Optimization of Chemical Cleaning for Removal of Biofouling Layer

Abstract

Biofouling is one of the most important problems associated with the application of membrane in bioprocessing. A strategy for membrane regeneration is the chemical cleaning of fouled membranes. The choice of chemical cleaning agent and operating parameters are critical to cleaning efficiency. In this work the cleaning efficiency of different cleaning agents for the removal of biofouling layer was studied. The cleaning agents include hydrogen peroxide (H2O2), sodium hydroxide (NaOH), hydrochloric acid (HCl), 1-propanol, urea and Ethylene Diamin Tetra Acetic acid (EDTA). The influences of different experimental variables on the cleaning efficiency were evaluated. Response surface methodology was employed to optimize the cleaning efficiency of the cleaning agents with three variables of concentration of cleaning agent, time of cleaning, and stirring speed for cleaning of GVHP microfiltration membrane fouled by E.coli in a dead end cell. To build the mathematical model and minimize the number of experiments for the design parameters, a response surface methodology with a face-centered central composite design (CCF) was defined. The adequacy of the calculated model for the response was confirmed by means of variance analysis and additional experiments. Predicted optimal conditions to achieve maximum flux recovery were elucidated. The validity of the response model was verified by a good agreement between predicted and experimental results.