scholarly journals Impact of microbial activity on the performance of planted and unplanted wetland at laboratory scale

2021 ◽  
Author(s):  
Priyanka Jamwal ◽  
Shahana Shirin
Keyword(s):  
Removal Efficiency ◽  
Operating Conditions ◽  
Loading Rates ◽  
N Removal ◽  
Ammonium N ◽  
Set Up ◽  
Reducing Bacteria ◽  
Nitrate Reducing Bacteria ◽  
P Removal

Abstract Three horizontal subsurface flow constructed wetland prototypes were set up to identify and understand the role of microflora in nutrient removal under diverse operating conditions. Out of three setups, one setup served as a control (without plants), and rest were planted with Typha domingensis. The setups were operated at two different hydraulic loading rates (5 cm/day and 16 cm/day) for two months each. Among 27 bacteria species isolated, 80% of nitrate-reducing bacteria were observed in control, and 50–77% of nitrate-reducing bacteria were observed in the plant setups. Presence of diverse denitrifying bacteria and soil organic carbon contributed to high Nitrate-N removal in control at both HLRs. Similar Ammonium-N (29%) and Ortho-P removal (30%) efficiency was observed at both HLRs in the control setup. Processes such as chemical sorption and adsorption dominated the Ammonium-N and Ortho-P removal in control setup. High average Ammonium-N removal efficiency of 89 and 52% was observed in plant setups at 5 cm/day and 16 cm/day HLR. At low HLR Ammonium-N removal in plant setups was dominated by nutrient uptake. In the plant setups, 35 and 15% Ortho-P removal efficiency was observed at low HLR (5 cm/day) and high HLR (16 cm/day) respectively. Hydraulic Retention Time (HRT) limited the uptake of Ortho-P thereby allowing mineralised phosphorus to escape the system without being absorbed by the plants.

A study of NH3-N and P refixation by struvite formation in hybrid anaerobic reactor

2004 ◽  
Vol 49 (5-6) ◽  
pp. 207-214 ◽  
Author(s):  
J.J. Lee ◽  
C.U. Choi ◽  
M.J. Lee ◽  
I.H. Chung ◽  
D.S. Kim
Keyword(s):  
Removal Efficiency ◽  
Ammonia Nitrogen ◽  
Magnesium Ions ◽  
Nitrogen And Phosphorus ◽  
X Ray ◽  
Naked Eye ◽  
N Removal ◽  
Magnesium Salts ◽  
Main Components ◽  
P Removal

This research is concerned with the removal of ammonia nitrogen and phosphorus in foodwaste by crystallization. Reductions have been achieved by struvite formation after the addition of magnesium ions (Mg2+). Magnesium ions used in this study were from magnesium salts of MgCl2. The results of our analysis using scanning electron microscopy and energy dispersive X-ray analysis showed that the amount of struvite in precipitated sludge grew enough to be seen with the naked eye (600-700μm). EDX analysis also showed that the main components of the struvite were magnesium and phosphorus. NH3-N removal efficiency using MgCl2 was 67% while PO4-P removal efficiency was 73%. It was confirmed that nitrogen and phosphorus could be stabilized and removal simultaneously through anaerobic digestion by Mg, NH3 and PO4-P, which were necessary for struvite formation.

Abiotically or microbially mediated transformations of magnetite by sulphide species: The unforeseen role of nitrate-reducing bacteria

2018 ◽  
Vol 142 ◽  
pp. 31-44 ◽  
Author(s):  
Marjorie Etique ◽  
Alexandre Romaine ◽  
Isabelle Bihannic ◽  
Renaud Gley ◽  
Cédric Carteret ◽  
...  
Keyword(s):  
Reducing Bacteria ◽  
Nitrate Reducing Bacteria

scholarly journals Role of Methanogens and Other Bacteria in Degradation of Dimethyl Sulfide and Methanethiol in Anoxic Freshwater Sediments

