A laboratory scale activated sludge sequencing batch reactor was operated in order to obtain total removal of influent ammonia (200; 300 and 500 mg NH3-N.L) with sustained nitrite accumulation at the end of the aerobic stages with phenol (1,000 mg C6H5OH.L) as the carbon source for denitrifying microorganisms during the anoxic stages. Ammonia removal above 95% and ratios of (NO2-N / (NO2-N + NO...

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...

In many experiments, a partial nitrification device is initiated with the use of highly active nitrating sludge because large number nitrifying bacteria. Ammonia-oxidizing bacteria (AOB) are more adaptable to low-dissolved oxygen environments than nitrite-oxidizing (NOB). NOB activity was inhibited when dissolved (DO) levels were decreased, causing nitrate-nitrogen concentration gradually decre...

Studies with nitric oxide (NO) inhalation suggest transformation of NO in the lung into a more long-lived bioactive NO species that also has distal effects [1,2]. The exact nature of these species has not been pinpointed, but probable candidates include circulating nitrite anions and/or S-nitrosothiols [3]. When using inhaled NO therapeutically for pulmonary disorders, the dose is typically exp...

This study demonstrates that exposure of primary rat hepatocytes or mouse BNL Cl.2 liver cell line to ethanol causes potentiation of tumor necrosis factor-alpha (TNF-alpha)- and lipopolysaccharide (LPS)-stimulated nitrite accumulation. The potentiating effect of ethanol (0.02-2 mM) appears to be time and concentration dependent. Consistent with nitrite production, the amount of inducible nitric...

Nitrous oxide can be a harmful by-product in nitrogen removal from wastewater. Since wastewater treatment systems operate under different aeration regimens, the influence of different oxygen concentrations and oxygen fluctuations on denitrification was studied. Continuous cultures of Alcaligenes faecalis TUD produced N2O under anaerobic as well as aerobic conditions. Below a dissolved oxygen co...

Here, we investigate the functionality of the oxygen-responsive nitrogen regulation system NreABC in the human pathogen Staphylococcus aureus and evaluate its role in anaerobic gene regulation and virulence factor expression. Deletion of nreABC resulted in severe impairment of dissimilatory nitrate and nitrite reduction and led to a small-colony phenotype in the presence of nitrate during anaer...

Abstract Nitrate widely exists in water pollution and is the most stable form of nitrogen pollution. This study investigated effect current density (CD) wheat-rice stone powder (WP) on denitrification performance, microbial diversity enzyme activity a bio-electrochemical reactor (BER). It was found that an optimum CD 200 mA/m2 addition WP significantly improved nitrate removal rate constant com...