A system for treating feedwater includes a fluidized bed heat exchanger unit connected to receive feedwater and a flash concentrator column connected to receive feedwater discharged from the fluidized bed heat exchanger unit. A spray dryer is provided to receive a solids/liquid slurry discharged from the flash concentrator column. Feedwater can be treated by converting dissolved solids in the feedwater to suspended solids, vaporizing a portion of the feedwater to produce a solids/liquid slurry, and separating solids from the solids/liquid slurry.