抽屉式生物滤器净化效果

以浸没式生物滤器为对照，研究了抽屉式生物滤器对循环养殖水的净化效果和不同氧含量对NH4-N、NO2-N、化学需氧量（COD）、异养菌、弧菌去除率的影响。结果表明：抽屉式生物滤器单位体积对NH4-N、NO2-N、COD、异养菌、弧菌的去除率均显著高于浸没式生物滤器，前者分别是后者的2.68、7.37、3.33、24.87、46.67倍；高溶氧对生物滤器NH4-N、NO2-N、COD、异养菌的去除率显著高于低溶氧条件下的去除率，高溶氧可维持养殖系统较低的NH4-N、NO2-N、COD、弧菌数量。在抽屉式循环系统预计最大养殖密度下，养鱼池水质良好，NH4-N质量浓度＜0.2 mg/L，NO2-N质量浓度＜0.4 mg/L，鱼成活率高于98%。该试验表明：抽屉式生物滤器是一种易冲洗、占地面积小、净化效率高的生物滤器；高溶氧能提高鱼类生长率、生物滤器净化率和抑制弧菌的生长。

Purify effect of drawer-type biofilter

In contrast to submerged fixed bed biofilter, purifying effect of a drawer filter used in recirculating aquaculture system and effect of oxygen content on removal rates of TAN, NO2-N, COD, heterotrophic bacteria and vibrio were studied. The results showed that removal rates of TAN, NO2-N, COD, heterotrophic bacteria and vibrio of unit volume drawer filter were significantly higher than those of submerged fixed bed biofilter, which was 2.68, 7.37, 3.33, 24.87, 46.67 times higher than that of submerged fixed bed biofilter, respectively. The removal rates of TAN, NO2-N, COD, heterotrophic bacteria of unit volume filter material in high oxygen content condition were significantly higher than those in low oxygen content condition, but the removal rates of vibrio was lower than those in the low oxygen content condition; meanwhile the contents of TAN, NO2-N, COD, vibrio bacteria in high oxygen content condition were lower than that in low oxygen content condition. The fish grew well and the concentrations of TAN, NO2-N, COD were lower in the highest breed density. The survive rate of fish exceeded 98%. So, the drawer biofilter is a kind of biofilter with easy wash, small volume, high purifying efficiency. High oxygen content can increase fish growth rate and biofilter purifying rate, and can bate vibrio growth.