The Role of Microbial Biofilm in Removing Ammonia in Floating Treatment Wetlands

Abstract Laboratory experiments were conducted under controlled conditions to quantify the potential of microbial transformation associated with floating matrix of floating treatment wetland (FTW) in ammonia removal and nitrification kinetics. The effect of different design parameters on ammonia removal from synthetic medium was investigated to optimize system performance. Effects of surface area of mat material, range of ammonia concentrations, and aeration on ammonia removal kinetics were studied using microcosm systems. A simple dynamics model of mineral nitrogen transformation was used as a framework for interpreting the experimental results. The results revealed that ammonia removal was enhanced in FTWs, and the magnitude of removal was controlled by the design factors examined. Removal by nitrification was directly proportional to mat surface area. The higher ammonia removal efficiency was caused by a larger surface area, which could support the growth of more microbes. Removal rate constants for treatments were 0.011, 0.015, 0.026, 0.035, and 0.033 day–1 for T1, T2, T3, T4, and T5, respectively. There was also a clear inhibitory effect of NH3 on second-stage nitrification manifested as low production of NO3–. Quantitative index of optimized knit/calibrated knit indicated high inhibition effects of NH3 at high concentration of total ammonia (60 mg N L–1). There was no major effect of oxygen saturation on NHx removal using aerated and nonaerated conditions. Better mechanistic understanding of the fundamental processes operating in FTWs should provide the basis for improving FTW design and efficacy.

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Biological treatment of ammonia gas at high loading

Water Science & Technology ◽

10.2166/wst.2004.0285 ◽

2004 ◽

Vol 50 (4) ◽

pp. 283-290 ◽

Cited By ~ 9

Author(s):

T. Kanagawa ◽

H.W. Qi ◽

T. Okubo ◽

N. Tokura

Keyword(s):

Removal Rate ◽

Space Velocity ◽

Packed Bed ◽

Porous Ceramics ◽

Ammonia Removal ◽

Ammonium Ion ◽

Nitrifying Bacteria ◽

High Concentration ◽

Ammonia Gas ◽

Cylinder Diameter

The exhaust gas from compost processing plants contains a large amount of ammonia. To treat ammonia gas at high loads, bench-scale experiments were carried out. First, nitrifying bacteria were enriched from soil and immobilized on porous ceramics. The ceramics were packed in an acrylic cylinder (diameter, 100 mm; packed height, 190 mm) and ammonia gas was introduced to the top of the cylinder. The concentration and flow rate of ammonia gas were gradually increased and finally 85 ppm was introduced at a space velocity of 800 h-1 (empty bed residence time (EBRT), 4.5 sec). The ammonia load was 1.0 kg N/m3 day-1. The exhaust contained 1.5-2 ppm of ammonia. Then the packed ceramics were transferred to another acrylic cylinder (diameter, 50 mm; packed height, 800 mm). A high concentration of ammonia gas (1,000 ppm) was introduced at a space velocity of 96 h-1 (ammonia loading, 1.44 kg N/m3 day-1; EBRT, 37.5 sec). The exhaust contained 2 ppm of ammonia (removal rate, 99.8%). The packed bed was washed with water intermittently or continuously, and the wastewater from the cylinder contained a large amount of ammonium and nitrate ions of at a 1:1 ratio. Stoichiometric analysis showed that half of the introduced ammonia was oxidized to nitrate, and the rest was converted to ammonium ion. Thus, ammonia gas was effectively treated at a high load by biofiltration with nitrifying bacteria.

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High-Rate Nitrification Using Aerobic Granular Sludge

Water Science & Technology ◽

10.2166/wst.2006.087 ◽

2006 ◽

Vol 53 (3) ◽

pp. 147-154 ◽

Cited By ~ 16

Author(s):

S. Tsuneda ◽

M. Ogiwara ◽

Y. Ejiri ◽

A. Hirata

Keyword(s):

