A model for the simulation of nitrification in activated sludge is presented and calculations are compared with experimental results from different sources. The role of protozoa and the influence of reactor type and of diurnal variations in flow and strength of the sewage are considered. Favorable conditions for nitrification are low rates of sludge wasting, high temperatures, plug-flow-type re...

The Baltic Sea is one of the most eutrophic marine areas in the world. The role of nitrogen as a eutrophicating nutrient in the Baltic Sea has remained controversial owing to a lack of understanding of nitrogen cycling in the area. We investigated the seasonal variation in sediment nitrification, denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to amm...

Nitrification, mediated by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), is important in global nitrogen cycling. In estuaries where gradients of salinity and ammonia concentrations occur, there may be differential selections for ammonia-oxidizer populations. The aim of this study was to examine the activity, abundance, and diversity of AOA and AOB in surface oxic sedime...

Nitrous oxide (N(2)O) is a greenhouse gas with a global warming potential far exceeding that of CO(2). Soil N(2)O emissions are a product of two microbially mediated processes: nitrification and denitrification. Understanding the effects of landscape on microbial communities, and the subsequent influences of microbial abundance and composition on the processes of nitrification and denitrificati...

In unsaline loam soil, a laboratory experiment was undertaken studying the effect of using diluted saline water from Karoon lake at Fayoum Governorate, on transformations and subsequent nitrification of two ammoniacal fertilizers, namely (NH4)2SO4 and urea, in the presence or absence of natural organic amendments, namely clover and wheat straw. Ammonification and nitrification of both fertilize...

Nitrification, the chemoautotrophic process by which NH4-N is converted to NO,-N, is an integral biogeochemical transformation in stream ecosystems. Previous research has shown that experimental addition of dissolved organic C inhibits rates of nitrification, and that NH4-N addition stimulates rates of nitrification. In many streams, large amounts of C and N may be present in particulate and so...

The aim of this work was to study the effect of the herbicides glyphosate, nonanoic acid, and dichlorprop-P and the insecticides potassium oil, malation and Pyretrin and their combinations on nitrification. Nitrification was measured in slurries from the eutrophic and shallow Brabrand Lake (Aarhus, Denmark), by inhibiting oxidation of nitrite to nitrate with chloride. All herbicides and insecti...

Urease inhibitor [N-(n-butyl) thiophosphoric triamide (NBPT)] and nitrification (NI) (3,4-dimethylpyrazole phosphate) have been used to reduce nitrogen (N) losses from urea-based fertilizers. This study evaluated the effect of temperature, NBPT, NI on kinetic thermodynamic properties urea hydrolysis in six soils. Soils were amended (250 kg N·ha ?1 ) with (UR), NBPT treated (UR ), or + DI incuba...

Abstract Winter oilseed rape (WOSR) is the major oil crop cultivated in Europe and most important feedstock for biodiesel. Up to 90% of greenhouse gas (GHG) emissions from biodiesel production can occur during cultivation. Therefore, mitigation strategies are required need focus on direct nitrous oxide (N 2 O) emission as one largest GHG contributors production. Earlier studies show that nitrif...