河流疏浚底泥余水的固定化微生物处理技术

Immobilized microorganism technology for treatment of residual water from river dredged sediment

河道疏浚底泥在工业化处理过程中会产生大量余水,其含有较高浓度的氨氮、总氮、化学需氧量(CODCr)以及重金属等有害物质,如不对其进行有效处理,将会对受纳水体造成严重污染。采用固定化微生物技术,设计了处理量50 t/d的多级接触氧化装置,对疏浚底泥余水进行处理。结果表明,该工艺对氨氮和总氮的去除率可分别达到91.21%和59.00%,出水可满足地表水准Ⅳ类标准。基于分子生物学方法研究了多级接触氧化装置中功能微生物的丰度和群落多样性,结果表明反硝化功能基因narG、napA、nirS、cnorB、nosZ的丰度在前3级反应池中占主导地位,充分保障了系统的反硝化功能,该结果通过16S rRNA群落结果分析以及PICRUSt功能预测得到了进一步证实。定量PCR和群落结构分析表明氨氧化细菌(AOB)和完全氨氧化菌(CAOB)可能是系统中的主要氨氧化微生物。AOB主要来源于N. oligotropha分支,亚硝酸盐氧化细菌(NOB)主要来源于Nitrospira lineage Ⅰ,两者均在好氧池中得到了富集。因此,固定化微生物技术可实现对硝化细菌和反硝化细菌的富集,增强系统的抗冲击负荷能力,对疏浚底泥余水处理具有重要的参考意义。

Industrial treating river dredged sediment produces a large amount of residual water,which contains relatively high concentrations of contaminants like ammonia nitrogen,total nitrogen,chemical oxygen demand(CODCr),heavy metals,etc.If the residual water is not treated effectively,it will cause serious pollution to the receiving water body.A multistage contact oxidation equipment with a capacity of 50 t/d was designed based on immobilized microorganism technology to treat the residual water.The results showed that the process could efficiently remove ammonia nitrogen and total nitrogen from the residual water with the removal rates of 91.21%and 59.00%respectively,and the effluent could meet the quasi-classⅣof surface water standards.Based on molecular biological methods,the abundance and community diversity of functional microorganisms in the multistage contact oxidation equipment were studied.The results showed that the abundance of denitrification functional genes narG,napA,nirS,cnorB and nosZ dominanted in the first three stages,which fully ensured the denitrification function of the system.This result was further confirmed by 16S rRNA community analysis and PICRUSt function prediction.Quantitative PCR and community structure analysis showed that ammonia oxidizing bacteria(AOB)and complete ammonia oxidizing bacteria(CAOB)were the main ammonia oxidizing microorganisms in the system.AOB was mainly affiliated with N.oligotropha branch,and nitrite oxidizing bacteria(NOB)was mainly affiliated with Nitrospira lineage I,both of which were enriched in the aerobic stages. The current results suggested that the immobilized microorganism technology fa cilitated the enrichment of nitrifying and denitrifying bacteria and enhanced the resistance of impact load on the sys tem,which was of great reference significance for the treatment of dredged sediment residual water.