Activated Sludge ◽

Removal Rate ◽

Granular Sludge ◽

Ammonia Removal ◽

High Rate ◽

Pure Oxygen ◽

Synthetic Wastewater ◽

Aerobic Granular Sludge ◽

Fluidised Bed ◽

High Concentration

The performance of nitrifying granules, which had been produced in an aerobic upflow fluidised bed (AUFB) reactor, was investigated in various types of ammonia-containing wastewaters. When pure oxygen was supplied to the AUFB reactor with a synthetic wastewater containing a high concentration of ammonia (500 g-N/m3), the ammonia removal rate reached 16.7 kg-N/m3/day with a sustained ammonia removal efficiency of more than 80%. The nitrifying granules possessing a high settling ability could be retained with a high density (approximately 10,000 g-MLSS/m3) in a continuous stirring tank reactor (CSTR) even under a short hydraulic retention time (44 min), which enabled a high-rate and stable nitrification for an inorganic wastewater containing low concentrations of ammonia (50 g-N/m3). Moreover, the nitrifying granules exhibited sufficient performance in the nitrification of real industrial wastewater containing high concentrations of ammonia (1,000–1,400 g-N/m3) and salinity (1.2–2.2%), which was discharged from metal-refinery processes. When the nitrifying granules were used in cooperation with activated sludge to treat domestic wastewater containing organic pollutants as well as ammonia, they fully contributed to nitrification even though a part of activated sludge adhered onto the granule surfaces to form biofilms. These results show the wide applicability of nitrifying granules to various cases in the nitrification step of wastewater treatment plants.

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Study on the Industrial Wastewater Treatment by Modified Bentonite

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.182-183.323 ◽

2012 ◽

Vol 182-183 ◽

pp. 323-327 ◽

Cited By ~ 1

Author(s):

Hong Shao ◽

Zhi Fang Zhang ◽

Ning Cao

Keyword(s):

Surface Area ◽

Removal Rate ◽

Mixing Time ◽

Monosodium Glutamate ◽

Basic Structure ◽

Raw Material ◽

Coking Wastewater ◽

High Concentration ◽

Modified Bentonite ◽

Cod Removal Rate

The natural bentonite as raw material, chitosan as a modifier to prepare chitosan modified bentonite. The use of modified bentonite, each dealing with a high concentration of COD monosodium glutamate (MSG)wastewater and coking wastewater .The optimal conditions: mixing time : 10 ~ 12 min;centrifugation time :25 ~ 30min; PH: 8.5 ~ 9.5; dosage: 10~14g / L. The results showed that the treatment of modified bentonite is better than the bentonite and chitosan. The COD removal rate of MSG wastewater and coking wastewater were 60.1% and 82.3%. So the treatment of coking wastewater is efficiency.. By scanning electron microscopy, surface area and X-ray diffraction analysis shows that modification does not change the basic structure of the bentonite only increased the specific surface area of bentonite, and the adsorption capacity of pollutants.

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Impact of Raw Water Ammonia on the Surface Water Treatment Processes and Its Removal by Nitrification

Bangladesh Journal of Microbiology ◽

10.3329/bjm.v24i2.1249 ◽

1970 ◽

Vol 24 (2) ◽

pp. 85-89 ◽

Cited By ~ 1

Author(s):

M Alamgir Hossain ◽

ANM Fakhruddin ◽

Sirajul Islam Khan

Keyword(s):

Water Quality ◽

Water Treatment ◽

Surface Water ◽

Removal Rate ◽

Treatment Plant ◽

Ammonia Removal ◽

Raw Water ◽

High Concentration ◽

Treated Water ◽

Treatment Processes

Impact of raw water ammonia on the treated water quality and removal of ammonia from surface water were studied. Raw water ammonia and physicochemical quality of treated water of Saidabad Water Treatment Plant were analyzed for the period of one year (January through December 2006). The monthly averages of maximum (7.55 mg/l) and minimum (0.34 mg/l) ammonia-N level of the raw water were recorded in March and September 2006 respectively. During dry season raw water containing high concentration of ammonia reacted with chlorine at pre-chlorination step of treatment processes and disrupted the total treatment system. It was found from the study that when the concentration of ammonia was high in raw water the aesthetic characters such as turbidity, colour, taste, odour, alkalinity, total dissolved solids (TDS), conductivity, total chlorine etc. of the treated water were changed significantly. Chemical consumption is increased as a result water treatment costs is increased. To mitigate the above problems of the treated water nitrification was used for the removal of ammonia from raw water. Ammonia removal rate was monitored with some other water quality parameters during the study. In the nitrification process ammonia was removed from raw water very effectively, i.e., maximum about 98% raw water ammonia was removed during the study. Additionally other water quality factors were improved significantly.Keywords: Raw water, Treated water, Raw water ammonia, Water quality, NitrificationDOI: http://dx.doi.org/10.3329/bjm.v24i2.1249 Bangladesh J Microbiol, Volume 24, Number 2, December 2007, pp 85-89

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Measurement of the Platelet Response to Laser- induced Microvascular Injury

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648118 ◽

1974 ◽

Vol 32 (02/03) ◽

pp. 704-713 ◽

Cited By ~ 2

Author(s):

F. N McKenzie ◽

K.-E Arfors ◽

N. A Matheson

Keyword(s):

