Optimization of Integrated Ultrafiltration Processes Using Response Surface Methodology

摘要

In this study, coagulation condition and prechlorination on membrane fouling were investigated. Optimum operation parameters of overall process were obtained through a proposed combined process of coagulation and ultrafiltration (UF) with the prechlorination unit set after the coagulation unit and before the UF unit. Effects of velocity gradient of the coagulation unit and the dosage of NaClO on the range of workable flux and water purification were assessed using response surface methodology. The range of workable flux of UF module obtained under an agitator rotational velocity of 40rpm in the coagulation unit represented the maximum one. Removing as much organic contaminants as possible is the key to alleviating membrane fouling. The proposed process does not require use of the prechlorination unit and is not necessary and suitable for treatment of this type of raw water. Higher velocity gradient and operating flux presented a slower rate of filtration resistance growth. Optimum values of 40rpm, 0mg/L, and 100 L/[m(-2) h] were obtained for the agitator rotational velocity, NaClO dosage, and operating flux, respectively. Under this condition, the specific flux decay rate reached the minimum value during a single filtration.