Abstract

A new hybrid process has been proposed and evaluated the feasibility for complete removal of chromate and selenate at high level. The process consists of a H2-based membrane biofilm reactor (MBfR) and reverse osmosis (RO)/nanofiltration (NF) stages. The essential feature of the process is the recycling of the RO and NF concentrate into the membrane biofilm reactor. First, two different H2-based denitrifying MBfR initially reduced selenate (Se (VI)) or chromate (Cr (III)) stably to Se° or Cr (III) to limited levels (approximately 70-85% removal for selenate and approximately 40-65% removal for chromate). In order to achieve more stable and lower levels, two different membrane (NF and RO) filtration technologies as sequential process were combined. Two wastewaters produced from two MBfRs having similar amounts of target toxic ions (C o = 366 μg-Cr L-1 and C o = 326 μg-Se L-1), pH, and conductivity were tested to determine the solute rejection and the membrane flux for one RO and one NF membranes at varying recovery conditions (10-90%). The results show that the rejection of solutes decreases with increasing the recovery due to the increase in osmotic pressure. The rejections by the RO membrane were >99-98% for chromate and 99-94% for selenate, while slightly lower rejections (<20%) were observed for the NF membrane at the recovery conditions.

Original languageEnglish (US)
Pages (from-to)29-37
Number of pages9
JournalWater, Air, and Soil Pollution
Volume207
Issue number1-4
DOIs
StatePublished - Mar 1 2010

Keywords

  • Chromate
  • Hydrogen-based membrane biofilm reactor
  • Nanofiltration
  • Reverse osmosis
  • Selenate

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Ecological Modeling
  • Water Science and Technology
  • Pollution

Fingerprint

Dive into the research topics of 'Integration of H<sub>2</sub>-based membrane biofilm reactor with RO and NF membranes for removal of chromate and selenate'. Together they form a unique fingerprint.

Cite this