循环水养殖系统中浸没式生物滤器的水处理效果

Study on the water treatment efficiency of submerged biological filter in the recirculating aquaculture system

生物过滤技术是循环水超高密度工厂化养殖系统维持生产正常进行的核心技术。运转良好的生物过滤装置都有很好的硝化效果,但不同工况参数会影响生物滤器的硝化效率。已有的相关生物滤器报道均是实验室试验结果,缺乏直接以生产系统为对象的研究。本试验对浮球式生物滤器在不同工况下的水处理效率进行比较,结果发现:(1)无曝气条件下,NH4-N转化率在HRT为18 min时最大为28.77%;NO2-N转化率随着水力停留时间增加而增加,在HRT为36 min工况时达到最大,为67.20%;COD去除率在HRT为36 min时最高,达到6.56%;另外,不曝气各工况下出水溶氧和pH都有较明显下降。(2)曝气量为1 m3/h条件下,滤器水处理效率随HRT延长而增加;NH4-N转化率和NO2-N转化率分别由HRT为9 min时的7.54%和49.30%增加到HRT为36 min时的39.03%和71.78%;COD去除率在HRT为36 min时最高,为6.16%;曝气量为1 m3/h各工况下出水溶氧和pH略有增加。(3)曝气量为2 m3/h条件下,滤器水处理效率也随HRT延长而增加;NH4-N转化率和NO2-N转化率在HRT为36 min时达到最高,分别为27.27%和74.92%;COD去除率在HRT为9 min时最高,为5.30%;曝气量为2 m3/h各工况下出水溶氧和pH也都略有增加。(4)对无曝气和有曝气各工况进行比较,结果显示有曝气组各工况水处理效率优于无曝气组,曝气水平为1 m3/h时处理效率最好。

Biological filtering is the core technology in maintaining the regular running of the high density of factory aquaculture. The proper running filter will be effective in nitrification, which will be affected by different working parameters. Although there are some reports on biological filtering, all lack the research on the practical system directly. In this paper, the water treatment rates of submerged biological filter under different conditions are compared. The results indicated that ： （ 1 ） Without aeration, the best removal rate of NH4-N is 28.77% when the HRT is 18min. The removal rates of NO2-N is increased with the decreased water flow rates, which reach the top efficiency, 67.20%, at the condition with 36 min HRT; The COD removal rate reaches the top at the condition with 36 min HRT, which is 6.65%. Additionally, the DO and pH of outlet water from the submerged biological filter at the conditions without aeration are lower obviously. （2） Under the conditions with aeration of 1 m^3/h, the water treatment efficiency also increased with the reducing of the water influent. The removal rates of NH4-N and NO2-N are increased respectively from 7.54% and 49.30% at 9min HRT to 39.03% and 71.78% at 36 min HRT. The best removal rate of COD reaches 6.16% when the HRT is 36 min. And under these conditions, the DO and pH of outlet water have somewhat increased. （3） Under the conditions with aeration of 2 m^3/h, the water treatment efficiency also increased with the decreased water flow rates. The best removal rate of NH4-N and NOz-N are 27.27% and 74.92% respectively which achieved at 36 min HRT. The removal rate of COD reaches the top when the HRT is 9min, which is 5.30% , and the DO and pH of outlet water also have some increase at these conditions with 2 m^3/h aeration. （4） The results of comparison of the conditions without aeration to the conditions with aeration indicate that the water treatment efficiency under conditions with aeration is superior to that without aeration, and the treatment efficiency which achieved with 1 m^3/h is relatively better than others.