A new approach to controlling halogenated DBPs by GAC adsorption of aromatic intermediates from chlorine disinfection: Effects of bromide and contact time

2018 ◽  
Vol 203 ◽  
pp. 260-267 ◽  
Author(s):  
Jingyi Jiang ◽  
Wanxin Li ◽  
Xiangru Zhang ◽  
Jiaqi Liu ◽  
Xiaohu Zhu
Keyword(s):  
Contact Time ◽  
New Approach ◽  
Chlorine Disinfection ◽  
Gac Adsorption

A local approach to reduce industrial uranium wound contamination in rats

2004 ◽  
Vol 82 (2) ◽  
pp. 73-78 ◽  
Author(s):  
P Houpert ◽  
V Chazel ◽  
F Paquet
Keyword(s):  
Phosphonic Acid ◽  
Contact Time ◽  
Wound Dressing ◽  
Uranium Oxide ◽  
Chelating Ligands ◽  
Local Approach ◽  
New Approach ◽  
Wound Contamination

The aim of this work is to develop a new approach to partially decontaminate wounds after industrial uranium contamination, during the interval of time between contamination and transfer of the patient to the infirmary. A wound dressing and a paste mixed or not with uranium-chelating ligands, ethane-1-hydroxy-1,1-bisphosphonate (EHBP) and carballylic amido bis phosphonic acid (CAPBP), were tested in vitro on muscles and in vivo on rats after deposit of uranium oxide compounds. The dressing and the paste, composed of carboxymethylcellulose-based hydrocolloids known to be highly absorbent, were applied on simulated wounds a few minutes after the contamination. The incorporation of chelating ligands did not improve the efficacy of the dressing or paste, and the best results were obtained with the dressing. In vivo, after 1 h of contact with the wound, the dressing absorbed about 30% and 60% of a UO4 compound deposited intra- and intermuscularly, respectively. After intramuscular deposit, the efficacy of the dressing was not reduced if the contact time decreased from 1 h to 15 min. Therefore, this wound dressing could be a practical option to treat uranium-contaminated wounds, but its efficacy depends on the localization of the uranium deposit.Key words: uranium, wound, rat, treatment.

Experimental Study on Secondary Effluent Disinfection with Ultrasound and Chlorine

2011 ◽  
Vol 383-390 ◽  
pp. 3786-3791
Author(s):  
Zi Fu Li ◽  
Xin Zhao ◽  
Fu Rong Deng ◽  
Xin Jin ◽  
Hao Wu
Keyword(s):  
Contact Time ◽  
Irradiation Time ◽  
Low Frequency ◽  
Coliform Bacteria ◽  
Secondary Effluent ◽  
Chlorine Disinfection ◽  
Low Frequency Ultrasound ◽  
Ultrasound Intensity ◽  
High Power Consumption ◽  
Economic Considerations

Ultrasonic disinfection is safe and effective, but requires high power consumption. For economic considerations, ultrasound and chlorine can be combined to promote a wider range of applications. In this paper, we investigated the disinfection effect of secondary effluent with low-frequency ultrasound and sodium hypochlorite. The optimal conditions were determined by changing the ultrasound intensity, exposure time, chlorine dosage, and chlorine contact time. The results showed that ultrasound can significantly enhance the effects of chlorine disinfection. When the coliform bacteria is 106~107CFU/L, the dosage of chlorine at 4~6mg/l can meet the national discharge standard (less than 104 CFU /L). However, the chlorine dosage can be further reduced to 1~2mg/l if we add 30 s of ultrasonic radiation, thereby reducing the disinfection by-products. Orthogonal experimental results show that the relative importance of the disinfection factors: chlorine dosage> ultrasonic irradiation time >chlorine contact time> ultrasound intensity.

scholarly journals Chlorine Disinfection of Atypical Mycobacteria Isolated from a Water Distribution System

2002 ◽  
Vol 68 (3) ◽  
pp. 1025-1032 ◽  
Author(s):  
Corinne Le Dantec ◽  
Jean-Pierre Duguet ◽  
Antoine Montiel ◽  
Nadine Dumoutier ◽  
Sylvie Dubrou ◽  
...  
Keyword(s):  
Distribution System ◽  
Contact Time ◽  
Water Distribution ◽  
Arrhenius Equation ◽  
Water Distribution System ◽  
Mycobacterium Fortuitum ◽  
Nutrient Media ◽  
Medium Ph ◽  
Chlorine Disinfection ◽  
Different Temperatures

