Sulphate Reducing Bacteria for the Treatment of Heavy Metals Contaminated Waters in Permeable Reactive Barriers

2009 ◽  
Vol 71-73 ◽  
pp. 565-568 ◽  
Author(s):  
Carolina Cruz Viggi ◽  
Francesca Pagnanelli ◽  
Alessio Cibati ◽  
C. Berteletti ◽  
Luigi Toro
Keyword(s):  
Fixed Bed ◽  
Operating Conditions ◽  
Permeable Reactive Barriers ◽  
Electron Donors ◽  
Silica Sand ◽  
Fixed Bed Column ◽  
Batch Tests ◽  
Reactive Mixture ◽  
Reducing Bacteria ◽  
Blank Column

The aim of the work was the comparison between a selected reactive mixture containing organic matter for SRB and other electron donors, such as ethanol and polysaccharides. The comparison was performed in order to select the best operating conditions in terms of organic sources for SRB. A continuously operating fixed-bed column was filled with a batch-optimised solid reactive mixture (6% leaves, 9% compost, 3% zero valent iron, 30% silica sand, 30% perlite, 22% limestone) and inoculated by SRB. At steady state 50±10% sulphate abatement was reached and metals were totally removed. Batch tests with ethanol showed the ability of SRB to grow on this substrate efficiently. Experimentation using ethanol was performed using two different column reactors filled with perlite, one inoculated by SRB and the other used as blank. Sulphate abatements of the inoculated column were 70±10% against 10±5% of the blank column. Preliminary batch tests with polysaccharides showed the ability of bacteria to grow on these substrates.

Predictions of Xylene Adsorption on Agglomerated Activated Carbon Pellets in a Fixed Bed Column

2014 ◽  
Vol 802 ◽  
pp. 636-641
Author(s):  
Izabel de Oliveira da Mota ◽  
Leonardo Martins da Silva ◽  
José Adilson de Castro
Keyword(s):  
Activated Carbon ◽  
Effective Means ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Author Study ◽  
Fixed Bed Column ◽  
Carbon Particles ◽  
Volatile Organic ◽  
Gaseous Stream ◽  
Activated Carbon Particles

Volatile organic compounds (VOCs) are an important category of air pollutants and adsorption has been widely recognized as an effective means of controlling emissions to the atmosphere. The current study used theoretical model to analyze the rate of xylene adsorption from inert gaseous stream on the granular activated carbon in a fixed bed column under varying operating conditions. The model considers the inner diffusion of VOC into the activated carbon particles. Experimental results of another author study were used to validate the present model and the methodology proposed to determine the xylene concentrations at the outlet of the column and corresponding inner particles.

scholarly journals Fixed-bed Column Dynamics of Ultrasound and Na-functionalized Diatomite to Remove Phosphate from Water

2021 ◽  
Author(s):  
Junxiu Ye ◽  
Min Yang ◽  
Xuemei Ding ◽  
Wei Tan ◽  
Guizhen Li ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Correlation Coefficients ◽  
Operating Conditions ◽  
Phosphate Adsorption ◽  
Breakthrough Time ◽  
Fixed Bed Column ◽  
Bed Height ◽  
Column Dynamics ◽  
Phosphorous Concentration ◽  
Column Process

Abstract A continuous fixed-bed column study has been used to evaluate phosphate adsorption performance of U-D-Na which was functionalized by the cheap NaCl reagent after simple ultrasonic purification of diatomite. Experimentally, various effect factors, the flow rate, the initial phosphate concentration, and the bed height on breakthrough time of fixed column were studied. Experimental results showed that the breakthrough time declined with the increase of inlet phosphorous concentration and feed rate, whereas the increase of bed height turned out to significantly prolong the breakthrough time. The dynamic adsorption data could better be fitted by the Thomas model, with the correlation coefficients obtained, R2 > 0.9000 at the majority of operating conditions (5/7). At least thrice loop of adsorption and desorption was achieved with 0.1 M hydrochloric acid eluent and deionized water. The results proved that U-D-Na could be used as a better alternative phosphate adsorbent from wastewater in a continuous column process.

scholarly journals Desorption of Vitamin E from Silica-Packed Fixed-Bed Column by Isopropanol

2010 ◽  
Vol 6 (5) ◽  
Author(s):  
Boon-Seang Chu ◽  
Siew-Young Quek ◽  
Badlishah Sham Baharin ◽  
Yaakob Bin Che Man
Keyword(s):  
Vitamin E ◽  
Flow Rate ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Desorption Rate ◽  
Fixed Bed Column ◽  
Desorption Process ◽  
Column Temperature ◽  
Percentage Recovery ◽  
Bed Height

