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Post  cottontop on Sat May 03, 2008 8:26 pm

This is the water thread. Please post any messages dealing with water here. Filters, storage, handpumps, ect.

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Activated Carbon Filtration Water Treatment

Post  cottontop on Thu Jul 17, 2008 7:00 am

Activated Carbon Filtration Water Treatment
by larry G Today at 11:46

Activated Carbon Filtration
Activated carbon (AC) filtration is most effective in removing organic contaminants from water. Organic substances are composed of two basic elements, carbon and hydrogen. Because organic chemicals are often responsible for taste, odor, and color problems, AC filtration can generally be used to improve aesthetically objectionable water. AC filtration will also remove chlorine. AC filtration does remove some organic chemicals that can be harmful if present in quantities above the EPA Health Advisory Level (HAL). Included in this category are trihalomethanes (THM), pesticides, industrial solvents (halogenated hydrocarbons), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). THMs are a byproduct of the chlorination process that most public drinking water systems use for disinfection. AC filtration is a viable alternative to protect private drinking water systems from organic chemical contamination. Radon gas can also be removed from water by AC filtration, but actual removal rates of radon for different types of AC filtration equipment have not been established.

Water Contaminants Not Removed by AC Filtration
Similar to other types of water treatment, AC filtration is effective for some contaminants and not effective for others. AC filtration does not remove microbes, sodium, nitrates, fluoride, and hardness. Lead and other heavy metals are removed only by a very specific type of AC filter. Unless the manufacturer states that its product will remove heavy metals, the consumer should assume that the AC filter is not effective in removing them.

Activated Carbon Filtration Equipment
AC filters can be placed in the three following categories: pour-through; faucet-mounted; and high-volume.
► Pour-through AC filters are the simplest. They work like a drip coffee maker. Water is poured in the top and filters by gravity through the filter to the bottom. They are quite slow and handle only small volumes of water.
► Faucet-mounted AC filters are small units attached on the end of a standard kitchen faucet. They are convenient to use, but because of their size require frequent change. Some units have bypass valves, so that just water for cooking and drinking is filtered.
► High-volume AC filters contain much more AC than either the pour-through or faucet-mounted models. High-volume units are designed to be installed in-line, generally under the sink. They are installed on the cold water line, and some units are installed with a bypass to separate cooking and drinking water from other uses. Under exceptional circumstances all water may need to be treated by AC filtration. A high-volume unit may be installed at the point of entry to the house if all water needs to be treated.

Eventually the AC filter loses its ability to remove contaminants, because it becomes clogged with material. In the case of taste and odor, the time to change the filter is easy to detect. However, in the case of other contaminants, it is more difficult to determine when the filter is no longer performing at an adequate level. Most manufacturers recommend a filter change after a certain volume of water has passed through the filter. Some AC units actually meter the water and automatically shut down after a specific quantity of water has passed through the filter. A general rule of thumb for high-volume AC filters is to change the filter after six months of use or 1000 gallons of filtered water.
Tests done by Rodale Press Product Testing Department indicated that filtering performance was reduced dramatically after 75 percent of the manufacturer's recommended lifetime. These results suggest that filters should be changed more often than suggested by the manufacturer. Some AC filters are claimed to last for five years, because they are rechargeable with hot water (145 degrees F). The heat is supposed to release adsorbed organic chemicals. Little information is available on the prolonged effectiveness of rechargeable AC units. General recommendations are somewhat useful guidelines, but there is no guarantee that they apply to any specific situation. Remember, the only certain way of knowing whether contaminant levels are acceptable or not is by having your water tested. A sediment filter installed ahead of any AC filter will prolong the life of the AC unit. Sediment can easily clog the pores of an AC filter within a short period of time. A good sediment filter can be purchased for only a fraction of the price of most high volume AC filters.

Bacteria Issue
AC filters can be a breeding ground for microorganisms. The organic chemicals that are adsorbed to the AC are a source of food for various types of bacteria. Pathogenic bacteria are those that cause human diseases such as typhoid, cholera, and dysentery. Public water systems must treat for disease causing bacteria; therefore, the likelihood of disease causing bacteria being introduced to an AC filter from public drinking water is remote. AC filtration should only be used on water that has been tested and found to be bacteria free or effectively treated for pathogenic bacteria.

Other types of non-pathogenic bacteria that do not cause diseases have been regularly found in AC filters. There are times when high amounts of bacteria (non-pathogenic) are found in water filtered through an AC unit. Research by R. L. Caldron and E. W. Mood (1987) shows little risk to healthy people that consume high amounts of non-pathogenic bacteria. We regularly take in millions of bacteria every day from other sources. However, there is some concern for certain segments of the population, such as the very young or old and people weakened by illness. Some types of non-pathogenic bacteria can cause illness in those whose natural defenses are weak. Flushing out bacteria that have built up in the filter can be accomplished by running water through an AC filter for about 30 seconds prior to use.

