WATER: DISINFECTION
Disinfection is a preferred method of removing contaminants in most water supplies. Disinfection works by using chemicals or ultraviolet light to kill organisms found in water supplies. In other words we expose dangerous organisms to harsh environments that either kill or deactivate them. Most contaminants found in water that are harmful to humans and animals are flora or fauna based, meaning living organisms and not chemicals. In fact in many cases water contaminated with hazardous chemicals are fairly diluted and have the ability to cause less damage in the immediate future but more danger in the long-term, because continued exposure increases the chances of illness and adverse effects such as cancer. Of course water supplies heavily saturated with chemicals are possible, and becoming increasingly common. Despite the growing chemical presence in water supplies the largest threat to human and animal life are other living organisms.
Most organisms that are defined as a hazard to human or animal life, effect our health by entering our bodies through orifices or piercing the body and entering through exposed under layers of epidermis. There are two primary forms of disinfection that everyday people can use; Chemical Disinfection and Non-Chemical Disinfection.
Most organisms that are defined as a hazard to human or animal life, effect our health by entering our bodies through orifices or piercing the body and entering through exposed under layers of epidermis. There are two primary forms of disinfection that everyday people can use; Chemical Disinfection and Non-Chemical Disinfection.
CHEMICAL DISINFECTION
Chemically treating water is a preferred method of water treatment for many municipalities. Generally speaking it is cheaper and easier to manage, and virtually all types of dangerous organisms are vulnerable to the same chemicals, in fact in larger doses these chemicals become lethal for humans. There are a handful of chemicals, when used in small quantities that are safe for human consumption and water disinfection.
Chlorine
One type of disinfectant commonly found in municipal treatment is chlorine gas. Chlorine gas is an extremely hazardous material and requires absolute care when handling. Despite its volatile nature chlorine gas makes an excellent disinfectant. It is a widely chosen method of treatment because of its relative low cost and being extremely effective against most organisms. However due to its volatile nature and reactive qualities with other chemicals it is virtually impossible for average consumers to obtain chlorine gas and utilize it in a safe and effective way. Because of the hazardous properties of chlorine gas we must rely on less potent forms of chlorine, such as household bleach for domestic use.
One type of disinfectant commonly found in municipal treatment is chlorine gas. Chlorine gas is an extremely hazardous material and requires absolute care when handling. Despite its volatile nature chlorine gas makes an excellent disinfectant. It is a widely chosen method of treatment because of its relative low cost and being extremely effective against most organisms. However due to its volatile nature and reactive qualities with other chemicals it is virtually impossible for average consumers to obtain chlorine gas and utilize it in a safe and effective way. Because of the hazardous properties of chlorine gas we must rely on less potent forms of chlorine, such as household bleach for domestic use.
Chemical Disinfection (a) Bleach: A common and preferred method of treating water in an emergency situation is by using Sodium Hypochlorite or household bleach, consisting of about 5.25% and 6.0% concentration. Pre-filter the water by removing all large particulate visible to the naked eye. Add 16 drops of bleach to every 1 gallon of water. Let set for fifteen minutes then smell the water, if you can smell a hint of chlorine the water is probably safe to drink, and if you can not repeat the process.
CAUTIONS
Caution: If you are unable to smell chlorine upon second treatment of bleach, discard water and locate another source.
Caution: Chlorine bleach dissipates over time, you should use unopened bottles to disinfect drinking water.
Caution: Do not use scented bleaches or bleaches with added detergents, some of these chemicals can dilute the chlorine and may even be toxic to consume in small quantities.
Caution: Do not attempt to add chlorine or any water treatment chemical to water with thick turbidity (cloudy water).
Caution: Do not add bleach to water containing pool or hot tub chemicals.
Caution: Do not attempt to treat water with bleach that has a smell of ammonia.
Caution: Chemically treating water does not remove other chemicals unless you use a coagulant.
Storability: Water treated with bleach is safe to drink as long as the water remains uncontaminated and the water maintains its smell of chlorine. It is important to remember that chlorine dissipates over time and further treatments prior to use may be necessary.
Caution: If you are unable to smell chlorine upon second treatment of bleach, discard water and locate another source.
Caution: Chlorine bleach dissipates over time, you should use unopened bottles to disinfect drinking water.
