scholarly journals Inactivation of human adenovirus by sequential disinfection with an alternative UV technology and free chlorine

2011 ◽  
Vol 9 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Jung-Keun Lee ◽  
Gwy-Am Shin
Keyword(s):  
Drinking Water ◽  
Uv Irradiation ◽  
Low Dose ◽  
Drinking Water Treatment ◽  
Human Adenovirus ◽  
Free Chlorine ◽  
Human Adenoviruses ◽  
Short Contact Time ◽  
System A ◽  
Uv Technology

There has been growing concern over human exposure to adenoviruses through drinking water due to the extreme resistance of human adenoviruses to the traditional UV technology (low-pressure (LP) UV). As an effort to develop an effective treatment strategy against human adenoviruses in drinking water, we determined the effectiveness of sequential disinfection with an alternative UV technology (medium-pressure (MP) UV) and free chlorine. Human adenovirus 2 (Ad2) was irradiated with a low dose of MP UV irradiation (10 mJ/cm2) through UV collimated apparatus and then exposed to a low dose of free chlorine (0.17 mg/L) at pH 8 and 5°C using a bench-scale chemical disinfection system. A significant inactivation (e.g. 4 log10) of Ad2 was achieved with the low doses of MP UV and free chlorine within a very short contact time (∼1.5 min) although there was no apparent synergistic effect on Ad2 between MP UV and free chlorine. Overall, it is likely that the sequential disinfection with UV irradiation and free chlorine should control the contamination of drinking water by human adenoviruses within practical doses of UV and free chlorine typically used in drinking water treatment processes.

Inactivation of human adenovirus by sequential disinfection with an alternative ultraviolet technology and monochloramine

2010 ◽  
Vol 56 (7) ◽  
pp. 606-609 ◽  
Author(s):  
Gwy-Am Shin ◽  
Jung-Keun Lee
Keyword(s):  
Drinking Water ◽  
Low Temperature ◽  
Human Exposure ◽  
Drinking Water Treatment ◽  
Human Adenovirus ◽  
High Dose ◽  
Human Adenoviruses ◽  
Treatment Processes ◽  
Uv Technology ◽  
Very High

In an effort to reduce human exposure to adenoviruses through drinking water, we determined the effectiveness of sequential disinfection with an alternative ultraviolet (UV) technology (medium-pressure (MP) UV) and monochloramine. The results of this study showed that MP UV was much more effective than traditional UV technology (low-pressure (LP) UV) against human adenovirus 2 (Ad2). Specifically, an inactivation of ~3 log10 was achieved by a dose of 40 mJ/cm2 of MP UV compared to ~1 log10 by the same dose of LP UV. However, because of the ineffective inactivation of Ad2 by monochloramine, a very high dose (40 mJ/cm2) of MP UV and a very large Ct99 value (~1200 mg/L·min) was still needed to achieve a significant inactivation (e.g., 4 log10) of Ad2. Also, it appears that the inactivation of Ad2 by monochloramine is not enhanced by prior exposure to MP UV. Overall, the results of this study indicated that, in spite of the enhanced effectiveness of alternative UV technologies on human adenoviruses, sequential disinfection with an alternative UV technology (MP UV) and monochloramine still may not provide adequate inactivation of human adenoviruses — especially at high pH and low temperature — in drinking water treatment processes.

Enhanced effectiveness of medium-pressure ultraviolet lamps on human adenovirus 2 and its possible mechanism

2009 ◽  
Vol 60 (4) ◽  
pp. 851-857 ◽  
Author(s):  
Gwy-Am Shin ◽  
Jung-Keun Lee ◽  
Karl G. Linden
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Human Exposure ◽  
Drinking Water Treatment ◽  
Human Adenovirus ◽  
Repair Process ◽  
Uv Disinfection ◽  
Medium Pressure ◽  
Treatment Processes ◽  
Uv Technology

There has been growing concern over human exposure to adenoviruses through drinking water due to their apparent high resistance to UV irradiation and the anticipated widespread use of ultraviolet (UV) disinfection in drinking water treatment processes. However, most inactivation studies on adenoviruses were performed using only one type of UV technology—low-pressure (LP) UV, and little is known about the effectiveness of different UV technologies such as medium- pressure (MP) UV or other polychromatic UV technologies. In this work, the kinetics and extent of inactivation of a human adenovirus (adenovirus 2 (Ad2)) by both monochromatic LP and polychromatic MP UV were evaluated to determine the effectiveness of these UV technologies on human adenoviruses. Inactivation of Ad2 by LP UV was very slow and only 0.87 and 2.17 log10 inactivation was achieved with UV doses of 30 and 90 mJ/cm2, respectively. However, inactivation of Ad2 by MP UV was much faster and 2.19 and 5.36 log10 inactivation was observed with the same UV doses (30 and 90 mJ/cm2, respectively). It appears that MP UV is more effective against Ad2 than LP UV and the enhanced effectiveness of MP UV on Ad2 is likely due to its ability to inhibit the repair process in UV-irradiated Ad2.

