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water:start [2021/06/18 11:06]
frater_secessus [disinfecting non-potable water for drinking] |
water:start [2022/02/17 14:10]
frater_secessus [Water] |
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| >"...you really appreciate every drop of water if you have to schlep it." -- gcal((http://www.cheaprvliving.com/forums/Thread-Water-Watching-for-Opportunities?pid=299849#pid299849)) | >"...you really appreciate every drop of water if you have to schlep it." -- gcal((http://www.cheaprvliving.com/forums/Thread-Water-Watching-for-Opportunities?pid=299849#pid299849)) |
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| | >"The problem is water..." -- Mark Watney, while stranded on Mars |
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| ====== Water ====== | ====== Water ====== |
| Water is critical for life, especially in hot/dry areas like deserts. | Water is critical for life, especially in hot/dry areas like deserts. |
| |
| | Vandwellers living minimally (no showers or slip-n-slides) will typically require 1 gallon of potable water every day for [[water:drinking|drinking]], and 1 additional gallon for cleaning, [[hygiene:bathing|hygiene]], [[food:cooking|cooking]], etc. |
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| Vandwellers living minimally (no showers or slip-n-slides) will typically require 1 gallon of potable water every day for drinking, and 1 additional gallon for cleaning, hygiene, cooking, etc. | Cleaning water to be suitable for use has two components; **filtration** and **purification**. //Filtration// means removing particulate matter such as mud, sand, large plant cells such as algae and phytoplankton. //Purification// means removing or killing the germs and bacteria that can make you sick. Many methods will do both, but not all. |
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| ===== potable water ===== | Not all water needs to be both filtered and purified. Some natural water from fast-flowing streams or springs may have very little particulate matter in it and be very clear already, and will only need purification if you're going to drink or cook with it. |
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| [[water:drinking|drinking water]] has the highest requirements since it is typically consumed untreated and at room temperature. | As a general rule, //filtered// water is fine for showering or cleaning with. //Purified// water is needed for drinking and cooking. |
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| | Not all water can be made safe for use; it is //not// practical to purify water that is chemically or mineralogically tainted. |
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| ==== disinfecting non-potable water for drinking ==== | See this [[https://www.nps.gov/articles/2wayspurifywater.htm|guide from the National Park Service]] about how to treat water. Also see [[https://www.rei.com/learn/expert-advice/water-treatment-backcountry.html|REI's guide that wants to sell you stuff]] (But is still useful). |
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| It is safest to start with known-drinkable water from public or commercial sources. It is possible to disinfect suspect water by several means; it is not practical to purify water that is chemically or minerologically tainted. | ===== conservation ===== |
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| When possible, multiple approaches should be used on the water. The first step in any disinfection routine is to **clarify the water** to remove haze or foreign matter. Much sediment can clear itself to the bottom if allowed to rest; pour or siphon off the top and leave the sediment behind. | It is far easier to //use less water// than to haul, store, and dispose of gray water. Each subpage will have a conservation section. |
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| Strain from coarse to fine: through a strainer then a coffee filter, for example. | ===== Water Filtration ===== |
| | [[https://www.amazon.com/Sawyer-Products-SP128-Filtration-System/dp/B00FA2RLX2/ref=mp_s_a_1_3|{{ https://m.media-amazon.com/images/I/812XaHTx24L._AC_SX118_SY170_QL70_ML3_.jpg}}]] \\ |
| | Mechanical filtration has become more common and less expensive. [[https://www.amazon.com/LifeStraw-Personal-Camping-Emergency-Preparedness/dp/B07C56LR6N/|Straw-like personal filters]] are now sold, for example. |
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| | The main drawback of filtration are clogging (addressed by adquate pre-filtration) and relatively slow filtration rate. Look for filters that can be gravity fed so the filtration time isn't tiresome. |
