Industrial application of ceramic nanofiltration membranes for water treatment in oil sands mines

A commercial titania ceramic nanofiltration membrane unit with a permeate flow capacity of 20 m3/h was used to reduce ion concentration, Total Suspended Solids (TSS) and Total Organic Carbon (TOC) in recycle water from a Canadian oil sands mine. This unit, the first of its kind, was tested for almost two years to evaluate membrane performance under actual recycle process water conditions. This paper focuses on the results at a 50% stage cut. A strong correlation between specific flux and rejection was found, with the highest mass rejections observed at the lowest specific flux values. A potential formation of a cake layer on the membrane surface seems to favour the rejection since lower specific flux values improved mass rejection. The analysis of more than 20 ions showed that differences in hydrated ionic sizes and electrostatic phenomena are at play with divalent cations showing the largest rejection. Additional 75–90% TOC and almost 100% TSS rejection was observed. These results indicate that it is possible to implement this technology in an oil sands mine and obtain significant water quality improvements and reducing river water intake.