C/N值对异养硝化同步脱氮系统效能的影响

Effect of C /N Ratio on Efficiency of Simultaneous Nitrogen Removal System Based on Heterotrophic Nitrification in Pressure Biofilm Reactor

针对现有自养硝化过程效能低的问题,以高盐高氮高有机物浓度榨菜废水为研究对象,考察了C/N值对基于异养硝化的压力生物膜反应器同步脱氮系统效能的影响。采用16S rDNA与PCR-DGGE技术探讨了C/N值对系统微生物种群的影响。结果表明:对COD为8 960 mg/L、NH+4-N为175 mg/L、TN为185 mg/L的高盐废水,C/N值对系统的脱氮效能影响显著,在盐度为3%(以NaCl计)、温度为(35±0.5)℃、C/N值为50、有机负荷为23.04 kgCOD/(m3·d)、氮负荷为0.48 kgN/(m3·d)时,对COD、NH+4-N、TN的去除率分别为97.87%、98.93%、98.18%。在高负荷条件下,反应器中氮和有机物呈现同步降解的规律,表明系统中的硝化过程为异养硝化。同时,C/N值对系统微生物的群落结构有影响,C/N值过高或过低时微生物种群丰富度和多样性指数值均有所降低;但不同C/N值条件下的微生物种群有较高的相似性。

To address the low efficiency of autotrophic nitrification process, the effect of C/N ratio on the efficiency of simultaneous nitrogen removal system based on heterotrophic nitrification in pressure biofilm reactor was investigated using mustard tuber wastewater with high salinity, high nitrogen and high concentration of organic matter. 16S rDNA sequencing and PCR-DGGE were used to study the effect of C/N ratio on microbial community structure. The results showed that the C/N ratio affected the removal efficiency of nitrogen significantly when the influent concentrations of COD, NH4＋ - N and TN were 8 960 mg/L, 175 mg/L and 185 mg/L respectively. Under the conditions of 3% of salinity （calculated as NaC1） , （35±0.5 ） ℃ , 50 of C/N ratio , 23.04 kgCOD/（ m3·d） of organic loading and 0.48 kgN/ （ m3·d） of nitrogen loading, the removal rates of COD, NH4 - N and TN were 97.87% , 98.93% and 98.18% respectively. Under the condition of high loading, nitrogen and organic matter presented the rule of synchronous degradation, showing that nitrification process was heterotrophic nitrification. At the same time, the C/N ratio affected the microbial community structure, and microbial richness and diversity in- dex decreased when C/N ratio was too high or low. Under the condition of different C/N ratios, microbialpopulations showed a high similarity.