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| Rainwater catchment systems have commonly found contaminants due to the location and isolation of rooftops. | | Rainwater catchment systems have commonly found contaminants due to the location and isolation of rooftops. |
| {|class=wikitable | | {|class=wikitable |
| |+Common contaminants of rainwater catchment systems<ref name=pacific> WATER QUALITY OF RAINWATER HARVESTING SYSTEMS http://www.pacificwater.org/userfiles/file/MR0579.pdf</ref> | | |+Common contaminants of rainwater catchment systems<ref name=pacific> WATER QUALITY OF RAINWATER HARVESTING SYSTEMS http://www.pacificwater.org/userfiles/file/MR0579.pdf</ref> <ref http://www.appropedia.org/Practivistas_rainwater_2014/Literature_Review#Roofing_Basics </ref> |
| !Contaminant | | !Contaminant |
| !Source | | !Source |
Revision as of 19:04, 14 June 2017
Literature Review
This page describes some of the basics behind designing Rainwater Catchment Systems. It is a collection of resources pulled from similar projects that are documented throughout Appropedia, and contains helpful resources for those interested in learning more. Please feel free to add even more helpful content!
Rainwater Catchment
A rainwater catchment system is a system that collects, filters, and stores rainwater for community or household use. [1]
Rainfall
One of the first steps to designing a Rainwater Catchment system is to determine the amount of rainfall that will fall in the desired location. A good practice is to determine the average precipitation depth in inches for each month. This data can typically be found from sources such as the PF Data Server from NOAHH.
Catchment Potential
Besides the amount of rainfall that is available to be collected, the size of the collection surface will determine how much of the available rainfall will be collected for usage. Sites such as the Rainwater Collection Calculator can aide the design process.
Roofing
The type of construction material is important for a rainwater catchment system. Depending on what material is used for the roof, the collected water can be contaminated by carcinogens[1]. The roofing materials used in a rainwater catchment system should be chemically inert to keep contaminants out of the system. In addition to the roof material itself, the climate can influence the contaminate runoff depending on the material.
Types of Roofing Material
The following are brief descriptions of a few common roofing materials and their benefits and drawbacks when being considered for Rainwater Catchment Projects.
Thatch: Filler
Wood: Filler
Tile: Filler
Concrete: Filler
Metal: Filler
Water Quality
There are three criteria to having acceptable quality drinking water.
- No fecal bacteria
- No harmful chemicals
- No bad taste or smell
Rainwater catchment systems have commonly found contaminants due to the location and isolation of rooftops.
Common contaminants of rainwater catchment systems[2] Cite error: Invalid <ref> tag; invalid names, e.g. too many
Carbon Block: "Carbon block filters contain pulverized activated carbon that is shaped into blocks under high pressure. They are typically more effective than granulated activated carbon filters because they have more surface area. Their effectiveness depends in part on how quickly water flows through."[3]
Granulated Activated Carbon: "These filters contain fine grains of activated carbon. They are typically less effective than carbon block filters because they have a smaller surface area of activated carbon. Their effectiveness also depends on how quickly water flows through."[3]
Ceramic: "Ceramic filters have very small holes throughout the material that block solid contaminants such as cysts and sediments. They do not remove chemical contaminants."[3]
Deionization: "These filters use an ion exchange process that removes mineral salts and other electrically charged molecules (ions) from water. The process cannot remove non-ionic contaminants (including trihalomethanes and other common volatile organic compounds) or microorganisms. EWG’s water filter guide does not include any filters based on this technology."[3]
Distillation: "This technology heats water enough to vaporize it and then condenses the steam back into water. The process removes minerals, many bacteria and viruses and chemicals that have a higher boiling point than water. It cannot remove chlorine, trihalomethanes or volatile organic chemicals (VOCs). EWG’s water filter guide does not include any filters based on this technology."[3]
Ion Exchange: "This technology passes water over a resin that replaces undesirable ions with others that are more desirable. One common application is water softening, which replaces calcium and magnesium with sodium. The resin must be periodically “recharged” with replacement ions."[3]
Mechanical Filters: "Like ceramic filters, these filters are riddled with small holes that remove contaminants such as cysts and sediments. They are often used in conjunction with other kinds of technologies, but sometimes are used alone. They cannot remove chemical contaminants."[3]
Ozone: "Ozone kills bacteria and other microorganisms and is often used in conjunction with other filtering technologies. It is not effective in removing chemical contaminants. EWG’s water filter guide does not include any filters based on this technology."[3]
Reverse Osmosis: "This process pushes water through a semi-permeable membrane that blocks particles larger than water molecules. Reverse osmosis can remove many contaminants not removed by activated carbon, including arsenic, fluoride, hexavalent chromium, nitrates and perchlorate. However, reverse osmosis does not remove chlorine, trihalomethanes or volatile organic chemicals (VOCs). Many reverse osmosis systems include an activated carbon component than can remove these other contaminants. Quality can vary tremendously in both the membrane system and the carbon filter typically used with it. Consumers should also be aware that reverse osmosis filters use 3-to-20 times more water than they produce. Because they waste quite a bit of water, they are best used for drinking and cooking water only."[3]
UV (ultraviolet): "These systems use ultraviolet light to kill bacteria and other microorganisms. They cannot remove chemical contaminants. EWG’s water filter guide does not include any filters based on this technology." [3]
Gutters, Pipes, and Downspouts
First Flush
Storage
References
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