1999 ◽  
Vol 65 (5) ◽  
pp. 2116-2121 ◽  
Author(s):  
Bart P. Lomans ◽  
Huub J. M. Op den Camp ◽  
Arjan Pol ◽  
Chris van der Drift ◽  
Godfried D. Vogels
Keyword(s):  
Hydrogen Transfer ◽  
Dimethyl Sulfide ◽  
Methanogenic Bacteria ◽  
Freshwater Sediments ◽  
Freshwater Systems ◽  
Sulfate Reducing ◽  
Degradation Rates ◽  
Reducing Bacteria ◽  
Nitrate Reducing Bacteria

ABSTRACT The roles of several trophic groups of organisms (methanogens and sulfate- and nitrate-reducing bacteria) in the microbial degradation of methanethiol (MT) and dimethyl sulfide (DMS) were studied in freshwater sediments. The incubation of DMS- and MT-amended slurries revealed that methanogens are the dominant DMS and MT utilizers in sulfate-poor freshwater systems. In sediment slurries, which were depleted of sulfate, 75 μmol of DMS was stoichiometrically converted into 112 μmol of methane. The addition of methanol or MT to DMS-degrading slurries at concentrations similar to that of DMS reduced DMS degradation rates. This indicates that the methanogens in freshwater sediments, which degrade DMS, are also consumers of methanol and MT. To verify whether a competition between sulfate-reducing and methanogenic bacteria for DMS or MT takes place in sulfate-rich freshwater systems, the effects of sulfate and inhibitors, like bromoethanesulfonic acid, molybdate, and tungstate, on the degradation of MT and DMS were studied. The results for these sulfate-rich and sulfate-amended slurry incubations clearly demonstrated that besides methanogens, sulfate-reducing bacteria take part in MT and DMS degradation in freshwater sediments, provided that sulfate is available. The possible involvement of an interspecies hydrogen transfer in these processes is discussed. In general, our study provides evidence for methanogenesis as a major sink for MT and DMS in freshwater sediments.

scholarly journals Multi-Year N and P Removal of a 10-Year-Old Surface Flow Constructed Wetland Treating Agricultural Drainage Waters

Agronomy ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 170 ◽  
Author(s):  
Massimo Tolomio ◽  
Nicola Dal Ferro ◽  
Maurizio Borin
Keyword(s):  
Removal Efficiency ◽  
Drainage Basin ◽  
Venice Lagoon ◽  
Surface Flow ◽  
Agricultural Drainage ◽  
Total N ◽  
N Removal ◽  
Nitrogen Concentrations ◽  
Drainage Waters ◽  
P Removal

Surface flow constructed wetlands (SFCWs) can be effectively used to treat agricultural drainage waters, reducing N and P surface water pollution. In the Venice Lagoon drainage basin (northeastern Italy), an SFCW was monitored during 2007–2013 to assess its performance in reducing water, N, and P loads more than 10 years after its creation. Nitrogen concentrations showed peaks during winter due to intense leaching from surrounding fields. Phosphorus concentrations were higher after prolonged periods with no discharge, likely due to mobilization of P of the decomposing litter inside the basin. Over the entire period, N removal efficiency was 83% for NO3–N and 79% for total N; P removal efficiency was 48% for PO4–P and 67% for total P. Values were higher than in several other studies, likely due to the fluctuating hydroperiod that produced discontinuous and reduced outflows. Nitrogen outlet concentrations were reduced by the SFCW, and N removal ratios decreased with increasing hydraulic loading, while no strong correlations were found in the case of P. The SFCW was shown to be an effective long-term strategy to increase water storage and reduce N and P loads in the Venice Lagoon drainage basin.

scholarly journals Role of Mesh Pore Size in Dynamic Membrane Bioreactors

2021 ◽  
Vol 18 (4) ◽  
pp. 1472
Author(s):  
Pompilio Vergine ◽  
Carlo Salerno ◽  
Barbara Casale ◽  
Giovanni Berardi ◽  
Alfieri Pollice
Keyword(s):  
Pore Size ◽  
Membrane Bioreactors ◽  
Operating Conditions ◽  
Major Influence ◽  
Solid Retention Time ◽  
Dynamic Membrane ◽  
Effluent Quality ◽  
Set Up ◽  
High Suction

