Ultrafiltration is demonstrated to be an effective method for characterizing industrial landfill leachates by molecular weight (MW) distribution. The majority of the organic matter (as TOC and COD) for the hazardous wastes examined was found to be below 500 MW. The applicability of ultrafiltration as an effective process for removal of low MW organic matter from industrial wastes is limited. Ultrafiltration, however, is useful as a pretreatment process for removal of large MW compounds that interfere with subsequent treatment processes. Ultrafiltration of raw landfill leachates is hindered by concentration polarization and severe fouling. Physiochemical lime treatment of the highly turbid raw leachate was found to aid in the stabilization of product flux.