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Rafaela Cáceres, Krystyna Malińska, Oriol Marfà
Composting could be regarded as a process of processes because it entails a number of complex chemical and microbiological reactions and transformations. Nitrification is one of such processes that normally takes place during the curing phase. This process has been studied in detail for wastewater treatment, and it is becoming an extensively studied topic within composting. In the past, nitrate presence in compost has been clearly perceived as a maturation indicator; however, nowadays, nitrate formation is also conceived as a way of conserving nitrogen in compost...
November 15, 2017: Waste Management
C Alan Rotz
Dairy farms have been identified as an important source of greenhouse gas emissions. Within the farm, important emissions include enteric CH4 from the animals, CH4 and N2O from manure in housing facilities during long-term storage and during field application, and N2O from nitrification and denitrification processes in the soil used to produce feed crops and pasture. Models using a wide range in level of detail have been developed to represent or predict these emissions. They include constant emission factors, variable process-related emission factors, empirical or statistical models, mechanistic process simulations, and life cycle assessment...
November 15, 2017: Journal of Dairy Science
(no author information available yet)
A demonstrated approach to design the, so-called, medium-bubble air diffusion network for oxygen transfer into the aerobic zone(s) of moving bed biofilm reactor (MBBR) and integrated fixed-film activated sludge (IFAS) processes is described in this paper. Operational full-scale biological water resource recovery systems treating municipal sewerage demonstrate that medium-bubble air diffusion networks designed using the method presented here provide reliable service. Further improvement is possible, however, as knowledge gaps prevent more rational process designs...
November 17, 2017: Water Environment Research: a Research Publication of the Water Environment Federation
Renato P Ribeiro, Rodrigo F Bueno, Roque P Piveli, Débora C Kligerman, William Z de Mello, Jaime L M Oliveira
The continuous measurements of N2O emissions from the aeration tanks of three activated sludge wastewater treatment plants (WWTPs) operated with biological nitrogen removal (BNR) and non-BNR were performed during the different operating conditions of several parameters, such as aeration, dissolved oxygen (DO) profiling and organic shock loading (with landfill leachate). The nitrification process is the main driving force behind N2O emission peaks. There are indications that the variation of the air flow rate influenced N2O emissions; high N2O emissions denote over-aeration conditions or incomplete nitrification, with accumulation of NO2(-) concentrations...
November 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Takafumi Kataoka, Koji Suzuki, Tomohisa Irino, Masanobu Yamamoto, Seigo Higashi, Hongbin Liu
Microbial nitrification is a key process in the nitrogen cycle in the continental shelf ecosystems. The genotype compositions and abundance of the ammonia monooxygenase gene, amoA, derived from ammonia-oxidizing archaea (AOA) and bacteria (AOB) in two size fractions (2-10 and 0.2-2 µm), were investigated in the East China Sea (ECS) in May 2008 using PCR-denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR). Four sites were selected across the continental shelf edge: continental shelf water (CSW), Kuroshio branch water (KBW), transition between CSW and KBW (TCSKB) and coastal KBW (CKBW)...
November 16, 2017: Archives of Microbiology
Serkan Şahan, Uğur Şahin, Mustafa Başaran, Oğuzhan Uzun, Adem Güneş
3,5 - Dimethylpyrazolium glyceroborate is a nitrification inhibitor (a member of pyrazole derivatives) used for the fixation of nitrogen into the soil. In this study, an HPLC-DAD method was developed and validated for determination of 3,5 - dimethylpyrazole in order to determine 3,5 - dimethylpyrazolium glyceroborate in fertilizer samples. For method development, analytical parameters like type of eluent solution and column filling material and device parameters like eluent flow rate, column oven temperature and measurement wavelength were all optimized...
November 2, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
R E Costa, A A Battistelli, J K B Bernardelli, J P Bassin, T J Belli, F R Lapolli
A conventional (SB-CMBR) and a hybrid moving bed (SB-HMBR) sequencing batch membrane bioreactor treating municipal wastewater were compared during their start-up in terms of organic matter and nutrient removal, membrane fouling characteristics and microbial community. Both systems exhibited similar COD, ammonium, total nitrogen (TN) and phosphorus removal efficiency, amounting up to 96%, 99%, 70% and 85%, respectively. Most of the COD removal was coupled to phosphate release and denitrification in the anaerobic/anoxic phase of the operating cycle, whereas the low COD/N environment established in the aerated phase allowed full nitrification...
