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Monday, March 17, 2014

History of Swimming Pool Filtration

Water filtration was first used as a means to keep drinking water free of germs. Most of our swimming pool filtration began as a way to purify drinking water for municipal water systems. 
     The ancient Sanskrit and Egyptian writings first described of this process of heating water and letting it drip through sand and/or charcoal.  Hippocrates commonly called the father of medicine wrote of public hygiene and mentioned how water could be purified.  The “Hippocrates’s sleeve” was invented by him and consisted of a cloth bag that could help remove hardness and bad smell from the water.  Water was boiled and poured through his “sleeve” for his patients.  He was able to prove that the water from the Greek aqueducts was not pure in quality.  Like others before him he also thought that if the water tasted good it was clean and pure.  The Greek and Romans also wrote of water treating devices.
     Desalination of water was elaborately talked about by Sir Francis Bacon in his compilation “A Natural History of Ten Centuries”.  He felt that if seawater was allowed to percolate through sand it could be purified.  Lucas Antonius Portius was a famous Italian physician that illustrated through the use of three sand filters a multiple sand filter experiment for clarifying water.  During this time of exploration, seashells were used on ships to clarify water.
     In the first decade of the 18th century La Hire, a Parisian scientist proposed in the French Academy of Sciences that every household had a sand filter and rainwater cistern to help keep drinking water pure and fresh.
     Municipal water treatment began in Scotland in 1804 and consisted of sand and gravel filters.  In 1829 London also installed filters using this method.  During the mid 19th century when outbreaks of disease such as cholera were rampant it was found that areas that had sand filtration there were less cases reported. In 1892, Wilhelm Berkefield recognized the filtration media diatomaceous earth, and the Berkefield candle filters were used during the cholera epidemic as well. 
Berkefeld Ceramic Filter
 ( I own a modern  "Berkey" version for my drinking water)
      John Snow a British scientist found that by using a microscope he was able to trace the disease back to a contaminated pump and disproved the myth that if water tasted and looked good it was pure.  He used chlorine to kill the bacteria and this started the process of treating water in addition to filtration for water municipalities.  After this discovery England mandated that all water be treated before drinking. This was the first government mandate on drinking water.  In 1835, Queen Victoria recognized health dangers in her drinking water and commissioned John Doulton (Doulton Pottery) to make a ceramic filter for her household.  His son in 1862 introduced the Doulton Manganous Carbon water filter around the same time that Louis Pasteur’s bacteria experiments conclusively showed Spontaneous Generation and the ceramic filter research went to providing a filter that could filter out these bacteria.       
     Moving forward we all began to swim and soak in the states for recreation in large contained bodies of water that were manmade, the swimming pool.  After use for a while it was found that the pools of water became dirty and did not look inviting. 
     In 1919 one of the first proclaimed pool builders was Ed L. Wagner of Connecticut.  As a builder of water and sewage treatment plants he applied his experience to building swimming pools. These pools were of the “fill and draw” type.  Concrete was poured into a hole in the ground and water let into it.  After a couple of weeks the pools became unsanitary and unsafe.  Pools were built on a slope so that the water could be drained by gravity and water re-introduced uphill from the pool by gravity as well.  In the 1950’s on the west coast many of these pools were built and a reservoir of water was located uphill of the pool.  Chlorine and soda ash were used to extend the water life but eventually they had to be drained and refilled.  Today there is an example of this pool at Biltmore Estate in Asheville, NC.

     As pumps and valves were not a part of the pool business yet they were purchased from marine suppliers and were crude beginnings.  Filters were purchased from the petroleum and dry cleaning industry and modified for pool service.  In 1925 a pool supply business was started by John Mudge a former chemical engineer.  After that water recirculation systems were developed and installed.  This alleviated the waste of water and allowed for building of pools not near a water source.
     Around 1940 water systems improved.  Paddock Pools invented a floating plastic skimmer around 1942 to skim the water and bring water back to the filter.  This worked on irregular shaped pools.  In wall skimmers that were fixed were available in 1952.
     Up to this point slow sand filtration was used fed by gravity and then with the equipment borrowed from other industries we moved into using rapid rate filtration which increased the filtration turnover time to 3-5 gpm/sq. ft. but the tanks were large and the process was still slow.  In the 1950’s came space exploration and also the discovery of newer materials that could withstand high pressure.  The high rate pressurized filter came into existence that could filter with the aid of a pump up to 20gpm/sq. ft.
     In 1956 Phil Anthony of Anthony pools placed an order with Dick Meissner who worked sewing in his garage on an order for the first “Anthony McIntosh Filter Bag”.  This was at a time when DE filtration was at its infancy for residential pools.  He then received orders from Swimquip, Landon, Paddock and Pac-Fab.  This nighttime extra job grew into the company we now know as Unicel in 1959.  By 1962 this business had tripled.
     When cartridge filters came into being Dick Meissner saw an opportunity to grow his company further.  As the first cartridge elements were paper and did not hold up well Unicel developed an element made of more durable polyester in 1964.  Now we see Microban which is a microbiocide being added to the filter elements as well.
     Bag filters are still available and used heavily in the beach areas to trap sand as a secondary filter system installed before the base filtration.  So this idea goes back to Hippocrates.  Drinking water uses ceramic filtration today in our small drinking water devices. 
     Although we have updated scientific information we have found that ancient methods of slow filtration through media are still the standard today.  But, I’m not drinking the pool water, unless I have to.

“Filtration Focus Builds Niche”  The History of Unicel 
Swimming Pool/Spa Age July 1997

“Swimming Pool Filtration: Pool water that sparkles like Diamonds”
Everything H20 /  & Rec Business December 2007

The Springboard in the Pond

Thomas A.P. van Leeuwen 1998