Effect of pressure and pH in ammonium retention for nanofiltration and reverse osmosis membranes to be used in recirculation aquaculture systems (RAS)

► This paper is about the ammonium removal using nanofiltration membranes. ► Pressure and pH were studied related to the ammonium retention coefficient. ► pHs 5 and 7 were tested which are an average of the most common range in aquaculture. ► Three nanofiltration membranes and one reverse osmosis membrane were tested. ► The ammonium retention mechanism corresponds to an electrochemical mechanism.