Abstruct. We investigated variations in resource availability (NO,-N and labile organic C [=I) as determinants of potential denitrification in stream sediments in the southern Appalachian Mountains, USA. stream-water and sediments were sampled seasonally in 2 streams of contrasting NO,N availability, Noland Creek (high NO,-N) and Walker Branch (low NO,-N). Eight additional streams with varying ...

conclusions based on nitrification and denitrification data, the best condition for nitrifying/ denitrifying performance was obtained by modified-ifas. hence, the modification can be used to obtain the best activities of microbial and nitrogen removal improvement. results employing the bet, surface area (sa), total pore volume (vp), and average size of the nanostructure were 0.4026 m2/g, 3.8089...

An intensified biofilm-electrode reactor (IBER) was developed to treat nitrate-contaminated drinking water. Different running conditions were conducted to investigate the behavior of autotrophic denitrification (AD) and heterotrophic denitrification (HD) in the IBER. In AD process, the nitrate nitrogen coulomb-reduction rate was used to evaluate the performance of the reactor. The maximum NO(3)...

Using internal carbon source contained in waste activated sludge (WAS) is beneficial for nitrogen removal from wastewater with low carbon/nitrogen ratio, but it is usually limited by sludge disintegration. This study presented a novel strategy based on free nitrous acid (FNA) pretreatment to intensify the release of organic matters from WAS for enhanced denitrification. During FNA pretreatment,...

Denitrification is a critical process that can alleviate the effects of excessive nitrogen availability in aquatic ecosystems subject to eutrophication. An important part of denitrification occurs in benthic systems where bioturbation by meiofauna (invertebrates <1 mm) and its effect on element cycling are still not well understood. Here we study the quantitative impact of meiofauna populations...

[1] Below its sill depth, the Santa Barbara Basin (SBB) is commonly suboxic ([O2] 3 mM), with only brief periods of ventilation. Associated with development of suboxia, the concentration of nitrate decreases with depth into the basin without an associated decrease in phosphate, indicating that a substantial fraction of the nitrate supplied to the basin is removed by denitrification. Coincident ...

Continuous cultures of Pseudomonas aeruginosa (ATCC 9027) maintained at different dissolved oxygen concentrations (DO) were studied for the effects of DO on various culture properties, especially aerobic respiration and denitrification. The DO was varied from 0 mg/liter (completely anoxic conditions) to 1.3 mg/liter and measured with optical sensors that could accurately determine very low DO b...

To quantify ground water denitrification in discrete locations of riparian aquifers, we modified and evaluated an in situ method based on conservative tracers and 15N-enriched nitrate. Ground water was "pushed" (i.e., injected) into a mini-piezometer and then "pulled" (i.e., extracted) from the same mini-piezometer after an incubation period. This push-pull method was applied in replicate mini-...

1 Nitrification is an important microbial process in humid tropical ecosystems because of its effects on potentials for nitrogen loss via nitrate leaching and denitrification and on the hydrogen ion cycle. Nitrification rates in humid tropical soils vary markedly among different forest types but in general appear to increase following disturbance. Proximal controls on nitrifiers include ammoniu...

Reservoirs are intrinsically linked to the rivers that feed them, creating a river–reservoir continuum in which water and sediment inputs are a function of the surrounding watershed land use. We examined the spatial and temporal variability of sediment denitrification rates by sampling longitudinally along an agriculturally influenced river–reservoir continuum monthly for 13 months. Sediment de...