Abstract
The surface analysis of the membranes used for advanced treatment of human excreta were examined in order to clarify the effects of membrane cleaning. The low desalting reverse osmosis membranes were used ; composit polyamide membranes, spiral wound type, the membrane area : 6.5m2, desalting degrees : ca.50% (RO-1) and ca.30% (RO-2). In the treatment experiments the membranes were periodically cleaned with tap water, an alkaline solution, and an acid solution. The membranes after the cleaning with each solution were analyzed by refrection FTIR, EPMA and ESCA. In addition, the exhausted cleaning solutions were analyzed by GPC.
The results obtained by the analyses were summarized as follows : (1) both inorganic and organic fouling materials were removed effectively by the acid cleaning and this corresponded to the recovery of the water flux by the cleaning, (2) the organic fouling materials consisted of high molecular weight components (ca.6000 and ca.20000 daltons) such as polysaccharides and proteins, and (3) the complete removal of proteins was difficult even by the acid cleaning, because a little proteins remained on the membranes after the acid celaning.
