Abstract
Different cleaning strategies for membranes from membrane bioreactors (MBR) were investigated and applied to a pilot MBR treating real refinery wastewater. It was assessed different cleaning agents (sodium percarbonate, dodecyl sulfate, citric acid, oxalic acid, and sodium hypochlorite) at different concentrations (500–5000 ppm), temperatures (22–40 °C), pH (without adjustment and pH 12), with and without air scouring, for membranes' permeability recovery. The best cleaning sequence was defined to be oxalic acid (pH 2.5) followed by NaOCl (5000 ppm), which was responsible for the inorganic fouling removal and allowed the oxidant agent to remove more effectively the organic fouling layer. Improvement in permeability recovery at 40 °C (92.7% of the initial permeability) and higher NaOCl concentration (5000 ppm) was found due to the increase in chemical oxidation kinetics and the diffusion rate of the cleaning agents within the fouled layer and membrane. Oxalic acid followed by sodium hypochlorite (40 °C) had a lower effect on membranes' morphology and thermal resistance, proven by thermogravimetric analysis and Fourier transform infrared spectroscopy. The pilot-scale operation was used to estimate the membrane lifespan which was approximately 1916 days of monitoring – about five years.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
