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Fu-Jun Yue, Si-Liang Li, Cong-Qiang Liu, Zhi-Qi Zhao, Hu Ding
A heavy load of nitrogenous compounds reflects nutrient loss and influences water quality in large rivers. Nitrogenous concentrations and dual isotopes of nitrate were measured to ascertain the spatial and temporal distributions of nitrate transformation in the Yellow River, the second-longest river in China. Assessment of the long-term record indicates that [NO3(-)-N] has increased by two-fold over the past three decades. Weekly observation of ammonium over a twelve-year period revealed high concentrations and suggests impairment of water quality, particularly since 2011...
August 17, 2017: Scientific Reports
S Ursula Salmon, Matthew R Hipsey, Geoffrey W Wake, Gregory N Ivey, Carolyn E Oldham
Assessment of water quality evolution in the thousands of existing and future mine pit lakes worldwide requires new numerical tools that integrate geochemical, hydrological, and biological processes. A coupled model was used to test alternative hypothesized controls on water quality in a pit lake over ∼8 years. The evolution of pH, Al, and Fe were closely linked; field observations were reproduced with generic solubility equilibrium controls on Fe(III) and Al and a commonly reported acceleration of the abiotic Fe(II) oxidation rate by 2-3 orders of magnitude...
August 16, 2017: Environmental Science & Technology
Verónica Torrijos, Isabel Ruiz, Manuel Soto
The effect of step-feeding (untreated wastewater by-pass) on the performance of lab-scale columns simulating a hybrid vertical flow (VF)-horizontal flow (HF) constructed wetland (CW) system was studied. Step-feeding strategies have been adopted in several kinds of CW, but this is the first report about the use of step-feeding in VF + HF hybrid systems treating domestic wastewater. Applied loading rates were 7-11 g BOD5/m(2) day and 2.1-3.4 g TN/m(2) day (overall system). Removal efficiency reached 98% TSS and COD and 99% BOD5 on average, whilst a 50% by-pass improved TN removal from 31 to 50%...
August 15, 2017: Environmental Science and Pollution Research International
Weihua Li, Yingjie Sun, Rongxing Bian, Huawei Wang, Dalei Zhang
The carbon-nitrogen ratio (COD/NH4(+)-N) is an important factor affecting nitrification and denitrification in wastewater treatment; this factor also influences nitrous oxide (N2O) emissions. This study investigated two simulated intermittently aerated semi-aerobic aged refuse bioreactors (SAARB) filled with 8-year old aged refuse (AR). The research analyzed how differences in and the combination of influent COD and NH4(+)-N impact N2O emissions in leachate treatment. Experimental results showed that N2O emissions increased as the influent COD/NH4(+)-N decreased...
August 12, 2017: Waste Management
Ruo-Nan Wu, Han Meng, Yong-Feng Wang, Wensheng Lan, Ji-Dong Gu
Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are the main nitrifiers which are well studied in natural environments, and AOA frequently outnumber AOB by orders especially in acidic conditions, making AOA the most promising ammonia oxidizers. The phylogeny of AOA revealed in related studies, however, often varied and hardly reach a consensus on functional phylotypes. The objective of this study was to compare ammonia-oxidizing communities by amoA gene and transcript based on both genomic DNA and RNA in extremely acidic forest soils (pH <4...
August 14, 2017: Microbial Ecology
Prangya Ranjan Rout, Puspendu Bhunia, Rajesh Roshan Dash
A newly isolated GS-5 strain exhibiting heterotrophic nitrification, aerobic denitrification and denitrifying phosphorous removal was identified as Bacillus cereus GS-5 based on its phenotypic and phylogenetic characteristics. The isolate had exhibited efficient NH4(+)-N, NO3(-)-N, NO2(-)-N and PO4(3-)-P removal from nutrient spiked real domestic wastewater with average rates of 2.62, 2.69, 1.16 and 0.42mgL(-1)h(-1), respectively under aerobic condition. Metabolic inhibitor based mass balance analysis indicated that dinitrogen gas (41%), intracellular nitrogen (29%) and intracellular phosphorous (60%) were the major fates of the initial NH4(+)-N and PO4(3-)-P...
August 3, 2017: Bioresource Technology
Wenting Qian, Yongzhen Peng, Xiyao Li, Qiong Zhang, Bin Ma
The free ammonia (FA) inhibition on ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) under anaerobic condition was investigated in this study. The results indicated that NOB was more sensitive to the FA anaerobic treatment than AOB. The FA anaerobic inhibition on nitrifier gradually heightened with the increase of FA concentration. Accompanied with FA concentration increase from 0 to 16.82mgNH3-N·L(-1) (the highest concentration adopted in this study), the activity of AOB reduced by 15...
