水耕植物过滤法对溶解性氮磷去除的影响因子

Factors affecting dissolved nitrogen and phosphorus by hydroponic bio-filter method

为改善水耕植物过滤法(HBFM)对溶解性氮、磷的去除效果,通过室内模拟试验定量分析HBFM试验床中植物吸收、底泥释放及生物脱氮3个影响因子的作用.试验结果表明:底泥NH4+-N释放速率滤床上游高出中游及下游的1.6～3倍;水相的高溶解氧条件抑制了底泥释放PO43--P;试验床中植物平均氮吸收量、底泥平均氮释放量和微生物平均脱氮量分别为352.9,492.8和153.1 mg/(m2·d),植物吸收与微生物脱氮量之和近似等于底泥氮释放量.因此合理控制底泥清除周期减少底泥释放量,是提高HBFM溶解性氮、磷去除能力的重要途径之一.

The roles of plant absorption, sediment release and denitrification were quantitatively analyzed by indoor simulating tests in order to improve removal effect of hydroponic bio-filter method （HBFM） for dissolved nitrogen and phosphorus. According to the test results, the NH4^＋-N release from sediment mainly occurs in upper past, and its release rate is 1.6 to 3 times higher than that in middle and lower past. The release rate of PO4^3- -P by sediment is small because of the high level of dissolved oxygen in filter bed water phase. The average absorption rate of nitrogen by plants, nitro- gen release rate from sediment and denitrification rate are 352.9,492.8 and 153. 1 mg/（ m2 ·d） respectively. The sum of nitrogen removed by denitrification and plant assimilation is approximately equal to the amount released by sediment. Reducing the nutrient quantity released by sediment through manipulating the period for digging up sediment is necessary to enhance removal ability of HBFM for dissolved nitrogen and phosphorus.