Comparative evaluation of physical cleaning method for organic and inorganic foulants mitigation in pressure retarded osmosis (PRO)

摘要

Membrane fouling is one of the major problems to be solved to sustain stable pressure-retarded osmosis (PRO) performance. This phenomenon caused diminished water flux productivity. So an effective cleaning method for fouled membrane is necessary. This study was carried out to compare applicable cleaning methods to mitigate organic and inorganic foulants on the PRO membrane. Fouling experiments were divided into two types: organic fouling and inorganic-organic fouling. Humic substance and calcium carbonate were used as model compounds. The fouled PRO membranes were cleaned by seven types of cleaning methods namely: (i) physical flushing, (ii) pressure-assisted physical flushing at feed side, (iii) pressure-assisted physical flushing at draw side, (iv) osmotic backwashing, (v) reverse osmosis flushing, (vi) pressure-assisted osmotic backwashing with low pressure (PAOB-I), (vii) pressure-assisted osmotic backwashing with high pressure. PAOB-I was a more effective method to mitigate foulants on the PRO membrane compared with the other cleaning methods in this study.