Swimming Pool Water Filters
Whether you have a pool in your back yard or manage a large public swimming pool, the water in the pool must be filtered to remove all sorts of things that can adversely affect the health of swimmers. Swimming pool water filters come in all sizes from small, compact systems for backyard use to the large, complex systems used in municipal swimming pools with wave machines and water slides.
When we take a dip in a pool for exercise, relaxation, or both, the pores in our skin open up and make us more susceptible to infections. Also, water inevitably gets into our noses and mouths, and unless that water is filtered correctly, it can become a potentially dangerous soup of contaminants. Basically, the water in swimming pools is filtered in two ways:
Mechanical filters remove leaves, bugs, and all other solids from the water so that the water remains clear and inviting.
Chemical treatment consists of adding chlorine and other chemicals to the water so that bacteria, viruses, and other pathogens are killed which makes it safe to swim in.
Components of a Swimming Pool
Except for the smallest backyard pools that can be filled with a garden hose, every pool consists of these basic components:
The basin which holds the water.
The pump which circulates the water.
A water filter to keep the water clear.
A chemical feeder to add the disinfecting chemicals.
Drains so that the water can be cycled through the filter.
Returns to add treated water back into the pool.
Pipes to connect all of the components together.
Types of Mechanical Filters
There are exceptions, but the majority of swimming pools use one or a combination of these types of mechanical filters.
Strainer basket filters strain the biggest pieces of debris such as leaves and twigs. Usually, they are found in the intakes on the sides of a pool, and another larger one is located in front of the main pump.
Sand filters use gravity and water pressure to pass the water through graduated layers of sand which remove the smaller particles that the basket filters cannot catch.
Diatomaceous earth filters use the tiny skeletons of sea organisms called diatoms to filter out even smaller particles. These work pretty much the same way that sand filters work except that the filter media is smaller to filter out the tiniest particles.
Cartridge filters are usually made of corrugated paper, polyester cloth, or other materials which can be easily removed, rinsed off, and reinserted. They need to be replaced every few years but are very simple to use.
Chemical Filtration
The chemistry of pool water is very important to eliminate bacteria and other pathogens, keep the water clear, keep the chemicals from damaging pipes and other components, and keep the chemicals from irritating our skin and eyes. As mentioned before, chlorine, which is available in many forms and compounds, is the most popular chemical filter because it does a good job of keeping pool water safe to swim in.
Chemicals are often added, in carefully measured doses, right after the mechanical filtration to ensure that they are evenly dispersed in the water. The problem with chlorine is that when it is exposed to ultraviolet light from the sun, it can form unstable compounds with other chemicals and emit gases such as chloroform which irritates our eyes, lungs, and skin. To counter the effects of these compounds, pool managers often add stabilizing agents such as cyanuric acid which acts as a buffer and makes chlorine less likely to become unstable.
Summary
As you can see, there�s a lot more going on in a swimming pool than meets the eye. Most of this filtration and equipment is hidden away behind the scenes, but it all must work together and be monitored regularly so that pools are safe to swim in. What�s more, there are laws governing swimming pool water and all of the water in a pool must be cycled through the filters numerous times each day to meet regulations.
So the next time you take a refreshing dip on a hot day, take a look around and observe these systems for yourself. There will be clues in and around the pool about where the water goes and how it comes back in. If you get lucky, maybe a pool manager will be working on the maintenance and you can get a first-hand view of how the process works.