[1] Nitrification rates, as well as the relationships between rates and ammonia oxidizer abundance (both archaeal and bacterial), were investigated in the Arabian Sea. Ammonia oxidation rates were measured directly using N-NH4 + stable isotope additions in gas-impermeable, trace metal clean trilaminate bags (500 mL) at in situ temperature. Tracer incubations were performed at three stations at ...

A synthetic pharmaceutical manufacturing facility was experiencing recurring upsets of nitrification at its wastewater treatment plant. The main treatment train consisted of trickling filters followed by a conventional activated sludge process with ostensibly adequate treatment capacity (average F/M of 0.1, COD/MLSS-based). An evaluation of the plant’s operating conditions and performance indic...

Aims Land use management affects plant carbon (C) supply and soil environments and hence alters soil nitrogen (N) dynamics, with consequent feedbacks to terrestrial ecosystem productivity. The objective of this study was to better identify mechanisms by which land-use management (clipping and shading) regulates soil N in a tallgrass prairie, OK, USA. Methods We conducted 1-year clipping and sha...

Nitrification is a fundamental component of the global nitrogen cycle and leads to significant fertilizer loss and atmospheric and groundwater pollution. Nitrification rates in acidic soils (pH < 5.5), which comprise 30% of the world's soils, equal or exceed those of neutral soils. Paradoxically, autotrophic ammonia oxidizing bacteria and archaea, which perform the first stage in nitrification,...

The coupling between nitrification and denitrification and the regulation of these processes by oxygen were studied in freshwater sediment microcosms with O(2) and NO(3) microsensors. Depth profiles of nitrification (indicated as NO(3) production), denitrification (indicated as NO(3) consumption), and O(2) consumption activities within the sediment were calculated from the measured concentratio...

The aim of the study was to determine how soil contamination with diesel oil affected biochemical properties of soil and to determine whether the application of compost, bentonite or lime could recover the biochemical equilibrium of soil. The experiments were carried out in a greenhouse. Typical Eutric Cambisols soil formed from sandy loam was polluted with the following amounts of diesel oil: ...

Research so far has provided little evidence that benthic biogeochemical cycling is affected by ocean acidification under realistic climate change scenarios. We measured nutrient exchange and sediment community oxygen consumption (SCOC) rates to estimate nitrification in natural coastal permeable and fine sandy sediments under pre-phytoplankton bloom and bloom conditions. Ocean acidification, a...

In wastewater treatment plants, nitrifying systems are usually operated with elevated levels of aeration to avoid nitrification failures. This approach contributes significantly to operational costs and the carbon footprint of nitrifying wastewater treatment processes. In this study, we tested the effect of aeration rate on nitrification by correlating ammonia oxidation rates with the structure...

BACKGROUND Chemoautotrophic ammonia oxidizing bacteria (AOB) have the metabolic ability to oxidize ammonia to nitrite aerobically. This metabolic feature has been widely used, in combination with denitrification, to remove nitrogen from wastewater in wastewater treatment plants (WWTPs). However, the relative influence of specific deterministic environmental factors to AOB community dynamics in ...

Sun, Zhe. M.S.E., Purdue University, May 2014. Attached-Growth System for Nitrification at Low Temperature. Major Professor: Ernest R. Blatchley III. Lagoon systems are commonly used in small communities for domestic wastewater treatment. These systems are simple and economical to operate, and are often appropriate for use in areas where land costs are low. Lagoons are effective in removing con...