Investigating the performance of a UV/H2O2 integrated flow-through system followed by free chlorine

2012 ◽  
Vol 12 (6) ◽  
pp. 715-719
Author(s):  
Xiaona Chu ◽  
Jiangyong Hu ◽  
Yang Xu
Keyword(s):  
Uv Irradiation ◽  
Distribution System ◽  
Free Chlorine ◽  
Integrated System ◽  
Water Disinfection ◽  
Growth Potential ◽  
Assimilable Organic Carbon ◽  
Effective Removal ◽  
Flow Through ◽  
Drinking Water Disinfection

Ultraviolet (UV) irradiation is an emerging technique for drinking water disinfection due to effective removal of enteric pathogens without generation of disinfection by-products (DBPs). In order to overcome the drawback of UV irradiation the integration of UV disinfection with sequential disinfectant was proposed. Among all the possible combinations and sequences, a UV/H2O2-Cl2 integrated system has proven to be effective in many previous studies. In this study, a UV/H2O2 flow-through system followed by free chlorine was built and studied. MS-2 coliphage, as a model for a waterborne virus, were inactivated to evaluate the disinfection capacity. Assimilable organic carbon (AOC) tests and an Ames assay using Salmonella typhimurium TA98 and TA100 on such a proposed integrated system were also performed to determine re-growth potential of bacteria and genotoxicity, respectively. Briefly, such a proposed flow-through system was effective in removal of MS-2 coliphage and no genotoxic potential was detected according to the results; however, an increase of AOC may raise concerns of bacterial re-growth along the subsequent distribution system.

Impact of Particulate Matter on Distribution System Disinfection Efficacy

2008 ◽  
Vol 43 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Linda Wojcicka ◽  
Carole Baxter ◽  
Ron Hofmann
Keyword(s):  
Helicobacter Pylori ◽  
Particulate Matter ◽  
Distribution System ◽  
Contact Time ◽  
Water Disinfection ◽  
Sphingomonas Paucimobilis ◽  
Soil Corrosion ◽  
Log Reduction ◽  
Drinking Water Disinfection ◽  
The Impact

Abstract Microorganisms have been shown to survive drinking water disinfection and remain viable in disinfected waters despite the presence of disinfectant residuals. This may be partially attributed to protection by particulate matter. The aim of this study was to determine the effects of the presence of particulate matter on disinfection kinetics. Sphingomonas paucimobilis ATCC 10829 and Helicobacter pylori ATCC 43504 were used in inactivation experiments in the presence and absence of soil, corrosion, and wastewater particles. The results showed that the presence of such particles tended to inhibit chlorine and monochloramine inactivation, although the magnitude of the impact under the conditions tested was small (e.g., 1-log reduction in inactivation for several minutes of contact time in the presence of less than 1 mg/L of disinfectant).

scholarly journals Degradation of Aqueous Polycyclic Musk Tonalide by Ultraviolet-Activated Free Chlorine

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 95 ◽  
Author(s):  
Lili Wang ◽  
Xiaowei Liu
Keyword(s):  
Disinfection Byproducts ◽  
Free Chlorine ◽  
Water Disinfection ◽  
Side Chain ◽  
Product Analysis ◽  
Direct Photolysis ◽  
Reaction Rate Constants ◽  
Water Matrix ◽  
First Order Kinetics ◽  
Drinking Water Disinfection

Chlorine-incorporating ultraviolet (UV) provides a multiple barrier for drinking water disinfection. Meanwhile, post-UV employment can promote the degradation of micropollutants by radical production from chlorine residual photolysis. This work studied the degradation of one such chemical, tonalide (AHTN), by low-pressure UV-activated free chlorine (FC) under typical UV disinfection dosage of <200 mJ·cm−2 and water matrix of filtered tank effluent. AHTN was rapidly degraded by UV/FC in accordance with pseudo-first-order kinetics. The reaction rate constants of AHTN with reactive chlorine species and hydroxyl radical (HO•) were estimated. Mechanistic exploration evidenced that under UV/FC, AHTN degradation was attributable to direct photolysis, ClO•, and HO•. The carbonyl side chain of AHTN served as an important attack site for radicals. Water matrices, such as natural organic matter (NOM), HCO3−, Cu2+, PO43−, and Fe2+, showed noticeable influence on the UV/FC process with an order of NOM > HCO3− >Cu2+ > PO43− > Fe2+. Reaction product analysis showed ignorable formation of chlorinated intermediates and disinfection byproducts.

