scholarly journals Pathways of N removal and N2O emission from a one-stage autotrophic N removal process under anaerobic conditions

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Kai Li ◽  
Fang Fang ◽  
Han Wang ◽  
Chao Wang ◽  
Youpeng Chen ◽  
...  
Keyword(s):  
N2o Emission ◽  
Anaerobic Conditions ◽  
Removal Process ◽  
One Stage ◽  
N Removal

Does intermittent aeration and/or an influent distributary affect nitrogen removal and nitrous oxide emission of an ecological soil wastewater infiltration system?

2019 ◽  
Vol 79 (7) ◽  
pp. 1417-1425 ◽  
Author(s):  
Yue Zhao ◽  
Zhiyu Zhang ◽  
Ziqi Li ◽  
Shiyao Wang ◽  
Chaoquan Tan ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Removal ◽  
Emission Rate ◽  
N2o Emission ◽  
Functional Genes ◽  
Intermittent Aeration ◽  
Anaerobic Conditions ◽  
N Removal ◽  
The Matrix ◽  
Removal Efficiencies

Abstract The effect of intermittent aeration and an influent distributary on NH4+-N removal, total nitrogen (TN) removal, nitrous oxide (N2O) emission and the abundances of nitrogen removal and N2O emission functional genes in four types of ecological soil wastewater infiltration systems (ESWISs) (which were conventional ESWIS 1 (operated without aeration and influent distributary), ESWIS 2 (operated with intermittent aeration), ESWIS 3 (operated with influent distributary) and ESWIS 4 (operated with intermittent aeration and influent distributary)) were studied. Intermittent aeration in ESWIS 2 and 4 created aerobic conditions above 50 cm depth of the matrix and anoxic or anaerobic conditions in the lower matrix (below 80 cm depth). ESWIS 4 improved NH4+-N (to 90.1%) and TN (to 87.8%) removal efficiencies and increased the abundances of eight nitrogen removal and N2O emission functional genes (amoA, nxrA, narG, napA, nirS, nirK, qnorB and nosZ) in contrast with other ESWISs. The combination of intermittent aeration and influent distributary achieved the lowest N2O emission rate of 34.7 mg/(m2 d) in ESWIS 4. Intermittent aeration combined with influent distributary was recommended for ESWISs to enhance nitrogen removal and reduce N2O emission.

The Reaction of Thiol Compounds with the Vitamin-K Dependent Clotting Factors

1969 ◽  
Vol 21 (03) ◽  
pp. 573-579 ◽  
Author(s):  
P Fantl
Keyword(s):  
Prothrombin Time ◽  
Vitamin K ◽  
Anaerobic Conditions ◽  
Clotting Factors ◽  
Thiol Compounds ◽  
Aerobic Conditions ◽  
One Stage ◽  
Factor Ii ◽  
Ph Dependent ◽  
The One

SummaryTreatment of human and dog oxalated plasma with 0.2 to 1.0 × 10−1 M 2.3-dithiopropanol (BAL) or dithiothreitol (DTT) at 2–4° C for 30 min results in the reduction of the vitamin-K dependent clotting factors II, VII, IX and X to the respective-SH derivatives. The reaction is pH dependent. Under aerobic conditions the delayed one stage prothrombin time can be partly reversed. Under anaerobic conditions a gradual prolongation of the one stage prothrombin time occurs without reversal.In very diluted plasma treated with the dithiols, prothrombin can be converted into thrombin if serum as source of active factors VII and X is added. In contrast SH factors VII, IX and X are inactive in the specific tests. Reoxidation to active factors II, VII, IX and X takes place during adsorption and elution of the SH derivatives. The experiments have indicated that not only factor II but also factors VII, IX and X have active-S-S-centres.