Desorption of vitamin E from silica-packed fixed-bed column was studied as functions of column bed height, column temperature and flow rate of isopropanol. Isopropanol was the desorbing solvent and it was eluted through the columns saturated with vitamin E. The desorption profiles of all systems showed that vitamin E might desorb at two distinct rates simultaneously. The slow desorbing step was the rate-controlling process for recovery of vitamin E. The desorption rate increased with the decrease of column bed height and flow rate, but increased with increasing column temperature. This indicated that the desorption process was an endothermic process. The percentage recovery of vitamin E upon completion of desorption was considered high for all systems, ranging from 94.8 to 98.8%, with vitamin E concentration in the extract of 18.5-21.5%. Although the bed height, column temperature and flow rate were functions of desorption rate, it appeared that percentage recovery and vitamin E concentration in the extract were rather unaffected by the operating conditions tested if the column was eluted by isopropanol for a sufficient time to desorb vitamin E. Nevertheless, the use of isopropanol would be more efficient if desorption was carried out at lower flow rate and higher column temperature.

scholarly journals Experimental and Numerical Study of Biochar Fixed Bed Column for the Adsorption of Arsenic from Aqueous Solutions

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 915
Author(s):  
Maria Rosaria Boni ◽  
Simone Marzeddu ◽  
Fabio Tatti ◽  
Massimo Raboni ◽  
Giuseppe Mancini ◽  
...  
Keyword(s):  
Contact Time ◽  
Laboratory Tests ◽  
Numerical Study ◽  
Low Cost ◽  
Kinetic Constant ◽  
Fixed Bed ◽  
Permeable Reactive Barriers ◽  
Fixed Bed Column ◽  
Economic Concept ◽  
Time Required

Two laboratory tests were carried out to verify the suitability of an Italian commercial biochar as an adsorbing material. The chosen contaminant, considered dissolved in groundwater, was As. The circular economic concept demands the use of such waste material. Its use has been studied in recent years on several contaminants. The possibility of using an efficient material at low cost could help the use of low-impact technologies like permeable reactive barriers (PRBs). A numerical model was used to derive the kinetic constant for two of the most used isotherms. The results are aligned with others derived from the literature, but they also indicate that the use of a large amount of biochar does not improve the efficiency of the removal. The particular origin of the biochar, together with its grain size, causes a decrease in contact time required for the adsorption. Furthermore, it is possible that a strong local decrease in the hydraulic conductibility does not allow for a correct dispersion of the flow, thereby limiting its efficiency.

Modeling of breakthrough curves for aqueous iron (III) adsorption on chitosan-sodium tripolyphosphate

2016 ◽  
Vol 74 (10) ◽  
pp. 2297-2304 ◽  
Author(s):  
Dalia I. Sánchez-Machado ◽  
Jaime López-Cervantes ◽  
Ma. A. Correa-Murrieta ◽  
Reyna G. Sánchez-Duarte
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Adsorption Process ◽  
Sodium Tripolyphosphate ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Operating Conditions ◽  
Feed Concentration ◽  
Fixed Bed Column ◽  
Continuous Adsorption

A fixed bed column packed with chitosan-sodium tripolyphosphate (CTPP) beads was used to remove aqueous Fe (III) ions. The adsorption of Fe (III) ions on CTPP beads was found to be dependent on operating conditions, such as the flow rate, adsorbent bed length, and feed concentration. The experimental data were assessed with Thomas, Adams-Bohart and Yoon-Nelson models to predict the breakthrough curves using linear regression. The breakthrough curves were better fitted with the Thomas and Yoon-Nelson models when the flow rate was varied and the feed concentration and the bed height of the column were fixed. Therefore, chemical adsorption may be the limiting step that controls the continuous adsorption process. The Adams-Bohart model presented a good fit to the experimental data, showing that external mass transfer was controlling the adsorption process in the initial part of the breakthrough curves. The parameters obtained from the continuous adsorption assays may be used as a basis for designing columns packed with CTPP beads for the removal of Fe (III) ions.

scholarly journals Optimasi Adsorpsi Ion Mg2+ pada Fixed Bed Column dengan Menggunakan Response Surface Methodology

REAKTOR ◽  
2017 ◽  
Vol 17 (3) ◽  
pp. 126
Author(s):  
Novi Sylvia ◽  
Meriatna Meriatna ◽  
Fikri Hasfita ◽  
Lukman Hakim
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Flow Rate ◽  
Adsorption Process ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Process Variables ◽  
Fixed Bed Column ◽  
Box Behnken Design

