When water is obtained from natural sources such as rivers, lakes, streams and wells, it can contain microbes, dissolved chemicals, and many other types of materials or particulate matter. In many cases it becomes necessary to treat this water before it is used as potable water, pure water systems, heating or cooling systems, or for other purposes such as irrigation. The objective of this treatment is to remove or at least reduce the contaminants to a level that allows the water to be considered safe and effective for its specific use.
There are a number of common water treatment and filtration methods in use today. These include sedimentation, boiling, chemical disinfection, desalination and filtration. Methods also include Ultraviolet Light which is effective with microbes and biological containments but is ineffective in removing dissolved chemicals and other particulate materials. Ozone Treatment which while expensive removes biological contaminants and reduces odor problems along with concentrations of minerals such as iron and manganese. Another effective treatment method is Reverse Osmosis which removes offensive materials and microbes while not affecting the taste or smell of the water. A drawback of this method is that the purified water after treatment is devoid of useful minerals. Some of these methods also waste water as a result of the process.
In many other situations water must be filtered or purified to a higher level of purity than potable water. Using water in manufacturing or heath care industry processes may require pure or distilled water. A perfect example is the use of water in Hemodialysis. During a typical patient dialysis treatment, a system may use anywhere from 23 to 50 gallons of treated water.
Water is also treated when used in heating and cooling systems. Chemicals are added during the treatment process to inhibit the corrosion of metal parts within these systems. Antifreeze is often added to cooling tower and cooling or heating system piping to prevent freezing conditions within the system piping. Plumbing codes require the use of non-toxic antifreeze in these systems, however the use of toxic chemical is common in many installations. This results in high or health hazard cross-connections being created.
Water softening equipment is another possible installation where unprotected cross-connections may occur. While we think of filters and water softeners as pass through equipment which only improve the quality of the potable water within the system, this is not always a factual statement. Reversing the flow through even a dirt and sediment system can significantly affect the quality of the water. When a water softener is installed it is critical that its drain line be piped to a proper location in accordance with the applicable plumbing code.
In residential settings many of these products are sold in home centers as do it yourself projects. To quote a popular web site: “These systems are designed to be installed right away with minimal effort and expenses, which means that you do not have to pay extra for hiring a handyman or plumber to do the job for you.” I think that anytime you are working on the potable water system you need to understand the ramifications of altering the system, and the possible problems that may occur because of adding additional components to it. While the increasing use of push-fit fittings and plastic pipe may allow a home owner of do it yourselfer to install a filter or softener without leaks, a lack of understanding of pressure loss, thermal expansion and cross-connection can spell disaster.
These problems can also exist in commercial settings. Untrained individuals installing kitchen equipment, soap dispensers and other cleaning equipment often do not have the training or knowledge of the plumbing code or hydraulic conditions and can create unprotected cross-connections. Many of these problem installations occur after a system has been inspected and approved by the Authority Having Jurisdiction during the facility’s construction. I was once called to a location that had recently installed a new coffee maker in their remodeled kitchen. There were complaints about an aftertaste in the coffee and although their equipment installer had returned and installed a taste and odor filter in addition to the sediment filter they had originally installed they were still getting complaints about the taste of the coffee. Looking at the installation and tracing the piping back to the water supply, I found that the installer had used a saddle valve and connected the coffee maker to a copper line in the hydronic heating system instead of the potable water piping in the building. Thankfully this was discovered before anyone became ill and the problem was quickly corrected.
Anytime we connect any price of equipment or plumbing fixture to the potable water system we need to answer several questions:
- How will this installation affect the quality of the water within the system?
- How will this installation affect the pressures or hydraulic conditions within the system?
- Does this installation create a direct or indirect cross-connection?
- Does this installation change the degree of hazard for the facility?
- What if any type of backflow protection is required?
- How will the installation of the required cross-connection affect the system?
- What types of maintenance or testing requirements are necessary to protect the integrity of the plumbing or potable water system?
These questions need to be answered before any type of water filtration or water treatment system is installed. The installation needs to be completed by individuals who understand not only the equipment they are installing, but also the effect the installation will have on the system itself as a whole. As with any type of mechanical equipment the end user must also be educated as to the safety and maintenance requirements needed in the future. The required protection may be as simple as a proper air gap, or an atmospheric vacuum breaker, or it may be as complicated as the installation of a reduced pressure principle backflow prevention assembly. Each installation needs to be looked at individually by qualified individuals who have the knowledge and experience to protect our most precious resource, the water we need to sustain life.
About the Author |
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Sean is a 40 year member of the United Association Local 524 Scranton Pa. He has worked in all phases of the plumbing and mechanical industry and is a licensed master plumber. Sean is a Past President of the American Society of Sanitary Engineering. Sean is also the member of the ASSE Cross-Connection Control, Technical Committee. Sean is employed by IAPMO as the Vice President of Operations for the IAPMO Backflow Prevention Institute. |