循环水养殖系统中流化床生物滤器净水效果影响因素

Influencing factors of purifying effluent of recirculating aquaculture system by fluidized-sand biofilter

为优化流化床生物滤器的工作性能，采用新型填料玻璃珠作为滤器的基质，并将其应用于罗非鱼循环水养殖系统，研究了玻璃珠粒径、床层膨胀率、碱度和氨氮负荷4个可控因素对其处理养殖废水效果的影响。结果表明，流化床生物滤器挂膜23d后生物膜成熟稳定，当床层膨胀率低于160％时，床层增高和填料流失现象不明显。选用0．2～0．4mm粒径的玻璃珠为填料时，对TAN和NO2--N的去除率显著高于以0．4～0．6mm玻璃珠为填料的滤器；随着床层膨胀率的提高，滤器对TAN和NO2--N的去除率逐渐下降，但对TAN的去除负荷有一定的提高；碱度和TAN负荷的增加有利于滤器的硝化作用。流化床生物滤器对养殖水体中的TAN的平均去除负荷和NO2--N的去除率分别可以达到（673．11±23．26）g／（m3·d）和（90．24±3．45）％，显示出较好的硝化性能。

In order to optimize the performance of fluidized-sand biofiher, it was applied to the Tilapia re- circulating aquaculture systems, which used micro glass bead as media. The effects of four controllable impact factors, such as size of micro glass bead, sand bed expansion ratio, alkalinity and TAN pollution load on the per- formance of purifying effluent were discussed. The results showed that the biofilm of fluidized-sand biofilter be- came mature after 23 days＇cultivation. The sand bed growth and micro glass bead loss were not obvious under the condition of sand bed expansion ratio lower than 160%. When choosing micro glass bead with a range of 0.2 to 0.4 mm diameter as packing, the removal rates of TAN and NO2--N were significantly higher than 0.4 to 0.6 mm diameter. Alone with the sand bed expansion rising, the removal rates of TAN and NO2- -N were gradu- ally declined with biofiher, but the TAN removal load was improved. Increasing alkalinity and TAN load were beneficial to the nitrification. The average TAN removal load and removal rate of NO2- -N of aquaculture effluent could be achieved to （673.11 ±23.26） g/（ m3 . d） and （90.24 ± 3.45） % , respectively, which showed a good nitrification performance through fluidized-sand biofiher.