View article

Dairy wastewater can be concentrated by membrane technology to produce reusable water, and the retentate with high concentration could be reutilized as feed supplement for animals or substrate for biohydrogen production. Treatment of a model dairy wastewater (diluted skim milk) by nanofiltration (NF) with a rotating disk membrane (RDM) module was investigated using a NF membrane NF270 (Dow-Filmtec). Compared with the Desal-5 DK (Ge-Osmonics) membrane studied previously, the NF270 membrane gave much higher permeate flux, but same rejection. At a high enough shear rate for reducing concentration polarization, permeate flux and solutes rejection increased while specific energy per m³ of permeate decreased when transmembrane pressure (TMP) rose from 10 to 40bar. Because the RDM module could produce very high shear rates, concentration of dairy wastewater by NF could be operated …