Effect of carbon-to-nitrogen ratio on high-rate nitrate removal in an upflow sludge blanket reactor for polluted raw water pre-treatment application

Abstract The drinking water treatment plants (DWTPs) in the developing countries urgently need an efficient pre-treatment for nitrate (NO 3 − ) removal to cope with increasing NO pollution raw water. An upflow sludge blanket (USB) reactor applied from domestic wastewater may be adopted by DWTPs. However, studies on optimal carbon-to-nitrogen ratio (C/N) and operation of USB at short hydraulic retention times (HRT) high-rate polluted are lacking. In this study, we first investigated C/N biological a sequencing batch (SBR). was then operated pre-treating synthetic contaminated (40 mg N L 1 monitor performance examine opportunities reducing HRT. After operating SBR designed 4, 2 g C N, selected as due lower carbon breakthrough nitrite accumulation SBR. achieved complete longer time when compared that (10 d). high specific denitrification rate (18.7 ± 3.6 mixed liquor volatile suspended solids h suggested possible HRT reduction 36 min. We successfully demonstrated removal, which could promising technology DWTPs pre-treat sources .