I've been interested in the water purification process since I studied conservation in high school. After a field trip to a wastewater treatment facility, we were asked to explain water purification briefly. It's hard to be brief about such a lengthy topic. But I thought that you might be interested in the different processes used by treatment facilities and homeowners. So, here's a quick look.
You might say that the water purification process begins with soil. The earth cleanses rainwater of various kinds of contaminants. So, groundwater is one of the purest and cleanest sources we have. When you see bottles of natural spring-water, they are actually taken from deep wells, not bubbling springs. The mineral content in these bottles varies, because as the rain passes through the soil, some of the minerals become dissolved in it.
So, that's how you explain water purification that occurs naturally. The soil acts as a filter. Now, to explain water purification performed by man, let's start with wastewater treatment facilities.
The facilities are usually located near a lake, river, or ocean. All of the raw sewage that goes down a customer's drains ends up at these facilities. The sewage goes through a number of processes. First, it is allowed to settle. Solid material sinks to the bottom of storage tanks and is eventually pelletized for use as fertilizer. From there, the treatment steps vary. Some facilities use reverse osmosis to further purify. Others simply dump the resulting solution into the local water supply.
If they dump into a river, further down stream there may be a drinking water purification process. Many cities use rivers as the water source for the city's population. There a number of additional steps are performed. Rocks, sand and other large particles are removed with the use of screens. Smaller particles are removed using sand beds or reverse osmosis. UV light is sometimes used to reduce bacteria. Chlorine is added as a final step to further reduce bacteria and prevent algae from building up in the pipelines.
When some people explain water purification, they fail to mention that the steps taken by large-scale facilities are not "perfect". In the US, we have some of the safest drinking water in the world, but there are still problems.
A public water purification process will not get rid of cysts, which are tiny parasites that cause illness and, in some cases, death. The steps that they use can only reduce some of the common chemical contaminants, such as herbicides, pesticides and prescription drugs. Lead is sometimes found when testing the waters in homes and offices, because chlorine corrodes the pipelines. So, the lead content in homes is higher than what exists at the facility level. Luckily, we can take care of these problems in our homes.
To explain water purification processes available for homeowners, you start with granular carbon to remove chlorine and other chemicals. But, a complete home water purification process includes a variety of steps. Take the time to learn more about it and protect your health.