ABSTRACT We studied the resistance of various mycobacteria isolated from a water distribution system to chlorine. Chlorine disinfection efficiency is expressed as the coefficient of lethality (liters per minute per milligram) as follows: Mycobacterium fortuitum (0.02) > M. chelonae (0.03) > M. gordonae (0.09) > M. aurum (0.19). For a C · t value (product of the disinfectant concentration and contact time) of 60 mg · min · liter−1, frequently used in water treatment lines, chlorine disinfection inactivates over 4 log units of M. gordonae and 1.5 log units of M. fortuitum or M. chelonae. C · t values determined under similar conditions show that even the most susceptible species, M. aurum and M. gordonae, are 100 and 330 times more resistant to chlorine than Escherichia coli. We also investigated the effects of different parameters (medium, pH, and temperature) on chlorine disinfection in a chlorine-resistant M. gordonae model. Our experimental results follow the Arrhenius equation, allowing the inactivation rate to be predicted at different temperatures. Our results show that M. gordonae is more resistant to chlorine in low-nutrient media, such as those encountered in water, and that an increase in temperature (from 4°C to 25°C) and a decrease in pH result in better inactivation.

scholarly journals Chlorine disinfection against Legionella pneumophila biofilms

2020 ◽  
Vol 10 (4) ◽  
pp. 885-893
Author(s):  
Abdelwahid Assaidi ◽  
Mostafa Ellouali ◽  
Hassan Latrache ◽  
Hafida Zahir ◽  
Abdelaziz Karoumi ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Bacterial Resistance ◽  
Galvanized Steel ◽  
Opportunistic Pathogens ◽  
New Approach ◽  
Force Microscopy ◽  
Chlorine Disinfection ◽  
Atomic Force ◽  
Premise Plumbing ◽  
Planktonic Form

Abstract Premise plumbing promotes the regrowth and survival of opportunistic pathogens, such as Legionella pneumophila (L. pneumophila), especially within biofilms. The purpose of this study was to investigate the effectiveness of chlorine disinfection against L. pneumophila serogroup 1 and serogroup 2–15 planktonic form and biofilms. Planktonic cells were able to survive during the study period in the presence of chlorine at recommended free chlorine levels (0.2–0.5 mg/L). Biofilms were developed on galvanized steel and polyvinyl chloride (PVC) for 18 and 30 days and exposed to 50, 100, 150, and 200 mg/L for 2 hours. No colony appeared immediately after chlorination; however, persistent cells were able to tolerate treatment and continue to grow on subsequent days. The biofilm formation was evaluated by atomic force microscopy. This study demonstrates that the biofilm formed on the surfaces of plumbing materials increases bacterial resistance against high levels of chlorination. A new approach towards monitoring and eradicating L. pneumophila from water systems is required.

A New Approach for the Prediction of Surface and Subsurface Properties after Grinding

2014 ◽  
Vol 1018 ◽  
pp. 189-196 ◽  
Author(s):  
Stepan Jermolajev ◽  
Ekkard Brinksmeier
Keyword(s):  
Surface Layer ◽  
Contact Time ◽  
Mechanical Load ◽  
X Ray Diffraction ◽  
Workpiece Material ◽  
Workpiece Surface ◽  
New Approach ◽  
Characteristic Values ◽  
Maximum Contact ◽  
Zone Temperature

This paper presents a diagram of maximum contact zone temperatureTmaxversus contact timeΔt, based on the analysis of workpiece surface layer properties after cylindrical grinding experiments. Apart from resulting surface layer properties, process quantities (Tmax, normal and tangential grinding forcesFn,Ft) are investigated with reference to the resulting workpiece surface layer state as well. Ground workpieces are analyzed by performing Barkhausen noise level measurements together with subsequent metallographic and X-ray diffraction investigations. By mapping characteristic valuesTmaxand the contact timeΔtto corresponding surface layer properties, a general analysis of workpiece material response to the thermo-mechanical load during grinding is possible.

scholarly journals Use of Integrated Cell Culture-PCR To Evaluate the Effectiveness of Poliovirus Inactivation by Chlorine

2000 ◽  
Vol 66 (5) ◽  
pp. 2267-2268 ◽  
Author(s):  
Felisa Blackmer ◽  
Kelly A. Reynolds ◽  
Charles P. Gerba ◽  
Ian L. Pepper
Keyword(s):  
Cell Culture ◽  
Contact Time ◽  
Free Chlorine ◽  
Chlorine Concentration ◽  
Chlorine Disinfection ◽  
Complete Inactivation ◽  
Cell Culture Assay ◽  
Current Standards

ABSTRACT Current standards, based on cell culture assay, indicate that poliovirus is inactivated by 0.5 mg of free chlorine per liter after 2 min; however, integrated cell culture-PCR detected viruses for up to 8 min of exposure to the same chlorine concentration, requiring 10 min for complete inactivation. Thus, the contact time for chlorine disinfection of poliovirus is up to five times greater than previously thought.