Inhibitory Effect ◽

Microvascular Blood Flow ◽

Platelet Response ◽

High Concentration ◽

Platelet Activity ◽

Microvascular Injury ◽

Arterial Blood ◽

Proximal Site ◽

Adenosine Phosphates

SummaryA study has been made of the biochemical factors underlying the platelet response to laser-induced microvascular injury. A platelet aggregating substance is produced at sites of laser-induced injury which markedly stimulates platelet activity at a site of injury inflicted a short distance downstream. Distal sites of injury are not similarly influenced if the distance between the injuries is increased or if the proximal site no longer shows platelet-stimulating activity. The stimulating effect of an adjacent proximal injury on platelet activity at a distal site is inhibited by local intra-arterial infusion of adenosine. Measurements of arterial blood pressure and microvascular blood flow velocity during adenosine infusion showed that its inhibitory effect on platelet activity is largely independent of its vasodilator properties. The effect of infusion of different adenosine phosphates (AMP, ADP, ATP) was also studied. Very small amounts of ADP markedly stimulated platelet activity and the emboli formed were similar to those normally produced at sites of laser injury. At high concentration AMP inhibited while ATP stimulated platelet activity in vivo. The results emphasise the fundamental role of ADP as a mediator of the platelet response at sites of laser- induced microvascular injury.

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Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

10.26434/chemrxiv.7770338.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Kailun Yang ◽

Recep Kas ◽

Wilson A. Smith

Keyword(s):

Surface Area ◽

High Surface ◽

High Surface Area ◽

Catalyst Layer ◽

Active Surface ◽

Active Surface Area ◽

High Concentration ◽

Copper Electrodes ◽

Surface Enhanced ◽

Local Current

This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO2 electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO2 electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO2 electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer.

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Ti/RuO2-IrO2-SnO2 Anode for Electrochemical Degradation of Pollutants in Pharmaceutical Wastewater: Optimization and Degradation Performances

Sustainability ◽

10.3390/su13010126 ◽

2020 ◽

Vol 13 (1) ◽

pp. 126

Author(s):

Guozhen Zhang ◽

Xingxing Huang ◽

Jinye Ma ◽

Fuping Wu ◽

Tianhong Zhou

Keyword(s):

Removal Rate ◽

Inorganic Compounds ◽

Oxide Coating ◽

X Ray Diffraction ◽

Pharmaceutical Wastewater ◽

High Concentration ◽

Dimensionally Stable Anodes ◽

X Ray ◽

Initial Ph ◽

Cod Removal Rate

Electrochemical oxidation technology is an effective technique to treat high-concentration wastewater, which can directly oxidize refractory pollutants into simple inorganic compounds such as H2O and CO2. In this work, two-dimensionally stable anodes, Ti/RuO2-IrO2-SnO2, have been developed in order to degrade organic pollutants from pharmaceutical wastewater. Characterization by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) showed that the oxide coating was successfully fabricated on the Ti plate surface. Electrocatalytic oxidation conditions of high concentration pharmaceutical wastewater was discussed and optimized, and the best results showed that the COD removal rate was 95.92% with the energy consumption was 58.09 kW·h/kgCOD under the electrode distance of 3 cm, current density of 8 mA/cm2, initial pH of 2, and air flow of 18 L/min.

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Heterogeneous Photo-Fenton Catalytic Degradation of Practical Pharmaceutical Wastewater by Modified Attapulgite Supported Multi-Metal Oxides

Water ◽

10.3390/w13020156 ◽

2021 ◽

Vol 13 (2) ◽

pp. 156

Author(s):

Manjing Lu ◽

Jiaqi Wang ◽

Yuzhong Wang ◽

Zhengguang He

Keyword(s):

