Friday, September 21, 2012

Solar Water Purification and Lime Juice

Thirty-three years after learning about water purification from a Mexican fisherman while sailing the Sea of Cortez - then using it camping and on solo adventure trips - I read a research study that proves what the Mexican fisherman knew.

The research said: "It's estimated that half of all hospital beds in the world are occupied by people who have become sick from drinking contaminated water. In fact, over one billion people (or about one-sixth of the world's population) do not have access to safe drinking water and millions in developing countries die each year from water-related diseases."
Areas of the world where other means of water purification aren't available, exposure to sunlight for six to 48 hours, depending on factors like cloud cover, is used to help make water safer.
Researchers at Johns Hopkins Bloomberg School of Public Health and Johns Hopkins School of Medicine found adding lime juice to water before exposing it to sunlight made disinfection more effective and much faster.
Researchers contaminated water with various types of bacteria and viruses, added lime juice, or lime slurry, to the water and then exposed it to sunlight. They found levels of E. coli and MS2 bacteriophage virus were significantly lower than with solar disinfection alone.
Kellogg Schwab, PhD, MS, senior author of the study, said: "The preliminary results of this study show solar disinfection of water combined with citrus could be effective at greatly reducing E. coli levels in just 30 minutes, a treatment time on par with boiling and other household water treatment methods. In addition, the 30 milliliters of juice per two liters of water amounts to about one-half Persian lime per bottle, a quantity that will likely not be prohibitively expensive or create an unpleasant flavor."
I've found water treated with lime juice to be quite pleasant, many times better than chlorine and other commercial water purification methods.
The research found the lime juice/sunlight technique was not effective on noroviruses, which means it isn't a perfect solution. If you're not certain what norovirus is and how it's transmitted, Wikipedia has a good explanation.
A few limes in my backpack don't take a lot of space and can save a lot of grief. Bottled lime juice is a waste of money so don't bother. For more information see
If you use a clear glass bottle to treat your water and can haul it in full, there's no reason you can't haul it out empty. Nothing's worse than finding empty cans, bottles and trash in the forest, in the water, in the desert and in the streams.
Limes add zest to campfire meals and have health benefits from digestion and skin care to weight loss, ulcers, eye care, scurvy and more. Recent research indicates lime, and other citrus, may be effective as treatment and prevention against some cancers.

By Larry R.

1 comment:

  1. Room-temperature lemons, limes and orange will yield more juice than those that are refrigerated.