Water filtered after the initial flushing will have much lower levels of bacteria and ingestion of a high concentration of bacteria will have been avoided. The flushing procedure is most important in the morning or any other time of the day when the filter has not been used for several hours. Some compounds of silver have been used as disinfectants. Silver has been added to certain AC filters as a solution to the bacteria problem. Unfortunately, product testing has not shown silver impregnated AC to be much more effective in controlling bacteria than normal AC filters. Only in the first month of operation did there appear to be any advantage to using an AC filter that contained silver. EPA requires registration of all types of water treatment equipment that contain an active ingredient for the purpose of inhibiting the growth of microorganisms. Registration does not guarantee that the product is effective. It only guarantees that the active ingredient will not leach from the filter at levels that would be a health hazard.

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July 17, 2008

Post  cottontop on Thu Jul 17, 2008 7:08 am

Hi Larry G!

Thank you for helping us out. Alot of folks have questions on this topic, so I hope they will find their answers here.

I moved your new topic into the water thread and deleted the new topic as we discussed.


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Water Requirements and Planning – Part 1

Post  larry G on Fri Jul 18, 2008 5:53 am

I have been in the municipal water and wastewater treatment career field, both in operations and in management, for well over 20 years and am still currently licensed to operate these facilities. Therefore I have set out to produce this document, using the best of my knowledge, in a concise and accurate format for the benefit of those who are preparing for pandemic or other disasters. There will be several future additional sections added concerning water collection, treatment, storage and wastewater disposal as time permits, hopefully with a document completion target date of Sept. 1, 2008

My primary concern is a human pandemic of H5N1 avian influenza, which may materialize in the future, and in my opinion, the VERY near future. But even if a worldwide pandemic does not materialize as soon as I expect, there are still other disasters that can should be considered and planned for including severe weather, fire, flood, terrorist attack, disease and drought. Any of these events could severely limit or completely cut off a community’s potable (drinkable quality) water supply for extended periods of time.

A normally active person needs to drink at least two quarts of water each day just for basic hydration. People in hot environments, nursing mothers, children and the sick will require even more. If you cook, calculate an increase of one full gallon per person per day. To stay clean, you should also calculate an additional two or three gallons per person per day. Please note that these quantities are for personal SURVIVAL water requirements, not your normal day-to-day usage.

If you have a limited intake of water, watch for signs of dehydration:
-Thirst and dry mouth, a ‘trench line’ down center of the tongue
-Dark urine with a very strong odor and low output
-Sunken eyes, normal tears may cease
-Fatigue, muscle cramps, nausea and vomiting
-Loss of skin elasticity, sweating may cease
-Increase in heart rate
-Coma, organ failure and death will occur if dehydration remains untreated

An excellent article addressing dehydration and treatment can be found here:


A second excellent source for rehydration methods can be found here:


For the kidneys to eliminate waste products effectively, the average person needs to drink enough water so that the body urinates at least one pint each day. Most people drink enough to urinate 2 pints daily when water quantity is not an issue; additional water is lost in perspiration, exhaled breath, and excrement.

-Drinking alcohol or salty foods will increase water requirements
-Minimize protein intake, as protein takes water to digest
-Sweating heavily and a limited salt intake may produce a salt deficiency; symptoms of cramping are likely to develop within a few days

A few items that you should know when planning water requirements:
-Water weighs 8.34 pounds per gallon. Therefore a 55-gallon plastic drum fill to capacity tips the scales at nearly 480 pounds, you will not easily move a filled drum manually!
-1 cubic foot (12”x12”x12”) of water closely equals 7.5 gallons
-Water does not ‘go bad’ in the sense that it degrades and becomes unfit for consumption simply due to age, it is billions of years old anyway. It can become contaminated, but can be re-purified.
-Water changes states (liquid, solid, vapor) in nature continuously, able to dissolve inorganic solids (rocks, soil, minerals) and can support microbiological life.
-Disinfection is not the same as sterilization. Sterilization is the total destruction of all living organisms.

Outline of Water Sources:
-Stored and alternate sources (water heater, ice cubes, bathtub, drums and containers)
-Ground water wells and catchment cisterns
-Snow and rainwater catchment
-Surface water (lakes, streams, ponds)
-Salt and brackish water

Most of these sources will require treatment to ensure potability, some are obviously better than others; well and rain water should contain less contaminants than open surface water sources, which in turn would be better than water containing large quantities of dissolved salts. However, availability of sufficient quantities of water, regardless of original source, is of the utmost importance. Treatment methods will differ widely depending on the raw water source contamination and may include mechanical and biological filtration, distillation, coagulation and flocculation, disinfection. Each treatment method will be dealt with in following sections.

larry G

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