Research was conduced on pretreatment and biological treatment of METC gas producer wastewaters. During this first year of effort, approximately 1500 gallons of gas producer wastewater was provided to the University of Pittsburgh. Wastewater was pretreated by a linkage of operations which included one stage cold or two stage hot ammonia stripping, judicious pH adjustment followed by chemical coagulation and flocculation, and aerobic biological processing at 1 day detention time. The overall objective of research was to document and demonstrate the capabilities of a properly designed aerobic biological system for the stable treatment of fixed bed gas producer wastewaters. A comprehensive flow sheet design based upon laboratory derived parameters is included for the treatment of METC gas producer wastewaters. The observations of difficulties which may accrue in the commercial scale operation of a wastewater treatment train are the result of approximately one year of continuous steady state operation of physical, chemical and biological systems for the treatment of such gasifier wastewater. Suggestions are made as to the capabilities and limits of such processing schemes for wastewater treatment. For tertiary treatment, preliminary data are presented on the ozonation of pretreated and biologically treated gasifier wastewaters both with and without the use of activated carbon. Preliminary chemical data are also presented from GC/Mass Spec determinations of acid and base extractable portions of wastewaters at various sampling locations within the pretreatment and biological treatment scheme.