scholarly journals First Derivative UV Spectra of Surface Water as a Monitor of Chlorination in Drinking Water Treatment

2001 ◽  
Vol 1 ◽  
pp. 39-43 ◽  
Author(s):  
V. Zitko
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Surface Water ◽  
Distribution System ◽  
Drinking Water Treatment ◽  
Uv Spectra ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
First Derivative ◽  
Derivative Spectra

Many countries require the presence of free chlorine at about 0.1 mg/l in their drinking water supplies. For various reasons, such as cast-iron pipes or long residence times in the distribution system, free chlorine may decrease below detection limits. In such cases it is important to know whether or not the water was chlorinated or if nonchlorinated water entered the system by accident. Changes in UV spectra of natural organic matter in lakewater were used to assess qualitatively the degree of chlorination in the treatment to produce drinking water. The changes were more obvious in the first derivative spectra. In lakewater, the derivative spectra have a maximum at about 280 nm. This maximum shifts to longer wavelengths by up to 10 nm, decreases, and eventually disappears with an increasing dose of chlorine. The water treatment system was monitored by this technique for over 1 year and changes in the UV spectra of water samples were compared with experimental samples treated with known amounts of chlorine. The changes of the UV spectra with the concentration of added chlorine are presented. On several occasions, water, which received very little or no chlorination, may have entered the drinking water system. The results show that first derivative spectra are potentially a tool to determine, in the absence of residual chlorine, whether or not surface water was chlorinated during the treatment to produce potable water.

scholarly journals The efficacy of chlorine-based disinfectants against planktonic and biofilm bacteria for decentralised point-of-use drinking water

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gillian E. Clayton ◽  
Robin M. S. Thorn ◽  
Darren M. Reynolds
Keyword(s):  
Antimicrobial Activity ◽  
Drinking Water ◽  
Hypochlorous Acid ◽  
Drinking Water Treatment ◽  
Distribution Networks ◽  
Free Chlorine ◽  
Biofilm Reactor ◽  
E Coli ◽  
Point Of Use ◽  
Biofilm Bacteria

AbstractChlorine solutions are used extensively for the production of biologically safe drinking water. The capability of point-of-use [POU] drinking water treatment systems has gained interest in locations where centralised treatment systems and distribution networks are not practical. This study investigated the antimicrobial and anti-biofilm activity of three chlorine-based disinfectants (hypochlorite ions [OCl-], hypochlorous acid [HOCl] and electrochemically activated solutions [ECAS]) for use in POU drinking water applications. The relative antimicrobial activity was compared within bactericidal suspension assays (BS EN 1040 and BS EN 1276) using Escherichia coli. The anti-biofilm activity was compared utilising established sessile Pseudomonas aeruginosa within a Centre for Disease Control [CDC] biofilm reactor. HOCl exhibited the greatest antimicrobial activity against planktonic E. coli at >50 mg L−1 free chlorine, in the presence of organic loading (bovine serum albumen). However, ECAS exhibited significantly greater anti-biofilm activity compared to OCl- and HOCl against P. aeruginosa biofilms at ≥50 mg L−1 free chlorine. Based on this evidence disinfectants where HOCl is the dominant chlorine species (HOCl and ECAS) would be appropriate alternative chlorine-based disinfectants for POU drinking water applications.

scholarly journals A comparison of DNA repair and survival of Escherichia coli O157:H7 following exposure to both low- and medium-pressure UV irradiation

2007 ◽  
Vol 5 (3) ◽  
pp. 407-415 ◽  
Author(s):  
J. L. Zimmer-Thomas ◽  
R. M. Slawson ◽  
P. M. Huck
Keyword(s):  
Dna Repair ◽  
Drinking Water ◽  
Water Treatment ◽  
Uv Irradiation ◽  
Drinking Water Treatment ◽  
Uv Exposure ◽  
E Coli ◽  
Medium Pressure ◽  
Treatment Conditions ◽  
Low Levels