Coupling of partial nitritation and anammox in two- and one-stage systems: Process operation, N2O emission and microbial community

2018 ◽  
Vol 203 ◽  
pp. 559-573 ◽  
Author(s):  
Romain Connan ◽  
Patrick Dabert ◽  
Marina Moya-Espinosa ◽  
Gilbert Bridoux ◽  
Fabrice Béline ◽  
...  
Keyword(s):  
Microbial Community ◽  
N2o Emission ◽  
Partial Nitritation ◽  
One Stage ◽  
Process Operation

Denitrification capacity in the vadose zone at three sites in the Lake Taupo catchment, New Zealand

Soil Research ◽  
2007 ◽  
Vol 45 (2) ◽  
pp. 91 ◽  
Author(s):  
Greg Barkle ◽  
Tim Clough ◽  
Roland Stenger
Keyword(s):  
Vadose Zone ◽  
Root Zone ◽  
Soil Surface ◽  
Gas Production ◽  
The Other ◽  
Carbon Substrate ◽  
Surface Sampling ◽  
Anaerobic Conditions ◽  
Sampling Depth ◽  
N Removal

Land use in the Lake Taupo catchment is under scrutiny, as early signs of deteriorating water quality in Lake Taupo have been observed. Although the fate of contaminants in soil and groundwater are comparatively well studied, the transformations in the lower vadose zone, i.e. the zone between the soil and the groundwater, are less well understood. The capacity for NO3-N removal via biological denitrification, based on utilising the resident C substrate, in the vadose zone of the Lake Taupo catchment is quantified in this work. Complete vadose zone profiles were sampled at 3 sites (Rangiatea, Waihora, and Kinloch), from the soil surface down to the watertable in approximately 0.5-m depth increments. Texture, allophane content, pH, and concentrations of extractable NO3-N, NH4-N, and dissolved organic carbon were determined. Incubations were undertaken to determine the denitrification capacity of the vadose zone materials amended with NO3-15N, but no added carbon substrate, and maintained under anaerobic conditions at 28°C. Gas samples were taken from the headspace after 48 h and analysed for N2 and N2O. In soil depths down to about 1.2 m, the denitrification capacity ranged from 0.03 to 9.18 kg N/ha.day, and below this depth it ranged from <0.01 to 0.09 kg N/ha.day. A palaeosol layer in the Waihora profile had an enhanced denitrification capacity compared with the other samples in deeper zones of the profiles. In the surface sampling, at least 99.9% of the gas recovered from the 15N applied was in the form of N2. In contrast, no N2 gas production could be detected in any sample from below the second sampling depth, with only N2O detected. Denitrification capacities of all vadose zone materials were low when compared with other studies. Thus, careful land management is required to avoid groundwater contamination by nitrate leaching from the root-zone of the pasture.

scholarly journals Pollutants removal, greenhouse gases emission and functional genes in wastewater ecological soil infiltration systems: influences of influent surface organic loading and aeration mode

2021 ◽  
Vol 83 (7) ◽  
pp. 1619-1632
Author(s):  
Jingna Chen ◽  
Zefang Jiang ◽  
Yue Chen ◽  
Yu Qiu ◽  
Tingting Tao ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Removal Efficiency ◽  
Emission Rate ◽  
Oxygen Demand ◽  
N2o Emission ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Soil Infiltration ◽  
N Removal ◽  
Pollutants Removal

Abstract The influences of influent surface organic loading rate (SOLR) and aeration mode on matrix oxygen, organic matter, nitrogen, phosphorus removal, greenhouse gases emission and functional gene abundances in lab-scale wastewater ecological soil infiltration systems (WESISs) were investigated. In WESISs, intermittent or continuous aeration improved oxygen supply at 50 cm depth and hardly changed anaerobic condition below 80 cm depth, which enhanced chemical oxygen demand (COD), NH4+-N, total nitrogen (TN) removal, the abundances of bacterial 16S rRNA, amoA, nxrA, narG, napA, nirK, nirS, qnorB, nosZ genes and reduced CH4, N2O conversion efficiencies with SOLR of 16.9 and 27.6 g BOD/(m2 d) compared with non-aeration. Increased SOLR resulted in high TN removal, low N2O emission in aeration WESIS, which was different from non-aeration WESIS. High average COD removal efficiency of 90.7%, NH4+-N removal efficiency of 87.0%, TN removal efficiency of 84.6%, total phosphorus (TP) removal efficiency of 93.1% and low average N2O emission rate of 12.8 mg/(m2 d) were achieved with SOLR of 16.9 g BOD/(m2 d) in intermittent aeration WESIS. However, continuous aeration WESIS obtained high average removal efficiencies of 90.1% for COD, 87.5% for NH4+-N, 84.1% for TN, 92.9% for TP and low average emission rate of 13.1 mg/(m2 d) for N2O with SOLR of 27.6 g BOD/(m2 d). Aeration could be an optional strategy for WESISs to achieve high pollutants removal and low CH4, N2O emission when treating wastewater with high SOLR.

