Require expertise on economical solutions for Iron removal from an open well in Ashok Nagar, Chennai, Tamil Nadu

An open well containing clean water comes out as reddish brown when pumped

I am a resident in Manthoppe Colony, Ashok Nagar Chennai, Tamil Nadu. We are an apartment building with 16 flats sharing water from a single underground sump. This sump gets water from the Chennai Metro Water. Due to water shoratage crisis in Chennai, we decided to clean the open well we had for abut 30 years and use the water along with Metro water. The open well is 30 feet in depth and 8 feet in diameter. It presently contains 12 feet of water from which atleast 3 feet of water is pumped out using a 1HP water pump into the underground sump twice per week.

In the sump, the open well water mixes with the Metro water and is then pumped up by a 3 HP pump to the overhead tanks which are used by all the residents. We have never had a filtration system as we were dependent only on the Metro water so far. Now that the well water mixes with the Metro water in the sump, the water is a reddish brown or rust color in the tank. The well water when taken directly and seen contains no visible color and turbidity. The reaction and color change happens only when it mixes with the Metro water.

As a Chemical Engineer myself, I did some research and found that water containing Iron ions when mixed with chlorinated water such as Metro water forms iron chlorides which are insoluble in water. If this is what's happenning in our sump, is there a way to filter the iron chlorides and get clearer water? If yes, please advise on how to go about the selection, iInstallation and maintanace of the filtration system.

Prabhu Palanichamy