Hydrogen production and ammonium recovery from urine by a Microbial Electrolysis Cell

We investigated the use of a Microbial Electrolysis Cell (MEC) for the ammonium removal, COD removal and hydrogen production from five times diluted urine. During operation with a batch cathode, a current density of 23.07 +/- 1.15 A m(-2) was achieved corresponding to a hydrogen production rate of 48.6 +- 7.47 m(3) H-2 m(-3) MEC d(-1), an ammonium removal rate of 173.4 +/- 18.1 g N m(-2) d(-1) and a COD removal rate of 171.0 +/- 16.9 g COD m(-2) d(-1). Ammonia stripping was not possible in the applied MEC and ammonia diffusion from cathode to anode compartment led to a relatively short stable operation period. The stable operation period was prolonged by addition of new cathode media (HRT 6 h), but this resulted in a lower current density (14.64 +/- 1.65 A m(-2)), hydrogen production rate (32.0 +/- 0.89 m(3) H-2 m(-3) MEC d(-1)), ammonium removal rate (162.18 +/- 10.37 g N m(-2) d(-1)) and COD removal rate (130.56 +/- 4.45 g COD m(-2) d(-1)). Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved