Fouling and cleaning of microfiltration membrane in municipal wastewater reclamation

This paper presents an investigation on fouling and cleaning of a tubular microfiltration membrane for municipal wastewater reclamation. A bi-level complex model, namely channel clogging and pore plugging, was introduced to elucidate the fouling mechanism. Based on 135 days of microfiltration of activated sludge, a preventive method for channel clogging was reasonably proposed and proven to be effective. Without channel clogging, the operation period was observed a five-fold increase on average, reaching 3-4 weeks. To remove pore plugging, a multi-step chemical cleaning was employed and further optimized in terms of temperature and alkaline concentration. Generally, the chemical cleaning could restore the membrane permeability to higher than 90%.