Photocatalytic Oxidation ◽

Removal Rate ◽

Catalytic Degradation ◽

Gas Chromatography Mass Spectrometry ◽

Pharmaceutical Wastewater ◽

High Concentration ◽

Modified Attapulgite ◽

Cod Removal Rate ◽

Pre Treatment ◽

Almost All

Chemical synthetic pharmaceutical wastewater has characteristics of high concentration, high toxicity and poor biodegradability, so it is difficult to directly biodegrade. We used acid modified attapulgite (ATP) supported Fe-Mn-Cu polymetallic oxide as catalyst for multi-phase Fenton-like ultraviolet photocatalytic oxidation (photo-Fenton) treatment with actual chemical synthetic pharmaceutical wastewater as the treatment object. The results showed that at the initial pH of 2.0, light distance of 20 cm, and catalyst dosage and hydrogen peroxide concentration of 10.0 g/L and 0.5 mol/L respectively, the COD removal rate of wastewater reached 65% and BOD5/COD increased to 0.387 when the reaction lasted for 180 min. The results of gas chromatography-mass spectrometry (GC-MS) indicated that Fenton-like reaction with Fe-Mn-Cu@ATP had good catalytic potential and significant synergistic effect, and could remove almost all heterocycle compounds well. 3D-EEM (3D electron microscope) fluorescence spectra showed that the fluorescence intensity decreased significantly during catalytic degradation, and the UV humus-like and fulvic acid were effectively removed. The degradation efficiency of the nanocomposite only decreased by 5.8% after repeated use for 6 cycles. It seems appropriate to use this process as a pre-treatment for actual pharmaceutical wastewater to facilitate further biological treatment.

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Fresh State Behaviour of Cement Paste Containing Nano Kaolin

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.925.28 ◽

2014 ◽

Vol 925 ◽

pp. 28-32 ◽

Cited By ~ 1

Author(s):

Muhd Sidek Muhd Norhasri ◽

M.S. Hamidah ◽

A. Mohd Fadzil ◽

A.G. Abd Halim ◽

M.R. Zaidi

Keyword(s):

Surface Area ◽

Cement Paste ◽

Setting Time ◽

High Energy ◽

Major Effect ◽

Cement Replacement ◽

High Energy Milling ◽

Replacement Method ◽

Fresh State ◽

State Behaviour

The application of nanomaterials in cement by replacement method in concrete is becoming a trend in cement research. The utilisation of nanosilica, nanoalumina, titanium oxide and others are proven to enhance properties of concrete. The major effect of nanomaterials is its size in which it contributes to the packing theory due to increase in the surface area. nanokaolin which comes from kaolin, was tansformed to the nanoform by using high energy milling. The process of developing nanokaolin by using high energy milling is referred to process top to bottom approach in nanoprocessing technique. In this research, the nanokaolin will be used as an additive in cement by 7% weight of cement. Four (4) cement replacement materials catered by using metakaolin on weight basis from 0, 10%, 20% and 30% will also be adopted. To determine the fresh state, cement paste contains nanokaolin and metakaolin are tested its standard consistency and setting time. The effect of the inclusion of the nanokaolin as additive in cement paste that also contains metakaolin as cement replacement material will be investigated. It was found the inclusion of 7% nanokaolin increases the water demand of the cement paste level of metakaolin replacement. In addition to that, the setting time namely initial and final set was been delayed as compared to that of plain OPC. The nanoparticles of nanokaolin and also finer particles of metakaolin increase the surface area and refining the internal structure of cement paste which reduce the flow capabilities of cement paste containing nanokaolin and metakaolin.

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Evaluation of the corrosion behavior of AZ31 magnesium alloy with different protein concentrations

Anti-Corrosion Methods and Materials ◽

10.1108/acmm-08-2021-2524 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Yucong Ma ◽

Mohd Talha ◽

Qi Wang ◽

Zhonghui Li ◽

Yuanhua Lin

Keyword(s):

Corrosion Resistance ◽

Corrosion Behavior ◽

Electrochemical Impedance ◽

Surface Film ◽

Energy Dispersive Spectrometer ◽

Inhibitory Effect ◽

Corrosion Process ◽

High Concentration ◽

Content Type ◽

Atomic Force

Purpose The purpose of this paper is to study systematically the corrosion behavior of AZ31 magnesium (Mg) alloy with different concentrations of bovine serum albumin (BSA) (0, 0.5, 1.0, 1.5, 2.0 and 5.0 g/L). Design/methodology/approach Electrochemical impedance spectroscopy and potential dynamic polarization tests were performed to obtain corrosion parameters. Scanning electrochemical microscopy (SECM) was used to analyze the local electrochemical activity of the surface film. Atomic force microscope (AFM), Scanning electron microscope-Energy dispersive spectrometer and Fourier transform infrared spectroscopy were used to determine the surface morphology and chemical composition of the surface film. Findings Experimental results showed the presence of BSA in a certain concentration range (0 to 2.0 g/L) has a greater inhibitory effect on the corrosion of AZ31, however, the presence of high-concentration BSA (5.0 g/L) would sharply reduce the corrosion resistance. Originality/value When the concentration of BSA is less than 2.0 g/L, the corrosion resistance of AZ31 enhances with the concentration. The adsorption BSA layer will come into being a physical barrier to inhibit the corrosion process. However, high-concentration BSA (5.0 g/L) will chelate with dissolved metal ions (such as Mg and Ni) to form soluble complexes, which increases the roughness of the surface and accelerates the corrosion process.

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