3 ways to make safe drinking water

As previously discussed, most of the water projects and problems we see throughout a typical year are primarily focused on clean drinking water. The problem is getting enough volume of water and a quality of the water fit for human consumption. We call this “potable” water – water safe for human consumption.

Let’s assume we have enough water volume-wise (We’ll talk about ways to get more water in later blogs). Let’s also assume the problem is that our water is not fit for drinking. Maybe it is has organic contaminants such as bacteria and viruses causing waterborne diseases such as various forms diarrhea or even typhoid or cholera. Or maybe there are inorganic contaminants like heavy metals either from the groundwater/parent material or man-made activities. One of the most common inorganic contaminants in the world’s drinking water are chemical compounds from agricultural activities (insecticides and pesticides).

Okay. So what can we do to water to make it safe for drinking? Basically, there are only three things we can do to make water potable:

1. Filter water. Water filtration is one of the oldest ways known to help clean water for drinking purposes. There are thousands of filters on the market but only a handful of common filter materials are utilized. The smaller the pore size for water molecules to pass through and filter out the contaminants, the better.
   • Paper or cloth filters are simple but basic types of materials used as a filtration unit. Most of these are used as pre-filters to strain out the larger particles. They usually are not enough to filter out the smaller, disease causing organisms.
   • Ceramic filters are probably the most abundant on the world market today. They are cheap, relatively durable, and can be manufactured with small enough pores to get out a lot of the contaminants. Some are better than others. Always check for the pore size. Again, generally the smaller the better.
   • There are also several homemade water filtration systems that can be constructed with locally available materials such as sand, gravel, cement, and charcoal. These can be made into family or even community filtration systems. A good example of this is the upflow biosand filter- Google it!
   • A simple sedimentation period (letting the water sit and the larger particles – called flocculants – settle to the bottom) combined with a filtration unit can help get a lot of bad things out of your water.
2. Disinfect or purify water using either chemical purification and heat treatments.
   • Boiling is probably the oldest method for purification and is still used today all over the world. Boiling water, if done correctly, is one of the surest ways to purify water. Slowly bring a pot of water to a rolling boil and let it boil for one minute (with a cool down period of 20+ minutes) to kill most harmful bacteria and organisms.
   • The most common chemical purification method for water treatment is sodium hypochlorite (chlorination). Add 2 drops of 4-6% chlorine to one quart of water, mix it well and let it stand for 30 minutes. There are other chemicals used in water purification such as silver and iodine as well.
   • Solar purification using glass or plastic bottles exposed long periods of time (at least 6 hours) to strong sunlight can purify water. This is a bit more tricky and takes longer if the sunlight is intermittent or there is a lot of flocculent in the water.
   • Other means of water purification include irradiation with UV lights, pasteurization, and reverse osmosis (technically a filtration technique).
3. Finally, you can make safe drinking water using a combination of the above two ways: filtration and purification. In actuality, there are only two things you can do to water to make it drinkable-filtration and purification- but I add this third way because it is common to see combo systems when it comes to producing good drinking water.

In short, the common process to cleaning water for drinking is this:

Straining — Storage/Settlement — Filtration — Disinfection

When you hear of someone inventing a new way to obtain clean drinking water, I bet you will find, if you search deep enough, that they do the very same things described above (or variations thereof).

The great thing about filtering and purifying water? It can be done, in most cases, with locally available resources and materials.

And helping people have clean drinking water is a great way to really help them and develop deep relationships!