Caution: Do not use scented bleaches or bleaches with added detergents, some of these chemicals can dilute the chlorine and may even be toxic to consume in small quantities.
Caution: Do not attempt to add chlorine or any water treatment chemical to water with thick turbidity (cloudy water).
Caution: Do not add bleach to water containing pool or hot tub chemicals.
Caution: Do not attempt to treat water with bleach that has a smell of ammonia.
Caution: Chemically treating water does not remove other chemicals unless you use a coagulant.
Storability: Water treated with bleach is safe to drink as long as the water remains uncontaminated and the water maintains its smell of chlorine. It is important to remember that chlorine dissipates over time and further treatments prior to use may be necessary.
Iodine
Iodine is just as much a poison if not more so than chlorine gas. The main difference, other than state is that iodine is openly used in the medical field to disinfect surfaces, where as chlorine gas is primarily used to disinfect water for municipal consumption. On the other hand iodine has been used in tablet form called "Potable Water" to disinfect hikers, soldiers, and campers water sources for many years, (treatment c). Tincture of Iodine has also been a favorite for water treatment on the trail, but not found as often today as yesterday. There are many pros and cons for using iodine in tablet or liquid form, here are a few below. Pro: Iodine has been found to be very effective against Giardia Cysts. Iodine has many uses, in liquid form it can be used to disinfect equipment and epidermis prior to surgery. Liquid Iodine is a fairly common product found in most Drug Stores and Iodine Tablets are even easier to obtain and found in most Outdoor or Camping supply stores and departments. Con: Liquid or Tablet form Iodine is very light sensitive and must be kept in a dark bottle. Because of iodines extreme toxicity women who are pregnant, persons with thyroid problems or those on lithium, people with liver problems, and women over fifty should consult their physician to see if Iodine is a safe water treatment for them. A general rule of thumb; before using any chemical to treat your water supply consult a physician.
Iodine is just as much a poison if not more so than chlorine gas. The main difference, other than state is that iodine is openly used in the medical field to disinfect surfaces, where as chlorine gas is primarily used to disinfect water for municipal consumption. On the other hand iodine has been used in tablet form called "Potable Water" to disinfect hikers, soldiers, and campers water sources for many years, (treatment c). Tincture of Iodine has also been a favorite for water treatment on the trail, but not found as often today as yesterday. There are many pros and cons for using iodine in tablet or liquid form, here are a few below. Pro: Iodine has been found to be very effective against Giardia Cysts. Iodine has many uses, in liquid form it can be used to disinfect equipment and epidermis prior to surgery. Liquid Iodine is a fairly common product found in most Drug Stores and Iodine Tablets are even easier to obtain and found in most Outdoor or Camping supply stores and departments. Con: Liquid or Tablet form Iodine is very light sensitive and must be kept in a dark bottle. Because of iodines extreme toxicity women who are pregnant, persons with thyroid problems or those on lithium, people with liver problems, and women over fifty should consult their physician to see if Iodine is a safe water treatment for them. A general rule of thumb; before using any chemical to treat your water supply consult a physician.
Chemical Disinfection (b) Tincture of Iodine: Some tests have shown iodine to be more effective against certain organisms than chlorine bleach. Tincture of Iodine or Iodine Solution is about 2% elemental iodine. Iodine in any form works best if the temperature of the water is over 70 degrees. Add 20 drops of solution for every 1 gallon of water. Let mixture set for 1/2 an hour or longer.
CAUTIONS
Caution: Some people have a strong allergy to iodine. People who have allergies to shellfish, may have an allergy to iodine because shellfish contain a naturally high amount of iodine.
Caution: Iodine is extremely toxic and women who are pregnant, persons with thyroid problems or those on lithium, people with liver problems, and women over fifty should consult their physician to see if Iodine is a safe water treatment for them.
Caution: As with any chemical treatment the correct dosage is everything. Never overdose a water source.
Caution: The effects of iodine on the human organism are not completely understood, use this product with extreme caution and only in emergencies.
Caution: Some people have a strong allergy to iodine. People who have allergies to shellfish, may have an allergy to iodine because shellfish contain a naturally high amount of iodine.
Caution: Iodine is extremely toxic and women who are pregnant, persons with thyroid problems or those on lithium, people with liver problems, and women over fifty should consult their physician to see if Iodine is a safe water treatment for them.
