Biodegradable polymers as solid substrate and biofilm carrier for denitrification in recirculated aquaculture systems

A simple process for nitrate removal is proposed for its application in aqu aculture. Biodegradable polymer pellets are acting as solid substrate and b iofilm carrier for denitrification. Laboratory experiments with conventiona l aquaria and fish were used to examine the feasibility and a first evaluat ion of the process performance in a recirculated aquaculture system. All ov er the test-period the fish were in a good condition. Nitrate concentration s in the aquaria with treatment were low compared to the untreated referenc e system. A further advantage was the stability of the pH in the units with denitrification whereas pH of the untreated water decreased due to nitrifi cation. (C) 2000 Elsevier Science B.V. All rights reserved.