon source,with the removal rate of over 85%.The mixed culture of NF21 and FX32 had a synergistic effect on NO_(3)^(-)-N removal from wastewater,and the denitrification performance was better than that of single strain.They were more suitable for removing low concentration nitrate from the wastewater when PBS was used as the slow-release solid carbon source.The optimal conditions for NO_(3)^(-)-N removal by the mixed culture were temperature 30℃,and pH 7.5 for 30 mg·L^(-1)of nitrate.