Développement d'une technologie de biorémediation efficace pour l'élimination des composés monoaromatiques volatils des eaux contaminées

The work reported focus on the biodegradation of volatile aromatic compounds (benzene, toluene, xylenes) present in aqueous solutions. The main issue addressed is quantification and control of gas-liquid solute transfers. These transfers lead to organic compounds loss in the gas at each step of handling of an aqueous solution. It has been demonstrated that biomass removal from a liquid suspension must be performed with special care and a protocol based on centrifugation with Teflon capped, filled tubes is proposed. A new protocol for determination of solute activity coefficient at infinite dilution, also based on centrifugation experiments, is presented. Main work at the microbial level reveals that solute stripping in gassed systems cannot be avoided, even with the use of liquid-liquid systems. An anaerobic approach, involving a nitrate-respiring bacterium, is shown to have a great potential when used in combination with heterogeneous media.Le travail rapporté porte sur la biodégradation des composés aromatiques volatils (benzène, toluène, xylènes) en solution aqueuse. La principale question abordée est la quantification et le contrôle des transferts gaz-liquide de soluté. Il a été démontré que la séparation de la biomasse d'un liquide doit être effectuée avec une attention particulière et un protocole basé sur la centrifugation de la suspension est proposé. Une nouvelle technique pour la détermination expérimentale du coefficient d'activité à dilution infinie, également basée sur des expériences de centrifugation est présentée. Le travail principal au niveau microbien révèle que les pertes de soluté par stripping gazeux ne peuvent pas être évitées même avec l'utilisation d'un système biphasique liquide-liquide. Une approche anaérobie mettant en oeuvre une bactérie effectuant la respiration des nitrates a montré que cette technique pouvait présenter un grand intérêt lorsqu'elle est utilisée avec un milieu hétérogène

Développement d'une technologie de biorémediation efficace pour l'élimination des composés monoaromatiques volatils des eaux contaminées

Le travail rapporté porte sur la biodégradation des composés aromatiques volatils (benzène, toluène, xylènes) en solution aqueuse. La principale question abordée est la quantification et le contrôle des transferts gaz-liquide de soluté. Il a été démontré que la séparation de la biomasse d'un liquide doit être effectuée avec une attention particulière et un protocole basé sur la centrifugation de la suspension est proposé. Une nouvelle technique pour la détermination expérimentale du coefficient d'activité à dilution infinie, également basée sur des expériences de centrifugation est présentée. Le travail principal au niveau microbien révèle que les pertes de soluté par stripping gazeux ne peuvent pas être évitées même avec l'utilisation d'un système biphasique liquide-liquide. Une approche anaérobie mettant en oeuvre une bactérie effectuant la respiration des nitrates a montré que cette technique pouvait présenter un grand intérêt lorsqu'elle est utilisée avec un milieu hétérogèneCLERMONT FD-BCIU Sci.et Tech. (630142101) / SudocSudocFranceF

Decolorization of Ionic Dyes from Synthesized Textile Wastewater by Nanofiltration Using Response Surface Methodology

Decolorization of aqueous solutions containing ionic dyes (Reactive Blue 19 and Acid Black 172) by a TFC commercial polyamide nanofilter (NF) in a spiral wound configuration was studied. The effect of operating parameters including feed concentration (60-180 mg/l), pressure (0.5-1.1 MPa) and pH (6-10) on dye removal efficiency was evaluated. The response surface method (RSM) was utilized for the experimental design and statistical analysis to identify the impact of each factor. The results showed that an increase in the dye concentration and pH can significantly enhance the removal efficiency from 88% and 87% up to 95% and 93% for Reactive and Acid dye, respectively. The effect of pressure on the removal efficiency showed different behavior such that by the raise of pressure from 0.5 to 0.8 MPa, the removal efficiency increased to its maximum, then reduction in removal efficiency was observed by further increases in pressure above the optimum range. The maximum dye removal efficiencies which were predicted at the optimum conditions by Design Expert software were 97 % and 94 % for Reactive Blue 19 and Acid Black 172, respectively. According to the results of this study, NF processes can be used at a significantly lower pressure and fouling issue for reuse applications as an alternative to the widely used RO process

The effects of operating factors on the removal of total ammonia nitrogen and florfenicol antibiotic from synthetic trout fish farm wastewater through nanofiltration

An aquaculture system can be a potentially significant source of antibacterial compounds and ammonia in an aquatic environment. In this study, the removal of total ammonia nitrogen and florfenicol antibiotic from synthetic aqueous wastewater was assessed by applying a commercial TFC (thin film composite) polyamide nanofilter. The effects of pH (6.5-8.5), pressure (4-10 bar), concentration of total ammonia nitrogen (1-9 mg/L), and florfenicol (0.2-5 mg/L) on the removal efficiency of the nanofilter were studied at a constant 70% recovery rate. It was found that by increasing the pH within the range of 6.5 to 8.5, it enhanced the removal efficiency by up to 98% and 100% for total ammonia nitrogen and florfenicol, respectively. With an increase in pressure from 4 to 7 bar, the removal percentage increased and then, it decreased from 7 to 10 bar. The interactions factors did not have significant effects on the both pollutants removal efficiencies. To obtain optimal removal efficiencies, an experimental design and statistical analysis via the response surface method were adopted

The Relationship Between Salivary Alpha Amylase Activity and Score of McGill Pain Questionnaire in Patients With Tension Type Headache

