Application of membrane distillation to anaerobic digestion effluent treatment: Identifying culprits of membrane fouling and scaling

Membrane distillation (MD) has great potential in the treatment of high-salinity and low-biodegradability wastewater, but membrane fouling restricts its real applications. In this work, MD was applied to treat anaerobic digestion effluent, and the feed pH was adjusted to investigate the membrane organic fouling and inorganic scaling. The results show that the fouling of MD membranes during the treatment of anaerobic digestion effluent was substantially alleviated at a low feed pH (pH=5). Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) were used to characterize the fouled membranes. The MD membrane scaling was primarily attributed to the deposition of calcium-, magnesium-, phosphate-, and silicon-related inorganic compounds during the treatment of cow dung anaerobic digestion effluent. Feed acidification significantly decreased inorganic scaling as well as fouling by organic matter, and organic fouling dominated the fouling process in the low-pH environment. By comparing the components in acid and alkaline cleaning solutions, it was found that the deposition of organics on the membranes via adsorption to inorganic scaling was the primary cause of more severe organic fouling with increasing feed pH. Hence, restricting inorganic scaling could be an effective way to control MD membrane fouling by organics during treatment of anaerobic digestion effluent.

Jaar van publicatie:2019

BOF-keylabel:ja

IOF-keylabel:ja

BOF-publication weight:6

CSS-citation score:3

Auteurs:International

Authors from:Higher Education

Toegankelijkheid:Closed