Abstract: A process for treating high strength BOD containing liquors includes the step of mildly mixing and contacting the liquors with anaerobic bacteria and a powdered adsorbent support medium to remove a substantial portion of the organic matter and generate a methane fuel gas. Use of the powdered support medium at 0.1-20 g/l enables high removal of BOD in short treatment times, rapid clarification of treated liquors, and increased adsorbability of liquor color.In a subsequent decolorizing embodiment, digested and clarified liquors are contacted with reduced concentrations of powdered color adsorbent to produce a treated liquor low in dissolved organic matter and color.The spent streams of powdered adsorbent support medium-biomass and/or powdered color adsorbent are preferably regenerated and reused.