池塘循环流水养殖模式集污系统效能分析

The effect analysis of sewage collection system in pond circulating water culture model

为研究池塘循环流水养殖模式集污系统的效能,以草鱼为养殖对象开展试验,分析比较了沉淀池、养殖池上游及水源等处的总氮(TN)、总磷(TP)、悬浮物(SS)、高锰酸盐指数(COD_(Mn))、氨氮(NH_(4)^(+)-N)、亚硝酸盐氮(NO_(2)^(-)-N)、硝酸盐氮(NO_(3)^(-)-N)、溶解氧(DO)和酸碱度(pH)等水质指标。结果显示:集污系统可通过吸取和沉淀将鱼类排泄物分离出池塘,养殖水体中TN和TP的去除率分别为5.69%和63.42%。沉淀池的TP、SS、COD_(Mn)含量高于养殖池上游的,最高时分别高出221.85%、241.67%、102.18%。养殖池上游的TN、NH_(4)^(+)-N含量与沉淀池没有明显差异,但NO_(2)^(-)-N和NO_(3)^(-)-N含量频繁高于沉淀池。水源、养殖池上游、沉淀池水体中的SS、pH、COD_(Mn)、TP、TN、NO_(3)^(-)-N有显著差异(P<0.05),DO、NH_(4)^(+)-N和NO_(2)^(-)-N无显著差异(P>0.05)。水源的SS、COD_(Mn)、TN、TP显著低于养殖池上游的(P<0.05),二者的pH和NO_(3)^(-)-N无显著性差异(P>0.05)。水源SS、COD_(Mn)、TN、TP极显著低于沉淀池,而NO_(3)^(-)-N极显著高于沉淀池(P<0.01)。沉淀池的SS显著高于养殖池上游,pH和NO_(3)^(-)-N则显著低于养殖池上游(P<0.05)。沉淀池DO均值最低,为(5.16±3.44)mg/L,但与其他两处样本无显著性差异(P>0.05),NO_(3)^(-)-N则极显著低于其他两处(P<0.01)。总体而言,集污系统在污染物降解和水质调控方面能发挥较有效的作用,但基于水质净化体量较大的现实,今后研究的重点应是进一步提高系统对COD_(Mn)、NH_(4)^(+)-N、TP的降解效率。

A culture experiment was carried out to study the effect of sewage collection system in pond circulating water culture model.The results showed that the sewage collection system could separate the mixture of fish excreta and aquaculture water by precipitation and the removal proportion of TN and TP in aquaculture water was 5.69%and 63.42%,respectively.According to the annual variation trend and the comparison results between the upstream and the sedimentation tank in the three groups of samples,TP,SS and COD_(Mn) contents in upstream were 221.85%,241.67%and 102.18%higher than the sedimentation tank,respectively.The contents of TN and NH_(4)^(+)-N in the upstream of the pond showed little difference when compared with those indices in the sedimentation tank,and the contents of NO_(2)^(-)-N and NO_(3)^(-)-N were higher than those in the sedimentation tank.The contents of SS,COD_(Mn),TN and TP in the water source were significantly lower than those in the upstream of the aquaculture pond.SS,COD_(Mn),NH_(4)^(+)-N and TP contents in water source were significantly lower than those of sedimentation tank,while NO_(3)^(-)-N were significantly higher than those of sedimentation tank.The content of SS in sedimentation tank was significantly higher than that of the upstream of aquaculture pond,while the pH and NO_(3)^(-)-N level were significantly lower than that of the upstream of aquaculture pond.There was no significant difference between sedimentation tank among three groups,but the mean value of DO[(5.16±3.44)mg/L]in the three groups was the lowest.At the same time,NO_(3)^(-)-N in sedimentation tank was significantly lower than the other two groups.In general,the sewage collection system plays a positive and effective role in the degradation of pollutants and the control of water quality.However,based on the reality that the volume of water purification is large,it is necessary to further improve the technical breakthrough of the degradation efficiency of COD_(Mn),NH_(4)^(+)-N and TP as the key direction of future research.