Treating drinking water with toxic chlorine is recognized in the West as unhealthy yet NATO and the U.S. Embassy continue to foster such technology onto the Afghan people. Chlorinated drinking water is sub-lethal. Drinking it will not cause immediate death, but it will increase the rate of illness within the consuming population, ultimately decreasing their life-spans. The World Health Organization (WHO) has determined that there are better and safer methods for purifying drinking water than using chlorine.
Some of the processes endorsed by the WHO were developed by investigators who traveled to remote areas of the world to research local water treatment practices. Those investigators made some interesting discoveries. One investigator came upon a village cistern filled with cloudy water. He watched in puzzlement as a village elder threw a rotting tree branch into the water and then told the WHO investigator to return the next day. He returned and found to his surprise that the water was now clear. This was not magic but basic chemistry. The bark on the rotting tree limb turned out to be a very efficient floc, meaning it acts on suspended solids in the water and precipitates them out, pushing them to the bottom of the cistern. The reason is that the bark releases lignins (humic acid). The acid reacts with the water to create hydrogen peroxide that acts as a “floc.” Flocs can reduce the concentrations of suspended solids such as phosphorus, nitrogen, iron, manganese and ammonia, this producing clear water.
The WHO is a success because it listens and learns from local communities. It tries to use local materials and employ local solutions, rather than adopting the attitude that the West knows best.
The WHO has documented that numerous natural substances, in addition to tree bark, which are effective as flocs. They include:
- coconut shells
- M.oleifera seeds
- theythancottai tree seeds
- wheat straw
- barley straw
The ideal water treatment systems are those that are:
1. simple to manufacture and operate,
2. made from locally available materials; and which will
3. produce clean and healthy water.
The balance of this article discusses a few of the more promising technologies. They include making filters from cotton, sand, wood charcoal and ceramic materials, boiling water, adding air to water, using the sun to distill and disinfect, and using ultraviolet light to disinfect. Finally, one of the easiest techniques is to simply place water into alternating pots for three days. Western engineers make money from the construction of large and expensive, high-technology water treatment facilities. In reality, modest and rudimentary low-technology treatment facilities can produce water of the same or better quality at a fraction of the cost.
The following processes are effective at removing contaminants from drinking water. Each process does not remove every contaminant, so the processes have to be grouped and used together in various configurations depending on how polluted the source water. All of these processes are preferable to Western chlorine-centric systems. These technologies can be used both at the village or town level, and they could be provided to individual households so that each family can independently treat their own water.
Filtration is perhaps the oldest water treatment method. The range of filter types and media is extensive. Most treatment plants commence their treatment by running the influent water through one or more metal mesh filter screens to remove leaves, plant material, wood and other debris.
a. Cloth Filters:
Cloth filters were reportedly used in ancient Greece. This is a simple process in which water is poured through a piece of cotton cloth. Cloth filters are called sediment filters because they will remove some of the suspended sediments or solids in the water and will help to purify the water to a degree. The more tightly the cotton is woven, the more effective the filter and the longer it will take the water to seep through the filter. These filters will eventually become saturated with dirt and other materials. In those instances, they either need to be replaced, or washed and returned to use.
b. Wood Charcoal Filters:
The use of various forms of carbon to filter either air or water was known in ancient Egypt. Carbon filters were also used in early gas masks because of their superior ability to absorb toxic organic chemicals. Carbon or wood charcoal (not the petroleum-based charcoal used in the West) has a natural attraction for many pollutants and by running water over or through a bed of charcoal, many contaminants can be removed. They include chlorine, benzene, radon, solvents and possibly some iron and hydrogen sulfide. Charcoal can also remove odors and colors and it can improve the overall taste of the water. A simple carbon filter can be manufactured from charcoal.
Charcoal is usually produced by heating a container of wood, especially pine, and decanting the gases produced. Charcoal can also be made out of coconut husks or nut shells. While specialty forms of carbon, such as “carbon block” and granular activated carbon (GAC) work best and can produce removal efficiencies down to about 0.5 microns, ordinary charcoal can be very effective.
c. Sand Filters:
In 1829, the Chelsea Water Works Company in London began using a process called slow sand filtration to treat drinking water. It was successful in removing 98% of bacteria from Thames River water. Slow sand filtration was later largely abandoned by the West because it required large volumes of sand of various grain types, was labor intensive (as the sand had to be changed periodically), and did not produce the high volume of processed drinking water that was required. Slow sand filtration still has a place in the developing world as it is a very effective treatment technique which has the support of the WHO. It is effective because it is both a sediment filter and a unique biological filter.
d. Lime Filters:
Lime or calcium hydroxide is inexpensive and readily available in most countries. It is a strong alkaline that attacks metals. Used in a filter, it can decrease the total dissolved solids in water, especially carbonates. Lime has a drawback in that the sludge produced has to be properly managed and disposed of due to the fact that lime is naturally corrosive.
