Agenda - 01-20-1998 - 10a - Laserfiche WebLink

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(alum) eases filtration by causing larger iron/manganese particles to form. A multistage treatment operation may be necessary if your water has high levels of iron and manganese and they are in both the dissolved and solid forms. For example, the water could first be aerated, than chlorinated to oxidize residual iron and kill iron bacteria, and then filtered through a mechanical device to remove particles. This can be followed by activated carbon filtration to remove excess chlorine and a water-softener for hardness control as well as removal of any residual dissolved iron and manganese. Summary of Treatment Options for Iron and Manganese Symptom Cause Treatment Water clear when drawn, Dissolved iron or Water softener (less than 5 mg/L of reddish-brown or black particles manganese. iron) appear as water stands; reddish- Aeration (less than 25 mg/L of iron). brown or black stains on fixtures Oxidation/Filtration (less than 15 or laundry. mg/L of iron plus manganese). Chlorination-Filtration (greater than 10 mg/L of iron). Water contains reddish-brown Iron particles from Raise pH with neutralizing filter that particles when drawn; particles corrosion of pipes also filters particles. settle out as water stands. and equipment. Water contains reddish-brown Oxidized iron, Particle filter cif quantity of oxidized or black particles when drawn; manganese, or both material is lvgh, use lazger filter than particles settle out as water due to exposure of in line, e.g. sand fifilter). stands. water to air prior to tap. Reddish-brown or black slime Iron bacteria. Kill bacteria masses by shock treat- appears in toilet tank or from Manganese bacteria. ment with chlorine or potassium faucet. permanganate, then filter; may re- quire continuous feed of chlorine or potassium permanganate, then filter. Reddish or black color that Colloidal iron, Chemical oxidation with chlorine or remains after 24 hours. manganese, or both. potassium permanganate. Organic-complexed iron, manganese, or both. Summary Iron and manganese are common household water contaminants with no known direct health effects at levels found in water. Their presence may cause staining and offensive tastes and odors. Treatment of these secondary contaminants de pends on the form in which they occur, and the levels of concentration. Iron and manganese removal, bacteria cocrtrol, water softening and treatment for any other contamination may be separate problems, yet they must be considered together. Accurate testing is important prior to selection of a treatment system. The table on page 3 may help you identify and determine treatment(s) for iron and manganese in household water supplies. i3