Bioaugmentation with Mixed Hydrogen-Producing Acetogen Cultures Enhances Methane Production in Molasses Wastewater Treatment.

Shuo Wang,Guocheng Du,Ji Li,Guochen Zheng,Jianzheng Li

doi:10.1155/2018/4634898

Abstract

Hydrogen-producing acetogens (HPA) have a transitional role in anaerobic wastewater treatment. Thus, bioaugmentation with HPA cultures can enhance the chemical oxygen demand (COD) removal efficiency and CH4 yield of anaerobic wastewater treatment. Cultures with high degradation capacities for propionic acid and butyric acid were obtained through continuous subculture in enrichment medium and were designated as Z08 and Z12. Bioaugmentation with Z08 and Z12 increased CH4 production by glucose removal to 1.58. Bioaugmentation with Z08 and Z12 increased the COD removal rate in molasses wastewater from 71.60% to 85.84%. The specific H2 and CH4 yields from COD removal increased by factors of 1.54 and 1.63, respectively. Results show that bioaugmentation with HPA-dominated cultures can improve CH4 production from COD removal. Furthermore, hydrogen-producing acetogenesis was identified as the rate-limiting step in anaerobic wastewater treatment.

Highlights

High-strength organic wastewater and municipal sludge can be efficiently treated through anaerobic processes, which produce CH4 as the main product [1]
The microbial cultures used in anaerobic wastewater treatment are highly complex and include fermentative bacteria, hydrogen-producing acetogens (HPA), and methanogenic bacteria (MB) [2, 3]
Z08, a mixed culture dominated by propionate-oxidizing HPA, was successfully obtained after ten generations of continuous subculture

Summary

Introduction

High-strength organic wastewater and municipal sludge can be efficiently treated through anaerobic processes, which produce CH4 as the main product [1]. The microbial cultures used in anaerobic wastewater treatment are highly complex and include fermentative bacteria, hydrogen-producing acetogens (HPA), and methanogenic bacteria (MB) [2, 3]. HPA species are applied in anaerobic wastewater treatment as an alternative to MB, sulfate-reducing bacteria, and other hydrogen-consuming bacteria [4]. Only a few strains of HPA have been isolated and purified because the species are obligate or facultative anaerobe. HPA mainly converts volatile fatty acids (VFAs) and ethanol into acetic acid, H2, and CO2 [5, 6]. The metabolic products of HPA, in turn, promote CH4 production by MB [7]

Methods

Results

Conclusion