Recent Papers on Disinfection

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Health impacts of long-term exposure to disinfection by-products in drinking water in Europe: HIWATE

Journal of Water and Health Vol 07 No 2 pp 185–207 © IWA Publishing 2009 doi:10.2166/wh.2009.073

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Mark J. Nieuwenhuijsen, Rachel Smith, Spyros Golfinopoulos, Nicky Best, James Bennett, Gabriella Aggazzotti, Elena Righi, Guglielmina Fantuzzi, Luca Bucchini, Sylvaine Cordier, Cristina M. Villanueva, Victor Moreno, Carlo La Vecchia, Cristina Bosetti, Terttu Vartiainen, Radu Rautiu, Mireille Toledano, Nina Iszatt, Regina Grazuleviciene and Manolis Kogevinas

Centre for Research in Environmental Epidemiology (CREAL), Parc de Recerca Biomèdica de Barcelona-PRBB (office 183.05), C. Doctor Aiguader, 88, 08003, Barcelona, Spain Tel.: (+34) 93 316 0646 Fax: (++34) 93 316 05 75 E-mail: mnieuwenhuijsen@imim.es
 Municipal Institute of Medical Research (IMIM-Hospital del Mar) and CIBER Epidemiologia y Salud Pública (CIBERESP), Spain
 Imperial College London, UK
 University of the Aegean, Greece
 National Public Health Institute, Finland
 University of Crete, Greece
 Université de Rennes, France
 University of Modena and Reggio, Italy
 ICON Ltd, UK
 Vytautas Magnus University, Lithuania
 Istituto di Ricerche Farmacologiche ‘Mario Negri’, Italy
 Hylobates Consulting Srl, Italy
 Catalan Cancer Institute (ICO), Spain

Abstract

There appears to be very good epidemiological evidence for a relationship between chlorination by-products, as measured by trihalomethanes (THMs), in drinking water and bladder cancer, but the evidence for other cancers, including colorectal cancer appears to be inconclusive and inconsistent. There appears to be some evidence for a relationship between chlorination by-products, as measured by THMs, and small for gestational age (SGA)/intrauterine growth retardation (IUGR) and preterm delivery, but evidence for other outcomes such as low birth weight (LBW), stillbirth, congenital anomalies and semen quality appears to be inconclusive and inconsistent.

The overall aim of the HIWATE study is to investigate potential human health risks (e.g. bladder and colorectal cancer, premature births, SGA, semen quality, stillbirth, congenital anomalies) associated with long-term exposure to low levels of disinfectants (such as chlorine) and DBPs occurring in water for human consumption and use in the food industry. The study will comprise risk–benefit analyses including quantitative assessments of risk associated with microbial contamination of drinking water versus chemical risk and will compare alternative treatment options. The outcome will be improved risk assessment and better information for risk management. The work is divided into different topics (exposure assessment, epidemiology, risk assessment and management) and studies.

The effect of cyanuric acid on the disinfection rate of Cryptosporidium parvum in 20-ppm free chlorine

Journal of Water and Health Vol 07 No 1 pp 109–114 © IWA Publishing 2009 doi:10.2166/wh.2009.008

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Joan M. Shields, Michael J. Arrowood, Vincent R. Hill and Michael J. Beach

Centers for Disease Control and Prevention, National Center for Zoonotic, Vector-borne, and Enteric Disease, Division of Parasitic Diseases, 4770 Buford Highway, Mail Stop F-36, Atlanta, GA 30341-3724, USA Tel.: (770) 488-7090 Fax: (770) 488-4253 E-mail: jshields1@cdc.gov
 Centers for Disease Control and Prevention, National Center for Zoonotic, Vector-borne, and Enteric Diseases, Division of Parasitic Diseases, Atlanta, Georgia, USA

Abstract

Cyanuric acid is used to stabilize free chlorine to reduce photodegradation in outdoor swimming pools. While there have been numerous studies examining its effect on the disinfection rates of bacteria and viruses, it is not known whether cyanuric acid can significantly impact the effectiveness of hyperchlorination for inactivating Cryptosporidium oocysts present in fecally-contaminated swimming pools. This study examined the effect of cyanuric acid on the disinfection rate of Cryptosporidium parvum under swimming pool hyperchlorination conditions (20 mg/ml free chlorine). When 50 mg/L cyanuric acid was present there was a 0.70-log10 reduction in oocyst viability after 10 hours as compared to a 3.7-log10 reduction without cyanuric acid. Aids to remediation, such as decreasing the pH to enhance the germicidal efficiency of the free chlorine and doubling the amount of free chlorine residual, were still unable to achieve a 3-log10 reduction. Current public health recommendations for hyperchlorination and pool remediation are insufficient for pools using cyanurate-stabilized chlorine to achieve a three log inactivation of the parasite.

