Impact of selectively enriched microbial communities on long-term fermentative biohydrogen production.

The effect of selectively enriched inoculum for biohydrogen production and shifts in microbial communities was observed using anaerobic sequencing batch reactor (AnSBR). Significantly, combined pretreatment using acid and iodopropane resulted 3 fold increase in H2 production (8.65mol/kgCODR) over untreated control (2.63mol/kgCODR). Pretreatment showed significant shifts in the microbial communities which are thus accounted for enhanced H2 production. The high-throughput pyrosequence analysis depicted shifts in phylum Firmicutes and Proteobacteria. In the case of Proteobacteria, there was an increase in Betaproteobacterial, decrease in Epsilonproteobacterial and compositional variation in Alphaproteobacterial species. The decreased OTU number after pretreatment indicate, reduction of undesirable microbial populations while favouring conditions for microbiome that are involved in acidogenic, acetogenic and H2 production.

Bioelectrochemical treatment of paper and pulp wastewater in comparison with anaerobic process: integrating chemical coagulation with simultaneous power production.

The efficiency of a bioelectrochemical treatment system (BET) to treat complex paper and pulp wastewater at two different pH conditions (6 and 7) in comparison with conventional anaerobic treatment process (AnT) was evaluated. Among the operating conditions, BET showed good treatment efficiency at pH 7 in terms of COD (BET/AnT: 55%/51%), nitrates (33.5%/19.1%), phosphates (33%/19%) and sulfates (58%/41%) in removal. The effluent obtained from BET system was subjected to coagulation for further treatment which showed good COD removal (BET/AnT, 95%/69%) and color (100%/68%). Bioelectrochemical analysis revealed higher catalytic currents in BET than AnT specific to oxidation and reduction. Besides, derivative of cyclic voltammetric scans (DCV) also supported the involvement of various membrane bound electron transferring complexes like FAD(H) bound enzymes, ubiquinone, NADH(+)/H(+) bound enzymes, etc. Experimental results demonstrated that BET system can be a viable platform to treat complex wastewaters with simultaneous energy recovery in integrated approach.