Clack Birm For Iron and Manganese Reduction

CapBirm is an efficient and economicalmedia for the reduction of dissolvediron and manganese compounds fromraw water supplies. It may be used ineither gravity fed or pressurized watertreatment systems. Birm acts as aninsoluble catalyst to enhance the reactionbetween dissolved oxygen (D.O.) and theiron compounds. In ground waters thedissolved iron is usually in the ferrousbicarbonate state due to the excess offree carbon dioxide and is not filterable.Birm, acting as a catalyst between theoxygen and the soluble iron compounds,enhances the oxidation reaction of Fe++ toFe+++ and produces ferric hydroxide whichprecipitates and may be easily filtered. Thephysical characteristics of Birm providean excellent filter media which is easilycleaned by backwashing to remove theprecipitant. Birm is not consumed in theiron removal operation and therefore offersa tremendous economic advantage overmany other iron removal methods.Other advantages of Birm include; longmaterial life with relatively low attritionloss, a wide temperature performancerange and extremely high removalefficiency. Negligible labor costs areinvolved because Birm does not requirechemicals for regeneration, only periodicbackwashing is required.When using Birm for iron removal, itis necessary that the water: contain no oil or hydrogen sulfide, organic matter not toexceed 4-5 ppm, the D.O. content equalat least 15% of the iron content with a pHof 6.8 or more. If the influent water has apH of less that 6.8, neutralizing additivessuch as Clack Corosex, Calcite or sodaash may be used prior to the Birm filter toraise the pH. A water having a low D.O.level may be pretreated by aeration.Additions of chemicals to influent orbackwash water which contacts Birmmedia may inhibit iron or manganeseremoval or may break down or coat Birmmedia. Chlorination greatly reducesBirms activity. High concentrationsof chlorine compounds may depletethe catalytic coating. Polyphosphatesare known to coat Birm and reduceBirms ability to remove iron ormanganese. Before adding any chemicalto the influent or backwash water, thechemicals compatibility with Birmshould be thoroughly tested.Clack Birm may also be used formanganese reduction with the samedependability as iron removal. In theseapplications the water to be treated shouldhave a pH of 8.0-9.0 for best results. If thewater also contains iron, the pH should bebelow 8.5. High pH conditions may causethe formulation of colloidal iron whichis very difficult to filter out. All otherconditions remain the same for eithermanganese or iron removal.