scholarly journals AOC reduction by biologically active filtration

2005 ◽  
Vol 5 ◽  
pp. 113-142 ◽  
Author(s):  
M. W. Lechevallier ◽  
W. C. Becker ◽  
P. Schorr ◽  
R. G. Lee
Keyword(s):  
Distribution System ◽  
Treatment Plant ◽  
Active Filters ◽  
Free Chlorine ◽  
Biologically Active ◽  
Coliform Bacteria ◽  
Biological Removal ◽  
Assimilable Organic Carbon ◽  
System A ◽  
Treatment Processes

Biological treatment was examined for production of biologically stable water, increase disinfectant stability, and reduced formation of disinfection by products. Monitoring of assimilable organic carbon (AOC) levels in the effluent of the Swimming River Treatment Plant (SRTP) showed that values >100 µg/L could be related to the occurrence of coliform bacteria in the distribution system. A treatment goal of <100 µg/L was established for biologically active treatment processes. Granular activated carbon (GAC) filters were found to support a larger bacterial population, and thus, provide better biological removal of AOC and total organic carton (TOC). All biologically active filters showed good performance relative to effluent turbidity levels, and headloss development. Preozonation of raw water increased AOC levels an average of 2.3 fold, and always increased filter effluent AOC levels relative to nonozonated water. Application of free chlorine to GAC filters did not inhibit biological activity. Application of chloramines to GAC filters showed a slight inhibitory affect relative to free chlorine. Effluent AOC levels averaged 82 µg/L at an EBCT of 5 min, and decreased to an average of 57 µg/L at 20 min EBCT. EBCT did affect TOC removals, with efficiencies averaging 29, 33, 42, and 51 % removal at EBCTs of 5, 10, 15 and 20 min, respectively. Trihalomethane formation potentials (THMFP) were related to TOC levels. Processes Chat decreased TOC levels also decreased THMFP. A preozonated GAC/sand filter (EBCT 10 min) achieved an annual average 54 % removal of THMFP precursors. Post disinfection of biologically treated effluents reduced HPC bacterial counts by 2-2.5log10. Post chlorination or chloramination of prechlorinated GAC/sand effluents resulted in a 20 %, or a 44 % (respectively) increase in AOC levels. Post disinfection of preozonated water resulted in small (<8%) AOC increases. Despite increases in AOC levels, prechlorinated water had lower AOC levels than preozonated water, even after post disinfection.

Evaluation of approaches for consumers to eliminate chlorine off-flavors from drinking water at point-of-use

2014 ◽  
Vol 15 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Yichao Qian ◽  
Wei Wang ◽  
Xing-Fang Li ◽  
Steve E. Hrudey
Keyword(s):  
Drinking Water ◽  
Uv Irradiation ◽  
Tap Water ◽  
Free Chlorine ◽  
Water Disinfection ◽  
Reaction Products ◽  
Water Safety ◽  
Drinking Water Safety ◽  
Point Of Use ◽  
Off Flavors

Chlorine off-flavors of tap water have caused dissatisfaction and distrust from some consumers, placing pressure on operators concerning water disinfection. Evaluating practical approaches for eliminating chlorinous off-flavors by consumers at point-of-use while avoiding production of toxic byproducts is a practical concern. Three recognized dechlorination methods: ultraviolet (UV) irradiation, ascorbic acid (AA) and hydrogen peroxide (HP), were evaluated for chlorinated and chloraminated waters. AA is the most efficient for removing free chlorine and chloramine from water samples. Three new chlorine-containing compounds were detected and identified from the reaction between AA and chlorine. High doses of UV irradiation at 254 nm virtually eliminated chlorine. HP could effectively remove free chlorine but was not effective for chloramine elimination. AA shows promise as a practical household dechlorination agent. However, to assure consumers about drinking water safety, further investigation is needed to evaluate any potential toxicity concerns for reaction products in treated water.

