Bio-electrochemical COD removal for energy-efficient, maximum and robust nitrogen recovery from urine through membrane aerated nitrification

WATER RESEARCH

卷:185

Article

De Paepe, Jolien^1,2,3  De Paepe, Kim¹  Godia, Francesc²  Rabaey, Korneel^1,3  Vlaeminck, Siegfried E.^3,4  Clauwaert, Peter^1,3 

[1] Univ Ghent, Fac Biosci Engn, Ctr Microbial Ecol & Technol CMET, Dept Biotechnol, Coupure Links 653, B-9000 Ghent, Belgium

[2] Univ Autonoma Barcelona, Dept Engn Quim Biol & Ambiental, Escola Engn, E-08193 Barcelona, Spain

[3] Ctr Adv Proc Technol & Urban Resource Efficiency, Ghent, Belgium

[4] Univ Antwerp, Dept Biosci Engn, Res Grp Sustainable Energy Air & Water Technol, Groenenborgerlaan 171, B-2020 Antwerp, Belgium

关键词: Resource recovery;    Regenerative life support system;    Nitrogen recovery;    Yellow water;    Source separation;    Membrane biofilm reactor;   

DOI  :  10.1016/j.watres.2020.116223

来源: Elsevier

【 摘 要 】

Resource recovery from source-separated urine can shorten nutrient cycles on Earth and is essential in regenerative life support systems for deep-space exploration. In this study, a robust two-stage, energy-efficient, gravity-independent urine treatment system was developed to transform fresh real human urine into a stable nutrient solution. In the first stage, up to 85% of the COD was removed in a microbial electrolysis cell (MEC), converting part of the energy in organic compounds (27-46%) into hydrogen gas and enabling full nitrogen recovery by preventing nitrogen losses through denitrification in the second stage. Besides COD removal, all urea was hydrolysed in the MEC, resulting in a stream rich in ammoniacal nitrogen and alkalinity, and low in COD. This stream was fed into a membrane-aerated biofilm reactor (MABR) in order to convert the volatile and toxic ammoniacal nitrogen to non-volatile nitrate by nitrification. Bio-electrochemical pre-treatment allowed to recover all nitrogen as nitrate in the MABR at a bulk-phase dissolved oxygen level below 0.1 mg O-2 L-1. In contrast, feeding the MABR directly with raw urine (omitting the first stage), at the same nitrogen loading rate, resulted in nitrogen loss (18%) due to denitrification. The MEC and MABR were characterised by very distinct and diverse microbial communities. While (strictly) anaerobic genera, such as Geobacter (electroactive bacteria), Thiopseudomonas, a Lentimicrobiaceae member, Alcaligenes and Proteiniphilum prevailed in the MEC, the MABR was dominated by aerobic genera, including Nitrosomonas (a known ammonium oxidiser), Moheibacter and Gordonia. The two-stage approach yielded a stable nitrate-rich, COD-low nutrient solution, suitable for plant and microalgae cultivation. (C) 2020 Elsevier Ltd. All rights reserved.

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