Two identical bench-scale Self-Forming Dynamic Membrane BioReactors (SFD MBR) were set-up and operated for the treatment of real urban wastewater. The two bioreactors were equipped with meshes of different mesh pore size. Meshes having pore size values of 20 and 50 µm were tested under solid retention time (SRT) of 15 d, whereas meshes with 50 and 100 µm pore sizes were compared under SRT of 50 d. The results of long-term experiments showed very good overall performances by all systems at the steady state. High flux (in the range 61–71 L m−2 h−1) and very good effluent quality were obtained, with average suspended solids and chemical oxygen demanding values below 10 mg L−1 and 35 mg L−1, respectively. The mesh pore size did not have a major influence on the average cleaning frequency. However, the pore size affected the effluent quality in correspondence of two particular conditions: (i) immediately after mesh cleaning; and (ii) during operation under high suction pressures (mesh clogging not promptly removed through cleaning). Moreover, the mesh cleaning frequency was observed to be dependent on the SRT. In tests with 50 d SRT, the cleaning requirements were very low (one every five days), and this limited the influence of the mesh pore size on the effluent quality. In conclusion, in SFD MBR, the role of the mesh pore size on the effluent quality may be more or less relevant depending on the operating conditions that directly influence the Dynamic Membrane formation.

Sex differences in the nitrate-nitrite-NO• pathway: Role of oral nitrate-reducing bacteria

2018 ◽  
Vol 126 ◽  
pp. 113-121 ◽  
Author(s):  
Vikas Kapil ◽  
Krishnaraj S. Rathod ◽  
Rayomand S. Khambata ◽  
Manpreet Bahra ◽  
Shanti Velmurugan ◽  
...  
Keyword(s):  
Sex Differences ◽  
Reducing Bacteria ◽  
Nitrate Reducing Bacteria

scholarly journals Ammonia nitrogen removal and recovery from acetylene purification wastewater by air stripping

2017 ◽  
Vol 75 (11) ◽  
pp. 2538-2545 ◽  
Author(s):  
Lei Zhu ◽  
DeMing Dong ◽  
XiuYi Hua ◽  
Yang Xu ◽  
ZhiYong Guo ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Air Flow ◽  
Ammonia Nitrogen ◽  
Operating Conditions ◽  
H2so4 Solution ◽  
Air Flow Rate ◽  
Air Stripping ◽  
Experimental Conditions ◽  
N Removal

Ammonia nitrogen (NH4-N) contaminated wastewater has posed a great threat to the safety of water resources. In this study, air stripping was employed to remove and recover NH4-N from acetylene purification wastewater (APW) in a polyvinylchloride manufacturing plant. Investigated parameters were initial APW pH, air flow rate, APW temperature and stripping time. The NH4-N removal by air stripping has been modeled and the overall volumetric mass transfer coefficient (KLa) of the stripping process has been calculated from the model equation obtained. In addition, the ability of H2SO4 solution to absorb the NH3 stripped was also investigated. The results indicated that under the experimental conditions, the APW temperature and its initial pH had significant effects on the NH4-N removal efficiency and the KLa, while the effects of other factors were relatively minor. The removal efficiency and residual concentration of NH4-N were about 91% and 12 mg/L, respectively, at the optimal operating conditions of initial APW pH of 12.0, air flow rate of 0.500 m3/(h·L), APW temperature of 60 °C and stripping time of 120 min. One volume of H2SO4 solution (0.2 mol/L) could absorb about 93% of the NH3 stripped from 54 volumes of the APW.

scholarly journals Experimental Simulation of the Behaviour of Diagnostic First Mirrors Fabricated of Different Metals for ITER Conditions

2016 ◽  
Vol 3 (1) ◽  
pp. 23-54 ◽  
Author(s):  
V.S. Voitsenya ◽  
A.F. Bardamid ◽  
A.J.H. Donné
Keyword(s):  
Operating Conditions ◽  
Experimental Simulation ◽  
Science Center ◽  
Plasma Facing Component ◽  
Laser Diagnostic ◽  
Set Up ◽  
The Impact ◽  
Experimental Fusion