November 11, 2017: Environmental Technology
Zejiang Cai, Suduan Gao, Minggang Xu, Bradley D Hanson
Potassium thiosulfate (KTS, K2S2O3) has been shown to function as a nitrification inhibitor, thus has the potential to reduce nitrous oxide (N2O) emissions and play an important role in effective N management. The objective of this research was to determine the potential effects of KTS on N2O emissions and N transformation processes in comparison with commercial N transformation inhibitors (stabilizers). A laboratory incubation experiment was conducted using urea and ammonium nitrate (UAN) applied at 150mgNkg(-1) in a Hanford sandy loam soil (coarse-loamy, mixed, superactive, nonacid, thermic Typic Xerorthents)...
November 9, 2017: Science of the Total Environment
Anna Jurado, Alberto V Borges, Estanislao Pujades, Vivien Hakoun, Joël Otten, Kay Knöller, Serge Brouyère
This work aims to (1) identify the most conductive conditions for the generation of greenhouses gases (GHGs) in groundwater (e.g., hydrogeological contexts and geochemical processes) and (2) evaluate the indirect emissions of GHGs from groundwater at a regional scale in Wallonia (Belgium). To this end, nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) concentrations and the stable isotopes of nitrate (NO3(-)) and sulphate were monitored in 12 aquifers of the Walloon Region (Belgium). The concentrations of GHGs range from 0...
November 8, 2017: Science of the Total Environment
Christian Nyrop Albers, Lea Ellegaard-Jensen, Lars Hestbjerg Hansen, Sebastian R Sørensen
Ammonium oxidation to nitrite and then to nitrate (nitrification) is a key process in many waterworks treating groundwater to make it potable. In rapid sand filters, nitrifying microbial communities may evolve naturally from groundwater bacteria entering the filters. However, in new filters this may take several months, and in some cases the nitrification process is never sufficiently rapid to be efficient or is only performed partially, with nitrite as an undesired end product. The present study reports the first successful priming of nitrification in a rapid sand filter treating groundwater...
November 6, 2017: Water Research
Paul Moretti, Jean-Marc Choubert, Jean-Pierre Canler, Pierre Buffière, Olivier Pétrimaux, Paul Lessard
The integrated fixed-film activated sludge (IFAS) process is being increasingly used to enhance nitrogen removal for former activated sludge systems. The aim of this work is to evaluate a numerical model of a new nitrifying/denitrifying IFAS configuration. It consists of two carrier-free reactors (anoxic and aerobic) and one IFAS reactor with a filling ratio of 43% of carriers, followed by a clarifier. Simulations were carried out with GPS-X involving the nitrification reaction combined with a 1D heterogeneous biofilm model, including attachment/detachment processes...
November 10, 2017: Bioprocess and Biosystems Engineering
Wei Zhang, Yong Li, Bo Zhu, Xunhua Zheng, Chunyan Liu, Jialiang Tang, Fang Su, Chong Zhang, Xiaotang Ju, Jia Deng
Quantification of nitrogen losses and net greenhouse gas (GHG) emissions from catchments is essential for evaluating the sustainability of ecosystems. However, the hydrologic processes without lateral flows hinder the application of biogeochemical models to this challenging task. To solve this issue, we developed a coupled hydrological and biogeochemical model, Catchment Nutrients Management Model - DeNitrification-DeComposition Model (CNMM-DNDC), to include both vertical and lateral mass flows. By incorporating the core biogeochemical processes (including decomposition, nitrification, denitrification and fermentation) of the DNDC into the spatially distributed hydrologic framework of the CNMM, the simulation of lateral water flows and their influences on nitrogen transportation can be realized...
November 6, 2017: Science of the Total Environment
Qing-Fang Bi, Qiu-Hui Chen, Xiao-Ru Yang, Hu Li, Bang-Xiao Zheng, Wei-Wei Zhou, Xiao-Xia Liu, Pei-Bin Dai, Ke-Jie Li, Xian-Yong Lin
Soil amended with single biochar or nitrogen (N) fertilizer has frequently been reported to alter soil nitrification process due to its impact on soil properties. However, little is known about the dynamic response of nitrification and ammonia-oxidizers to the combined application of biochar and N fertilizer in intensive vegetable soil. In this study, an incubation experiment was designed to evaluate the effects of biochar and N fertilizer application on soil nitrification, abundance and community shifts of ammonia-oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) in Hangzhou greenhouse vegetable soil...