Wastewater disinfection and organic matter removal using ferrate (VI) oxidation

Journal of Water and Health Vol 07 No 3 pp 507–513 © IWA Publishing 2009 doi:10.2166/wh.2009.003

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Erick R. Bandala, Jocelyn Miranda, Margarita Beltran, Mabel Vaca, Raymundo López and Luis G. Torres

Departamento de Ingeniería Civil y Ambiental, Universidad de Las Americas-Puebla, Sta. Catarina Martir, Cholula 72820 Puebla, Mexico Tel.: +52 222 2292652 Fax: +52 222229200 ext. 4199 E-mail: erick.bandala@udlap.mx
 Universidad Autónoma Metropolitana, Unidad Azcapozalco, Av. San Pablo 180, Mexico DF 02200, Mexico
 Unidad Profesional Interdisciplinaria de Biotecnología, Instituto Politécnico Nacional, Av. Acueducto s/n Laguna de Ticoman, Mexico DF 07340, Mexico

Abstract

The use of iron in a +6 valence state, (Fe (VI), as FeO4-2) was tested as a novel alternative for wastewater disinfection and decontamination. The removal of organic matter (OM) and index microorganisms present in an effluent of a wastewater plant was determined using FeO4-2 without any pH adjustment. It was observed that concentrations of FeO4-2 ranging between 5 and 14 mg l-1 inactivated up to 4-log of the index microorganisms (initial concentration c.a. 106 CFU/100 ml) and achieved OM removal up to almost 50%. The performance of FeO4-2 was compared with OM oxidation and disinfection using hypochlorite. It was observed that hypochlorite was less effective in OM oxidation and coliform inactivation than ferrate. Results of this work suggest that FeO4-2 could be an interesting oxidant able to deactivate pathogenic microorganisms in water with high OM content and readily oxidize organic matter without jeopardizing its efficiency on microorganism inactivation.

A pilot-scale study on ultraviolet disinfection system for drinking water

Journal of Water Supply: Research and Technology—AQUA Vol 58 No 5 pp 346–353 © IWA Publishing 2009 doi:10.2166/aqua.2009.086

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Sun Wenjun and Liu Wenjun

Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China E-mail: sunwj05@mails.tsinghua.edu.cn

Abstract

In recent years, ultraviolet technology for drinking water disinfection has experienced rapid growth in North America and Europe, driven by the needs of disinfection by-product reduction and control of emerging pathogens such as Cryptosporidium which are resistant to chlorination. Tsinghua University has performed some work based on a pilot-scale UV system in Dongguan. The aim of this study was to evaluate the efficacy of UV systems for drinking water under pilot-scale conditions (continuous flow system) and to compare with the collimated-beam results in the laboratory for the same water quality. The experiment results showed that (1) UV was effective against E. coli and TBC. B. substilis and MS2 were more UV-resistant, especially when UVT was below 90%. (2) The inactivation of micro-organisms by UV could be described by first-order kinetics using fluence–inactivation data from laboratory studies in CB tests for a certain fluence range. No inactivation at low fluences (shoulder) and no further increase of inactivation at higher fluences (tailing) was observed for some challenge micro-organisms. (3) Water quality and UV sensitivity of the micro-organism influenced the inactivation rate. (4) For the daily monitor results of 13,000 h, UV could be a stable disinfection manner for total coliform and TBC. (5) The lamp intensity online monitor showed that the lamp efficiency decay was limited to within the first 12,000 h.

Chemical disinfection preceding UV treatment: An assessment of microbial regrowth in a model distribution system

Journal of Water Supply: Research and Technology—AQUA Vol 57 No 2 pp 115–125 © IWA Publishing 2008 doi:10.2166/aqua.2008.026

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Jennie L. Rand and Graham A. Gagnon

Ivan Curry School of Engineering, Acadia University, Wolfville, NS B4P 2R6, Canada
 Department of Civil & Resource Engineering, Dalhousie University, Halifax, NS B3J 1Z1, Canada graham.gagnon@dal.ca

Abstract

The goal of this study was to compare disinfection strategies for controlling microbial growth in distribution systems from a blended water source in a warm climate. This research compared the efficacy of chlorine (Cl2) to monochloramine (NH2Cl) with and without post-treatment with ultraviolet (UV) light for heterotrophic bacteria control. Two influent streams were pre-treated with either chlorine or monochloramine, and consisted of a blend of groundwater, surface water and desalinated water. Annular reactors (ARs) containing coupons made of PVC material were used to simulate common operating conditions in a distribution system. Two ARs acted as controls and received the chlorinated water or water treated with monochloramine. The remaining two ARs received water that was additionally treated with UV light. The data presented show that treatment with Cl2 alone was the most effective disinfection strategy against suspended heterotrophic (HPC) bacteria in influent and effluent samples and also against attached HPC bacteria. Chlorine with or without post-UV treatment was more effective than monochloramine at removing suspended and attached HPC bacteria. Levels of free chlorine concentration were reduced following treatment with UV light, which resulted in the increased bacteria counts in the AR. UV treatment also appeared to enable nitrification in the AR treated with NH2Cl, as ammonia was completely converted to nitrate in the NH2Cl/UV-treated AR whereas concentrations less than 0.2 mg l-1 of nitrate or nitrite were detectable in the NH2Cl-treated AR.

