Phase I and II cooling tower reuse tests have been completed using wastewater produced in the University of North Dakota Energy Research Center (UNDERC) pilot slagging fixed-bed gasifier (SFBG). In the UNDERC Phase I test, using solvent extracted and steam stripped wastewater, problems such as high carbon steel corrosion rates, severe biological fouling, and substantial phenol and ammonia emissions, were encountered. Phase II testing was performed to determine if further treatment of this liquor would yield a suitable cooling tower makeup supply. Extracted and stripped wastewater, similar to that used for Phase I testing, was further treated by biological oxidation, granular activated carbon adsorption, and multimedia filtration before being fed to the cooling tower. Phase II results indicated that the aqueous effluent from SFBG, after treatment by solvent extraction, steam stripping, biological oxidation, granular activated carbon adsorption, and multimedia filtration, was not directly usable as cooling tower makeup. Without chemical addition, this water was highly corrosive to carbon steel; measured corrosion rates ranged from 20 to 65 mpy. Severe fouling of carbon steel was also encountered, resulting in high pressure losses across heat exchangers and decreased heat transfer coefficients. Based on these results, the use of this water as cooling tower makeup would require control of corrosion and the associated fouling and/or extensive use of stainless steel, or a substitute corrosion resistant material, in all areas where carbon steel has traditionally been used. This report provides a detailed presentation of results from the Phase II test, and also a comparison of these results to those obtained from the Phase I test. 26 refs., 29 figs., 39 tabs.