The Sewage Ultrafiltration (SUF) process has been tested in a mobile pilot plant using tubular IDE Hybrid Ultrafiltration membranes (HUF). The plant was operated at 30% and 95% water recovery, at various circulation velocities on untreated oxidation pond effluent. Effects of circulation velocity, various cleaning procedures as well as frequency of cleaning, on product quality and flux were investigated. The SUF product typcially contained a BOD of less than 5 ppm (from a feed of 600 ppm), a COD of 40 ppm (from a feed of 3100 ppm) while the rejection of N kj (from a feed of 238 ppm) was 85%. Rejection of total phosphate (as P) was almost complete. Fluxes increased with increasing velocity reaching 37.2 gfd at 10ft/sec and 8 atm. Periodical mechanical cleanings performed by the passage of an oversized sponge ball through the membranes, combined with occassional chemical cleaning were found to be effective in membrane flux restoration. SUF is shown to be a membrane process eminently capable of treating municipal and industrial waste water containing suspended solids and undesirable organic compounds.