盐胁迫对间歇增氧垂直流人工湿地脱氮性能及微生物群落影响

利用新型间歇增氧垂直流人工湿地,揭示了不同进水N H4+-N浓度下盐度提升对湿地脱氮性能及微生物群落的影响.试验结果表明:间歇增氧垂直流人工湿地在盐胁迫下的脱氮性能明显优于传统垂直流人工湿地,高盐(2.0％ 盐度)对TN去除性能影响较大,对COD去除性能影响相对较小.进水NH4+-N浓度为40 mg/L时,当盐度由0％...

Effects of Salinity on Nitrogen Removal Performance and Microbial Community of Intermittent Aeration Vertical Flow Constructed Wetland

The effect of salinity on nitrogen removal performance and microbial community of a novel patent intermittent aeration vertical flow constructed wetland(IA-VFCW)was investigated under different influent NH⁺₄-N concentrations.The results revealed that the nitrogen removal performance of IA-VFCW was obviously excellent than that of traditional vertical flow constructed wetland at different salinities.High salinity(2.0%)had a great influence on the TN removal efficiency,at the same time the impact on the COD removal efficiency was relatively unobvious.During the salinity was increased from 0%to 2.0%,the effluent NH⁺₄-N concentration was increased from 3.88 mg/L to 12.44 mg/L as the influent NH⁺₄-N concentration was 40 mg/L,and the NH⁺₄-N removal efficiency was sharply decreased from 90.3%to 68.9%,at the same time there was no NO-2-N accumulation and the effluent NO-2-N concentration was slightly fluctuated.The effluent TN concentration was increased from 10.28 mg/L to 17.40 mg/L,and the TN removal efficiency was gradually decreased from 74.3%to 56.5%.The effluent COD concentration was strongly stable with the increase of salinity to 1.0%.Furthermore,the effluent COD concentration was increased to 37.0 mg/L when the salinity further increased to 2.0%.Meanwhile,the COD removal efficiency was decreased from 89.5%to 81.5%.The microbial richness in IA-VFCW was the highest at 0.5%salinity.In addition,the microbial richness in the bottom of aeration area under different salinities was higher than that in the area of aquatic plants.As the microorganisms were gradually adapted to salt stress,the microbial diversity was closely restored to initial level in salt-free condition.The microbial distribution and diversity in IA-VFCW could be significantly affected by salinity.The abundance of Nitrosomonas and Nitrospiraceae was individually decreased from 2.5%to 0.5%and 1.7%to 0.3%with the increase of salinity,respectively.However,the abundance of Thiobacillus and Denitratisoma belonging to denitrification microorganism was kept at 11.6%and 5.4%,respectively,and remained relatively stable,indicating that they had better tolerance to salt stress.The research could reveal the effect of salinity on nitrogen removal performance and provide a guidance for practical engineering applications of IA-VFCW.