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 aquaculture. Biodegradable polymer pellets are acting as solid substrate and biofilm carrier for denitrification. Laboratory experiments with conventional aquaria and fish were used to examine the feasibility and a first evaluation of the process performance in a recirculated aquaculture system. All over the test-period the fish were in a good condition. Nitrate concentrations in the aquaria with treatment were low compared to the untreated reference system. A further advantage was the stability of the pH in the units with denitrification whereas pH of the untreated water decreased due to nitrification.