A study was undertaken to assess the feasibility of carrying out oxidation of dilute sewage sludge by means of the vertical tube reactor (VTR) system. A pilot scale facility along with a laboratory reactor were used for this study. Dilute sewage sludge was oxidized in the laboratory reactor at temperatures up to 343 C with approximately 80% COD reduction, and to 265 C in the pilot scale reactor with approximately 50% COD reduction. The pilot scale study provided information on scale buildup and control, structural, and mechanical design, metallurgy, hydrodynamic behavior, heat transfer, and other significant engineering factors. The results of the program indicate that the VTR process potentially has technical and economic viability as a means of treating sewage sludge in certain cases and that a full scale demonstration is warranted.