NITRITE ACCUMULATION IN SUBMERGED BIOFILTERS - COMBINED EFFECTS

The combined effect of temperature, pH and ammmonium concentration ove r the nitrite accumulation phenomena in situations of free ammonia inh ibition, their effect over the ammonia and nitrite oxidizer microorgan iisms influence over the nitrification, have been studied in an Up-flo w Biological Aerated Filter (UBAF). The free ammonia inhibition effect highly depends on the values of pH, temperature and ammonium concentr ation. For the same specific free ammonia concentration different valu es of temperature, pH and ammonium concentration bring about different nitrite accumulations. In conditions of no free ammonia inhibition an d low values of temperature and pH, high ammonium concentrations bring about a higher relative activity of ammonia oxidizer microorganisms o f the filter increases the nitratation efficiency in zones close to th e outlet and will favour the nitrite accumulation in situations of fre e ammonia inhibition. Copyright (C) 1996 IAWQ. Published by Elsevier S cience Ltd.