There are many factors that may cause color in CT water. The most common causes are iron, manganese, tannins, organic matter, and/or colloidal solids that are too small and too fine to settle out properly.
These suspended particles can cause problems with disinfection processes, and also be an indicator of bacterial activity in the water. Turbidity is measured in NTU’s, (nephelometric turbidity units). The turbidity of drinking water in Connecticut should be less than 1 NTU. Most treated city water is less than .2 NTU.
If the color is from tannin’s or humic acids, then a self-cleaning automatic tannin filter might be applicable. These filters remove dissolved color by ion-exchange, using anion exchange media. While these are called tannin filters, they are really ion-exchange units. Frequently we see shallow wells, or wells under the influence of surface run-off water, achieve high levels of tannin’s during heavy rainy periods.
Tannin filters are often an relatively low-cost technology to use for this type of problem, if the actual cause of the problem (such as sealing off the well from the surface) cannot be achieved.
Sometimes tannin’s are accompanied with iron or manganese. Water high in iron or manganese can sometimes be red, rust colored, brown, tan, black, or greenish in color. Chlorination, followed by a well designed iron filter can be very effective at removing tannin and these oxidized iron particles in Connecticut wells.
A very effective method to remove color is with reverse osmosis or ultra-filtration membrane systems. These water treatment systems can be used by homeowners, small communities and commercial sites to reduce turbidity and produce crystal clear water.
Direct filtration can also be used. Depending on the nature of the color, a back-washing sediment filter using a special type of zeolite filter does a great job at clarifying water. Sediment down to the 5 to 10 micron range can be removed, and then back-washed out periodically by the automatic control valve.
Another low cost option is to use a whole house cartridge filter. These filters are large size filter cartridge systems which come in various micron ratings and can filter down to the 1 micron size. One option frequently used by CT homeowners with cloudy water is to use a back-washing sediment filter, followed by a 1 or 5 micron filter cartridge system.
There are many different designs and application criteria that must be considered, including water chemistry, water flow rates, how the water will be disinfected, and what types of filtration to use.
