This study investigated how removal rates of urea, ammonia, and nitrite in laboratory scale moving bed
biofilters were affected by long-term feed loading. To generate different loadings, five identical freshwater
flow-through systems (100 l/h) with rainbow trout (Oncorhynchus mykiss) were fed increasing fixed
rations of a commercial diet. The filtered effluent from each system was lead through a moving bed
biofilter installed end-of-pipe. After an acclimatization period of four months, the moving bed biofilters
were spiked separately with urea, ammonia and nitrite in batch mode in three successive trials
to investigate degradation kinetics