In the experimental fusion reactor ITER, the plasma-facing component of each optical and/or laser diagnostic needs to be based on reflective optics with at least one mirror (first mirror) facing the thermonuclear plasma. The different kinds of radiation emanating from the burning plasma (neutrons, neutral atoms, electromagnetic radiation) create hostile operating conditions for the first mirrors. Therefore, a special program has been set up under the ITER framework aimed at solving the first mirror problem. This paper will review the main results in this field that have been obtained in the Institute of Plasma Physics, National Science Center “Kharkov Institute of Physics and Technology” (in many cases in cooperation with groups of other countries, as indicated in corresponding parts of the manuscript) during long-term investigations directed to find a solution of this problem,i.e., to find a material and accompanying precautions in order to satisfy the requirements for first mirrors. The main efforts were devoted to finding solutions to overcome the impact of the most severe deteriorating factors resulting in degradation of the optical properties of mirrors: sputtering by charge exchange atoms and deposition of contaminants. The obtained results are focused on: the effects of long term sputtering on mirror specimens fabricated from different metals with different structures (polycrystals, single crystals, metal film on metal substrates, amorphous), the effects of contaminating film and the possible protection to avoid of its appearance, the role of chemical processes for some metal mirrors, and the choice of material of laser mirrors.

A reconnaissance of tropical resources during Revolutionary years: the role of the Paris Museum d'Histoire Naturelle

1991 ◽  
Vol 18 (3) ◽  
pp. 333-362 ◽  
Author(s):  
MADELEINE LY-TIO-FANE
Keyword(s):  
South Africa ◽  
Natural History ◽  
Scientific Research ◽  
Extensive Literature ◽  
War Of Independence ◽  
Leading Role ◽  
Scientific Principles ◽  
Set Up ◽  
Joseph Ii

SUMMARY The recent extensive literature on exploration and the resulting scientific advances has failed to highlight the contribution of Austrian enterprise to the study of natural history. The leading role of Joseph II among the neutral powers which assumed the carrying trade of the belligerents during the American War of Independence, furthered the development of collections for the Schönbrunn Park and Gardens which had been set up on scientific principles by his parents. On the conclusion of peace, Joseph entrusted to Professor Maerter a world-encompassing mission in the course of which the Chief Gardener Franz Boos and his assistant Georg Scholl travelled to South Africa to collect plants and animals. Boos pursued the mission to Isle de France and Bourbon (Mauritius and Reunion), conveyed by the then unknown Nicolas Baudin. He worked at the Jardin du Roi, Pamplemousses, with Nicolas Cere, or at Palma with Joseph Francois Charpentier de Cossigny. The linkage of Austrian and French horticultural expertise created a situation fraught with opportunities which were to lead Baudin to the forefront of exploration and scientific research as the century closed in the upheaval of the Revolutionary Wars.

Comparative Bio-sorption of Cadmium and Nickel Ions from Aqueous Solution onto Fibers of Date Palm using Fluidized Bed Column

2019 ◽  
Vol 70 (5) ◽  
pp. 1507-1512
Author(s):  
Baker M. Abod ◽  
Ramy Mohamed Jebir Al-Alawy ◽  
Firas Hashim Kamar ◽  
Gheorghe Nechifor
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal ◽  
Metal Ions ◽  
Fluidized Bed ◽  
Removal Efficiency ◽  
Heavy Metal Ions ◽  
Date Palm ◽  
Operating Conditions ◽  
Initial Concentration ◽  
Bed Height

The aim of this study is to use the dry fibers of date palm as low-cost biosorbent for the removal of Cd(II), and Ni(II) ions from aqueous solution by fluidized bed column. The effects of many operating conditions such as superficial velocity, static bed height, and initial concentration on the removal efficiency of metal ions were investigated. FTIR analyses clarified that hydroxyl, amine and carboxyl groups could be very effective for bio-sorption of these heavy metal ions. SEM images showed that dry fibers of date palm have a high porosity and that metal ions can be trapped and sorbed into pores. The results show that a bed height of 6 cm, velocity of 1.1Umf and initial concentration for each heavy metal ions of 50 mg/L are most feasible and give high removal efficiency. The fluidized bed reactor was modeled using ideal plug flow and this model was solved numerically by utilizing the MATLAB software for fitting the measured breakthrough results. The breakthrough curves for metal ions gave the order of bio-sorption capacity as follow: Cd(II)]Ni(II).

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