Vol. 10 No 1 February 2002
Water Iron Removal Unit
A Water Iron Removal Unit has been designed and developed by DRDO for removing high contents of iron from water. The iron removal unit, made of mild steel, is cylindrical in shape, consists four chambers and has sludge/backwash outlet valves for cleaning. It has an efficient aeration system and a double (up flow and gravity flow) filtration device. The various steps involved for removal of iron in the unit are: (i) aeration/gas transfer, (ii) pH adjustment, (iii) oxidation of ferrous into ferric iron by dissolved oxygen and catalytic action of iron oxide coated contact media, (iv) precipitation of ferric iron, and (v) removal of precipitated iron by sedimentation, up flow and gravity flow filtration.
The unit is designed for 300 l/hr output and can cater to the need of small population particularly, in rural areas. Iron contents in water treated through this unit were found below 0.3 mg/l with feed water having iron contents up to 40 mg/l. The advantages of the unit are