生物过滤和蔬菜浮床组合系统对温室甲鱼废水的处理效果

Treatment effect of biological filtration and vegetable floating-bed combined system on greenhouse turtle breeding wastewater

高浓度温室甲鱼养殖业废水的无序排放已严重危害了我国长三角地区农村生态环境.生物过滤和蔬菜浮床组合系统是温室甲鱼养殖废水生态化处理的潜在方式.为了探索生物过滤和蔬菜浮床组合系统处理温室甲鱼养殖废水的可行性,以及植物直接吸收同化作用对组合系统N、P去除的贡献率,本文选择空心菜、生菜和芹菜等3种蔬菜植物,开展了生物过滤和蔬菜浮床组合系统对温室甲鱼养殖废水的处理试验.结果表明:生物过滤与蔬菜浮床组合系统对废水化学需氧量(COD)、铵氮(NH4+-N)、总氮(TN)和总磷(TP)的去除率分别可达93.2%~95.6%、97.2%~99.6%、73.9%~93.1%和74.9%~90.0%.组合系统均表现出良好的碳氮磷同步脱除性能,空心菜系统对废水N、P的去除效能明显优于生菜和芹菜系统.蔬菜直接吸收作用并不是组合系统N、P去除的最主要途径,其贡献率仅为9.1%~25.0%,推测N、P主要依靠微生物作用去除.相对而言,空心菜对废水N、P的直接吸收贡献率最高,而蔬菜对N、P的直接吸收与植物生物量密切相关.研究结果显示,生物过滤和蔬菜浮床组合系统可以作为温室甲鱼养殖废水生态化处理的有效方式.

Unorganized discharge of greenhouse turtle breeding wastewater has brought several nega- tive influences on the ecological environment in the rural area of Yangtze River Delta. Biological fil- tration and vegetable floating-bed combined system is a potential ecological method for greenhouse turtle breeding wastewater treatment. In order to explore the feasibility of this system and evaluate the contribution of vegetable uptake of nitrogen （N） and phosphorus （P） in treating greenhouse turtle breeding wastewater, three types of vegetables, including Ipomoea aquatica, lettuce and celery were selected in this study. Results showed the combined system had a high capacity in simultaneous removal of organic matter, N and P. The removal efficiencies of COD, NH4 ^-N, TN and TP from the wastewater reached up to 93.2% -95.6%, 97.2% -99.6%, 73.9% -93.1% and 74.9% -90.0% , respectively. System with L aquatica had the highest efficiencies in N and P removal, followed by lettuce and celery. However, plant uptake was not the primary pathway for TN and TP removal in the combined system. The vegetable uptake of N and P accounted for only 9.1% -25.0% of TN and TP removal from the wastewater while the effect of microorganisms would be dominant for N and P removal. In addition, the highest amounts of N and P uptake in I. aquati- ca were closely related with the biomass of plant. Results from the study indicated that the biologicalfiltration and vegetable floating-bed combined system was an effective approach to treating green- house turtle breeding wastewater in China.