A SHARON system has been constructed at the Utrecht WWTP and at the Rotterdam Dokhaven WWTP. In the SHARON process rejection water from dewatering of digested sludge is treated for N-removal. It concerns a high active process operating without sludge retention. Due to differences in growth rate nitrite oxidisers can be washed out of the system while ammonia oxidisers are maintained, resulting i...

BACKGROUND Bio-cathode denitrifying microbial fuel cell (MFC) is a promising bio-electrochemical system (BES) where both the reactions of anodic oxidation and cathodic reduction are catalyzed by microorganisms. In this nitrogen removal process, a complete biological denitrification from nitrate (NO3 (-)) to molecular nitrogen (N2) was achieved by four reduction steps, forming nitrite (NO2 (-)),...

Analyses of the nitrite reductase gene diversities (nirK and nirS) in an activated sludge community fed with both nitrite and glucose were conducted. Results suggest that the topology of nirK and nirS gene fragment-based phylogenetic trees is influenced more by the available electron acceptor than by the carbon source. A denitrification reactor was operated for 53 days and a clone library const...

The major aetiological agent of human bacterial meningitis is Neisseria meningitidis. During the course of disease and host colonization, the bacterium has to withstand limited oxygen availability. Nitrogen oxide and nitrogen oxyanions are thought to be present, which may constitute an alternative sink for electrons from the N. meningitidis respiratory chain. A partial denitrification pathway i...

Serial femtosecond crystallography (SFX) has enabled the damage-free structural determination of metalloenzymes and filled the gaps of our knowledge between crystallographic and spectroscopic data. Crystallographers, however, scarcely know whether the rising technique provides truly new structural insights into mechanisms of metalloenzymes partly because of limited resolutions. Copper nitrite r...

Agricultural soils are the most important anthropogenic source of nitrous oxide (N2O) emissions. This occurs via two main pathways: (1) from microbial-mediated oxidation ammonium to nitrite and nitrate; (2) denitrification. Most agro-ecological models explicitly deal with these pathways albeit different degrees process understanding empiricism. Models that integrate impact multiple environmenta...

During the purification of an aquarium for carp breeding, a relatively high level of chemical oxygen demand (COD) was removed by filtration systems packed with both alginate- and polyvinyl alcohol (PVA)-immobilized gel beads of Rhodobacter sphaeroides S. Low nitrate accumulation was observed in the alginate gel beads packed system due to denitrification, but high levels of nitrate and nitrite a...

Oxygen had an immediate and reversible inhibitory effect on nitrate respiration by denitrifying cultures of Pseudomonas aeruginosa. Inhibition of nitrate utilization by oxygen appeared to be at the level of nitrate uptake, since nitrate reduction to nitrite in cell extracts was not affected by oxygen. The degree of oxygen inhibition was dependent on the concentration of oxygen, and increasing n...

The purpose of this study was to investigate the nitrification and nitrogen removal from centrate produced in the dewatering process of anaerobically digested sludge, using a single-unit, single-zone submerged attached-growth bioreactor. The nitrogen loading varied from 0.54 to 1.51 kg-N/m3 x d. Stable ammonia oxidation (nitritification) to nitrite was demonstrated. A nitritification efficiency...