Assessment of fouling-resistant membranes for additive-free treatment of high-strength wastewaters

Abstract

In this contribution, we investigate the use of fouling-resistant and cleanable membranes designed for treatment of oily water in the treatment of high-strength industrial wastewaters that present challenges to classical treatment technologies. Membrane surfaces were characterized by spectroscopy and electron microscopy pre- and post-filtration to determine the extent of fouling. Low molecular weight cutoff membranes showed stable permeate fluxes without the need for intermittent cleaning, characteristic of systems with low degrees of internal fouling. For 100kDa molecular weight cutoff membranes, flux decline was more severe. While polymer-modified membranes processed ~26% more permeate than the unmodified membranes in this case, flux recovery after a membrane cleaning step was low and similar for the unmodified and modified membranes, characteristic of high degrees of internal fouling. All membranes reduced turbidity nearly 100% and chemical oxygen demand was reduced 70–84%. These results indicate that ‘tight’ ultrafiltration membranes designed for treatment of oily waters can be used for primary treatment of other highly impaired wastewaters, and the use of more ‘open’ ultrafiltration membranes will require further development and optimization of cleaning protocols.