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The concept of load ratio applied to bioelectrochemical systems for ammonia recovery
Author(s) -
Rodríguez Arredondo Mariana,
Kuntke Philipp,
ter Heijne Annemiek,
Buisman Cees JN
Publication year - 2019
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5992
Subject(s) - current (fluid) , ammonia , current density , chemistry , limiting , limiting current , analytical chemistry (journal) , electrochemistry , chromatography , thermodynamics , electrode , engineering , physics , organic chemistry , quantum mechanics , mechanical engineering
Abstract BACKGROUND The load ratio is a crucial parameter to optimize the current driven recovery of total ammonia nitrogen (TAN) from urine. The load ratio is the ratio between the current density and the TAN loading rate. It is currently not known if the load ratio concept applies to a bioelectrochemical system (BES) because the current density and TAN loading rate cannot be controlled independently. RESULTS We found a clear increasing trend in TAN removal efficiency with respect to load ratio in the BES for both human and synthetic urine. The maximum TAN removal efficiency was 60.9% at a load ratio of 0.7, corresponding to a TAN transport rate of 119 gN m −2 day −1 at an electrical energy input of 1.9 kWh kgN −1 (synthetic urine). Low load ratios (<1) were obtained, indicating that the current was not enough to transport all the TAN across the membrane. CONCLUSIONS BES and ES show the same general relationship between TAN removal efficiency and load ratio. Therefore, given a stable current density, the concept of load ratio can also predict the TAN removal efficiency in BES. Higher current densities, and insights into the factors limiting current, are needed to increase the load ratio and therefore the TAN removal efficiency. © 2019 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.