不同水力负荷下凤眼莲去除氮、磷效果比较

Effect of Eichhornia crassipes on Removing Nitrogen and Phosphorus From Eutrophicated Water as Affected by Hydraulic Loading

采用人工模拟方法,研究了不同水力负荷(0.14、0.20、0.33和1.00m3.m-2.d-1)对凤眼莲去除富营养化水体氮、磷效果的影响,试验期间进水TN、NH4+-N、NO3-N、TP平均质量浓度分别为4.85、1.33、2.92和0.50mg.L-1。结果表明,凤眼莲净化系统对富营养化水体具有较好的去除效果,低水力负荷(0.14、0.20m3.m-2.d-1)下,出水TN、NH4+-N和TP均达到了GB3838—2002《地表水环境质量标准》的Ⅳ类水质标准;当水力负荷提高到1.00m3.m-2.d-1后,出水TN、NH4+-N、NO3-N和TP质量浓度明显上升。4种水力负荷下,凤眼莲净化系统对TN和TP去除率分别为84.95%和80.65%、73.87%和73.04%、51.60%和64.05%、30.77%和47.79%,即随水力负荷的提高而降低;相应的TN、TP去除负荷分别为0.58和0.06、0.72和0.07、0.83和0.11、1.47和0.23g.m-2.d-1,即随水力负荷的提高而增加。综合考虑净化效果和污水处理能力,本试验条件下凤眼莲系统的水力负荷宜控制在0.33m3.m-2.d-1。

A simulation experiment was carried out to study effect of Eichhornia crassipes on removing nitrogen and phosphorus from eutrophicated water as affected by hydraulic loading （0. 14, 0. 20, 0. 33, 1.00 m^3 · m^-2 · d^-1 ）. The average concentrations of total nitrogen （TN）, ammonia-nitrogen （NH4^＋-N）, nitrate-nitrogen （NO3^--N） and total phosphorus in the influent were 4.85, 1.33, 2. 92 and 0. 50 mg · L^-1, respectively during the experiment. Results of the experiment show that the effect of the Eichhornia crassipes purifying system was satisfactory. When the hydraulic loading was low （0. 14 and 0. 20 m^3 · m^-2 · d^-1 ） , the average concentrations of TN, NH4^＋-N and TP in the effluent all met the national standard for surface water body quality 1V （GB 3838-2002）. But when the hydraulic loading was raised to 1.00 m^3 · m^-2 · d^-1, the average concentrations of TN, NH4^＋-N, NO3^--N and TP in the effluent increased significantly. Although the removal rates of TN and TP decreased, the load removal rates of TN and TP increased with the increasing hydraulic loading for the Eichhornia crassipes purifying system. For the four hydraulic loadings （0. 14, 0. 20, 0. 33 and 1.00 m^3 · m^-2·d^-1 ） , the average removal rates of TN and TP by the system were 84. 95% and 80. 65% , 73.87% and 73.04%, 51.60% and 64. 05%, 30. 77% and 47.79% , respectively, that is, decreasing with rising of hydraulic loading, and the corresponding for TN and TP loading removal was 0. 58 and 0. 06, 0. 72 and 0. 07, 0. 83 and 0. 11, 1.47 and 0. 23 g · m^-2·d^-1 , respectively, that is, increasing with rising of hydraulic loading. Comprehensively considering removal efficiency and wastewater treatment capacity, the hydraulic loading should be controlled at 0. 33 m^3 · m^-2 · d^-1 for the Eichhornia crassipes purifying system in conditions like this experiment.