Abstract For the purpose of clarifying animal wastewater, an automatic administration with inorganic cohesion and ultrafiltration was tried. As an inorganic agglutinant, 0.385g Ferric Trichloride was added to 1g total suspended solids of slurry. The ultrafiltration module, which had the membrane made of vacant string tubes of poly sulfon, had an effective membrane area 1.0m2 . Maximum tolerable pressure of the module was 3kg/cm . For an automatic operation of the unit, a programmable controller PL 40‐III was used. The administration procedure was as follows; Pumping up of the wastewater ———‐Addition of agglutinant solution —‐ Agitation (circulation) of the slurry in the tank —‐ Pumping out to the sedimentation tank —‐ Sedimenting administration —‐ Drainage of the muddy slurry —‐ Ultrafiltration of the supernatant —‐ Reverse cleansing of the filter. The unit worked according to the program. During the experimental operation, original sewage(diluted 125 fold), supernatant and sediment after inorganic cohesi...