I'm getting ready to collect my DBP's samples in a few hours. We use Sodium Permanganate to oxidize our raw water going into the flocculation / settling basin. We shoot for some purple color at the top of the basin, turning to brown at the end of the flocculator. It does a nice job, but you must pay attention to it and adjust it as the water changes. This oxidizes without adding to the DBPs load.
Our second strategy is to use self generated chlorine from brine as a mixed oxidant for pre filter and post filter chlorination. Expensive but worth every penny.
We regularly get 35 - 45 % removal, so it works for us.