The effect of C/N ratio on nutrient removal by aerobic granules

Abstract

Granulirani mulj spontano je oblikovana kompaktna mikrobna biomasa nastala samoimobilizacijom mješovitih mikrobnih zajednica u matriksu izvanstaničnih polimernih tvari u stresnim uvjetima. U ovom je radu ispitan utjecaj različitih C/N omjera (4, 8 i 12) u otpadnoj vodi na učinkovitost istovremenog uklanjanja organskih sastojaka, amonijaka, ukupnog dušika i ortofosfata iz sintetske otpadne vode s natrijevim acetatom kao izvorom ugljika te s početnom vrijednosti amonijakalnog dušika 70±10 mg/L, pomoću aerobnih granula. Povećanje omjera C/N od 4 do 12 povoljno je djelovalo na učinkovitost uklanjanja svih ispitanih sastojaka. Nakon obrade, kvaliteta sintetske vode bila je zadovoljavajuća za ispust u površinske vode obzirom na KPK vrijednost i amonijakalni dušik, odnosno zadovoljavajuća za ispust u sustav javne odvodnje obzirom na ukupni dušik i ortofosfat, pri svim istraživanim omjerima C/N.Granular sludge is a compact microbial biomass spontaneously formed by self-immobilized mixed microbial communities in a matrix of extracellular polymeric substances under stressful conditions. This thesis examined the effect of different C/N ratios (4, 8 and 12) in wastewater on the efficiency of the simultaneous removal of organic compounds, ammonia, total nitrogen and orthophosphate from synthetic wastewater, with sodium acetate as a carbon source and with an initial ammoniacal nitrogen of 70±10 mg/L, by aerobic granules. The increase of the C/N ratio from 4 to 12 had a favorable effect on the removal efficiency of all tested pollutants. After treatment, the quality of the synthetic water was satisfactory for discharge into surface waters in terms of COD value and ammoniacal nitrogen, i.e. satisfactory for discharge into the public drainage system in terms of total nitrogen and orthophosphate at all investigated C/N ratios