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Activated Carbon Filtration system

Activated carbon is widely used in water filtration systems. Carbon is very effective at

improving taste, removing chlorine and many other contaminants. A drawback to Activated

Carbon is that its high surface area and the Carbon itself promote bacterial growth.

Pseudomonas Bacteria has been found to grow in many carbon filters and activated carbonsystems.

Activated carbon for drinking water systems should always be followed by:

ultraviolet sterilization systems.

What Contaminants Do Activated Carbon Filters Remove From Water?

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, odour, and colour problems, AC

filtration can generally be used to improve aesthetically objectionable water. AC filtrationwill also remove chlorine. AC filtration is recognized by the Water Quality Association as an

acceptable method to maintain certain drinking water contaminants within the limits of the

EPA National Drinking Water Standards.

Water contaminants that can be reduced to acceptable standards by activated carbon

filtration: (Water Quality Association, 1989)

Activated carbon filtration does remove some organic chemicals that can be harmful if

present in quantities above the EPA Health Advisory Level. Included in this category are

Trihalomethanes, pesticides, industrial solvents 'halogenated hydrocarbons', polychlorinated

biphenyls, and polycyclic aromatic hydrocarbons.

The Safe Drinking Water Act mandates EPA to strictly regulate contaminants in community

drinking water systems. As a result, organic chemical contamination of municipal drinking

water is not likely to be a health problem. Contamination is more likely to go undetected and

untreated in unregulated private water systems. Activated carbon filtration is a viable

alternative to protect private drinking water systems from organic chemical contamination.

Radon gas can also be removed from water by activated carbon filtration, but actual removal

rates of radon for different types of activated carbon filtration equipment have not been

established.

What activated carbon does not remove?

Similar to other types of water treatment, activated carbon filtration is effective for some

contaminants and not effective for others. Activated carbon filtration does not remove

microbes, sodium, nitrates, fluoride, and hardness. Lead and other heavy metals are removed

only by a very specific type of activated carbon filter. Unless the manufacturer states that its

product will remove heavy metals, the consumer should assume that the activated carbon

filter is not effective in removing them. Refer to the other circulars in the Treatment Systems

http://www.apswater.com/shopdisplaycategories.asp?id=49&cat=Ultraviolet_Sterilizer_Systemshttp://www.apswater.com/shopdisplaycategories.asp?id=49&cat=Ultraviolet_Sterilizer_Systems

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for Household Water Supplies series for information on systems that do remove the

contaminants listed above.

Forces of physical attraction or adsorption of contaminants to the pore walls is the most

important activated carbon filtration process. The amount and distribution of pores play key

roles in determining how well contaminants are filtered. The best filtration occurs when pores

are barely large enough to admit the contaminant molecule. Because contaminants come in

all different sizes, they are attracted differently depending on pore size of the filter. In general

activated carbon filters are most effective in removing contaminants that have relatively large

molecules 'most organic chemicals'. Type of raw carbon material and its method of activation

will affect types of contaminants that are adsorbed. This is largely due to the influence that

raw material and activation have on pore size and distribution.

References

Activated carbon filtration by APS Water Product for Science and Home viewed on 25

April 2012

(http://www.apswater.com/article.asp?id=24&title=About_Activated_Carbon_Filtration)

Taraba, J. L., L. M. Heaton, and T. W. Ilvento. 1990. Using activated carbon filters to treat

home drinking water, IP-6. University of Kentucky Cooperative Extension Service,

Lexington, KY.

Activated Carbon Filtration by Frank Desilva. Published in water Quality products Magazine,

January 2000. Retrieved on 24 April 2012

(http://www.resintech.com/pdf/ActivatedCarbonFiltration.pdf)

Prevention method from bacteria and mosquitoes

Light proofing:

Tanks, covers, plumbing pipes and fitting should be light proof to minimise daylight

penetration and algae growth in the water.

Kerosene layer on top of the water:

It is one of the old ways to prevent mosquitoes breeding from water and has been used for

year. It makes layer on top of the water and so it does not affect the drinkability. For most of

the types of the tanks, adding a teaspoon of domestic kerosene will stop mosquitoes from

breeding. Kerosene should not be used in aqua plate tanks or in some plastic tanks. Kerosene

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may initially be tasted in the water but is harmless and taste will subside over time, excessive

amounts can taint the water and it is a human poison.

Other method:

Screens and strainers

The inlet to the rainwater tank should incorporate a mesh screen or strainer to prevent the

entry of live insects and to catch leaves and undesirable roof deposits. A mesh similar to

flyscreen with openings smaller than one millimetre is very effective against mosquitoes.

Covers and lids

A rainwater tank should have a proper cover to prevent the entry of dust, leaves, pollens,

debris, vermin, mosquitoes, birds, animals and insects. It is essential to seal access hatches

with strong, close-fitting, childproof lids. There are different types of lids available in market

such as:

Threded type Inter lock type Hinges type Loft tank type Seal lids ISI specified lids.

Cover lid should be tight fitting to prevent entry of bacteria, insects and mosquitoes.

References

Water storage lids and covers by sunrise group, retrieved on 30 April 2012.

http://www.sunriseintls.com/water-tank-lids.html

Rainwater tanks, Guidelines for residential properties in Canberra, Retried on 29 April 2012.

http://www.actpla.act.gov.au/latest_news/news/?a=3378

Mosquito control information, retrieved on 30 April 2012.

http://www.marion.sa.gov.au/webdata/resources/files/mosquito_control.pdf

http://www.sunriseintls.com/water-tank-lids.htmlhttp://www.sunriseintls.com/water-tank-lids.htmlhttp://www.actpla.act.gov.au/latest_news/news/?a=3378http://www.actpla.act.gov.au/latest_news/news/?a=3378http://www.marion.sa.gov.au/webdata/resources/files/mosquito_control.pdfhttp://www.marion.sa.gov.au/webdata/resources/files/mosquito_control.pdfhttp://www.marion.sa.gov.au/webdata/resources/files/mosquito_control.pdfhttp://www.actpla.act.gov.au/latest_news/news/?a=3378http://www.sunriseintls.com/water-tank-lids.html