The SpinTek rotary ultraflltration system (ST-II) uses membrane rotation to provide the turbulence required to mininaize concentration polarization and flux decline. The ST-II system was effective in concentrating oily wastes from about 5% to as high as 75%. The decoupling of turbulence promotion from feed pressurization/recirculation by rotating the membrane is the primary reason for the improvement in performance over that observed with conventional UF systems. Flux increased by about 45% when the temperature was increased from 110 to 140°F. A larger decrease in waste viscosity, over that predicted for water alone, was the primary reason for the stronger than expected flux-temperature relationship. The flux decreased with decreasing rotational speed (ω) and the gel layer did exhibit some sustainable stability with increases in ω. A ceramic membrane was superior to a polymeric membrane in regards to flux quantity and quality as well as membrane cleaning/durability.
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