Water, Sanitation and its impact on everyday safety and health

Treating water safely at home

Treating water is the process of removing harmful microbiomes, chemicals, and objects like dirt. Unsafe water can harbor disease-causing pathogens like Vibrio cholerae that cause diseases like cholera when consumed. 

Contaminated stagnant water also acts as a breeding ground for parasites like mosquitoes that transmit malaria and other diseases and host vectors like snails, which carry pathogens that cause bilharzia.

Sources of water include harvesting rainwater, boreholes/wells, municipal water, and water from natural bodies like rivers, lakes, and springs.

Proper storage

Once collected, water can be temporarily stored before treatment in pots, tanks, buckets, and containers. Basically, anything that can hold the water without exposing it to further contamination. After treatment, it is stored in;

• Clean and well-covered bottles/containers/tanks.

• Use of a modified water dispenser or bucket with a tap.

• Use clean cups to collect water, and do not directly dip hands into the container.

• Do not store for prolonged periods of time.

Treatment methods

Filtration

This can be done through the use of commercial filter heads, sand filters, and a clean muslin cloth. For the muslin cloth, it is advisable to use it in combination with other methods like chemical disinfection since the cloth filter, even after impregnation with antimicrobial agents like iodine and silver, is not sufficient to properly remove all the pathogens.

Sand filters are another option that can be easily made and used at home. It requires a bottle with different crafted layers beginning with a mesh at the bottom, followed by gravel, coarse sand, fine sand, and an extra layer of charcoal at the top to adsorb odors and some organic compounds. Water is poured slowly at the top and let to run to the bottom and collected. This method should also be followed by secondary disinfection.

Commercial water filters that use nanofiltration and ultrafiltration membranes like reverse osmosis systems (often coupled with a carbon stage to combat stage and chemicals) are efficient at removing objects, pathogens, and organic matter. An example like the UV disinfection tap filter system achieves full filtering and purification; no extra disinfection is needed.

Boiling

This is the easiest method to perform at home. Begin by filtering your collected water to remove any objects and particles. Place water in a clean sauce pan and boil for 30 minutes to an hour until continuously simmering. Remove from heat and let it cool down. When the water is cool, strain once again and store in a safe place.

Chemical treatment

Chemicals like chlorine and iodine are commonly used to treat water at home. They act by targeting the pathogens directly through mechanisms like denaturing their proteins or interfering with DNA synthesis. 

In chlorine treatment, dosing for emergency treatment is 2-3 drops of 5-6% chlorine product per liter of water. Mix this thoroughly and let it sit for around 30 minutes. At the end, there should be a faint chlorine smell. This dose is doubled when treating cloudy water; the same process is followed afterwards. 

Chlorine dioxide usually comes in tablet form and is dosed at 2-4 mg per liter. It works anywhere between 30 minutes and 4 hours depending on the protozoa being targeted. Directions for use are always on the product, depending on the manufacturer.

Use of iodine is old school but just as effective, though not recommended for continuous use due to risk of thyroid problems. The typical dosing is 5 drops of 2% iodine tincture per liter, with the dose doubling in cloudy water. Wait for thirty minutes before decanting/filtering and use.

SODIS

This method uses natural sunlight by harvesting its UV-A properties plus heat. In combination, these two factors inactivate pathogens. The most appropriate material is the common PET plastic bottle; don’t use PVC or colored plastic. Pre-filter the water first to ensure you use low-turbidity water. Shake the water well for 15 seconds and seal it properly.

Place the bottles horizontally in full sunlight, preferably on a reflective surface like corrugated iron sheets. Expose the water for at least 6 hours (and more if possible.) You can do this for two days if the water is cloudy. SODIS is an easy stand-alone method if the water is low-turbid clear water in areas where long hours of sunlight are guaranteed.