e. Red Mud Filters:
Red mud is a byproduct of bauxite mining. It can be effective at removing nitrogen (fertilizer runoff) from water. Nitrates can cause Methemoglobinemia, a potentially fatal disease affecting small children.
f. Ceramic Filters:
Ceramic filters are the latest addition to the filtration world. As the name describes they are rigid filters made of ceramic material. Their benefits are that they can be manufactured in micron and even submicron sizes in order to filter out even the smallest viruses. They can also be cleaned and reused. The WHO standard is a 1 micro filter. This is a good filter for removing most bacteria such as E-Coli and Vibrio Cholera, especially the nasty 0157:H7 and 0139 spiral strains (respectively), which are 1-5 microns in size, but Listeria and Salmonella Typhi rods can be as small as 0.5 microns. Ceramic filters are now being manufactured which can remove all sediments down to 0.22 microns.
2. The Three Pot System:
The WHO recommends the simple three pot system as an emergency treatment process. The idea is to line up three clean pots in a row. They can be made of glass, clay, metal or other materials. The first pot is filled with water and covered. It needs to be kept away from heat and direct sunlight. 24 hours later the water is poured into the second pot taking care not to transfer any of the sediment that has collected at the bottom of the pot. The same process is repeated with the second pot and a day later the third pot. Each day the water will have less contaminants. The water in pot three can be used for drinking water in an emergency. Simply permitting water to stand will, surprisingly, remove a significant percentage of suspended solids and with them a percentage of bacteria and other contaminants. The water becomes cleaner, but it is not advisable to drink such water regularly because it is unlikely that this process alone will be sufficient, except perhaps with some well water. This process can be used successfully in combination with some of the other processes discussed here.
Water can be boiled for at least five minutes and preferably up to 20 minutes, which will kill almost all of the bacteria and destroy most chlorine in the water. Again, boiling by itself will not produce clean water, but can do so in combination with some of these other processes.
Aeration is simply the process of mixing air in with the water. A hand pump can be used to push air into the water or a pump can be used to operate a water fountain which will expose and mix falling water with the surrounding air. An aeration tank can also be made by stacking several plastic containers on top of each other, creating a gravity fountain. Aeration can remove carbon dioxide, volatile organic compounds, hydrogen sulfide and help precipitate metals such as iron.
5. Solar Distillation:
A solar still uses sunlight to naturally evaporate and separate water from most of its associated pollutants. All this technique requires is about $20 worth of materials, plus sunlight. The theory is that sunlight boils the water and turns it into steam. The steam rises up to the slanted sheet of glass, condenses (cools) on the glass and the resulting water drips down and is collected in a separate container. The water produced is considered distilled, which means that under normal conditions, it consists of hydrogen, oxygen and little else. The distillation process is indiscriminate. It will remove pollutants and contaminants such as lead, iron, arsenic, bacteria and viruses, but it will also remove the minerals that give water its taste and chemical balance. A problem with distillation is that synthetic chemicals which have a lower boiling point than water may wind up being evaporated and condensed along with the distilled water.
Distilled water is harmful to drink in the long term because de-mineralized water has an affinity for minerals and may begin to pull them from the body of anyone drinking such water over the long term. Solar distillation is a valuable tool, but the distilled water has to be mixed back in with other mineral water in order to produce healthy drinking water.
A general rule for solar stills is that 1 pint of water can be distilled (recovered) per day for every square foot of solar still exposed to significant sunlight over a 12- hour period.
6. Solar Disinfection:
The WHO is promoting a wonderfully simple technology called “solar disinfection.” The way it works is that water is placed into a large glass jar with a tight lid. The outside of half of the jar is painted black. The jar is placed on the ground or a roof-top with the black side positioned next to the ground or roof-top. The jar is then exposed to the sun from four to eight hours. The heat and ultraviolet waves in the sunlight are absorbed by the black paint and pushed back into the water, accelerating the thermal effects. This process is germicidal in that it will destroy bacteria, virus, algae, yeast, protozoa, oocysts, including TB and vibrio cholerae.
7. Ultra-Violet Light (UV pulse):
As explained above, ultraviolet light is the primary mechanism that permits solar disinfection to work. Technology widely exists to mechanically create UV light within pipes or water tanks. These UV pulse systems are germicidal (destroy germs) and are effective at destroying bacteria, virus, algae, yeast, protozoa, oocysts, TB, chlorera (vibrio cholerae) and other materials. They are designed to sit within pipes and disinfect the water as it passes over or under them. The drawbacks of UV systems are that they probably cannot be locally manufactured, they require electricity to operate and they do not work well treating cloudy water (i.e., water with significant levels of sediments). Their primary benefits are that they disinfect water better than chlorine, with no side effects or toxic byproducts being produced.
In conclusion, every Afghan citizen has the right to clean, healthy drinking water. In order to achieve that goal, NATO, Western donor countries and organizations have to abandon their efforts to impose their chlorine-centric technologies on Afghanistan. They must instead embrace the lessons learned by the World Health Organization.