Fouling control in ultrafiltration of secondary effluent using polyaniline/TiO2 adsorption and subsequent treatment of desorption eluate using electrochemical oxidation

Performance of three adsorbents, polyaniline-modified TiO2 (PANI/TiO2), Dow resin IRA(a) and Dow resin IRA(b), in removing organics from secondary effluent (SE) was evaluated, and the objective of this study is to deliver a treatment loop including membrane fouling control using adsorption and treatment of correspondingly formed desorption eluate using electrochemical oxidation, so that the contaminants could be effectively handled within a wastewater treatment plant. Results show that PANI/TiO2 is a promising adsorbent in the removal of effluent organic matter (> 55%) and its regeneration was superior to the two others. Specifically, PANI/TiO2 could remove over 70% of the fraction of biopolymers from the SE and therefore alleviated subsequent membrane fouling to a large extent, while the other two presented less antifouling effect due to limited removal of the major foulants, though they both showed comparable effect as PANI/TiO2 in the removal of other organic fractions. BOD5/COD of the concentrated desorption eluate was gradually increasing along with the extension of the electrochemical oxidation. It reached > 0.4 after 4.5 h of treatment, which is of suitable biodegradability for recycling to the influent of the wastewater treatment plant. The improvement on BOD5/COD was due to the mineralization of effluent organic matter and simultaneous minifying of their molecular size. Moreover, the operation cost of the treatment loop was estimated at about 0.12-0.15 USD/m(3) for delivering effect fouling control and significant improvement on effluent quality.