曝气-电解生态浮床的净化效果与机理分析

为强化生态浮床对重污染河道水体的净化能力,采用曝气-电解生态浮床联合技术增强生态浮床的净化功能.试验考察了电流密度、曝气量和处理时间对模拟的高氮磷重污染水体的净化潜力,分析了电解反应对填料细菌群落结构组成和浮床水生植物黄菖蒲(Iris pseudacorus)生长的影响.结果表明:在进水NH₃-N浓度为10 mg·L^-1,PO₄^3-浓度为0.8 mg·L^-1,电流密度为0.74 mA·cm^-2,水力停留时间为3 d的条件下,相比于电解生态浮床和传统的生态浮床,曝气-电解生态浮床有利于水体中NH₃-N的去除(p<0.001),其NH₃-N浓度下降至(0.92±0.24) mg·L^-1,而电解生态浮床处理的水体NH₃-N浓度为(6.85±0.17) mg·L^-1,传统生态浮床处理水体中NH₃-N浓度高达(8.09±0.40)...

Purification effects and mechanisms of aeration-electrolysis ecological floating bed

The combined aeration-electrolysis ecological floating bed (A-EEFB) was established to enhance the purification ability of ecological floating bed (EFB) for heavily polluted river water. For this purpose, we investigated the effects of current density, aeration amount, and processing time on the purification ability of A-EEFB to the water with high concentrations of nitrogen and phosphorus, and the influence of electrolysis reaction on the bacterial community structure of the substrate and floating bed plants. During the experiment, the influent concentration of NH₃-N was 10 mg·L^-1, PO₄^3--P was 0.8 mg·L^-1, hydraulic retention time (HRT) was 3 days and the current density was 0.74 mA·cm^-2. The results showed that comparing with EEFB and the traditional EFB, the A-EEFB was beneficial to the removal of NH₃-N from the water (p<0.001), as the concentration of NH₃-N decreased from 10 mg·L^-1 to (0.92±0.24) mg·L^-1 in A-EEFB, but to (6.85±0.17) mg·L^-1 and (8.09±0.40) mg·L^-1 in EEFB and EFB, respectively. Aeration promoted the transformation of NH₃-N into NO₂^--N and NO₃^--N. The electrolysis reaction was beneficial to the removal of PO₄^3--P as its concentration was reduced to (0.46±0.02) mg·L^-1 and (0.43±0.02) mg·L^-1 in A-EEFB and EEFB, respectively. The insignificant difference (p=0.265) between A-EEFB and EEFB further suggests that aeration didn''t increase the removal of PO₄^3--P. When evaluating the effect of electrolysis on the aquatic plant Iris pseudacorus, we found that aeration reduced the damage of electrolysis on I. pseudacorus, while electrolysis reaction increased the number of autotrophic denitrifying microorganisms in the substrate of EEFB.