Technology Study on Fluidized Bed Biofilter Purify cutnre Fish Recirculation Water

In order to decrease the cost and improve the fish production of per unit water.A new method of water treatment which having a good result of purification and a high loading rate need to be select.The fluidized bed biofilter technology combines the best features of both trickling filters and acti- vated sludge suspended growth system.The media materials become suspended in upflow water cur- rents through the biofilter.Fluidized bed biofilter can reduce the clogging that often occurs in submerged fixed bed biofilter.The results showed that: 1.High—rate nitrification in a fluidized bed biofilter and recirculating water fish culture system is designed for industry apple scale.The optimization parameters were advanced.The unit of fluidized bed biofilter remove water 30～50m3/hr 2.we choose the natural porosint,cheaper,facile fluldized media materials.The fluidized bed bio- filter can reduce the clogging and channelization problem which often occur in fix bed biofilter.Compared with fix bed bioflter at same conditions,the nitrification and hydraulic loading rate of fluidized bed bio- filter is as three times as which of fix bed biofilter. 3.The closed recirculating water fish culture system using fluidized bed biofilter improve treatment and cut costs.The capital investment required to construct a fluidized bed biofilter is under half that nee- ded for the extensions to coventlonal biofilter.Maximum carps fish load is 25±2Kg/m~3 in closed recircu- lating water fish culture system,saving water 85%～90%.Fluidized bed biofilter influent total ammonia N1.3mg/l,nitrite N0.068mg/l and fluidized bed biofilter effluent total ammonia N0.2mg/l,ni- trite N0.024mg/l to satisfy water quality for fisheries.Total ammonia N removal rate is 80%～95%, nitrite N removal rate is over 65%.