Caution: As with any chemical treatment the correct dosage is everything. Never overdose a water source.
Caution: The effects of iodine on the human organism are not completely understood, use this product with extreme caution and only in emergencies.
Chemical Disinfection (c) Potable Water Tablets: Potable water tablets are found in almost any outdoor store or department. Potable water tablets are fairly adequate water treatments, however it has been shown to be less effective on cryptosporidium cysts. Potable water tablets usually come as a kit with a neutralizing agent to be used after water treatment to reduce the taste and color of the iodine tablets.
NON-CHEMICAL DISINFECTION
Chemicals are not the only form of disinfection many people around the world boil their water or use the sun to disinfect. (For boiling see chapter on distillation). Chemical disinfection is a preferred method and when people have them it is best to use them, but do so with caution. However chemicals are not always available or cheap enough in the third world so other methods are required. One particular method favored is Solar Disinfection or SODIS.
SODIS
Solar Disinfection also known as SODIS is the process of exposing water to the suns ultraviolet light and temperature in an effort to kill microorganisms. This method is used in many parts of the world, and has been proven to be fairly effective against most microbes. SODIS is also fairly easy to do, but takes several hours if not days depending upon weather, climate, elevation, and the extent to which the water is contaminated. Caution: It is important to note that SODIS does not remove chemicals from water.
SODIS Treatment: To treat a water source using the SODIS method you must first obtain a 16 oz, or up to a 2 liter soda or water bottle. The bottle should be clear, but it can be glass or plastic. The bottle must have a working cap. (1) Screen the water source, removing all particulate visible to the naked eye, (organic material can hide in this material). (2) Fill the bottles completely, removing as much oxygen as possible. (3) Screw the cap on tight and set the bottle on its side in the open sun. (4) It will take four to six hours, but most organic material will be dead. (5) For added treatment I prefer to lay my bottles on top of a reflective surface. The added reflection will increase the effectiveness of the suns ultraviolet light and raise the temperature. Caution: Water boils at 212 degrees Fahrenheit and although I have yet see a SODIS Treatment raise the temperature this high, a reflective panel makes it possible, so use caution. As the water reaches boiling point, it expands, creates steam, and if that steam has nowhere to go. I am sure you get the idea.
Solar Disinfection also known as SODIS is the process of exposing water to the suns ultraviolet light and temperature in an effort to kill microorganisms. This method is used in many parts of the world, and has been proven to be fairly effective against most microbes. SODIS is also fairly easy to do, but takes several hours if not days depending upon weather, climate, elevation, and the extent to which the water is contaminated. Caution: It is important to note that SODIS does not remove chemicals from water.
SODIS Treatment: To treat a water source using the SODIS method you must first obtain a 16 oz, or up to a 2 liter soda or water bottle. The bottle should be clear, but it can be glass or plastic. The bottle must have a working cap. (1) Screen the water source, removing all particulate visible to the naked eye, (organic material can hide in this material). (2) Fill the bottles completely, removing as much oxygen as possible. (3) Screw the cap on tight and set the bottle on its side in the open sun. (4) It will take four to six hours, but most organic material will be dead. (5) For added treatment I prefer to lay my bottles on top of a reflective surface. The added reflection will increase the effectiveness of the suns ultraviolet light and raise the temperature. Caution: Water boils at 212 degrees Fahrenheit and although I have yet see a SODIS Treatment raise the temperature this high, a reflective panel makes it possible, so use caution. As the water reaches boiling point, it expands, creates steam, and if that steam has nowhere to go. I am sure you get the idea.
BOILING
A Time tested and true way to eliminate all organic hazards found in water is to boil. Water boils at 212 degrees Fahrenheit 100 degrees Celsius, or 373.15 Kelvin under standard atmospheric conditions (Sea Level). It is best to boil your water source for a minimum of ten minutes. Caution: Boiling does not remove chemicals, but if you are interested in a process to kill organic material and remove chemicals see; Distillation.
A Time tested and true way to eliminate all organic hazards found in water is to boil. Water boils at 212 degrees Fahrenheit 100 degrees Celsius, or 373.15 Kelvin under standard atmospheric conditions (Sea Level). It is best to boil your water source for a minimum of ten minutes. Caution: Boiling does not remove chemicals, but if you are interested in a process to kill organic material and remove chemicals see; Distillation.