title: Anaerobic-ion exchange (AN-IX) process for local-scale nitrogen recovery from wastewater.
abstract: An anaerobic-ion exchange (AN-IX) process was developed for point-of-origin recovery of nitrogen from household wastewater. The process features upflow solids-blanket anaerobic treatment (ammonification) followed by ammonium ion exchange onto natural zeolite. The AN-IX system is configured as a series of linked upflow chambers that operate passively without energy input, and is amenable to intermittent and seasonal operation. A 57L prototype was operated for over 1.8 years treating actual wastewater under field conditions. Total nitrogen removal exceeded 96% through the first 160 days of operation and effluent ammonium nitrogen remained below detection for 300 days. Ion exchange chambers exhibited sequential NH4(+)-N breakthrough over extended operation and complete media exhaustion was approached at Day 355. The ammonium capacity of zeolite was estimated as 13.5mg NH4(+)-N per gram dry weight. AN-IX is a resilient and cost effective process for local-scale nitrogen recovery and reuse, suitable for small scale and larger systems.
authors.affiliation: Applied Environmental Technology, PO Box 576, Garrett Park, MD 20896, USA. Electronic address: DPSmith_AET@verizon.net.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Smith
authors.affiliation: Civil and Environmental Engineering, University of Maryland, College Park, MD 20742, USA.
authors.forename: Nathaniel T
authors.initials: NT
authors.lastname: Smith
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry; D000693:Anaerobiosis; D019149:Bioreactors; D004867:Equipment Design; D005431:Florida; D007474:Ion Exchange; D009584:Nitrogen / Q000302:isolation & purification* / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D062065:Wastewater / Q000737:chemistry; D017641:Zeolites / Q000737:chemistry
chemical_list: D064751:Ammonium Compounds; D009584:Nitrogen; D062065:Wastewater; D017641:Zeolites
keywords: Ammonium; Ion exchange; Nitrogen; Resource recovery; Wastewater