Water Disinfection for Wilderness, International Travel and Austere Situations
Publication Date: December 1, 2019
Last Updated: March 14, 2022
Recommendations
Etiology and Risk of Waterborne Infection
Treat water when traveling in developing countries. (1A)
315340
Treat water in wilderness areas with nearby agricultural use, animal grazing, or upstream human activity. (1A)
315340
Treat water in wilderness settings without evidence of domestic animal and little to no wildlife or human activity. (2B)
315340
Treat water in disaster situations affecting municipal or private drinking water sources. (1A)
315340
Clarification Techniques
Clarification reduces cloudiness, particulate matter, and waterborne microorganisms; improves the taste and esthetics of water; and improves the effectiveness of chemical disinfectants, filtration, and ultraviolet disinfection. However, it does not reliably disinfect if used alone. (1A)
315340
Granular activated carbon (GAC) is highly effective at removing taste and odor compounds but is not adequate for microbial removal. (1A)
315340
Sedimentation is effective for removing large particles such as sand and dirt but will not remove suspended or dissolved substances (see C-F). (2B)
315340
Coagulation–flocculation (C-F) removes most microorganisms, but it does not reliably disinfect if used alone. (1A)
315340
Traditional or improvisational C-F techniques (other than alum or those used in municipal disinfection plants) have empiric evidence but do not have robust scientific evidence or practical use guidance and should be used with caution to protect the health of consumers. (2C)
315340
Disinfection Methods
Bringing water to boil (100°C/212°F) will kill pathogenic microorganisms. (1A)
315340
Bringing water at 5000 m (16,000 ft) elevation to boil (83°C/181°F) will kill pathogenic organisms. (1B)
315340
Tap water that has been tanked for 30 min or longer and is too hot to touch (60°C) has a significantly reduced number of pathogenic microorganisms, but this cannot be relied on as the sole means of disinfection. Such water may contain increased amounts of lead or other chemicals from the water heater and piping. (2B)
315340
Pasteurization temperatures can be achieved with a solar oven. (2B)
315340
UV light is an effective means of water disinfection. (1A)
315340
Full sunlight exposure of clear water in a clear plastic bottle for at least 4 h significantly reduces and possibly eliminates microorganism contamination. (1B)
315340
However, studies evaluating this technique for reduction of childhood diarrhea show mixed results. (2B)
315340
Filtration is effective as a primary or adjunctive means of water treatment. (1A)
315340
Standard commercially available microfilters with a pore size of 0.2 microns are effective in removing protozoa and bacteria. (1A)
315340
Ultrafiltration with pore size of less than 0.01 is needed to completely remove pathogenic viruses. (1A)
315340
Filters may clog, so users should know how to clean them or consider carrying a backup method of disinfection. (1C)
315340
Biosand filters are a reasonable improvised technique for filtration. (1B)
315340
Halogens chlorine and iodine are an effective means of disinfecting water of bacteria, viruses, and Giardia in the field or household when using appropriate contact time and halogen concentration. (1A)
315340
Usual field concentrations of iodine and chlorine are not effective for other protozoa including Cryptosporidium and Cyclospora. (2A)
315340
Extended use of iodine should be weighed against risks of iodine toxicity. (1B)
315340
Simple techniques for improving taste of halogenated water are available for field use. (1B)
315340
Mixed species electrolytic disinfection techniques are effective for water disinfection of microbes that are susceptible to halogens. (1B)
315340
Chlorine dioxide is a widely used and potent water disinfectant, including efficacy against the protozoan parasites Cryptosporidium. (1A)
315340
Individual use products have limited data demonstrating effective concentration and contact time. (2B)
315340
Use of silver in wilderness settings should be limited to water preservation and not as a primary disinfectant. (1B)
315340
Hydrogen peroxide in typical concentration of 3% cannot be used as a primary drinking water disinfectant, and effective concentrations are not practical for field use. (1B)
315340
Citrus juice and potassium permanganate have limited applications for drinking water disinfection. (1C)
315340
New technology using nanoparticles and photocatalytic disinfection is highly promising for translation into point-of-use water disinfection. (2A)
315340
Recommendation Grading
Overview
Title
Water Disinfectionfor Wilderness, International Travel and Austere Situations
Authoring Organization
Wilderness Medical Society
Publication Month/Year
December 1, 2019
Last Updated Month/Year
April 13, 2023
Supplemental Implementation Tools
Document Type
Guideline
External Publication Status
Published
Country of Publication
US
Inclusion Criteria
Female, Male, Adolescent, Older adult
Health Care Settings
Ambulatory
Intended Users
Healthcare business administration, nurse, nurse practitioner, physician, physician assistant
Scope
Prevention, Management, Treatment
Diseases/Conditions (MeSH)
D004203 - Disinfection, D014195 - Travel, D055814 - Wilderness
Keywords
water purification, water microbiology, pasteurization, halogens, drinking water, water disinfection