scholarly journals Effects of a new water disinfection technology on water quality

2018 ◽  
Vol 44 ◽  
pp. 00052
Author(s):  
Artur Jachimowski
Keyword(s):  
Water Supply ◽  
Distribution System ◽  
Free Chlorine ◽  
Water Disinfection ◽  
Supply Network ◽  
Water Supply Network ◽  
Water Chlorination ◽  
Quantitative Changes ◽  
Sudden Decrease

The article assesses the effects of use of ultraviolet radiation and electrolytically generated sodium hypochlorite on the quality of drinking water produced at “Raba” plant of the Municipal Water and Sewerage Company in Cracow as well as in the water supply network. The analysis included selected microbiological indicators, total organic carbon, water chlorination products from the group of trihalomethanes and free chlorine. The research conducted indicated that disinfectant change caused quantitative changes in THMs and free chlorine in water supplied to the water supply network. After an upgrade of the chlorination plant in 2014, an increase in water disinfection by-products at most of the tested points of the water supply network was observed. A sudden decrease in free chlorine in the distribution system was also observed in that period, whereas a bacteriological water analysis confirmed the effectiveness of use of the new water disinfection technology.

DISINFEKSI UNTUK PROSES PENGOLAHAN AIR MINUM

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Nusa Idaman Said
Keyword(s):  
Drinking Water ◽  
Water Purification ◽  
Distribution System ◽  
Residual Effect ◽  
Drinking Water Treatment ◽  
Disinfection Byproducts ◽  
Water Disinfection ◽  
Pathogenic Microorganisms ◽  
Microbiological Contamination ◽  
Disinfection Process

Water disinfection means the removal, deactivation or killing of pathogenic microorganisms. Microorganisms are destroyed or deactivated, resulting in termination of growth and reproduction. When microorganisms are not removed from drinking water, drinking water usage will cause people to fall ill. Chemical inactivation of microbiological contamination in natural or untreated water is usually one of the final steps to reduce pathogenic microorganisms in drinking water. Combinations of water purification steps (oxidation, coagulation, settling, disinfection, and filtration) cause (drinking) water to be safe after production. As an extra measure many countries apply a second disinfection step at the end of the water purification process, in order to protect the water from microbiological contamination in the water distribution system. Usually one uses a different kind of disinfectant from the one earlier in the process, during this disinfection process. The secondary disinfection makes sure that bacteria will not multiply in the water during distribution. This paper describes several technique of disinfection process for drinking water treatment. Disinfection can be attained by means of physical or chemical disinfectants. The agents also remove organic contaminants from water, which serve as nutrients or shelters for microorganisms. Disinfectants should not only kill microorganisms. Disinfectants must also have a residual effect, which means that they remain active in the water after disinfection. For chemical disinfection of water the following disinfectants can be used such as Chlorine (Cl2),  Hypo chlorite (OCl-), Chloramines, Chlorine dioxide (ClO2), Ozone (O3), Hydrogen peroxide etch. For physical disinfection of water the following disinfectants can be used is Ultraviolet light (UV). Every technique has its specific advantages and and disadvantages its own application area sucs as environmentally friendly, disinfection byproducts, effectivity, investment, operational costs etc. Kata Kunci : Disinfeksi, bakteria, virus, air minum, khlor, hip khlorit, khloramine, khlor dioksida, ozon, UV.

Both viable and inactivated amoeba spores protect their intracellular bacteria from drinking water disinfection

2021 ◽  
Vol 417 ◽  
pp. 126006
Author(s):  
Zhenzhen He ◽  
Luting Wang ◽  
Yuexian Ge ◽  
Siyi Zhang ◽  
Yuehui Tian ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Disinfection ◽  
Intracellular Bacteria ◽  
Drinking Water Disinfection
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