August 1, 2017: Bioresource Technology
Stephen M Decina, Pamela H Templer, Lucy R Hutyra, Conor K Gately, Preeti Rao
Atmospheric deposition of nitrogen (N) is a major input of N to the biosphere and is elevated beyond preindustrial levels throughout many ecosystems. Deposition monitoring networks in the United States generally avoid urban areas in order to capture regional patterns of N deposition, and studies measuring N deposition in cities usually include only one or two urban sites in an urban-rural comparison or as an anchor along an urban-to-rural gradient. Describing patterns and drivers of atmospheric N inputs is crucial for understanding the effects of N deposition; however, little is known about the variability and drivers of atmospheric N inputs or their effects on soil biogeochemistry within urban ecosystems...
August 7, 2017: Science of the Total Environment
Yaoli Ye, Pascal E Saikaly, B E Logan
Dissolved methane and a lack of nutrient removal are two concerns for treatment of wastewater using anaerobic fluidized bed membrane bioreactors (AFMBRs). Membrane aerators were integrated into an AFMBR to form an aeration membrane fluidized bed membrane bioreactor (AeMFMBR) capable of simultaneous removal of organic matter and ammonia without production of dissolved methane. Good effluent quality was obtained with no detectable suspended solids, 93±5% of chemical oxygen demand (COD) removal to 14±11mg/L, and 74±8% of total ammonia (TA) removal to 12±3mg-N/L for domestic wastewater (COD of 193±23mg/L and TA of 49±5mg-N/L) treatment...
August 3, 2017: Bioresource Technology
Qing Cao, Alan D Steinman, Xiaomei Su, Liqiang Xie
A 30-day indoor incubation experiment was conducted to investigate the effects of different concentrations of microcystin (1, 10, 100 and 1000 μg eq. MC-LR L(-1)) on soil enzyme activity, soil respiration, physiological profiles, potential nitrification, and microbial abundance (total bacteria, total fungi, ammonia-oxidizing bacteria and archaea) in two lakeside soils in China (Soil A from the lakeside of Lake Poyanghu at Jiujiang; Soil B from the lakeside of Lake Taihu at Suzhou). Of the enzymes tested, only phenol oxidase activity was negatively affected by microcystin application...
August 7, 2017: Environmental Pollution
Yunzeng Zhang, Jin Xu, Nadia Riera, Tao Jin, Jinyun Li, Nian Wang
BACKGROUND: Roots are the primary site for plant-microbe interactions. Among the three root-associated layers (i.e., rhizosphere, rhizoplane, and endorhiza), the rhizoplane is a key component serving a critical gating role that controls microbial entry into plant roots. The microbial communities colonizing the three layers are believed to be gradually enriched from the bulk soil inoculum. However, it is unknown how this enrichment process, particularly the rhizosphere to rhizoplane step, is affected by biotic stresses, such as disease...
August 10, 2017: Microbiome
Guangsheng Qian, Xiaomin Hu, Liang Li, Linlin Ye, Weijian Lv
This study explored the nitrification mechanism of a periodic reversal bio-electrocoagulation system with Fe-C electrodes. The ammonia nitrogen removal was compared in four identical cylindrical sequencing bath reactors. Two of them were reactors with Fe-C electrodes (S1) and C-C electrodes (S2), respectively. The other two were a reactor with iron ions (S3) and a traditional SBR (S4), respectively. The results demonstrated that the effect on enhancing nitrification in S1 was the best among all four SBRs, followed by S3, S2 and S4...
July 29, 2017: Bioresource Technology
Yanling Zheng, Lijun Hou, Min Liu, Silvia E Newell, Guoyu Yin, Chendi Yu, Hongli Zhang, Xiaofei Li, Dengzhou Gao, Juan Gao, Rong Wang, Cheng Liu
Silver nanoparticles (AgNPs) are the most common materials in nanotechnology-based consumer products globally. Because of the wide application of AgNPs, their potential environmental impact is currently a highly topical focus of concern. Nitrification is one of the processes in the nitrogen cycle most susceptible to AgNPs but the specific effects of AgNPs on nitrification in aquatic environments are not well understood. We report the influence of AgNPs on nitrification and associated nitrous oxide (N2O) production in estuarine sediments...
