Biological Iron and Manganese removal

Željezo i mangan u vodi predstavljaju ozbiljan tehnološki i zdravstveni problem. Prisutnost otopljenoga željeza i mangana potiču razvitak raznih bakterija tolerantnih na klor koje koriste energiju oksidacije željeza i/ili mangana za rast i razvoj. Pri tome nastali talog željezova/manganova oksida uzrokuje sužavanje profila cijevi i nakupljanje biomase raznih bakterija i potencijalnih patogena. Kako bi se otklonio taj problem, razvijene su razne metode uklanjanja tih metala. Pored fizikalno-kemijskih metoda, pojavljuju se suvremenije biološke metode za uklanjanje željeza i mangana koje koriste spomenute bakterije što oksidiraju željezo, pri čemu se ono taloži i filtrira na pješčanom filtru. Kao najbolji primjer bioloških metoda uklanjanja željeza i mangana uzeti su Degrémontovi procesi Ferazur i Mangazur, kao i primjeri pilot studija koje je proveo Degrémont u Kanadi za praktičnu primjenu tih dvaju procesa. Na kraju je dana usporedba troškova konvencionalnih fizikalno-kemijskih metoda s biološkima.Iron and manganese in water pose a serious technological and health problem. The presence of iron or manganese promotes growth of a variety of chlorine-tolerant bacteria which use the energy from iron and/or manganese oxidation for growth and procreation. Consequently the iron/manganese hydroxide flocs created by the bacteria narrow the diameter of the pipes and accumulate the biomass of various, potentially pathogenic bacteria. To eliminate the problem, many iron/manganese removal methods have been developed. Alongside of the conventional physical-chemical iron/manganese removal, more modern biological methods have appeared which use the already mentioned bacteria that oxidize iron/manganese, and precipitate it on a sand filter. As the best example of the biological iron and manganese removal methods, Ferazur and Mangazur form Degrémont are taken, as well as the examples of the pilot studies undertaken by Degrémont in Canada for the practical use of these two processes. At the end a comparison of the costs of conventional physical-chemical treatment methods and biological treatment methods is given