Biological-ion exchange process for ammonium removal from secondary effluent

Michal Green*, Adriaan Mels, Ori Lahav, Sheldon Tarre

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

60 Scopus citations

Abstract

A new concept for ammonium removal from secondary effluent by zeolite followed by bio-regeneration has been studied. In contrast to other studies of hybrid biological-ion exchange multireactor systems, the proposed process uses the ion exchange material, zeolite, as the carrier for the nitrifying biomass. This enables the two mode process to be carried out in a single reactor. ammonium is released gradually and converted to nitrate by the active biomass residing on the zeolite. Nitrification is carried out batchwise and in a small volume reactor where optimal conditions can easily be maintained. Moreover, the addition of chemicals for the desorption of ammonium is minimal due to regenerant reuse during several cycles of nitrification. As a result, operational costs and production of large volumes of brine are minimized. Batch and breakthrough experiments showed that the amount of ammonium adsorbed on the chabazite is strongly affected by the presence of competing cations present in secondary effluent. A reduction of about 75% was observed when using a typical Israeli sewage ion composition. The attached biomass did not significantly effect the efficiency of the ion exchange column. Ammonium desorption experiments showed that regeneration with 10,000 mg/L Na+ is much faster than with 2,440 mg/L (more than 90% ammonium recovery after 40 and 70 bed volumes, respectively). A nitrification rate of 6 g NH4-N/(L reactor (*)day) was obtained in a fluidized bed reactor with chabazite as the carrier. Although this rate is in the high range of reported values for biofilm reactors, desorption experiments proved that nitrification will be the process's rate limiting step, rather than the desorption rate when regenerant solutions as low as 2,440 mg/L Na+ are used.

Original languageEnglish
Pages (from-to)449-458
Number of pages10
JournalWater Science and Technology
Volume34
Issue number1-2 -2 pt 1
DOIs
StatePublished - 1996
Externally publishedYes
EventProceedings of the 1996 18th Biennial Conference of the International Association on Water Quality. Part 1 - Singapore, Singapore
Duration: 23 Jun 199628 Jun 1996

Keywords

  • Ammonium removal
  • Fluidized bed
  • Ion exchange
  • Nitrification
  • Zeolite

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