WATER: FILTRATION
Filtration is the concept that comes to mind when most people hear the term "water treatment". Filtration is a very basic concept of water treatment and one almost anybody can understand and easily accomplish, which is probably the reason it is a favorite and growing in popularity and use in the field. Filtration is a process of physically extracting or the straining of particulate from a liquid. The process literally has thousands of applications for science and industry and not limited to water. Filtration in water treatment follows the same concept, except we attempt to remove particulate from unsafe water, making it consumable or drinkable.
One thing you need to learn about filtration is; not all filtration is equal. Filtering water involves passing water through a porous material (filter) in an attempt to catch all particulate that can not fit through, "thus a filter only removes particulate that are larger in diameter to that of the holes in the porous material". Any material smaller in diameter than the holes will pass thru. Therefore water filtered does not necessarily mean purified, safe, or drinkable. As previously noted filtration is the process of physically removing contaminants, but it only removes what it can catch. It is important to rap your head around the understanding of filtration because many suppliers commonly refer to their products as water purifiers when in fact they are filtration systems designed to only remove particulate of a certain diameter. Before we get too much into the different types of filters I will list some important notes you need to retain concerning water filtration.
Note: Most chemicals and organic hazards are invisible to the naked eye. Most hazardous particulate are on a micron scale (a micron is one-millionth of a meter). All filters designed to remove are often thick membranes with holes not visible to the naked-eye, thus household coffee filters are not a good source for water filtration. Household coffee filters, water softeners, and most tap water filtration systems do not remove much of anything.
Note: Viruses such as Hepatitis A are so small that they require a ceramic filter rated to 0.004 microns. There are numerous ceramic filters on the market, but most do not filter to 0.004 microns, so shop around.
Note: Filtration is not the same as purification. When you filter water you are removing contaminants based upon the perforation of the filter, therefore only the organisms that are larger than the designated hole will be filtered out of the water, while all others small enough to pass-thru, will.
Note: Filters work by straining particulate out of water, therefore particulate collects on the intake side of the filter. It is important to remember and keep in mind all areas of contamination, even surfaces.
Note: Particulate collects on the intake side of the filter, most filters have a short lifespan or use time. Some filters are designed to allow the consumer to flush treated water back through the filter in reverse to remove particulate that has begun to collect, thus extending the life of the filter.
Note: Filters are made of fragile material, making them extremely vulnerable to damage from mishandling or dropping. Please take the following into consideration; (1) Use extreme care when handling all filters. (2) If possible purchase backup filters. (3) Keep filters in container they were purchased in, because in many instances these may be the best containers to protect the filter from damage. (4) If needed rap filter in additional material for added protection. (5) Throw away filters that appear damaged or those you suspect. Caution: It only takes a microscopic fracture in a filter for particulate
to enter, making visual inspection of the filter unreliable.
to enter, making visual inspection of the filter unreliable.
Note: Using multiple stages to treat water is still the best way of producing drinking water. A multistage treatment can be accomplished even for a Bug Out Pack by purchasing a Quart sized filtration system for the field and adding a chemical treatment such as Potable Aqua Tablets or a small amount of household bleach to your kit. Potable Water Tablets are great and I always keep some on hand, but my favorite is the household bleach. If the chemical your treating your water with kills all organisms, than you only need to have a filter that removes chemicals and elements. Make sure to filter water first, than treat with chemical because treating with chemicals first will quickly lower the lifespan of your filter.
CERTIFICATION of WATER FILTERS
The American National Standards Institute (ANSI) is a private organization that overseas the development for voluntary consensus standards for personnel, processes, products, services, and systems in the United States, for use in the United States and for coordination of American standards with International Standards so American made products can be sold abroad. In short ANSI ensures that all characteristics of an item, such as a filter, are tested the same, defined by the same terms, and perform consistently. Another service ANSI/NSF fulfills is the accredit organizations for specific quality. This means that if a particular product has specific claims such as "removes cyst" the ANSI/NSF tests, retests, and when confirmed it then certifies the product. This is an extremely important service that ANSI/NSF performs, because we live in a world of commercialism and people do not always tell the truth. A certification by ANSI/NSF is as good as a guarantee that you can get. If you do not see this certification it is not worth your time or your life. Also keep in mind that ANSI/NSF issues certification for two reasons; health concerns and aesthetic concerns.
TYPES of WATER FILTERS
There are various types of water filters usually designed around the concept of removing a specific type of particulate or process for doing so; media filters, screen filters, disk filters, slow sand filters, rapid sand filters, and cloth filters. The most common among survivalists, preppers, homesteaders, and homeowners are the Portable Water Purifiers, better known as Point-of-Use (POU) and Commercial Portable Water Purification Systems.
