Biodegradable organic matter removal alter ultrafiltration treatment
"Compagnie des Eaux de Banlieue" water facilities located at the Mont-Valérien treat the Seine river water downstream Paris. A first facility (5000 m3/day) includes the following processes : preozonation, coagulation, settling, sand filtration, postozonalion, GAC filtration and a final desinfection (CIO2). A second one consists in a biological sand filtration (80000 m3/day). An ultrafiltration demonstration plant including a CAP addition into the recirculation loop is currently tested on a small scale (8 m3/h) to compare the conventional treatments with new ultrafiltration process. In this study, the TOC removal as well as the biodegradable organic matter (BOM) removal are evaluated on the different processes. The BOM has been assessed by the Werner methodology (1980). During the cool season (october-january) all the biodegradable organic matter were removed by the clarification process (preozonation + coagulation decantation + sand filtration). More than 90 % of the BOM were also removed by the ultrafiltration demonstration plant (including granular activated carbon) although the addition of preozonation slightly increases the effluent BOM concentrations and modifies its composition. 80 % of the dissolved organic compounds were removed by the preozonation + ultrafiltration + powder treatment line. This performance should be compared with the 70 % removal obtained with conventional treatments. This study demonstrate that the combination 03 + UF + CAP can advantageously replace traditional treatment such as preozonation + coagulation clarification + ozonation + granular activated carbon + desinfection.