Suggestions for re-treatment method for water mixed with solids and mud after coagulation and sedimentation process?

We have a problem in a drinking water station here in Egypt for which I would appreciate suggestions about how to solve. The station treats about 70,000 cubic meter a day. After the coagulation and sedimentation processes, a lot of sludge remains in the sedimentation pool. To clean this sludge the station pumps back the sludge to a tank which is 500 meters away from  the incoming source, where about 5000 cubic meters of water is mixed with sludge every day. We are therefore losing every day about 5000 cubic meters of water and bearing a high cost for this. I am trying to find a solution to re-treat this 5000 cubic meter water a day . I am working with this water treatment plant and looking out for some equipment for treating water mixed with solids and mud after coagulation and sedimentation process. We need to retreat about 5000cu/m per day Best Regards  Mahmoud Zedan