Does influent COD/N ratio affect nitrogen removal and N2O emission in a novel biochar-sludge amended soil wastewater infiltration system (SWIS)?

2018 ◽  
Vol 78 (2) ◽  
pp. 347-357 ◽  
Author(s):  
Fanping Zheng ◽  
Chaoquan Tan ◽  
Wanyuan Hou ◽  
Linli Huang ◽  
Jing Pan ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Emission Rate ◽  
N2o Emission ◽  
Nitrifying Bacteria ◽  
N2o Emissions ◽  
Intermittent Aeration ◽  
Ratio Increase ◽  
Removal Rates ◽  
N Removal ◽  
Amended Soil

Abstract Nitrogen removal and N2O emission of a biochar-sludge amended soil wastewater infiltration system (SWIS) with/without intermittent aeration under different influent COD/N ratios was investigated. Nitrogen removal and N2O emission were affected by influent COD/N ratio. Under a COD/N ratio between 1:1 and 15:1, average chemical oxygen demand (COD), NH4+-N and total nitrogen (TN) removal rates decreased with COD/N ratio increase in non-aerated SWISs amended with/without biochar-sludge; an increasing COD/N ratio hardly affected COD and NH4+-N removal in a biochar-sludge amended SWIS with intermittent aeration; the N2O emission rate decreased with COD/N ratio increase in the studied SWISs. The biochar-sludge amended SWIS with intermittent aeration achieved high COD (92.2%), NH4+-N (96.8%), and TN (92.7%) removal rates and a low N2O emission rate (10.6 mg/(m2 d)) under a COD/N ratio of 15:1, which was higher than those in non-aerated SWISs amended with/without biochar-sludge. Combining the biochar-sludge amended SWIS with intermittent aeration enhanced the number of nitrifying bacteria, denitrifying bacteria, nitrate reductase activities, nitrite reductase activities, and improved the abundance of nitrogen removal functional genes under a high influent COD/N ratio. The results suggested that the joint use of intermittent aeration and biochar-sludge in a SWIS could be an effective and appropriate strategy for improving nitrogen removal and reducing N2O emissions in treating high COD/N ratio wastewater.

Partial Nitrification in Microaerobic Tank of “Anoxic-Anaerobic- Microaerobic-Aerobic (A2O2)” Biological Nitrogen Removal Process

2013 ◽  
Vol 295-298 ◽  
pp. 1039-1044 ◽  
Author(s):  
Jian Lei Gao ◽  
Bing Nan Lv ◽  
Yi Xin Yan ◽  
Jian Ping Wu
Keyword(s):  
Nitrogen Removal ◽  
Removal Rate ◽  
Pilot Scale ◽  
Partial Nitrification ◽  
Biological Nitrogen Removal ◽  
Nitrogenous Fertilizer ◽  
Removal Process ◽  
Batch Tests ◽  
N Removal ◽  
Biological Nitrogen

The pilot-scale Anoxic-Anaerobic-Microaerobic-Aerobic (A2O2) biological nitrogen removal process was used to treat the wastewater from nitrogenous fertilizer production with C/N ratio of 1~2. Batch tests were conducted to investigate the patial nitrification using the activated sludge from the microaerobic tank rich in nitrite bacteria as the experimental object. Results showed that 95% removal efficiency of NH3-N could be obtained with the HRT of 30 h. The SVI affected the NH3-N removal rate and the optimal SVI was 106 mL/g. The ORP was well correlated with the logarithm of NH3-N concentration with the linear regression equation of y=-57.233x+3.308. Moreover, the kinetic model for partial nitrification was determined as v=4.762s/(9.86+s).

