Keywords: multibarriers, PRB, permeable reactive barriers, landfill leachate, ammonium removal, bioregeneration, clinoptilolite, nitrification, leachate treatment, ion exchange
A laboratory-scale mixed multibarrier for removal of ammonium from landfill leachate contamination
A column-scale multibarrier, combining nitrification and ion exchange processes in a mixed configuration, was evaluated for the removal of ammonium (325 ± 60 mg N L
−1) from landfill leachate contamination. Inoculating granular clinoptilolite with nitrifying bacteria resulted in a 3.2 times higher overall ammonium removal, compared with a non-inoculated control. Interestingly, nitrifying activity resulted in desorption of ammonium from saturated clinoptilolite and subsequent microbial oxidation of the released ammonium. These findings indicate that ammonium-saturated clinoptilolite can be in-situ bioregenerated in a multibarrier, which implicates that periodic (and particularly costly) removal and external regeneration of the ion exchange material can be avoided.