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...

Chopped wheat straw, containing increasing amounts of added water was treated with a constant level of ammonia (3.3 percent of straw dry matter) as ammonium hydroxide, and stored for I to 60 days before determing in vitro dry matter digestibility (IVD MD), nitrogen content and fiber-bound nitrogen (ADF-N) versus free ammonia nitrogen (NH3N) of the treated sample. The overall improvement (e.g., ...

Ocean acidification (OA), caused by the dissolution of increasing concentrations of atmospheric carbon dioxide (CO2) in seawater, is projected to cause significant changes to marine ecology and biogeochemistry. Potential impacts on the microbially driven cycling of nitrogen are of particular concern. Specifically, under seawater pH levels approximating future OA scenarios, rates of ammonia oxid...

Methylamine uptake, oxidation, and assimilation were studied in Hansenula polymorpha, a methylotrophic yeast. The constitutive ammonia transport system was shown to be effective at accumulating methylamine within cells cultured with methylamine or ammonia as a nitrogen source. [13C]methylamine oxidation rates were measured in vivo in methylamine-adapted cells by 13C nuclear magnetic resonance a...

Background: Qual2k is a stream water quality model and was used to evaluate the water quality of the Kine-Vars River and assess the response of the river to nutrient management strategies. Methods: For that purpose, 7 sample stations were selected and surface water samples were collected in the winter and summer of 2012 and were analyzed for temperature, dissolved oxygen, biological oxygen dem...

This study focused on water quality for Guanting Reservoir, the possible auxiliary drinking water source of Beijing. Through remote sensing (RS) approach, water quality retrieval models were established and analyzed for eight common concerned water quality variables, including algae content, turbidity, and concentrations of chemical oxygen demand, total nitrogen, ammonia nitrogen, nitrate nitro...

We examined the relationship between plasma cortisol levels, hepatic glutamine synthetase (GNS) activity and the form of nitrogen excreted (e.g. urea, ammonia) in undisturbed versus confined/crowded (acutely stressed) gulf toadfish. Specifically, we tested the hypothesis that acute increases in plasma cortisol levels are required to trigger the increase in GNS activity induced by the confinemen...