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| | * 1-micron filters will filter protozoa like giardia spores and Cryptosporidium out of clear water.((https://www.who.int/water_sanitation_health/hygiene/envsan/sdwtravel.pdf)) These may be labeled NSF/ANSI Standard 53.((https://www.cdc.gov/parasites/crypto/gen_info/filters.html)) |
| | * 0.1-micron will filter all waterborne enteric bacteria from clear water |
| | * Consumer-grade filtration will not remove viruses because of their tiny size. |
| | |
| | The CDC points out the difference between nominal and absolute((or "mean")) micron ratings: "The absolute 1 micron filter will more consistently remove Cryptosporidium than a nominal filter."((https://www.cdc.gov/parasites/crypto/gen_info/filters.html)) |
| | |
| | === Fabric filtration === |
| | |
| | Much sediment can clear itself if allowed to rest; Let the water sit still for 30-60 minutes, then pour or siphon off the top and leave the sediment behind. |
| | |
| | Alternately you can strain from coarse to fine: through a strainer then a coffee filter, for example. |
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| - sieve | - sieve |
| - actual water filter | - actual water filter |
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| | Note that filtration through layered fabric is much better than nothing. In India, for example, researchers found: |
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| | > a filter made of four layers of worn cotton material held back more than 99 percent of all cholera bacteria - using more layers or newer cloth slowed water collection too much.((https://www.fic.nih.gov/News/GlobalHealthMatters/january-february-2015/Pages/nursing-cholera-sari-water-filter.aspx)) |
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| === heat === | Both saris and coffee filters have about a 20-micron pore size: |
| | |
| | > Typically coffee filters are made up of filaments approximately 20 micrometres wide, which allow particles through that are less than approximately 10 to 15 micrometres((https://en.wikipedia.org/wiki/Coffee_filter)) |
| | |
| | The best we should assume for with such //ad hoc// filtration is a pathogen //reduction//. Combination with SODIS (below) might be useful. |
| | |
| | Further reading: [[https://www.maskfaq.com/test-results|this page]] is about reducing airborne pathogens with homemade mask materials, but may be useful. |
| | |
| | ---- |
| | |
| | ===== Water Purification ===== |
| | |
| | It is possible to disinfect suspect water by several means; it is //not// practical to purify water that is chemically or mineralogically tainted. |
| | |
| | When possible, multiple approaches should be used on the water. The first step in any disinfection routine is to **clarify or filter the water** to clear it of particulate/foreign matter. |
| | |
| | ==== Heat ==== |
| |
| Heat is an effective way to kill waterborne pathogens. Note that not all pathogens that survive heat treatment are //found// in water: | Heat is an effective way to kill waterborne pathogens. Note that not all pathogens that survive heat treatment are //found// in water: |
| Given that information, [[food:cooking:solar oven|solar ovens]] or similar devices that can hold 140F-160F for long periods may provide unpowered heat disinfection. Also see SODIS below. | Given that information, [[food:cooking:solar oven|solar ovens]] or similar devices that can hold 140F-160F for long periods may provide unpowered heat disinfection. Also see SODIS below. |
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| === chemical treatment === | ==== Chemical treatment ==== |
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| Chemical treatments require no power making them especially useful offgrid. Treated water can be run through a charcoal filter (Brita) after treatment to improve flavor. Pouring treated water energetically from container to container may allow chemicals to outgas. | Chemical treatments require no power making them especially useful offgrid. Treated water can be run through a charcoal filter (Brita) after treatment to improve flavor. Pouring treated water energetically from container to container may allow chemicals to outgas. |
| [[https://amzn.to/3d3NxWR|Iodine tablets]] were popular with hikers in the past but impart a noticeable flavor to the water. Some come with an additional tablet to be used after the waiting period, intended to remove iodine flavor and color from the water. Iodine treatment should be avoided by people with shellfish allergies.((https://www.wikihow.com/Purify-Water)) | [[https://amzn.to/3d3NxWR|Iodine tablets]] were popular with hikers in the past but impart a noticeable flavor to the water. Some come with an additional tablet to be used after the waiting period, intended to remove iodine flavor and color from the water. Iodine treatment should be avoided by people with shellfish allergies.((https://www.wikihow.com/Purify-Water)) |