Introduction: Tension-type headache is the most common type of headache across the world. Saliva as a non-invasive medium is used to detect a wide range of diseases. Salivary Alpha-Amylase (SAA) levels has been suggested as a potential indirect marker for detecting Sympathoadrenal Medullary (SAM) activity, which is activated by pain. Significant correlation was found between SAA levels and pain scale in patients with chronic pain. The purpose of the present study was to measure SAA activity in Frequent Episodic Tension-Type Headache (FETTH). In addition to the Visual Analogue Scale (VAS), we intend to assess intensity and various aspects of pain by McGill Pain Questionnaire (MPQ). Methods:.A total of 45 females with FETTH (case group) and 45 healthy voluntary females (control group) were enrolled in our case-control study. Unstimulated saliva by spitting method was taken from each participant. Results: SAA levels were significantly higher in patients with FETTH (P<0.001) when compared with the control group. There was significant correlation between SAA activity and MPQ score (P<0.001). Conclusion: This is the first study using MPQ as a subjective means of assessing quality and quantity of pain alongside the VAS as an objective tool for evaluating pain in patients with FETTH. SAA may be an appropriate marker for assessing of pain levels in patients with FETTH. MPQ versus the VAS may be a more accurate measurement tools along VAS

Effect of anions interaction on the removal efficiency of nanofilters for the potable water treatment

The interaction between the ions and the charge of membranes can affect the efficiency of pollutant removal. The present study investigated the removal efficiency of hexavalent chromium and nitrate ions from both actual and synthetic contaminated water via two different commercial spiral wound polyamide nanofilters. In addition, the interaction of ions under different experimental conditions was investigated by using a Box-Behnken design (BBD). The Box–Behnken design optimized the contributing factors which included pH (5-9), the initial concentration of Cr (VI) (0.05-5 mg/L) and the initial concentration of nitrate (40-160 mg/L). The maximum removal efficiency of both Cr (VI) and nitrate was achieved at a pH of 9.0, as 99 % and 90 % for the Iranian nanofilter (NF-I) and 98 % and 82 % for the Korean nanofilter (NF-K), respectively. The results also indicated that as the initial concentration of Cr (VI) increased, the removal efficiency was enhanced while the removal efficiency of nitrate decreased according to the pH. However, by increasing the initial concentration of nitrate, the removal efficiency of both the Cr (VI) and nitrate increased. For actual water samples at an optimum pressure of 0.6 Mpa (NF-K) and 0.8 Mpa (NF-I), the removal efficiency of Cr(VI) and nitrate obtained was 95% and 76 % for the NF-K and 97 % and 86 % for the NF-I, respectively

Interaction between diazinon and nitrate pollutant through membrane technology

The efficiency of diazinon (as insecticides) and nitrate (related to nitrogen fertilizer) removal from contaminated water is investigated through NF membrane technique. The effects of nitrate concentration (40-160 mg/l), diazinon concentration (10-1000 µg/l) and pH (5-9) on the efficiency of a commercial polyamide nanofilter membrane at a constant pressure of (800 KPa) are investigated. The response surface method (Box-Behenken design) is applied in design of experiment. As the diazinon concentration and pH are enhanced, the contaminant removal efficiency increases from 85% to 90%; while nitrate concentration has an opposite effect (removal efficiency reduces about 10%). The regression models obtained for nitrate and diazinon rejection show good fitting to the experimental results (r-squared equal to 94% and 98%, respectively). The models are able to predict the evolution of diazinon and nitrate as a function of concentration and pH at a constant pressure

Ergonomic evaluation of welders posture and biomechanical analysis of loads on spine by CATIA software in Iran Gas Transmission Company

Introduction: Nowadays, observational methods based on video recording of work processes and its analysis by using computers software are widely used. Therefore, the aim of this study is the assessment of welder&rsquo;s posture and its biomechanical analysis by using CATIA software. Methods: This research has been done on welders Iranian Gas Transmission Company. Evaluated postures, which include three postures were determined from photos and videos, which were recorded during the welding process. After determining the target postures, digital modeling of person posture was simulated in CATIA software. Then assessments using RULA method and biomechanical analysis of forces to human digital modeling were done. Results: The analytical results are directly extracted by CATIA software. The final score of three postures evaluated using RULA method indicated that for two postures, we need immediate corrective action and for one posture, the corrective action should be taken in near future. Also, biomechanical analysis of forces in one of those postures revealed excessive force higher than recommended limit by NIOSH. &nbsp;Conclusion: The results of this study show that we can provide a better assessment of workers conditions in workplaces using CATIA software. Analyzing according to RULA methods is a significant measure in evaluation and redesign of workstations

The Relationship Between Salivary Alpha Amylase Activity and Score of McGill Pain Questionnaire in Patients With Tension Type Headache

Introduction: Tension-type headache is the most common type of headache across the world. Saliva as a non-invasive medium is used to detect a wide range of diseases. Salivary Alpha-Amylase (SAA) levels has been suggested as a potential indirect marker for detecting Sympathoadrenal Medullary (SAM) activity, which is activated by pain. Significant correlation was found between SAA levels and pain scale in patients with chronic pain. The purpose of the present study was to measure SAA activity in Frequent Episodic Tension-Type Headache (FETTH). In addition to the Visual Analogue Scale (VAS), we intend to assess intensity and various aspects of pain by McGill Pain Questionnaire (MPQ). Methods:.A total of 45 females with FETTH (case group) and 45 healthy voluntary females (control group) were enrolled in our case-control study. Unstimulated saliva by spitting method was taken from each participant. Results: SAA levels were significantly higher in patients with FETTH (P<0.001) when compared with the control group. There was significant correlation between SAA activity and MPQ score (P<0.001). Conclusion: This is the first study using MPQ as a subjective means of assessing quality and quantity of pain alongside the VAS as an objective tool for evaluating pain in patients with FETTH. SAA may be an appropriate marker for assessing of pain levels in patients with FETTH. MPQ versus the VAS may be a more accurate measurement tools along VAS