Daniel P. Smitha, , ,
Nathaniel T. Smithb
a Applied Environmental Technology, PO Box 576, Garrett Park, MD 20896, USA
b Civil and Environmental Engineering, University of Maryland, College Park, MD 20742, USA
Received 18 June 2015, Revised 22 July 2015, Accepted 23 July 2015, Available online 29 July 2015
Highlights
Anaerobic-ion exchange (AN-IX) process recovers sanitation water nitrogen at source.
AN-IX couples anaerobic upflow solids blanket treatment and ion exchange.
57 L field prototype recovered >95% sanitation water nitrogen for 14 months.
AN-IX operates passively with small footprint, limited maintenance and no energy.
Anaerobic-ion exchange is a platform for local-scale nitrogen cycling.
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 57 L 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 13.5 mg 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.
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