by Rob Cox, October 22, 2010
Eco-Friendly Swimming Pool Filtration
Swimming pool filters don't often come to mind when thinking of more eco friendly methods of pool operation. Pool filters do however, make quite an impact on your swimming pool's carbon footprint.
In this article, we will cover the features and benefits of each filter type in this regard, but also discuss how filter size can be an important factor, discussing how bigger filters have less of an impact on the environment than smaller, undersized pool filters.
1. Larger filters need to be backwashed less often, saving water and reducing D.E. powder discharge.
2. Larger filters run at lower pressure and higher flow, which means a higher turnover rate.
3. Larger pool filters can prevent poor water conditions, requiring more sanitizing pool chemicals.
4. Larger pool filters may allow you to use a smaller, energy saving pool pump.
5. Larger pool filters operate under less pressure, which creates less work for your pool pump, reducing the amperage usage.
The Trio of Filtration, Sanitation and Circulation are what gives us clean, clear pool water. If one of these variables is more efficient, we can use less of the others. For instance, if we install a 15 horsepower pump on your 10,000 gallon pool, the water would be moving so fast that we would need very little filtration and sanitation - think of a rushing river, or a stagnant pond. Likewise, if we added 5 gallons of 12.5% bleach to the pool every week, we would need less filtration and circulation to keep the water blue. So, it stands to reason that if a larger filter is installed, we can circulate (pump the water) less and use fewer chemicals to treat the water.
Which Pool Filter is Best for the Environment?
Diatomaceous Earth Filters: D.E. filters, as they are known, filter down to the smallest particle size of all 3 types of pool filters, and in this regard, they can be considered green in that using a DE filter can reduce your pump run time and also the amounts of pool chemicals that need to be added. Diatomaceous Earth powder is a natural substance, the exoskeletons of microscopic diatoms, harvested from the ocean floor. Although organic, and useful in gardening for pest removal, and popular now to combat bedbugs, D.E. powder is classified as a mild carcinogen, and can choke small streams and estuaries, if discharged improperly.
Sand Filters: Typically, sand filters require more frequent backwashing, which wastes a lot of treated water. If your pool water is very highly chlorinated or has high levels of algaecide, this can cause environmental issues in your local watershed. See our previous blog post on proper pool filter discharge methods. A sand filter actually operates more efficiently when it is a little dirty, but if a sand filter becomes overly clogged, this raises pressure, reduces flow and creates more of a work load for your pool pump. Sand filters do have the benefit of being made of fewer non-biodegradable components. Fewer internal parts, mostly just natural, graded silica sand.
Cartridge Filters: These are considered to be the greenest of filters, in that they save a lot of water. Cartridge pool filters are not backwashed like other filter types - to clean them, the pleated cartridges are removed and hosed clean. A properly sized cartridge pool filter can operate for 6 months or more between cleanings. Cartridges wil need to be replaced at some point, however, which creates a disposal issue. Made of plastic and spun polyester (Reemay), cartridge filters are not a biodegradable filter media.