scholarly journals Model-based evaluation of the contribution of partial denitrification (PD) on the one-stage autotrophic nitrogen removal process

2021 ◽  
Author(s):  
Chi Zhang ◽  
Lianze Yu ◽  
Miao Zhang ◽  
Jun Wu
Keyword(s):  
Nitrogen Removal ◽  
Oxygen Demand ◽  
Anammox Bacteria ◽  
Removal Process ◽  
One Stage ◽  
Biofilm Model ◽  
Nitrite Oxidizing Bacteria ◽  
The One ◽  
Steady State Simulation ◽  
Autotrophic Nitrogen Removal

Abstract The nitrate produced by the one-stage partial nitritation-anammox (PN/A) process can be removed through partial denitrification (PD) by adding carbon source. In this study, a 1D multi-population biofilm model was developed to evaluate the contribution of partial denitrification on the one-stage autotrophic nitrogen removal process at influent NH4+ = 100 mg N/L. The dynamic simulation that was carried out to investigate the effect of nitrite-oxidizing bacteria (NOB) revealed that PD contributed to the reactor to obtain total nitrogen removal efficiency (TNR) of above 90% and the effluent nitrate was significantly decreased with the absence of NOB. However, PD decreased TNR of the one-stage PN/A process with the presence of NOB. Increased influent chemical oxygen demand (COD) widened the dissolved oxygen (DO) range required for high TNR whether NOB were present or not. The steady-state simulation results showed that NOB were always absent in the granules at high DO and COD levels and the optimum DO > 0.5 mg/L when influent COD was over 50 mg/L. Besides, higher influent COD/NH4+ (C/N) and larger granule diameter (diameter > 1600 µm) were contributed to widening the range of DO required for high TNR. The nitrogen removal contribution of anammox bacteria (AMX) was significantly higher than denitrification in the reactor.

Nitrogen removal from digested manure in a simple one-stage process

2011 ◽  
Vol 63 (9) ◽  
pp. 1991-1996 ◽  
Author(s):  
J. D. Villegas ◽  
H. Fruteau de Laclos ◽  
J. Dovat ◽  
Y. Membrez ◽  
C. Holliger
Keyword(s):  
Suspended Solids ◽  
Biogas Production ◽  
Gaseous Ammonia ◽  
Ammonia Emissions ◽  
Ammonium Oxidation ◽  
Removal Rates ◽  
Oxidation Activity ◽  
One Stage ◽  
N Removal ◽  
Stage Process

A process based on partial nitrification and recirculation into the anaerobic digester was studied to remove nitrogen from digested manure and thus reduce enhanced gaseous ammonia emissions due to on-farm biogas production. An anaerobic reactor representing an anaerobic manure digester was fed with a nitrite solution and digested manure liquor. Nitrite was efficiently removed from the influent and ammonium formation was observed first. Ammonium was subsequently eliminated up to a maximum of 90% of the influent concentration, indicating anaerobic ammonium oxidation activity. This activity, however, decreased again and was lost at the end of the 4-month operation period. In a 1.5 L aerobic CSTR that was fed with digested manure liquor, ammonium was efficiently removed from the influent. Nitrite and nitrate formation was observed but mass balances indicated significant N-removal. Accumulation of suspended solids was observed at the end of the experiment suggesting presence of oxygen-free environments. In a second test in a 15 L CSTR where suspended solids sedimentation could be avoided, low N-removal rates were observed in the absence of biofilm carrier elements whereas high N-removal rates were achieved in their presence. A simple one-stage process based on immobilized biomass could therefore be installed downstream of agricultural anaerobic digesters in order to mitigate undesirable gaseous ammonia emissions.

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