Several unit operations were evaluated for ability to treat Hanna IVB UCG condensate and UCG-affected groundwaters. These treatment processes included coagulation-precipitation, reverse osmosis (RO), ultrafiltration (UF), microporous filtration (MPF), and carbon-adsorption with coal and char. The objectives of the experiments were to remove colloidal and suspended solids, dissolved inorganics, and soluble organics from UCG wastewaters. In coagulation-precipitation experiments, a 60 mg/L dose of polymer Purifloc C-31 resulted in removal of 99.0% of the 2 to 90 ..mu..m-diameter particles and 92.9% of the acetone-soluble tar from Hanna IVB condensate. Similarly, addition of 50 gm/L of polymer DEAE-Dextran resulted in removal of 98.3% of the 2-90 ..mu..m-diameter particles and 95.2% of the acetone-soluble tar. Reverse osmosis treatment of Hanna groundwater reduced sulfate and total dissolved solids by 99.4% and 98.9%, respectively. Acetone-soluble tar was reduced by 77.0% during a UF experiment performed with a 50% conversion rate. Removals of soluble organics by UF were negligible, however. Treatment of simulated wastewater by MPF with powdered-activated-carbon addition effected much greater removals of dissolved organic carbon and phenols. Metals were also successfully removed by this configuration. Total organic carbon (TOC) and phenols in simulated wastewater were effectively adsorbed onto coal and char. The TOC removals by adsorbents were 71.4 to 92.6% with simulated wastewater and 11.2 to 37.5% with Hanna IVB condensate. The adsorption of TOC from simulated wastewater onto coal was well described by both the Langmuir and Freundlich isotherm models. The Freundlich isotherm best described the adsorption of TOC from simulated wastewater onto char. The adsorption of contaminants from Hanna IVB UCG condensate was poorly described by both isotherm models. 18 refs., 16 figs., 12 tabs.