DNA repair and survival of pathogenic E. coli O157:H7 was investigated following exposure to ultraviolet (UV) radiation from both low-pressure (LP) and medium-pressure (MP) lamps. This study included irradiation at UV doses used in drinking water treatment and lower doses indicative of potential treatment problems. Immediately following UV exposure, an average log inactivation of 4.5 or greater was observed following all tested doses of LP (5, 8, 20 and 40 mJ/cm2) or MP UV (5 and 8 mJ/cm2) indicating the sensitivity of E. coli O157:H7 to UV irradiation. Following conditions conducive to repair, maximum photo repair occurred rapidly within 30 minutes after low doses (5 and 8 mJ/cm2) of LP UV. The rate of repair was much higher than reported previously in non-pathogenic E. coli (which occurred within 2 hours). In contrast to LP UV, limited photo repair of E. coli O157:H7 was observed following MP UV exposure at reduced doses (5 and 8 mJ/cm2). At these lower doses, low levels of light independant repair were observed following LP UV, but not following exposure of MP UV irradiation. This study indicates that MP UV may enhance UV disinfection of E. coli O157:H7 by reducing the ability to repair following non-ideal treatment conditions. Following doses used in drinking water treatment (20 and 40 mJ/cm2), low levels of photo repair following LP UV were evident.

scholarly journals Occurrence of water-borne enteric viruses in two settlements based in Eastern Chad: analysis of hepatitis E virus, hepatitis A virus and human adenovirus in water sources

2011 ◽  
Vol 9 (3) ◽  
pp. 515-524 ◽  
Author(s):  
Laura Guerrero-Latorre ◽  
Anna Carratala ◽  
Jesus Rodriguez-Manzano ◽  
Byron Calgua ◽  
Ayalkibet Hundesa ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Hepatitis E Virus ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Human Adenovirus ◽  
Hepatitis E ◽  
Water Sources ◽  
Human Adenoviruses ◽  
Water Borne

Hepatitis E virus (HEV) is a common cause of water-borne acute hepatitis in areas with poor sanitation. In 2004 an outbreak of HEV infection affected around 2,000 people in Eastern Chad (Dar Sila). This paper describes the decrease in the incidence of acute jaundice syndrome (AJS) from 2004 until 2009 when a mean incidence of 0.48 cases/1,000 people/year was recorded in the region. Outbreaks of AJS were identified in some of the camps in 2007 and 2008. Moreover, water samples from drinking water sources were screened for human adenoviruses considered as viral indicators and for hepatitis A virus and HEV. Screening of faecal samples from donkeys for HEV gave negative results. Some of the samples were also analysed for faecal coliforms showing values before disinfection treatment between 3 and >50 colony forming units per 100 mL. All water samples tested were negative for HEV and HAV; however, the presence of low levels of human adenoviruses in 4 out of 16 samples analysed indicates possible human faecal contamination of groundwater. Consequently, breakdowns in the treatment of drinking water and/or increased excretion of hepatitis viruses, which could be related to the arrival of a new population, could spread future outbreaks through drinking water.

scholarly journals Drinking Water Treatment at Home: a Trial in Dhaka, Bangladesh

1970 ◽  
Vol 44 (2) ◽  
pp. 233-240
Author(s):  
NA Molla ◽  
KA Mollah ◽  
A Hossain ◽  
O Shipin ◽  
HP Nur ◽  
...  
Keyword(s):  
Drinking Water ◽  
Low Income ◽  
Strong Association ◽  
Pilot Trial ◽  
Drinking Water Treatment ◽  
Free Chlorine ◽  
Faecal Coliform ◽  
Residual Chlorine ◽  
Trial Period ◽  
Survey Analysis

The pilot trial on AquatabsTM disinfectant tablets was undertaken over a period of one month (three 10-day period excluding the pre- and post-trial activities) during October-December 2004 in an area of low-income urban communities suffering from a lack of basic health services including a lack of adequate and safe water and sanitation facilities (Lalbagh) as well as adjacent areas of old Dhaka. Drinking water consumed by 347 persons was treated in 50 households comprising 70 children under 5 years old. A pre-trial survey and testing of the water supplies demonstrated that the mean faecal coliform count was > 103 MPN/100mL and that all children (100%) belonged to a "Severe Diarrhoea Group" (> 3 incidences of light diarrhoea or any serious diarrhoeal condition). One effervescent AquatabsTM (67mg sodium dichloroisocyanurate) was added by the mother to the local container (filled from a community tap or standpipe, often through an illegal connection), which held about 20-25 litres of unsafe water, giving a dosage of about 2mg/L free chlorine. During the trial period water samples were tested at 3 x 10-day period for free residual chlorine levels and faecal coliform counts at all households. About 65.7% of children were reported to be free from diarrhoea during the trial period, there was a strong association between "under-chlorinated" water (<0.5mg/L residual free chlorine) and reported diarrhoea incidences. Survey analysis during the pilot trial concluded that 70% of mothers were not aware that health improvements were related to water supply and sanitation. Keywords: AquatabsTM, Diarrhoea, Low income urban community. DOI: 10.3329/bjsir.v44i2.3679 Bangladesh J. Sci. Ind. Res. 44(2), 233-240, 2009

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.

Sign in / Sign up

Export Citation Format

Share Document