Disinfection by-product formation and mitigation strategies in point-of-use chlorination of turbid and non-turbid waters in western Kenya

Journal of Water and Health Vol 6 No 1 pp 67–82 © US Government 2008 doi:10.2166/wh.2007.013

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D. S. Lantagne, R. Quick, B. C. Blount and F. Cardinali

Enteric Diseases Epidemiology Branch, M/S A-38, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30333, USA Tel.: 404 639 0231 Fax: 404 639 2205 dlantagne@cdc.gov
 Division of Laboratory Sciences, National Center for Environmental Health, U.S. Centers for Disease Control and Prevention, Atlanta, GA 30341, USA

Abstract

Over 1.1 billion people in the world lack access to improved drinking water. Diarrheal and other waterborne diseases cause an estimated 2.2 million deaths per year. The Safe Water System (SWS) is a proven household water treatment intervention that reduces diarrheal disease incidence in users in developing countries. Because the SWS recommends the addition of sodium hypochlorite to unfiltered water sources, concerns have been raised about the potential long-term health effects of disinfection by-products to SWS users. This study investigated the production of trihalomethanes (THMs) in water treated with sodium hypochlorite from six sources used for drinking water in western Kenya. The turbidity values of these sources ranged from 4.23 NTU to 305 NTU. THM concentrations were analysed at 1, 8, and 24 hours after addition of sodium hypochlorite. No sample exceeded the World Health Organization (WHO) guideline values for any of the four THMs: chloroform, bromodichloromethane, dibromochloromethane, or bromoform. In addition, no sample exceeded the WHO additive total THM guideline value. These results clearly show that point-of-use chlorination of a variety of realistic source waters used for drinking did not lead to THM concentrations that pose a significant health risk to SWS users.

Pilot plan protocol for optimization of UV dose required to obtain an appropriate municipal wastewater disinfection

Journal of Water Supply: Research and Technology—AQUA Vol 57 No 1 pp 57–63 © IWA Publishing 2008 doi:10.2166/aqua.2008.072

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E. Nebot Sanz, J. M. Quiroga Alonso, J. A. Andrade Balao and I. Salcedo Dávila

Department of Chemical Engineering, Food Technologies and Environmental Technologies, University of Cadiz, Cadiz, Spain Tel.: 34 956 016198 enrique.nebot@uca.es
 Aguas de Jerez, Empresa Municipal, S.A., Jerez de la Frontera, Spain
 Environmental Engineering Division Hydraulics, Coastal and Environmental Engineering Department, Technical University of Catalonia, Barcelona, Spain

Abstract

In this work a simple but comprehensive protocol for ultraviolet (UV) pilot plant studies was developed in order to meet the microbiological guidelines established by the Andalusian Regional Government (ARG) and Aguas de Jerez, Empresa Municipal, S.A. (AJEMSA). For this purpose, two pilot UV disinfection systems were tested at the municipal wastewater treatment plant in Jerez de la Frontera (Spain) over a period of thirteen months. Both pilot units were operated using unfiltered secondary wastewater. The results obtained from the pilot plant experiments suggest that an average UV dose of 50 mW s/cm2 is sufficient to meet required microbiological quality standards. The quality of the unfiltered wastewater shows that turbidity and total suspended solids could serve as good indicators for UV transmittance variations. The key parameters for an optimum protocol definition are temporal wastewater characterization, the planning and executing of UV disinfection experiments, determining the hydraulic behaviour of the UV channel, calculating the UV dose applied and, finally, evaluating experimental data.

Assessment of a low-cost, point-of-use, ultraviolet water disinfection technology

Journal of Water and Health Vol 6 No 1 pp 53–65 © IWA Publishing 2008 doi:10.2166/wh.2007.015

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Sarah A. Brownell, Alicia R. Chakrabarti, Forest M. Kaser, Fermin Reygadas, Micah J. Lang, Lloyd G. Connelly, Rachel L. Peletz, Daniel M. Kammen and Kara L. Nelson

