Hurricane Response Guide for Environmental Public Health Professionals
UV Light Ultraviolet light (UV light) can be used to kill some germs.
Portable units that deliver a measured dose of UV light help disinfect small amounts of clear water. UV light does not work well on cloudy water because small particles may block germs from the light. If the water is cloudy, first filter it through a clean cloth, paper towel, or coffee filter, OR allow it to settle. Then, draw off the clear water and disinfect it using the UV light. Always follow the manufacturer’s instructions. Solar Disinfection In emergencies, the sun’s rays can improve the quality of water. This method may reduce some germs in the water. To disinfect water using the sun: Fill clean, clear plastic bottles with clear water. Solar disinfection is not as effective on cloudy water because small particles may block germs from the light. If the water is cloudy, first filter it through a clean cloth, paper towel, or coffee filter, OR allow it to settle. Then, draw off the clear water and disinfect that water using the sun. Lay the bottles down on their sides and in full sun for 6 hours (if sunny) or 2 days (if cloudy). Laying the bottles down allows the sun’s rays to more effectively disinfect the water inside. Putting the bottles on a dark surface will also increase the effectiveness of the solar disinfection method. Removing Chemical Contamination from Water Distillation and Reverse Osmosis (RO) systems can remove some chemical contaminants from water. Distillation is the process of heating water to the boiling point and collecting water vapor as it condenses. Distillation Systems will remove common chemical contaminants, including arsenic, barium, cadmium, chromium, lead, nitrate, sodium, sulfate, and many organic chemicals. RO systems use the natural process of osmosis to reverse the flow of water so that it passes from a more concentrated solution to a more dilute solution through a semi-permeable membrane. Pre- and post-filters are often incorporated along with the reverse osmosis membrane itself. RO systems will remove common chemical contaminants (e.g., metal ions, aqueous salts), including sodium, chloride, copper, chromium, and lead. These systems may also reduce arsenic, fluoride, radium, sulfate, calcium, magnesium, potassium, nitrate, and phosphorus. Choosing a Container for Water Storage When storing water for emergencies, it is best to use FDA-approved food grade storage containers to prevent toxic substances from leaching into the water. These containers can be found at surplus or camping supply stores. If you are unsure whether a container is food grade, contact the manufacturer. If food grade containers are unavailable, choose containers that are made of durable, unbreakable materials and have tight-fitting lids. Preferably, opt for containers that have narrow necks or openings for easy pouring. Never use containers that previously held toxic chemicals like bleach or pesticides. Cleaning and Sanitizing a Water Storage Container Before Use To clean and sanitize water storage containers before filling, do the following: 1. Wash the container with soap and rinse thoroughly. 2. Make a sanitizing solution with 1 teaspoon of unscented bleach (5–9% sodium hypochlorite) per 1 quart of water. 3. Pour the solution into the container, cover tightly, and shake to ensure it touches all surfaces. 4. After 30 seconds, pour out the sanitizing solution. 5. Allow the container to air dry completely. 6. Fill the sanitized container with clean water and seal with a tight lid.
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