INFLUENCE OF ORGANIC-MATTER FROM WASTE-WATER ON THE PERMEABILITY OF MEMBRANES

The progress in the development of membranes for the treatment of aque ous solutions in the last years has attracted much interest in this te chnology. In order to find out the application limits, for example by ultrafiltration and reverse osmosis for waste water, research was carr ied out into the influence of organic matter, expressed as chemical ox ygen demand (COD), on the permeability of the membrane on a pilot-scal e. Different waste waters (pig and cattle slurry, milkhouse waste wate r and vegetable wash water) with different concentrations of organic m atter were treated by ultrafiltration, and the permeates were treated partly by reverse osmosis. These tests as well as experiments for ultr afiltration with anaerobically treated mixtures of pig slurry and pota to wash water showed that the permeability of membranes is determined by the concentration of organic matter of waste water and is independe nt of the kind of waste water. By ultrafiltration of different waste w aters with an anorganic silicon-carbide membrane with a nominal pore d iameter of 0.05 mu m for example, the permeability decreased from 158 l/m(2)h to 26 l/m(2)*h when the COD-concentration increased from 0.63 g/l to 42.8 g/l, respectively.