促生剂投量对菌剂-促生剂协同修复沉积物的影响

Effects of biostimulant dosage on the remediation of sediments in the collaborative repair of aerobic denitrifiers and biostimulant

采用5个110 L的模拟河道反应器,在投加菌剂的基础上(底泥稳定后向底泥和水中分别注射浓度为0.09%和0.03%的菌剂),生物促生剂投量分别设计为0(空白对照实验)、0.08、0.09、0.10和0.11 g·L^-1,通过为期115 d的修复实验研究菌剂与促生剂协同作用时底泥微生物群落特征变化规律,进而分析其对底泥修复效果的影响.实验表明,投加促生剂后,115 d时Chloroflexi、Proteobacteria、Firmicutes、Betaproteobacteria及Bacteroidetes等主要功能菌群相对丰度增加,脲酶活性与蛋白酶活性后期时总体上低于单独投加菌剂组.促生剂投量为0.10 g·L^-1时,上覆水CODCr稳定浓度为16.82 mg·L^-1,低于其余各组;底泥TOC含量由初始的0.808%下降至第115 d时的0.687%,去除率为14.9%,显著高于其余各组;促生剂投量为0.11 g·L^-1时,底泥全氮去除率最高为14.8%.生物促生剂促使微生物群落向更适宜降解去除氮素及有机质的方向演替,有效改善底泥环境.

Five 110 L simulated river reactors were used on the basis of the addition of aerobic denitrifiers (sediment and water were injected at a concentration of 0.09% and 0.03% of the aerobic denitrifiers), and the biostimulant dosage was designed as 0 (blank control), 0.08, 0.09, 0.10 and 0.11 g·L^-1, respectively. Through a 115 d restoration experiment, the various characteristics of sediment microbial communities in the collaborative effect of biostimulant and aerobic denitrifiers were studied, and then its impact on sediment remediation was analyzed. The results show that the relative abundance of Chloroflexi, Proteobacteria, Firmicutes, Betaproteobacteria, and Bacteroidetes increased after 115 days. The activities of urease and protease were generally lower in the later period than those in the control group. The concentration of CODCr in the overlying water was 16.82 mg·L^-1 when the dosage of the biostimulant was 0.10 g·L^-1, which was lower than the other groups. The content of TOC in the sediment decreased from 0.808% to 0.687% on the 115th day, and the removal rate was 14.9%, which was significantly higher than that of the other groups. The highest total nitrogen removal rate of sediments was 14.8% when the dosage of biostimulant was 0.11 g·L^-1. Biostimulant promotes microbial communities acclimation for the removal of nitrogen and organic matter and effectively improves the sediment environment.