IMPROVEMENT OF WASTE WATER TREATMENT, WATER RECYCLING, AND EFFICIENCY IN THE DAIRY INDUSTRY BY COMBINED MEMBRANE PROCESSES

In industrialized countries, food-processing is one of the major sources of environmental pollution. In the dairy industry, end-of-pipe technologies are still predominant. For a more advanced processing of substances in dairy industry, there are many potential applications for membrane processes. During pilot studies performed by the Fraunhofer Institute for Environmental, Safety, and Energy Technology in cooperation with a small dairy company, membrane processes were successfully used to make the processing of whey more efficient and environmentally friendly. That results in reduced operating costs and increased capacities for processing plants. Ultrafiltration was effectively used to improve the separation of proteins, fats and solids and to yield products more uniform in appearance and composition. Whereas, nanofiltration devices were most effective in demineralization processes. The load of harmful substances in the water was significantly reduced (COD reduction by 50 to 70 %) from the original loading. Based on the success of the results, a membrane filtration plant on an industrial scale was built and installed at the dairy company. The following paper gives an overview of membranes, of their utilization in the dairy industry, and of the results of the pilot study.