AWWA MTC61214

Vitens, Water Laboratory Noord and Drenthe Water Supply Company conducted a biofouling study on reverse osmosis (RO) after ultrafiltration. Using ultrafiltration as a pretreatment step, biofouling is likely the most important fouling phenomenon. The experiment was carried out in Klazienaveen where ultrafiltration permeate was used from a full scale industrial water plant. The effect of dosing of different chemicals was tested on test rigs each containing one 4'' RO module. This is supposed to simulate the first element of the first stage of a full scale installation. Membrane performance was measured as the normalized feed-concentrate pressure drop and the mass transfer coefficient. Results with chemical dosage were compared with a reference where no chemicals were added. At the end of the experiments the RO elements were autopsied to further investigate the fouling layer on the membrane. The results show that biofouling can be controlled by dosing a mild oxidizing agent in combination with a cleaning strategy. Includes tables, figures.