Some natural and low-cost ways of purifying water have been in our country for generations. Here are a few...
To conclude this series on safe drinking water for the home, we will examine some interesting ideas that have great potential and yet have not achieved acceptance.
Solar Water Charging
Our country has abundant sunshine through the year and solar drying is used even today for food preparation but this has not extended to water purification. If kept in direct sunlight for about six hours, water is purified by the UV rays of the sun and by the increase in temperature. WHO and several agencies worldwide are promoting solar disinfection as a zero cost method of water purification for lower income groups who are particularly susceptible to water-borne diseases. While this is a noble endeavor, it is a pity that this highly beneficial practice is not used by all strata of society.
To get solar-charged water all we need is a clear, transparent glass bottle. While WHO finds PET or plastic bottles acceptable for solar charging, I would not recommend it as plastic will leach chemicals into water over time. Clean and fill the glass bottle from the drinking water source, close it tightly with the cap and place it in direct sunlight. This method of course becomes less effective on cloudy overcast days. Also, this solar charged water should not be left exposed overnight or after sunset and should be stored and consumed within 24 hours.
The big question here of course is whether solar water charging can completely replace water purifier in the kitchen. It is also obvious that we need an alternative method during the monsoon. This method works by deactivating pathogens through the UV rays but there is no mechanical filtration process by which suspended dirt or other contaminants are physically removed from the water. Therefore, for solar water charging to be effective the source water must at least be clear and not turbid. As a thumb rule, after filling the clear glass bottle with water, one must be able to easily read a newspaper headline through it.
Most of you would already be using some type of water purifier at home. I recommend that at least some part of your purified drinking water be charged with sunlight and consumed to obtain the health benefits of the solar energy.
The Copper Pot In the last two articles we learnt that storing water in a copper pot overnight kills several pathogens and that this ancient Indian water purification idea has also been corroborated by several recent studies The health benefits of copper water mentioned in Ayurveda though have not been extensively studied in recent times. For instance, copper has anti-inflammatory properties and helps with arthritic pains. Copper is also an anti-oxidant, prevents cell damage and ageing. Apart from this, it is a vital element required in melanin production, works as a brain stimulant, helps in healing wounds faster and maintains digestive health. Of course we must place this in the context of an otherwise balanced healthy lifestyle and not expect the mere drinking of copper-charged water to work like magic and cure all ailments.
As mentioned before, BIS standards specify that drinking water should have a TDS of less than 500 ppm. Vetiver roots and the bark of the Indian gooseberry tree (Amla or Nellikkai) are capable of reducing TDS by half and help make the water potable. These herbs also vastly improve its taste.
The seeds of the Strychnos potatorum tree (Thethankottai in Tamil), also called the clearing nut tree are used to remove sediment or turbidity from drinking water. The seeds are rubbed on the inside of the water storage vessel and then filled with water. The seeds are natural coagulants that help the sediments settle down at the bottom of the vessel.
The search for safe drinking water is as old as human existence itself and the purpose of this article was to illustrate the fact that many natural, low-cost methods are known in India. Through this series, I hope to inspire many of you to explore these natural and innovative ideas, and think beyond what is now commonly available in a store as a water solution. Happy holidays and my best wishes for a sparkling 2014.