Rapid start-up of a bioelectrochemical system under alkaline and saline conditions for efficient oxalate removal
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This study examined a new approach for starting up a bioelectrochemical system (BES) for oxalate removal from an alkaline (pH > 12) and saline (NaCl 25 g/L) liquor. An oxalotrophic biofilm pre-grown aerobically onto granular graphite carriers was used directly as both the microbial inoculum and the BES anode. At anode potential of +200 mV (Ag/AgCl) the biofilm readily switched from using oxygen to graphite as sole electron acceptor for oxalate oxidation. BES performance was characterised at various hydraulic retention times (HRTs, 3–24 h), anode potentials (-600 to +200 mV vs. Ag/AgCl) and influent oxalate (25 mM) to acetate (0–30 mM) ratios. Maximum current density recorded was 363 A/m 3 at 3 h HRT with a high coulombic efficiency (CE) of 70%. The biofilm could concurrently degrade acetate and oxalate (CE 80%) without apparent preference towards acetate. Pyro-sequencing analysis revealed that known oxalate degraders Oxalobacteraceae became abundant signifying their role in this novel bioprocess.
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Sipos, Gabriella (2001)Sodium oxalate is one of the many organics present in Bayer liquor. Due to its limited solubility, sodium oxalate can co-precipitate with alumina trihydrate during precipitation. This can have detrimental effects on the ...
Kinetics of oxalate degradation in aerated packed-bed biofilm reactors under nitrogen supplemented and deficient conditionsWeerasinghe Mohottige, T.; Kaksonen, A.; Cheng, K.; Sarukkalige, Priyantha Ranjan; Ginige, M. (2019)© 2018 Elsevier Ltd Destruction of oxalate from alumina-refining process liquor is considered essential for many alumina refineries around the world. Some refineries have embraced the use of aerobic bioreactors as a ...
Oxalate degradation by alkaliphilic biofilms acclimatised to nitrogen-supplemented and nitrogen-deficient conditionsWeerasinghe Mohottige, T.; Cheng, K.; Kaksonen, A.; Sarukkalige, Priyantha Ranjan; Ginige, M. (2018)Background: Sodium oxalate is a key organic contaminant in alumina industry, which diminishes process yields and product quality. Given that Bayer process liquor is typically deficient in nitrogen (N), there is external ...