This study investigated relative magnitude of hydrolysis and ammonification by separate analysis of ammonia release and nitrification mechanisms. A peptone mixture was used as substrate in two parallel experiments seeded with nitrifying biomass conducted with and without nitrification inhibitor. Results were evaluated by means of model analysis of the ammonia and the oxygen uptake rate (OUR) profiles. A dual hydrolysis mechanism with maximum rate coefficients of 6.3 and 0.5/day characterized the peptone mixture and a kinetic balance was established for the ammonia release mechanism with a corresponding ammonification rate of 0.08 m(3)/g COD day. The experiments also showed a low soluble ammonia nitrogen generation that was rapidly depleted, confirming the existence of ammonification. These rate coefficients were verified using model calibration of the OUR profile related to simultaneous carbon removal and nitrification. Results indicated that ammonification would not be rate limiting for wastewaters such as domestic sewage, with lower hydrolysis kinetics.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.biortech.2012.03.017 | DOI Listing |
Hum Reprod
January 2025
IVIRMA Global Research Alliance, IVIRMA New Jersey, Basking Ridge, NJ, USA.
Study Question: Does the use of slush nitrogen (SN) for embryo vitrification improve embryo transfer outcomes compared to liquid nitrogen (LN)?
Summary Answer: SN is a safe method for embryo preservation and significantly improves post-warming survival rates during repeated vitrification-warming cycles; however, after a single freeze-thaw cycle, pregnancy outcomes are not improved when embryos are vitrified with SN compared to LN.
What Is Known Already: SN is a combination of solid and LN, with a temperature lower than regular LN, and it is an alternative to conventional LN in achieving a faster cooling speed. Studies have shown that SN improves survival in non-human embryos and human oocytes.
Glob Chang Biol
January 2025
Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Goettingen, Göttingen, Germany.
Carbon use efficiency (CUE) of microbial communities in soil quantifies the proportion of organic carbon (C) taken up by microorganisms that is allocated to growing microbial biomass as well as used for reparation of cell components. This C amount in microbial biomass is subsequently involved in microbial turnover, partly leading to microbial necromass formation, which can be further stabilized in soil. To unravel the underlying regulatory factors and spatial patterns of CUE on a large scale and across biomes (forests, grasslands, croplands), we evaluated 670 individual CUE data obtained by three commonly used approaches: (i) tracing of a substrate C by C (or C) incorporation into microbial biomass and respired CO (hereafter C-substrate), (ii) incorporation of O from water into DNA (O-water), and (iii) stoichiometric modelling based on the activities of enzymes responsible for C and nitrogen (N) cycles.
View Article and Find Full Text PDFSmall Methods
January 2025
Electric Mobility and Tribology Research Group, Council of Scientific and Industrial Research Central Mechanical Engineering Research Institute, Mahatma Gandhi Avenue, Durgapur, West Bengal, 713209, India.
Integration of different active sites by heterostructure engineering is pivotal to optimize the intrinsic activities of an oxygen electrocatalyst and much needed to enhance the performance of rechargeable Zn-air batteries (ZABs). Herein, a biphasic nanoarchitecture encased in in situ grown N-doped graphitic carbon (MnO/Co-NGC) with heterointerfacial sites are constructed. The density functional theory model reveals formation of lattice oxygen bridged heterostructure with pyridinic nitrogen atoms anchored Co species, which facilitate adsorption of oxygen intermediates.
View Article and Find Full Text PDFJ Environ Manage
January 2025
College of Environmental Science and Engineering, Key Laboratory of Beijing on Regional Air Pollution Control, Beijing University of Technology, Beijing, 100124, China.
The growth of population and changes in dietary structure have led to a continuous increase in demand for livestock and poultry products, resulting in the increase of the gaseous reactive nitrogen (GNr) emissions from livestock and poultry breeding systems and posing a threat to the human and ecosystem health. The characteristics from GNr emissions of six livestock and poultry breeding systems at the provincial level of China in 2020 were evaluated with the framework of life cycle analysis. Additionally, this study explored the impact of silage maize replacing traditional maize as feed on reducing GNr emissions.
View Article and Find Full Text PDFMar Pollut Bull
January 2025
State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China.
Investigations of the spatial-temporal variations of nutrients within mangrove coastal zones are essential for assessing the environmental status of an aquatic ecosystems. However, major processes controlling nitrate cycle along the submarine groundwater discharge (SGD) pathway from the mangrove areas to adjacent tidal creek remain underexplored. A time series measurement over a 25 h tidal cycle was conducted in Qinglan Bay tidal creek (Hainan Island, China).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!