an airlift-type activated sludge reactor using a sponge support medium was fed with wastewater containing 500 mg-n/l of nh4 +-n. in order to establish partial nitrification, the reactor was kept at 35°c. moreover, the reactor was started up with the nahco3 solution as an alkali agent to supply inorganic carbon for enhancement of partial nitrification. the partial nitrification was established d...

Partial nitrification was reported to be technically feasible and economically favorable, especially for wastewaterwith high ammonium concentration or low C/N ratio. In this study, the effect of dissolved oxygen (DO)and influent ratio of chemical oxygen demand to nitrogen (COD/N) ratio on biological nitrogen removal fromsynthetic wastewater was investigated. Experiments were c...

The goal of this study was to compare the microbial ecology, gene expression, biokinetics, and N2O emissions from a lab-scale bioreactor operated sequentially in full-nitrification and partial-nitrification modes. Based on sequencing of 16S rRNA and ammonia monooxygenase subunit A (amoA) genes, ammonia oxidizing bacteria (AOB) populations during full- and partial-nitrification modes were distin...

Surficial oxygen transfer plays an important role, when analyzing the complex biochemical and physical processes responsible for ammonia and dinitrogen gas emission in animal waste treatment lagoons. This paper analyzes if currently known nitrogen biochemical pathways can explain the enigmatic dinitrogen gas emissions recently observed from the treatment lagoons, based on the amount of wind-dri...

Simultaneous partial nitrification, anammox and denitrification (SNAD) process was developed in a sequential batch reactor (SBR) and the influence of hydraulic retention time (HRT) on the SNAD process was investigated. Around 96% NH(4)(+)-N removal and 87% COD removal were observed at 9 d HRT. Marginal decreases in the removal efficiencies were observed when the HRT was reduced to 3d or the loa...

Partial nitrification (ammonium oxidation to nitrite) has gained a lot of interest among researchers in the last years because of its advantages with respect to complete nitrification (ammonium oxidation to nitrate): decrease of oxygen requirements for nitrification, reduction of COD demand and CO(2) emissions during denitrification and higher denitrification rate and lower biomass production d...

Biological nitrogen removal (BNR) based on partial nitrification and denitrification via nitrite is a cost-effective alternate to conventional nitrification and denitrification (via nitrate). The goal of this study was to investigate the microbial ecology, biokinetics, and stability of partial nitrification. Stable long-term partial nitrification resulting in 82.1 +/- 17.2% ammonia oxidation, p...

In this research, the continuously operated laboratory scale Kaldnes (k1) moving bed biofilm reactors (MBBRs) under partial nitrification-denitrification process were used for treatment of synthetic wastewater containing ammonium and glucose. The Anoxic and Aerobic reactors were filled to 40 and 50 %( v/v) to attach and retain biomass with k1 biofilm carriers, respectively. The favorite interna...

Partial nitrification was reported to be technically feasible and economically favorable, especially for wastewater with high ammonium concentration or low C/N ratio. In this study, the effect of dissolved oxygen (DO) and influent ratio of chemical oxygen demand to nitrogen (COD/N) ratio on biological nitrogen removal from synthetic wastewater was investigated. Experiments were conducted in mov...