Regeneration of the ultrafiltration membranes at curds manufacturing

Experimental works have been carried out with the aim to intensify process of the UF-membranes regeneration. Effects of various types of the surface active substances and complexes formers on water permeability of the membranes were studied. The laboratory UF-module provided with membrane from polyvinilidenphtoride was applied for trials. After technological process of milk raw materials concentrating the UF-module was cleaned with solution having certain concentrations of sodium hydroxide during 15 minutes. Then the solution was introduced consecutively into the complex former, dispenser and surface active substance in the course of 15 minutes at each operation. After every operation water penetration of the membrane was measured on the water. When the technological process of concentrating of the fermented milk mixture and washing with water was completed capacity of the module was 0.11 l/min. When the alkali complex former in the concentration of 0.05% was added and the solution received with the pH value 10.8 was circulated in the system of the module during 15 minutes, capacity increased by 0.01 l/min. to 0.12 l/min. Additional introduction in the circulating solution of the week alkali dispenser (pH 8.5) and its circulating during 15 minutes resulted in the growth of the UF-module capacity to 0.15 l/min. When the pH value of the cleaning liquid was increased by introduction of the sodium hydroxide at its concentration 0.5% to the solution of the mixture of the complex former and disperse, capacity of the UF-module was 0.17 l/min. Addition of the surface active substance in the quantity of 0.02% resulted in additional improvement of the capacity to 0.18 l/min. that corresponded to the initial capacity of the UF-module before conducting technological process with raw materials Thus, in order to ensure required quality of cleaning of the membrane equipment it is necessary to apply cleaning compositions containing all the above mentioned components. However, it can be insufficient when operating industrial plants. As practice proved acid and periodically enzymes treatment can be needed.

regeneration, water permeability, UF-membranes, cleaning of the membrane equipment, acid and enzymes treatment