The main aim of this study was to evaluate the performance of a modified sequencing batch reactor (MSBR) using fixed Kaldnes carriers fed with acclimated sludge for ammonium removal via simultaneous nitrification-denitrification (SND) in synthetic wastewater. The results exhibited a SND of 82.3% within a 450-minute cycle time which was higher than that of a SBR without carrier (69.83%). Nitrite...

Denitrifying bacteria accumulate [Formula: see text], NO, and N2O, the amounts depending on transcriptional regulation of core denitrification genes in response to O2-limiting conditions. The genes include nar, nir, nor and nosZ, encoding [Formula: see text]-, [Formula: see text]-, NO- and N2O reductase, respectively. We previously constructed a dynamic model to simulate growth and respiration ...

Fish-meal factories generate waste waters with high chemical oxygen demand (COD), suspended solids (SS), fats and protein concentrations. After their treatment by anaerobic digestion, effluents with high ammoniaand organic-nitrogen contents and a fraction of residual COD are produced. A biological nitrification/denitrification process is proposed to reduce both the residual carbon and the nitro...

To elucidate the effect of macroalgae blooms on dissimilatory nitrate reduction pathways (denitrification, anammox, and DNRA) in sediments hypereutrophic Yatsu tidal flat, eastern Japan, sediment denitrification, DNRA rates were measured using a 15N tracer technique at two sites affected unaffected by (Ulva) incubation experiments with without Ulva. Anammox was insignificant both experiments. T...

Wetland loss along the Louisiana Gulf coast and excessive nitrate loading into the Gulf of Mexico are interrelated environmental problems. Nitrate removal by soil denitrification activity was studied in a ponded freshwater marsh receiving diverted Mississippi River water for the purpose of reversing or slowing wetland loss. Labeled (15)N-nitrate was applied at 3.8 g N m(-2) into four replicate ...

in this research, an experimental study to evaluate nutrient removal from synthetic wastewater by a lab-scale moving bed biofilm process was investigated. also, kinetic analysis of the process with regard to phosphorus and nitrogen removal was studied with different mathematical models. for nutrient removal, the moving bed biofilm process was applied in series with anaerobic, anoxic and aerobic...

Denitrification and consumption of oxygen and nitrate in sediments from Tama Estuary, Odawa Bay, and Tokyo Bay were measured in an experimental sediment-water system. Filtered seawater containing [N]nitrate flowed continuously over undisturbed sediments, and the concentrations of O(2), nitrate, and nitrite in the influent and effluent and of N(2) in the effluent were monitored. Under steady-sta...

nitrification rate of biofilters is influenced by ammonia concentration and levels of ammonia vary in response to feeding time. on the other hand, existence and activity of different groups of bacteria can be expected in the biofilters. hence in this research, nitrification dynamic of biofilters during day hours and also rules of different biofilteration process (nitrification, denitrification ...

Anaerobic lagoons are commonly used for the treatment of swine wastewater. Although these lagoons were once thought to be relatively simple, their physical, chemical, and biological processes are very complex. This study of anaerobic lagoons had two objectives: (i) to quantify denitrification enzyme activity (DEA) and (ii) to evaluate the influence of lagoon characteristics on the DEA. The DEA ...

A combined bioelectrochemical and sulfur autotrophic denitrification process for drinking water treatment was put forward and investigated extensively in this paper. In this new process, the bioelectrochemical denitrification was carried out in the upper part of the reactor while sulfur denitrification in the lower part. The H+ produced in Sulfur Part could be consumed by hydrogen denitrificati...