August 2017: Science Advances
Ping Han, Yunxiao Li, Xufeng Yang, Liang Xue, Longjun Zhang
Aerobic respiration and nitrification are important processes for dissolved inorganic nitrogen (DIN) composition change and CO2 production in human-perturbed coastal waters. On-site incubations and field investigations were conducted in the eastern Jiaozhou Bay, a high-urbanization region, from May to August 2014. Results show that aerobic respiration rates reached 15.58μmolO2L(-1)d(-1), and NH4(+) and NO2(-) oxidation rates were 0.53 and 0.13μmolNL(-1)d(-1), respectively, in the human-perturbed northeastern area...
August 3, 2017: Marine Pollution Bulletin
Co Thi Kinh, Toshikazu Suenaga, Tomoyuki Hori, Shohei Riya, Masaaki Hosomi, Barth F Smets, Akihiko Terada
The goal of this study was to investigate the effectiveness of a membrane-aerated biofilm reactor (MABR), a representative of counter-current substrate diffusion geometry, in mitigating nitrous oxide (N2O) emission. Two laboratory-scale reactors with the same dimensions but distinct biofilm geometries, i.e., a MABR and a conventional biofilm reactor (CBR) employing co-current substrate diffusion geometry, were operated to determine depth profiles of dissolved oxygen (DO), nitrous oxide (N2O), functional gene abundance and microbial community structure...
July 24, 2017: Water Research
Kang Zhao, Weidong Kong, Ajmal Khan, Jinbo Liu, Guangxia Guo, Said Muhanmmad, Xianzhou Zhang, Xiaobin Dong
Unraveling elevational diversity patterns of plants and animals has long been attracting scientific interests. However, whether soil microorganisms exhibit similar elevational patterns remains largely less explored, especially for functional microbial communities, such as ammonia oxidizers. Here, we investigated the diversity and distribution pattern of ammonia-oxidizing archaea (AOA) in meadow soils along an elevation gradient from 4400 m to the grassline at 5100 m on the Tibetan Plateau using terminal restriction fragment length polymorphism (T-RFLP) and sequencing methods by targeting amoA gene...
August 3, 2017: Applied Microbiology and Biotechnology
Willy Verstraete, Jo De Vrieze
Several needs in the context of the water-energy-food nexus will become more prominent in the next decades. It is crucial to delineate these challenges and to find opportunities for innovative microbial technologies in the framework of sustainability and climate change. Here, we focus on four key issues, that is the imbalance in the nitrogen cycle, the diffuse emission of methane, the necessity for carbon capture and the deterioration of freshwater reserves. We suggest a set of microbial technologies to deal with each of these issues, such as (i) the production of microbial protein as food and feed, (ii) the control of methanogenic archaea and better use of methanotrophic consortia, (iii) the avoidance of nitrification and (iv) the upgrading of CO2 to microbial bioproducts...
August 3, 2017: Microbial Biotechnology
Rodrigo F Bueno, Roque P Piveli, Fábio Campos, Pedro A Sobrinho
This study has investigated the biological nitrogen removal by simultaneous nitrification and denitrification processes (SND) in a system of continuous flow activated sludge process. The investigation had four stages and evaluated the system behavior under different solid retention times (SRT), food-to-mass ratios (F/M) and dissolved oxygen (DO) concentrations. The data showed that the concentration of DO 0.5±0.2 mgO2/L did not affect the growth of heterotrophic bacteria (2.2-3.1 d-1 at 20°C) and autotrophic nitrifying bacteria (0...
August 3, 2017: Environmental Technology
Ariel A Szogi, John H Loughrin, Matias B Vanotti
Large volumes of wastewater from confined pig production are stored in anaerobic lagoons. Control methods are needed to reduce contributions to air pollution by foul odors from these lagoons. In a replicated pilot-scale lagoon column experiment, we evaluated the effect of pig wastewater pre-treatment on water quality improvements and reduction in concentration of selected malodor compounds in lagoons receiving liquid from: 1) flocculant enhanced solid-liquid separation (SS), and 2) solid-liquid separation plus biological N treatment using nitrification-denitrification (SS+NDN)...
August 2, 2017: Environmental Technology
Shuxin Liu, Lan Li, Huiqiang Li, Hui Wang, Ping Yang
A continuous microbial fuel cell system was constructed treating ammonium/organics rich wastewater. Operational performance of MFC system, mechanisms of ammonium removal, effect of ammonium on organics removal and energy output, C and N balance of anode chamber and microbial community analysis of anode chamber were studied. It was concluded that 0.0914kg/m(3)d NH4(+)-N and 5.739kg/m(3)d COD were removed from anode chamber and simultaneous nitrification and denitrification (SND) occurred in cathode chamber resulting in COD, TN removal rate of 88...
July 16, 2017: Bioresource Technology
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