POU in particular are self-contained units, meaning the filter is in the form of a cartridge that screws or snaps into place. The unit does not require any additives, everything is already contained inside the filter. A growing trend among filter makers are to group different types of filters together to create a multi-barrier system. Multi-barrier systems often extend the life of the filter, but may also slow the flow down. On the other hand there are some commercial portable water purifiers that use chemical additives. Most of these types of units are used to purify a homes municipal or well service. The larger commercial units are great for removing excessive chlorine, foul odors or taste, and heavy metals. Before we go any further lets talk certification.
Homemade Filters
There are numerous ways to make homemade filters. Most homemade filters involve sand, fabric screening, coffee filters, and homemade or purchased Activated Charcoal. Similar to most store bought filters, homemade models usually try to incorporate multiple stages of filtration. In a pinch these devices might remove some particulate, mainly particulate that do little to harm you compared to the microscopic that can easily kill. Some of these devices might even remove parasites, however I have yet to find one homemade filter that successfully removes all organic material. To illustrate the difficulty in removing all organic material, consider that most Filter Manufacturers in the industry are nowhere near close to removing organic particulate smaller than 0.2 micrometer. That being said; I am currently working in my lab "garage" to develop a multi-stage process for eliminating all hazards. I will let you know!
There are numerous ways to make homemade filters. Most homemade filters involve sand, fabric screening, coffee filters, and homemade or purchased Activated Charcoal. Similar to most store bought filters, homemade models usually try to incorporate multiple stages of filtration. In a pinch these devices might remove some particulate, mainly particulate that do little to harm you compared to the microscopic that can easily kill. Some of these devices might even remove parasites, however I have yet to find one homemade filter that successfully removes all organic material. To illustrate the difficulty in removing all organic material, consider that most Filter Manufacturers in the industry are nowhere near close to removing organic particulate smaller than 0.2 micrometer. That being said; I am currently working in my lab "garage" to develop a multi-stage process for eliminating all hazards. I will let you know!
Portable Filters
Filtration systems are improving as time progresses, especially as interest in higher quality water continues to drive the industry to make better products. There are some commercial ceramic filters that will filter out pathogens down to 0.2-0.3 micron, and depending upon cartridge type water volume may be between 5,000 and 50,000 liters of drinking water. The problem is that some bacteria are actually smaller than 0.2 microns thus making it necessary to chemically treat or boil the water after filtration. Always assume the water your collecting to be contaminated with any and all things and only in emergency circumstances should you ever drink water that has not been treated to kill organisms. Also organisms that are filtered out will maintain themselves on the intake side of the filter, eventually clogging and stopping flow. In most cases this is what actually ends the life of a filter.
Filtration systems are improving as time progresses, especially as interest in higher quality water continues to drive the industry to make better products. There are some commercial ceramic filters that will filter out pathogens down to 0.2-0.3 micron, and depending upon cartridge type water volume may be between 5,000 and 50,000 liters of drinking water. The problem is that some bacteria are actually smaller than 0.2 microns thus making it necessary to chemically treat or boil the water after filtration. Always assume the water your collecting to be contaminated with any and all things and only in emergency circumstances should you ever drink water that has not been treated to kill organisms. Also organisms that are filtered out will maintain themselves on the intake side of the filter, eventually clogging and stopping flow. In most cases this is what actually ends the life of a filter.
Pretreatment
All filters require some form of pretreatment (SCREENING) of the water prior to using the main filter, this is necessary to
avoid damaging the filter. Portable Self-Contained Units may have some form of screen (built into the filter unit) to remove larger particulate, however it always helps to screen first. You may also choose to DOSE your water with Chlorine or another chemical, but remember that some filters can be damaged by adding chemicals, check your labels. Depending upon the instructions on the filter you may need to follow up a chlorine treatment with a disulfide dose to deactivate the chlorine, prior to using the pretreated source.
My Preferred Method of Pretreatment
In the event I have to utilize a filter for water treatment I have a process that I use. My personal preferred method of pretreatment is a two-stage process. The filter I prefer is a backwash system, where I can filter water through then backwash and remove particulate that has gathered on the intake. (1) I boil the water. It does not matter the source, boiling the water for about ten minutes or more before filtering will kill all organisms. This does not remove these organism from the water, (they will still collect on the intake) but it does destroy their ability to do me harm. (2) I then use the backwash system to remove all dead organic material from the intake. Note: As previously mentioned the filter may not have stopped all organisms from getting through, this is okay, because I have already killed all organism by boiling the water.
In the event I have to utilize a filter for water treatment I have a process that I use. My personal preferred method of pretreatment is a two-stage process. The filter I prefer is a backwash system, where I can filter water through then backwash and remove particulate that has gathered on the intake. (1) I boil the water. It does not matter the source, boiling the water for about ten minutes or more before filtering will kill all organisms. This does not remove these organism from the water, (they will still collect on the intake) but it does destroy their ability to do me harm. (2) I then use the backwash system to remove all dead organic material from the intake. Note: As previously mentioned the filter may not have stopped all organisms from getting through, this is okay, because I have already killed all organism by boiling the water.