Ammonium nitrogen removal from the permeates of anaerobic membrane bioreactors: economic regeneration of exhausted zeolite

Environ Technol. 2014 Aug;35(13-16):2008-17. doi: 10.1080/09593330.2014.889759.

Abstract

This study revealed that ammonium exchange of natural zeolite could be an economical method of nitrogen removal from the permeates of anaerobic membrane bioreactors (AnMBRs). It was found that the mass ratio of Na+ to Zeolite - NH4+ - N significantly affected regeneration efficiency (RE), not simply NaCI concentration. Batch experiments showed that the mass ratio of 750g Na+/g Zeolite - NH4+ - N was required to achieve RE over 90% in 2h at pH 9. However, the alkaline regeneration at pH 12 significantly decreased the mass ratio down to 4.2 in batch tests. It was confirmed that the alkaline regeneration only needed NaCl 10 g/L (the mass of Na+ to Zeolite - NH4+ - N of 4.2) for RE of 85% in 2 h of reaction time in continuous column tests. Economic analysis showed that this alkaline regeneration decreased chemical costs over 10 times as compared with a conventional regeneration method. A significant bottleneck of zeolite processes would be the requirement of substituting exhausted zeolite with virgin one, due to the reductions of ammonium exchange capacity and RE.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ammonium Compounds / isolation & purification*
  • Anaerobiosis
  • Bioreactors
  • Hydrogen-Ion Concentration
  • Sodium Chloride / chemistry
  • Zeolites / chemistry*
  • Zeolites / economics

Substances

  • Ammonium Compounds
  • Zeolites
  • Sodium Chloride