Abstract OPTIMIZATION ADSORPTION OF Mg2+ ION ON FIXED BED COLUMN USING RESPONSE SURFACE METHODOLOGY. Modeling of the adsorption process is used to establish the mathematical relationship between the interacting process variables and process optimization. This is important to determine the factor values that produce a maximum response. Adsorption of Mg from groundwater was optimized using response surface methodology based on Box-Behnken design was used to analyze adsorption data. The process was investigated by continuous experiments. Variables included in the process were: bed depths (7.5, 10, and 12.5 cm), time (20, 40, and 60 min), and flow rate (6, 10, and 14 L/min). Regression analysis was used to analyze the developed models. The outcome of this research showed that 72.784% of the variability in removal efficiency is attributed to the three process variables considered, that is, bed depths, time, and flow rate. Optimization tests showed that the optimum operating conditions for the adsorption process occurred at a bed depth of 11.37 cm, time of 55.53 min and flow rate of 6 L/min. Keywords: adsorption; Box-Behnken design; magnesium (Mg2+); optimization  AbstrakPemodelan dari proses adsorpsi digunakan untuk menentukan hubungan matematis antara variabel proses interaksi dan proses optimasi. Hal ini penting untuk menentukan nilai faktor yang menghasilkan respon maksimum. Adsorpsi magnesium (Mg2+) dari air tanah dioptimalkan menggunakan metodologi respon permukaan model Desain Box-Behnken yang digunakan untuk menganalisis data adsorpsi. Percobaan dilakukan secara kontinyu. Variabel yang termasuk dalam proses tersebut adalah: tinggi unggun (7,5, 10 dan 12,5 cm), waktu kontak (20, 40, dan 60 menit), dan laju alir (6, 10, dan 14 L/menit). Analisis regresi digunakan untuk menganalisis model yang dikembangkan. Hasil penelitian menunjukkan bahwa 72,784% efisiensi penyisihan Mg2+ ditentukan oleh tiga variabel proses, yaitu tinggi unggun, waktu kontak, dan laju alir. Hasil optimasi menunjukkan bahwa kondisi operasi optimum untuk proses adsorpsi terjadi pada tinggi unggun 11,37 cm, waktu kontak 55,53 menit dan laju alir 6 L/menit. Kata kunci: adsorpsi; Box-Behnken desain; magnesium (Mg2+); optimasi

Breakthrough analysis for hexavalent chromium removal from drinking water in a fixed bed column

2009 ◽  
Vol 9 (6) ◽  
pp. 661-670 ◽  
Author(s):  
S. P. Dubey ◽  
K. Gopal
Keyword(s):  
Aqueous Solution ◽  
Hexavalent Chromium ◽  
Fixed Bed ◽  
Entropy Change ◽  
Spectroscopic Technique ◽  
Fixed Bed Column ◽  
Chromium Vi ◽  
Fixed Bed Adsorption ◽  
Optimal Column ◽  
Eucalyptus Bark

The activated carbon of Eucalyptus globulus was tested for their effectiveness in removing hexavalent chromium from aqueous solution using column experiments. Result revealed that adsorption of chromium(VI) on eucalyptus bark carbon was endothermic in nature. Thermodynamic parameters such as the entropy change, enthalpy change and Gibbs free energy change were found to be 1.39 kJ mol−1 K−1, 1.08 kJ mol−1 and −3.85 kJ mol−1, respectively. Different chromium concentrations were used for the fixed bed adsorption studies. The pre- and post-treated adsorbents were characterized using a FTIR spectroscopic technique. It was concluded that Eucalyptus bark carbon column could be used effectively for removal of hexavalent chromium from aqueous solution at optimal column conditions. This study showed that this biological material is potential adsorbent of Cr(VI) from water.

Tertiary Nitrification Pilot Plants on Parisian Waste Water

1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles
Keyword(s):  
Waste Water ◽  
Metropolitan Area ◽  
Fixed Bed ◽  
Point Of View ◽  
Operating Conditions ◽  
Research Center ◽  
Daily Output ◽  
Practical Point ◽  
Fixed Bed Reactors

The Paris Metropolitan area, which contains over eight million inhabitants, has a daily output of about 3 M cu.meters of wastewater, the purification of which is achieved by SIAAP (Paris Metropolitan Area Sewage Service) in both Achères and Valenton plants. The carbon pollution is eliminated from over 2 M cu.m/day at Achères. In order to improve the quality of output water, its tertiary nitrification in fixed-bed reactors has been contemplated. The BIOFOR (Degremont) and BIOCARBONE (OTV) processes could be tested in semi-industrial pilot reactors at the CRITER research center of SIAAP. At a reference temperature of 13°C, the removed load is approximately 0.5 kg N NH4/m3.day. From a practical point of view, it may be asserted that in such operating conditions as should be at the Achères plant, one cubic meter of filter can handle the tertiary nitification of one cubic meter of purified water per hour at an effluent temperature of 13°C.

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