Development of exoelectrogenic bioanode and study on feasibility of hydrogen production using abiotic VITO-CoRE™ and VITO-CASE™ electrodes in a single chamber microbial electrolysis cell (MEC) at low current densities.

Single chamber membrane-free microbial electrolysis cell (MEC) was operated for the assessment of exoelectrogenic bacteria (EB) growth at carbon felt anode and resultant hydrogen (H2) production at abiotic cathodes, made using cold rolling (VITO-CoRE™) and casting (VITO-CASE™) methods. Progressive enrichment of EB was observed on anode during 70 days of operation at an applied potential of +0.2V vs Ag/AgCl, and a maximum current density (CD) of 330.59 mA/m(2) (1.38 mA) was recorded. H2 production at selected abiotic cathodes was observed, when the enriched bioanode was coupled to them in galvanostat mode between 0.1 and 1.0 mA current range for 10 min each. Higher H2 production of 114.46±3.75 mL/m(2) was documented with VITO-CoRE™ at 0.6 mA, while 102.76±3.75 mL/m(2) was recorded with VITO-CASE™ at 0.8 mA of current application. This study demonstrates the feasibility of H2 production on abiotic cathodes using enriched bioanode at low current densities.

Single-stage fermentation process for high-value biohythane production with the treatment of distillery spent-wash.

The current communication reports the development of a single-stage biosystem for biohythane production from wastewater treatment. A semi-pilot scale bioreactor with 34 L capacity was used for this study. Maximum biohythane production of 147.5 ± 2.4 L was observed after five cycles of operation with production rate of 4.7 ± 0.1L/h. The biohythane composition (H2/(H2+CH4)) varied from 0.60 to 0.23 during stabilized fifth cycle of operation. During each cycle of operation, higher H2 fraction was noticed within 12h of cycle period followed by CH4 production for rest of operation (36 h). During biohythane production, COD removal efficiency of 60 ± 5% (SDR, 29.0 ± 1.9 kg CODr/m(3)-day) was also achieved. The synergistic function of volatile fatty acids (VFA) production and consumption during process in hybrid biosystem played vital role on the composition of biohythane. The single-stage biosystem facilitates production of high valued and cost efficient biofuel (biohythane) with fewer controls than individual acidogenic and methanogenic processes.