Pilot scale study on water quality variation characteristics of recirculating aquaculture system
循环水养殖系统水质变化特征的中试研究

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.