Abstract:
Tri-stage biofilm processing was used to treat aquaculture recirculating water.The removal performance and mechanism of major contaminants in the water were investigated.Under proper operating conditions (pH=7.5-8.5,T=28-32 ℃,ρ(DO)=0.5-1.0 mg/L and ρ(FA)=5-10 mg/L),the removal efficiencies of COD
Cr,NH
4+-N and TN were 94.4%,91.6% and 70.1% respectively,and the average of ρ(NO
2--N) in the effluent was less than 5.2 mg/L.This indicates that tri-stage biofilm processing can be applicable for the biotreatment of aquaculture recirculating water with low ratio of ρ(C)/ρ(N),to satisfy the standard of recycled water for fishing and eliminate the potential threat of NO
2--N to aquaculture animals.