循环水养殖系统中流化床水处理性能及硝化动力学分析

为综合评价流化床生物滤器的水处理性能,选用玻璃珠和石英砂为生物填料,将两滤器应用于罗非鱼循环水养殖系统,探讨了其对养殖水体中营养盐和有机物的去除效果.结果表明,两滤器经过4周的流水挂膜后,生物膜稳定成熟,通过扫描电镜观察填料表面,发现挂膜前后载体表面发生了显著的变化.在优化工况下,以玻璃珠为填料的滤器对TAN的平均去除负荷达到了(346.8±150.5)g/(m3·d),显著高于以石英砂为填料的滤器,但两滤器对COD、BOD5和PO43--P的去除率无显著差别,去除率稳定于20%~21.4%、50.1%~58.4%和7.9%~31.9%之间,显示出较好的水处理性能,出水水质符合罗非鱼生长要求.最后,基于Monod方程,拟合了实际工况下以玻璃珠为填料流化床生物滤器的硝化动力学方程,为该滤器在循环水养殖系统中的高效运行和应用提供一定的技术支撑.

Performance of purifying effluent and nitrification kinetics of fluidized-sand biofilter in recirculating aquaculture system

In order to evaluate the performance of purifying effluent of fluidized-sand biofilter, two filters were applied to the Tilapia recirculating aquaculture systems, which were used micro glass bead and quartz sand as media. The removal effect of nutrient and organic in aquaculture water through fluidized-sand biofilter was discussed. The results showed that the biofilm of these two biofilters had matured after four weeks' cultivation using effluent. There were significant changes of the stuffing surface before and after the biofilm culturing, which was observed by scanning electron microscope. Under optimizing conditions, the average TAN removal load reached (346.8±150.5) g/m3·d with micro glass bead as the biofilter's media, which was significant higher than quartz sand as biofilter. But there was no significant difference in the removal rate of COD, BOD5 and phosphate between these two biofilters, and the removal rates were 20%~21.4 %, 50.1%~58.4 % and 7.9%~31.9%, respectively, which showed a better performance of effluent treatment. And the effluent water quality conformed to the requirements of the growth of tilapia. Finally, based on Monod equation, the nitrification dynamics equation of fluidized-sand biofilter with micro glass bead as media in actual working state was fitted according to the measured value by regression method, which could provide some technical support for the efficient running and application in recirculating aquaculture systems with this biofilter.