November 7, 2017: AMB Express
Guihua Chen, Lauren Kolb, Michel A Cavigelli, Ray R Weil, Cerruti R R Hooks
Nitrous oxide (N2O) is an important greenhouse gas and a catalyst of stratospheric ozone decay. Agricultural soils are the source of 75% of anthropogenic N2O emissions globally. Recently, significant attention has been directed at examining effects of conservation tillage on carbon sequestration in agricultural systems. However, limited knowledge is available regarding how these practices impact N2O emissions, especially for organic vegetable production systems. In this context, a three-year study was conducted in a well-drained sandy loam field transitioning to organic vegetable production in the Mid-Atlantic coastal plain of USA to investigate impacts of conservation tillage [strip till (ST) and no-till (NT)] and conventional tillage (CT) [with black plastic mulch (CT-BP) and bare-ground (CT-BG)] on N2O emissions...
October 27, 2017: Science of the Total Environment
Benjamin W Johnson, Simon W Poulton, Colin Goldblatt
The Neoproterozoic Earth was punctuated by two low-latitude Snowball Earth glaciations. Models permit oceans with either total ice cover or substantial areas of open water. Total ice cover would make an anoxic ocean likely, and would be a formidable barrier to biologic survival. However, there are no direct data constraining either the redox state of the ocean or marine biological productivity during the glacials. Here we present iron-speciation, redox-sensitive trace element, and nitrogen isotope data from a Neoproterozoic (Marinoan) glacial episode...
November 6, 2017: Nature Communications
Nadine Loick, Elizabeth Dixon, Diego Abalos, Antonio Vallejo, Peter Matthews, Karen McGeough, Catherine Watson, Elizabeth M Baggs, Laura M Cardenas
Agricultural soils are a major source of nitric- (NO) and nitrous oxide (N2O), which are produced and consumed by biotic and abiotic soil processes. The dominant sources of NO and N2O are microbial nitrification and denitrification, and emissions of NO and N2O generally increase after fertiliser application. The present study investigated the impact of N-source distribution on emissions of NO and N2O from soil and the significance of denitrification, rather than nitrification, as a source of NO emissions. To eliminate spatial variability and changing environmental factors which impact processes and results, the experiment was conducted under highly controlled conditions...
November 1, 2017: Geoderma
Jing Zhang, Hu Li, Yingchun Wang, Jia Deng, Ligang Wang
The greenhouse vegetable (GV) field is an important agricultural system in China. It may also be a hot spot of nitrous oxide (N2O) emissions. However, knowledge on N2O emission from GV fields and its mitigation are limited due to considerable variations of N2O emissions. In this study, we performed a multi-year experiment at a GV field in Beijing, China, using the static opaque chamber method, to quantify N2O emissions from GV fields and evaluated N2O mitigation efficiency of alternative nitrogen (N) managements...
November 2, 2017: Science of the Total Environment
Lu Yao, Chengrong Chen, Guihua Liu, Wenzhi Liu
Decline of submerged vegetation is one of the most serious ecological problems in eutrophic lakes worldwide. Although restoration of submerged vegetation is widely assumed to enhance ecological functions (e.g., nitrogen removal) and aquatic biodiversity, the evidence for this assumption is very limited. Here, we investigated the spatio-temporal patterns of sediment potential nitrification, unamended denitrification and N2O production rates along a vegetation gradient in the Lake Honghu, where submerged vegetation was largely restored by prohibiting net-pen aquaculture...
October 25, 2017: Science of the Total Environment
Juan Chen, Pei-Fang Wang, Chao Wang, Xun Wang, Han Gao
While nitrogen (N) fixation and ammonia oxidation by microorganisms are two important N cycling processes, little is known about how the microbes that drive these two processes respond when sediments are contaminated with persistent organic pollutants. In this study, we carried out a laboratory microcosm experiment to examine the effects of decabromodiphenyl ether (BDE-209), either on its own or combined with a common mangrove species, Avicennia marina, on the abundance, diversity, and community composition of N-fixing bacteria (NFB) and ammonia-oxidizing archaea (AOA) and bacteria (AOB) in mangrove sediments...
October 31, 2017: Science of the Total Environment
Fang Liu, Xiaomin Hu, Xin Zhao, Huixuan Guo, Yan Zhao, Binhui Jiang
Bioaugmentation was used to upgrade the nitrification process in a full-scale municipal WWTP with an A(2)/O system. A mixture of nitrifying bacteria was inoculated into the bioreactor for a final concentration of 1% (v/v). The upgrade process took 25 days, and the NH4(+)-N removals reached 94.6% (increased at least by 75%). The effluent concentrations of COD and NH4(+)-N stabilized at <30 mg/L and <4 mg/L even when the corresponding influent concentrations were over 300 mg/L and 60 mg/L, which met the first-class requirement of the National Municipal Wastewater Discharge Standards of China (COD ≤ 50 mg/L, NH4(+)-N ≤ 5 mg/L)...
October 19, 2017: Bioresource Technology
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