Single-Stage Operation of Hybrid Dark-Photo Fermentation to Enhance Biohydrogen Production through Regulation of System Redox Condition: Evaluation with Real-Field Wastewater.

Rashmi Chandra,S Mohan,G Nikhil

doi:10.3390/ijms16059540

Abstract

Harnessing hydrogen competently through wastewater treatment using a particular class of biocatalyst is indeed a challenging issue. Therefore, biohydrogen potential of real-field wastewater was evaluated by hybrid fermentative process in a single-stage process. The cumulative hydrogen production (CHP) was observed to be higher with distillery wastewater (271 mL) than with dairy wastewater (248 mL). Besides H2 production, the hybrid process was found to be effective in wastewater treatment. The chemical oxygen demand (COD) removal efficiency was found higher in distillery wastewater (56%) than in dairy wastewater (45%). Co-culturing photo-bacterial flora assisted in removal of volatile fatty acids (VFA) wherein 63% in distillery wastewater and 68% in case of dairy wastewater. Voltammograms illustrated dominant reduction current and low cathodic Tafel slopes supported H2 production. Overall, the augmented dark-photo fermentation system (ADPFS) showed better performance than the control dark fermentation system (DFS). This kind of holistic approach is explicitly viable for practical scale-up operation.

Highlights

A great deal of attention has been paid to the biological production of hydrogen (H2)as alternative and eco-friendly fuel throughout the world [1,2]
Further utilization of the organic acids towards H2 production is thermodynamically feasible only if there is an additional energy input [5]. This energy input can be in the form of electricity in microbial electrolysis cell (MEC) [6,7,8] or in the form of light in two-stage photofermentation [9,10] or augmentation of photosynthetic bacteria with dark fermentative culture in a single-stage hybrid system [11]
This study demonstrated the feasibility of biological H2 generation from distillery and dairy wastewater treatment in a single stage hybrid system

Summary

Introduction

A great deal of attention has been paid to the biological production of hydrogen (H2)as alternative and eco-friendly fuel throughout the world [1,2]. Further utilization of the organic acids towards H2 production is thermodynamically feasible only if there is an additional energy input [5]. This energy input can be in the form of electricity in microbial electrolysis cell (MEC) [6,7,8] or in the form of light in two-stage photofermentation [9,10] or augmentation of photosynthetic bacteria with dark fermentative culture in a single-stage hybrid system [11]. Photofermentataion can be carried out with a wide variety of organic substrates such as carbohydrates; lactate, malate, benzoate and sucrose which are utilized by different species of phototrophic bacteria as electron donors for H2 production [12,13,14,15]

Methods

Findings

Discussion

Conclusion