The model binary/ternary mixtures for actual EPS solution extracted from the activated sludge in MBR using dead-end membrane filtration cell.

In order to find a model solution to simulate actual extracellular polymeric substances (EPS) solution in terms of filterability behavior, a series of experiments were conducted in a dead-end unstirred cell with 0.1 μm polyvinylidene fluoride membranes using binary/ternary mixtures consisting of sodium alginate (SA), bovine serum albumin (BSA) and humic acid (HA). Three target parameters (cumulative filtrate volume (CFV), specific cake resistance (αc ) and rejection (R)) were compared and the roles of mixture components were investigated. The order of degree of influence on CFV, αc and R in ternary mixture was SA (94.5%, 85.6% and 88.2%, respectively) > BSA (5.2%, 10.3% and 8.0%) > HA (0.3%, 4.1% and 3.8%). Meanwhile, when the composition of ternary mixture was SA/BSA/HA = 285.1/150.1/10.2 mg·L-1 , the deviation for CFV, αc and R was 7.65%, 19.6% and 7.27%, respectively, while the corresponding values for the most suitable binary solution (SA/BSA = 140.4/50.35 mg·L-1 ) were -12%, 1% and 164% respectively. This indicated that the ternary solution demonstrated a more accurate estimation than the binary solution for imitating the filterability of actual EPS solution. Therefore, the ternary mixture could be employed efficiently to replace the actual EPS solution in terms of three target parameters in practice applications.