Heavy metals, volatile organics, and extractable organics were detected in water from wells located near an unapproved hazardous waste disposal site. As part of a program to clean up the dump site, treatability studies were conducted prior to development of the preliminary design for a groundwater treatment facility. These studies, which evaluated chemical precipitation, air stripping, steam stripping, activated carbon adsorption, and biological treatment, are described, along with some of the results obtained by using the treatment methods individually or in various combinations. It was determined that two alternative processes could be used to treat the groundwater at this site. One process consisted of chemical precipitation, steam stripping, and activated carbon adsorption, while the other consisted of physicalchemical and biological treatment. Includes 5 references, tables, figures.