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| === flocculation === | === Flocculation === |
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| Hybrid chlorinating-flocculating chemicals such as [[http://www.flochlor.com/product/flocculation-disinfection-powder/|Flo-Chlor]] show promise for turbid water, but they are not widespread yet. //Flocculation// means suspended particles are drawn together and either drop out of suspension or (less commonly) float to the top. | Hybrid chlorinating-flocculating chemicals such as [[http://www.flochlor.com/product/flocculation-disinfection-powder/|Flo-Chlor]] show promise for turbid water, but they are not widespread yet. //Flocculation// means suspended particles are drawn together and either drop out of suspension or (less commonly) float to the top. |
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| === filtration === | |
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| [[https://www.amazon.com/Sawyer-Products-SP128-Filtration-System/dp/B00FA2RLX2/ref=mp_s_a_1_3|{{ https://m.media-amazon.com/images/I/812XaHTx24L._AC_SX118_SY170_QL70_ML3_.jpg}}]] \\ | |
| Mechanical filtration has become more common and less expensive. [[https://www.amazon.com/LifeStraw-Personal-Camping-Emergency-Preparedness/dp/B07C56LR6N/|Straw-like personal filters]] are now sold, for example. | |
| |
| |
| The main drawback of filtration are clogging (addressed by adquate pre-filtration) and relatively slow filtration rate. Look for filters that can be gravity fed so the filtration time isn't tiresome. | |
| |
| |
| |
| * 1-micron filters will filter protozoa like giardia spores and Cryptosporidium out of clear water.((https://www.who.int/water_sanitation_health/hygiene/envsan/sdwtravel.pdf)) These may be labeled NSF/ANSI Standard 53.((https://www.cdc.gov/parasites/crypto/gen_info/filters.html)) | |
| * 0.1-micron will filter all waterborne enteric bacteria from clear water | |
| * Consumer-grade filtration will not remove viruses because of their tiny size. | |
| |
| The CDC points out the difference between nominal and absolute((or "mean")) micron ratings: "The absolute 1 micron filter will more consistently remove Cryptosporidium than a nominal filter."((https://www.cdc.gov/parasites/crypto/gen_info/filters.html)) | |
| |
| == fabric filtration == | |
| |
| Note that filtration through layered fabric is much better than nothing. In India, for example, researchers found: | |
| |
| > a filter made of four layers of worn cotton material held back more than 99 percent of all cholera bacteria - using more layers or newer cloth slowed water collection too much.((https://www.fic.nih.gov/News/GlobalHealthMatters/january-february-2015/Pages/nursing-cholera-sari-water-filter.aspx)) | |
| |
| Both saris and coffee filters have about a 20-micron pore size: | |
| |
| > Typically coffee filters are made up of filaments approximately 20 micrometres wide, which allow particles through that are less than approximately 10 to 15 micrometres((https://en.wikipedia.org/wiki/Coffee_filter)) | |
| |
| The best we should assume for with such //ad hoc// filtration is a pathogen //reduction//. Combination with SODIS (below) might be useful. | |
| |
| Further reading: [[https://www.maskfaq.com/test-results|this page]] is about reducing airborne pathogens with homemade mask materials, but may be useful. | |
| |
| |
| Optimal function may be found by placing small-diameter bottles in a solar oven. This will enhance UV collection and heating. | Optimal function may be found by placing small-diameter bottles in a solar oven. This will enhance UV collection and heating. |
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| | ---- |
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| ===== non-potable water ===== | ===== non-potable water ===== |
| [[water:cooking|Water for cooking]] has lower requirements for biological purity because the water is usually boiled during preparation (see above). | [[water:cooking|Water for cooking]] has lower requirements for biological purity because the water is usually boiled during preparation (see above). See [[https://www.reddit.com/r/HikerTrashMeals/comments/rpdn4h/minimum_water_fuel_testspasta_carbonara/|this article]] about using less water when cooking. |
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| Water used for [[water:cleaning|cleaning]] or [[hygiene:bathing|external hygiene]] may be of even lower quality assuming one is careful not to ingest the water, or get it in open sores or mucous membranes. | Water used for [[water:cleaning|cleaning]] or [[hygiene:bathing|external hygiene]] may be of even lower quality assuming one is careful not to ingest the water, or get it in open sores or mucous membranes. |
