Special Report 5

ODAK Corporation
Committed To Being the Industry Leader In a Leading Industry *Since 1979
The Ultimate In Residential, Commercial and Industrial
Sub-Micron Drinking Water Filtration Systems

SPECIAL REPORT #5

Color In Water

ODAK Corporation is a strong supporter of environmental education and the company feels privileged to make available this informational report as a means of environmental education and awareness. The mission statement of ODAK Corporation is to provide high quality products, service and support to its customers and distributors. In partial fulfillment of that obligation we are proud to make this report available to you. Most people believe that their water comes from pure sources without any contamination or that the water has been treated. Color in water can be caused by a number of contaminants such as iron which changes in the presence of oxygen to yellow or red sediment. Color from iron is referred to as "apparent color" rather than "true color". True color is distinguished from apparent color by filtering the sample.

Source:

The most common source of true color is decaying organic matter such as the yellowish "tea color" of water in tundra or wet bogs. True color is mostly found in surface water, although ground water may contain some color if the aquifer flows through a layer of buried vegetation, such as from a long buried slough of a river.

Potential Health Hazards:

Color is not a toxic characteristic, but is listed by the EPA as a secondary (aesthetic) parameter affecting the appearance and palatability of the water. When chlorinated, color-causing organic matter may form chlorinated organic compounds such as trihalomethanes. Chloroform is a common trihalomethane, and is along with several others, considered to be a potential carcinogen. For this reason The EPA is considering extensive revisions to the regulations covering disinfection by-products (DBP's). The limit for TTHM's would be lowered to 80 ug/l, and three additional categories of DBP's . This standard will replace the current standard of a maximum allowable annual average level of 100 parts per billion in December 2001 for large surface water public water systems. The standard will become effective for the first time in December 2003 for small surface water and all ground water systems Color is measured in units based on a platinum-cobalt standard solution which forms a yellow tint and is limited to 15 units in public water supplies.

Treatment:

Color can be removed by activated carbon filters (Check out the ODAK Carbon Block Filter) , sometimes marketed as taste and odor filters. The activated carbon or charcoal must be replaced after a period of time when its capacity for adsorption of the color is exhausted. Another treatment method is coagulation and sedimentation using alum or other chemicals. This process is normally used only in large plants since its complexity requires the care of a trained water treatment plant operator.

Testing:

Color analysis is done by visual comparison to a set of platinum-cobalt standards in Nessler tubes. Sample collection is done in a clean rinsed bottle which should be refrigerated if stored for more than a few hours. If the color of the water exceeds 15 color units and the water is being chlorinated, we suggest having the water examined for total trihalomethanes by gas chromatography. This is a more expensive and time consuming analysis, but is extremely sensitive with detection limits down to the ppb level. Sample vials specially designed to eliminate the air space above the sample are required for sampling.

References or other resources:

Environmental Quality Center

This is a copyright protected document. To obtain permission to reproduce, distribute, or reprint this article, you must obtain permission from B.F. Environmental Consultants, 15 Hillcrest Drive, Dallas, PA 18612, boram@wilkes.edu, copyright@1987.

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