Effects of low-concentration Cr(VI) on the performance and the membrane fouling of a submerged membrane bioreactor in the treatment of municipal wastewater

The effects of low-concentration Cr(VI) (0.4 mg l(-1)) on the performance of a submerged membrane bioreactor (SMBR) in the treatment of municipal wastewater, as well as membrane fouling were investigated. Compared with the SMBR for control municipal wastewater, the SMBR for Cr(VI)-containing municipal wastewater had a higher concentration of soluble microbial products (SMP) with lower molecular weights, and smaller sludge particle sizes. Furthermore, low-concentration Cr(VI) induced membrane fouling, especially irreversible membrane pore blocking, which markedly shortened the service life of the membrane.