Abstract
Permeability characteristics of the membrane in a commercial plant constructed on the basis of results of a pilot plant were investigated. The results concerning flux data for a three months period at a stage one and a half years after the start-up of the treatment plant using tubular polyolefin membrane are demonstrated. There was no significant difference in the rate of solute removal between activated sludge- and coagulated sludge-separating membranes during the one and a half years operation. Sodium hypochlorite and citric acidcleanings were both effective for activated sludge- and coagulated sludge-separating membranes. The frequency was once to twice a month for the activated sludge-separating membrane and approximately once a month for the coagulated sludge-separating membrane. In case of activated sludge-separating membrane, the flux just after cleaning was 35-47l/m2/hr/atm which decreased to 30l/m2/hr/atm 2-3weeks after cleaning whereafter it maintained this value. In case of coagulated sludge-separating membrane, designed flux was maintained although the after-cleaning flux fluctuated considerably.
