I agree with Park Winter , ...

I agree with Park Winter , Joseph Cotruvo and Thomas Getz . The most effective method for iron removal is to convert soluble iron to insoluble by oxidation followed by filtration for solids removal. Oxidation can take place via oxygenation (aeration) wich needs long time and big aeration tank, or by addition of oxidating agent like chlorine (the cheapest one). The problem using oxidating agent (let's say chlorine) is that you have to take care how to remove the exess residual from the outlet water in order to follow the needed standards using an appropriate reductive agent. For the case of chlorine the cheapest is sulfites, like sodium metabisulfite.