摘要:

The author of this letter discusses the use of ozone as a primary disinfectant with postdisinfection achieved through the use of preformed monochloramine. The preformation of a strong stock solution of monochloramine under optimum conditions gives a chemically well defined solution of pure monochloramine and no detectable amounts of free chlorine, dichloramine, or trichloramine, which are responsible for tastes and odors. Since the introduction of the use of preformed monochloramine there has been an improvement in taste and odor and no trihalomethanes have been found in the water.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05666.x

出版商:Wiley    

年代:1986

数据来源: WILEY

摘要:

This discussion took place during the AWWA annual conference in Washington, D.C., on June 25, 1985. Participants were: Richard J. Bull, associate professor of pharmacology and toxicology at Washington State University, Pullman, Wash.; Foster S. Burba, president of the Louisville Water Company, Louisville, Ky.; Joseph Cotruvo, director of the Criteria and Standards Division, Office of Drinking Water, US Environmental Protection Agency, Washington, D.C.; John R. Fowle III, acting director of the Water and Toxic Substances, Health Research Division, Office of Health Research, US Environmental Protection Agency, Washington, D.C.; and Robert Golden, vice‐president of Karch and Associates, Inc., Washington, D.C. John Gaston, senior consultant of CH2M Hill, Emeryville, Calif, was moderator of the panel.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05668.x

出版商:Wiley    

年代:1986

数据来源: WILEY

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05673.x

出版商:Wiley    

年代:1986

数据来源: WILEY

摘要:

In studying the causes of human gastroenteritis, electron microscopy and related techniques have led to the identification of new viral agents that had previously escaped detection by routine cell culture procedures. Efforts to characterize and study these agents further are currently being made by researchers in many areas of the world. Two of the best‐known agents, rotavirus and Norwalk virus, have been implicated in waterborne outbreaks of this illness. Another virus, the Snow Mountain agent, was first identified from the investigation of one waterborne gastroenteritis outbreak.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05674.x

出版商:Wiley    

年代:1986

数据来源: WILEY

摘要:

A waterborne nonbacterial gastroenteritis outbreak occurred in March 1981 in the Colorado communities served by the Eagle‐Vail Water District. The outbreak was linked to a chlorinator failure as well as a long‐standing filter deficiency and malfunction of an upstream sewage treatment plant. Illness was statistically associated with water consumption. The direct costs for medical care, time lost from work, purchase of bottled water, and emergency repairs to the water treatment system were estimated to have been $258 231, or $73 per resident. Costs to rectify the problems discovered in the water treatment plant, including long‐term improvements, were almost $1.2 million.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05675.x

出版商:Wiley    

年代:1986

数据来源: WILEY

摘要:

The cycling of mercury in the environment and in well water was studied to determine the seriousness of the threat to human health of the elemental mercury sometimes contained in water well equipment. Modeling of mercury cycling indicated that, because of unfavorable conditions, mercury in well water is highly unlikely to be methylated to the toxic methylmercury form. More important, aquatic organisms, such as fish and shellfish, that can concentrate methylmercury and could be consumed by humans are not present in well water.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05676.x

出版商:Wiley    

年代:1986

数据来源: WILEY

摘要:

An analysis of statistics compiled on outbreaks of waterborne disease from 1946 to 1980 and from 1965 to 1982 showed that disinfection was not provided where it was needed and was not properly operated where it was provided. Chlorine concentration, contact time, pH, temperature, and interfering substances all must be evaluated to determine disinfection requirements. Use of reliable chlorination facilities and proper application of current technology can control and prevent waterborne diseases.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05677.x

出版商:Wiley    

年代:1986

数据来源: WILEY

摘要:

Of 207 samples collected from various locations in five small municipal water distribution systems, 103 (49.8 percent) were positive for fungi. Counts ranged between 1 and 6 fungal propagules per 50‐mL sample. Four genera,Alternaria, Aspergillus, Cladosporium, andPenicillium, accounted for 58 percent of the isolates, withAspergillusthe most common (18.4 percent). Statistical analysis of the data to determine any relationship between the presence and number of fungal isolates and five physicochemical and two bacteriological parameters revealed no significant correlations.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05678.x

出版商:Wiley    

年代:1986

数据来源: WILEY

摘要:

Reduction of enteroviruses and rotaviruses averaged 81 and 93 percent, respectively, at a full‐scale 205‐mgd (776‐ML/d) plant whose treatment train includes chemical flocculation, sand filtration, and chlorination. The highest reduction of enteroviruses occurred during prechlorination‐flocculation and filtration, whereas the highest reduction of rotaviruses occurred during prechlorination‐clarification and final chlorination. Enteroviruses or rotaviruses occurred in 24 percent of the finished water samples, which had>;0.2 mg free chlorine/L and met coliform bacteria (1/100 mL) and turbidity (1 ntu) standards. Although major plant deficiencies may have been responsible for the occurrence of viruses in the finished water, the results of this study indicate that finished water, with measurable levels of free residual chlorine and meeting standards for coliform bacteria and turbidity, cannot be assumed to be virus free.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05679.x

出版商:Wiley    

年代:1986

数据来源: WILEY

摘要:

The bactericidal efficiencies of chloramines produced by (1) concurrent addition of chlorine and ammonia to the influent water, (2) prechlorination followed by addition of ammonia, and (3) preammoniation were compared with that of free residual chlorine during pilot testing. Coliform bacteria were found to be a poor indicator of the relative ability of the application schemes to disinfect water. Concurrent chlorine and ammonia application, prechlorination followed by addition of ammonia, and free residual chlorination generally produced low total bacteria counts in the pilot‐plant effluent. Preammoniation resulted in the highest frequency of elevated total bacteria counts (1 colony‐forming unit/mL) in the plant effluent.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1986.tb05680.x

出版商:Wiley    

年代:1986

数据来源: WILEY