High TDS in Brewery Effluent

I work in Brewery Effluent in Nigeria and total dissolved solids (TDS) have been a major challenge (1600 ppm). I introduced adsorption, it was able to remove between 20-30%, I still have about 1200 ppm TDS in the effluent. I am required to bring it down to 500 ppm at the cheapest cost possible. The daily ETP discharge is 470 cubic meter. The focus is on TDS as every other parameter met the consent requirement for discharge into the river. What is the cheapest and most efficient way to reduce the TDS from the brewery effulent?