循环水养殖系统水质变化特征的中试研究

Pilot scale study on water quality variation characteristics of recirculating aquaculture system

采用循环水养殖系统进行虹鳟、鲟鱼和鲢鱼的阶梯养殖中试研究,在不更换新鲜水的情况下,系统连续运行30天,分析其中COD、NH4+-N和TP的变化特征。结果表明,在相同养殖密度情况下,养殖虹鳟鱼使循环水COD、NH4+-N和TP浓度分别增加26.6%、45.7%和37.4%,养殖鲟鱼使COD、NH4+-N和TP浓度分别增加16.0%、21.6%和14.4%,生化池对COD、NH4+-N和TP的去除率分别为39.8%、50.0%和1.9%。系统还加入了鲢鱼养殖单元和配置水生植物的沉淀池,增加了系统对污染物的去除效果。实验自第21天起向沉淀池投加壳聚糖,使循环水浊度降低了46.6%,色度降低了38.0%。经过30 d的连续运行,除TP指标外,COD和NH4+-N浓度仍满足《地表水环境质量标准》(GB3838-2002)中地表水Ⅲ类功能区用水标准。

A recirculating aquaculture system on rainbow trout,sturgeon and chub multistep aquaculture was used in the pilot scale study.Without changing fresh water,the system continuously run for 30 days,the variation characrastics of COD,NH＋4-N and TP were analyzed.The results indicated that,with the same aquaculture density,COD,NH＋4-N and TP increased by 26.6%,45.7% and 37.4%,respectively in rainbow trout aquaculture part.COD,NH＋4-N and TP increased by 16.0%,21.6% and 14.4%,respectively in sturgeon aquaculture part.The removal rates of COD,NH＋4-N and TP were 39.8%,50.0% and 1.9%,resprectively in biofilter.The chub aquaculture part and aquatic plant sedimentation basin were also added in the system,with the purpose of increasing the contaminant removal efficiency.In 21 days later,with adding chitosan in sedimentation basin,the turbidity and chroma reduced to 46.6% and 38.0%,respectively.With 30 days continuously running,both COD and NH＋4-N achieved the Ⅲ level of GB 3838-2002,excepted TP.