Comparison of UV and chlorine inactivation of particle and non-particle associated coliform

2002 ◽  
Vol 2 (5-6) ◽  
pp. 403-410 ◽  
Author(s):  
B. Örmeci ◽  
K.G. Linden
Keyword(s):  
Wastewater Treatment ◽  
Uv Irradiation ◽  
Wastewater Treatment Plant ◽  
Contact Time ◽  
Treatment Plant ◽  
Uv Disinfection ◽  
Chlorine Disinfection ◽  
Naturally Occurring ◽  
Prolonged Contact ◽  
Wastewater Samples

Bacteria associated with particles may be sheltered from chlorine and ultraviolet (UV) disinfection. The objective of this study was to compare the disinfection effectiveness of UV irradiation and free chlorine for naturally occurring particle-associated coliform (PAC) and non-particle associated coliform (NPAC) in wastewater using a single wastewater source, under identical laboratory protocols. Samples containing NPAC were obtained using three different methods: EGTA extraction, filtration, and blending followed by filtration. Unaltered wastewater was used for samples containing PAC. Wastewater samples were inactivated with UV irradiation at doses between 0-100 mJ/cm2, and with chlorine at CT values between 0-525 mg min/L. The dose-survival relationships and inactivation rates between PAC, NPAC, and chlorine and UV irradiation were then compared. As expected, both UV and chlorine were effective for inactivation of NPAC. However, under prolonged contact times, chlorine appears to be more effective for inactivation of PAC than UV irradiation. Contact time appears to be the most important factor in determining the effectiveness of chlorine disinfection of PAC, and chlorine CT alone was not a good indicator of disinfection effectiveness in wastewater. PAC was found to survive at UV and chlorine disinfection doses typically applied in a wastewater treatment plant.

scholarly journals Modified Multiwalled Carbon Nanotubes for Treatment of Some Organic Dyes in Wastewater

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
M. I. Mohammed ◽  
Adnan A. Abdul Razak ◽  
Dhiyaa A. Hussein Al-Timimi
Keyword(s):  
Contact Time ◽  
Organic Dyes ◽  
Methyl Violet ◽  
Langmuir Model ◽  
Multiwalled Carbon ◽  
Freundlich Model ◽  
New Approach ◽  
Tigris River ◽  
As Adsorption ◽  
Maximum Removal

In Iraq, a large quantity of basic orange and methyl violet dyes contaminated wastewater from textile industries is discharged into Tigris River. So the aim of this work is to found an efficient and fast technique that can be applied directly for removal of such dyes from the wastewater before discharging into river. Accordingly, CNTs as a new approach prepared by CCVD technique were purified, functionalized, and used as adsorption material to remove dyes from wastewater. The effect of pH, contact time, CNTs dosage, and dyes concentration on removal of pollutants was studied. The removal percentage of both dyes was proportional to the contact time, CNTs dosage, and pH and inversely proportional to the dyes concentration. The results show that the equilibrium time was 20 and 30 min for basic orange and methyl violet dyes, respectively, and the maximum removal percentage for all dyes concentrations was at pH = 8.5 and CNTs dosage of 0.25 g/L and 0.3 g/L for methyl violet and basic orange dye, respectively. The adsorption isotherm shows that the correlation coefficient of Freundlich model was higher than Langmuir model for both dyes, indicating that the Freundlich model is more appropriate to describe the adsorption characteristics of organic pollutants.

scholarly journals Improving the Properties of Degraded Soils from Industrial Areas by Using Livestock Waste with Calcium Peroxide as a Green Oxidizer

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3132
Author(s):  
Angelika Więckol-Ryk ◽  
Maciej Thomas ◽  
Barbara Białecka
Keyword(s):  
Contact Time ◽  
Poa Pratensis ◽  
Poultry Manure ◽  
Livestock Waste ◽  
Calcium Peroxide ◽  
New Approach ◽  
Industrial Areas ◽  
E Coli ◽  
Seed Mixture ◽  
Germination And Growth

Over the past years, the treatment and use of livestock waste has posed a significant problem in environmental engineering. This paper outlines a new approach to application of calcium peroxide (CaO2) as a green oxidizer and microbiocidal agent in the treatment of poultry manure. It also presents the application of pretreated waste in improvement of degraded soils in industrial areas. The CCD (Central Composite Design) and RSM (Response Surface Methodology) were employed for optimizing the process parameters (CaO2 concentration 1.6–8.4 wt %, temperature 5.2–38.8 °C and contact time 7–209 h). The analysis of variance (ANOVA) was used to analyze the experimental results, which indicated good fit of the approximated to the experimental data (R2 = 0.8901, R2adj = 0.8168). The amendment of CaO2 in optimal conditions (8 wt % of CaO2, temperature 22 °C and contact time 108 h) caused a decrease in bacteria Escherichia coli (E. coli) in poultry manure from 8.7 log10 CFU/g to the acceptable level of 3 log10 CFU/g. The application of pretreated livestock waste on degraded soils and the studies on germination and growth of grass seed mixture (Lollum perenne—Naki, Lollum perenne—Grilla, Poa pratensis—Oxford, Festuca rubbra—Relevant, Festuca rubbra—Adio and Festuca trachypylla—Fornito) showed that a dose of 0.08 g of CaO2 per 1 gram of poultry manure induced higher yield of grass plants. The calculated indicators for growth of roots (GFR) and shoots (GFS) in soils treated with poultry manure were 10–20% lower compared to soils with amended CaO2. The evidence from this study suggests that CaO2 could be used as an environmentally friendly oxidizer and microbiocidal agent for livestock waste.

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