The proceed water should be ...

The proceed water should be oxidized by using chlorodioxide. Then you have to dose inorganic coagulant according to sand fülter fulux. I recommend you use serial connected 2 sand filters based on 10-15 unit flow rate. Then use activated carbon filters. ..

I had similiar problem; 5 ppm iron- around 1,5 ppm manganese and 2,5 ppm copper ions for raw water. Before RO plant , iron, manganese and copper contents are dropping 0,02 ppm with 2 sand filters + 2 activated carbon filters dosing chemicals.. If you want I can prepare technical project according to current rawwater analysis results.