Ammonia abatement for low-salinity domestic secondary effluent with a hybrid electrooxidation and adsorption reactor

A novel hybrid electrooxidation and zeolite adsorption reactor (HEAR) was proposed to remove ammonia from low-salinity, synthetic, or real wastewaters and compared in ammonia removal performance with the traditional single electrooxidation reactor (SER). Ammonia removal in the HEAR reached 69% versus 27% for the SER at 0.3 A h L^-1 electrical charge, and the HEAR also performed well at low temperatures. The HEAR performance in the presence of dissolved organic nitrogen (DON) was better than that of SER for ammonia and DON removal. DON removal of 20-55% in the HEAR was obtained. Ammonia degradation was mildly affected by dissolved organic carbon in the HEAR. After the electrolysis stage, 69% less ammonia was found on the zeolites used in electrolysis than those used in adsorption, indicating the occurrence of simultaneous regeneration in the HEAR. Zeolite adsorption of ammonia and electrochemical oxidation by in situ generated active chlorine ions responded to reactions occurring in low-chloride-containing solution. The combined electrooxidation and zeolite adsorption process is a promising reagent-free ammonia removal process for secondary effluent in cold regions. © 2014 American Chemical Society.