BBFR-IVCW工艺对微污染水体的脱氮效果

以BBFR(biomass bio-film reactor, 生物质生物膜反应器)和IVCW(integrated vertical-flow constructed wetland,复合垂直流人工湿地)构成小试系统,由改性水草塘、生态塘和IVCW构建中试系统,对高碳低氮水的脱氮效果及其影响因素进行了研究. 结果表明,小试系统中CW2(2#湿地)出水ρ(TN)低于CW1(1#湿地)；中试系统对TN的去除率为52.49%,出水达到GB 3838—2002《地表水环境质量标准》Ⅳ级标准. C/N〔ρ(COD_Cr)/ρ(TN)〕对BBFR中TN去除率的影响较大,但对NO₃--N去除率的影响并不明显. 从经济成本和反硝化效果来看,小试系统最优C/N为4.9,中试系统最优C/N为4.8. C/N为2.8时,CW1对NO₃--N的去除率为71.88%±15.70％,与C/N>2.8时相比,差异显著(F₃,6=21,P<0.05)；C/N为4.1时,CW2对NO₃--N的去除率为92.83%±11.26％,与其他C/N下NO₃--N去除率的差异显著(F₃,6=4.34,P<0.05). 小试系统中BBFR对COD_Cr的去除贡献率高于TN,但各单元作为一个有机整体优势互补,共同保证系统出水水质. 

Study of Nitrogen Removal from Lightly Polluted Water Treated with BBFR-IVCW Process

Following social and economic development and population growth, water pollution is getting more severe and becoming a worldwide problem. Currently, there are many techniques for the removal of nitrate pollution from water bodies; however, large-scale engineering applications are still at the preliminary stages. The biomass bio-film reactor (BBFR) and the integrated vertical-flow constructed wetland (IVCW) were combined in a small experiment to treat high nitrogen-low carbon lightly polluted surface water. A pilot system was proposed, and its performance was investigated. The results of the small experiment showed that the mean effluent TN concentration of CW2 (#2 wetland system), which met the Class Ⅳ surface water environmental quality standards, was lower than that of CW1. The average TN removal of the pilot experiment reached 52.49%. The ration of C/N greatly influenced the TN removal of the BBFR system, but did not obviously influence the removal of nitrate. Considering the economic cost of additional carbon and the system denitrification effect, the optimal C/N ratio in this experiment was 4.9, though the C/N of the pilot experiment was 4.8. The CW1 achieved its highest NO₃--N removal rate (71.88%±15.70%) under the condition of C/N=2.8, which was significantly different from the removal rates when C/N>2.8 (F3,6=21, P<0.05). For C/N=4.1, the NO₃--N removal rate of CW2 was 92.83%±11.26%, which was significantly different than results with other C/N ratios (F3,6=4.34, P<0.05). In the small experiment, BBFR had a higher contribution to the combined system in terms of removing COD_Cr as compared to TN. The removal of TN in the pilot experiment showed that each unit which had an integrated system had complementary advantages, maintaining the effluent quality.