Sustainable Organic Integrated Livelihoods, Berkeley, CA , USA
 East Bay Municipal Utility District, Oakland, CA , USA
 Energy and Resources Group, University of California, Berkeley, USA
 Department of Emergency Medicine, Oregon Health & Science University, Portland, OR , USA
 Centre for Affordable Water and Sanitation    Technology, Calgary, Canada
 Goldman School of Public Policy, University of California, Berkeley, USA
 Department of Civil and Environmental Engineering, University of California, Berkeley, CA , 94720-1710, USA Tel: (510) 643-5023E-mail:nelson@ce.berkeley.edu, www.ce.berkeley.edu/~nelson

Abstract

We describe a point-of-use (POU) ultraviolet (UV) disinfection technology, the UV Tube, which can be made with locally available resources around the world for under $50 US. Laboratory and field studies were conducted to characterize the UV Tube's performance when treating a flowrate of 5 L/min. Based on biological assays with MS2 coliphage, the UV Tube delivered an average fluence of 900±80 J/m2 (95% CI) in water with an absorption coefficient of 0.01 cm-1. The residence time distribution in the UV Tube was characterized as plug flow with dispersion (Peclet Number = 19.7) and a mean hydraulic residence time of 36 s. Undesirable compounds were leached or produced from UV Tubes constructed with unlined ABS, PVC, or a galvanized steel liner. Lining the PVC pipe with stainless steel, however, prevented production of regulated halogenated organics. A small field study in two rural communities in Baja California Sur demonstrated that the UV Tube reduced E. coli concentrations to less than 1/100 ml in 65 out of 70 samples. Based on these results, we conclude that the UV Tube is a promising technology for treating household drinking water at the point of use.

Disinfection performance of Fe(VI) in water and wastewater: a review

Water Science & Technology Vol 55 No 1-2 pp 225–232 © IWA Publishing 2007 doi:10.2166/wst.2007.019

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V.K. Sharma

Florida Institute of Technology, 150 West University Boulevard, Melbourne, , Florida 32901, USA (E-mail: vsharma@fit.edu)

Abstract

Ferrate(VI) [FeVIO2-4, Fe(VI)] has excellent disinfectant properties and can inactivate a wide variety of microorganisms at low Fe(VI) dosages. The final product of Fe(VI) is Fe(III), a non-toxic compound. The treatment by Fe(VI) does not give any chlorination by-products, which makes Fe(VI) an environmentally-friendly ion. The results demonstrate that Fe(VI) can inactivate Escherichia coli (E. coli) at lower dosages or shorter contact time than hypochlorite. Fe(VI) can also kill many chlorine resistant organisms, such as aerobic spore-formers and sulphite-reducing clostridia, and would be highly effective in treating emerging toxins in the aquatic environment. Fe(VI) can thus be used as an effective alternate disinfectant for the treatment of water and wastewater. Moreover, Fe(VI) is now becoming economically available in commercial quantities and can be used as a treatment chemical to meet the water demand of this century. This paper reviews the potential role of Fe(VI) as disinfectant in water and wastewater treatment processes.

Quaternary ammonium compounds: an alternative disinfection method for fresh produce wash water

Journal of Water and Health Vol 5 No 2 pp 329–333 © IWA Publishing 2007 doi:10.2166/wh.2007.009

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Cristobal Chaidez, Javier Lopez and Nohelia Castro-del Campo

Centro de Investigacion en Alimentacion y Desarrollo, A. C. Carretera a ElDorado, km. 5.5 Culiacan, Sinaloa, Mexico 80129, chaqui@ciad.edu.mx
 Soil, Water and Environmental Science Department, The University of Arizona, 1200 E. South Campus Dr. Shantz Bldg. 429. P.O. Box 210038Tucson, AZ 85721-0038, , USA

Abstract

Irrigation water can serve as a vehicle for transporting pathogenic microorganisms, and numerous cases of bacterial infections from consumption of irrigated fresh produce have been reported in recent years. Chlorine-based disinfectants applied when produce is packed are widely used to control microorganisms. When applied properly, the chlorine products are effective. However, hazardous disinfection breakdown products can be formed, and chlorine disinfectants have high oxidant activity that can affect produce quality and pose a risk to food handlers. Quaternary Ammonium Compounds (QACs) are a disinfectant alternative for the washing of fruits and vegetables. They can control a great number of microorganisms, have low toxicity when used at recommended doses, and are stable in storage. The purpose of this work was to assess the disinfectant activity of QACs against Escherichia coli and Staphylococcus aureus under worst-case and average-case turbidity conditions, (2 and 100 nephelometric units); two disinfectant concentrations (100 and 200 mg/L; and two contact times (30 and 120 seconds). Our research showed that QACs were effective against both bacteria. The percentage reduction of Escherichia coli was significantly higher in the less turbid solution (P=0.027), while turbidity did not affect the reduction of Staphylococcus aureus (P>0.05). E. coli was more resistant to QAC treatment than S. aureus. Based on the data obtained we can conclude that QACs could be an alternative in washing processes of fruits and vegetables.

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