Regulating acidogenesis and methanogenesis for the separated bio-generation of hydrogen and methane from saline-to-hypersaline industrial wastewater

Manal Ali; Ahmed Elreedy; Mona G Ibrahim; Manabu Fujii; Kota Nakatani; Ahmed Tawfik

doi:10.1016/j.jenvman.2019.109546

Regulating acidogenesis and methanogenesis for the separated bio-generation of hydrogen and methane from saline-to-hypersaline industrial wastewater

J Environ Manage. 2019 Nov 15:250:109546. doi: 10.1016/j.jenvman.2019.109546. Epub 2019 Sep 17.

Authors

Manal Ali¹, Ahmed Elreedy², Mona G Ibrahim³, Manabu Fujii⁴, Kota Nakatani⁴, Ahmed Tawfik⁵

Affiliations

¹ Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan; Environmental Engineering Department, Egypt-Japan University of Science and Technology, Alexandria, 21934, Egypt; Civil Engineering Department, Aswan University, Aswan, 81511, Egypt.
² Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan; Sanitary Engineering Department, Alexandria University, Alexandria, 21544, Egypt. Electronic address: elreedy.a.aa@m.titech.ac.jp.
³ Environmental Engineering Department, Egypt-Japan University of Science and Technology, Alexandria, 21934, Egypt; Environmental Health Department, High Institute of Public Health, Alexandria University, Alexandria, 21544, Egypt.
⁴ Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan.
⁵ Water Pollution Research Department, National Research Centre, Giza, 12622, Egypt.

PMID: 31545177
DOI: 10.1016/j.jenvman.2019.109546

Abstract

Given the limitations of acidogens and methanogens activities under saline environments, this work aims to optimize the main operational parameters affecting hydrogen and methane production from saline-to-hypersaline wastewater containing mono-ethylene glycol (MEG). MEG is the main contaminant in several saline industrial effluents. Anaerobic baffled reactor (ABR), as a multi-stage system, was used at different temperatures (i.e., 19-31 °C [ambient] and 35 °C), organic loading rates (OLRs) of 0.6-2.2 gCOD/L/d, and salinity of 5-35 gNaCl/L. Mesophilic conditions of 35 °C substantially promoted MEG biodegradability (92-98%) and hydrogen/methane productivity, even at elevated salinity. Hydrogen yield (HY) and methane yield (MY) peaked to 258 and 140 mL/gCOD_add, respectively, at OLR 0.64 gCOD/L/d and salinity up to 20-25 gNaCl/L. An immobilized sludge ABR (ISABR), packed with polyurethane media, was further compared with classical ABR, resulting in 1.8-fold higher MY, at 35 gNaCl/L. Microbial analysis showed that introducing attached growth system (ISABR) substantially promoted methanogens abundance, which was dominated by genus Methanosarcina. Among bacterial genera, Acetobacterium was dominant, particularly in 1^st compartment, representing MEG-degrading/salt-tolerant genus. At high salinity up to 35 gNaCl/L, the multi-phase and attached growth configuration can efficiently reduce the induced salt stress, particularly on methanogens, towards balanced and separated acidogenesis/methanogenesis. Overall, producing hydrogen and methane from anaerobic treatment of MEG-based saline wastewater is feasible at optimized parameters and configuration.

Keywords: Anaerobic digestion; Hydrogen and methane; Metabolites; Microbial dynamics; Mono-ethylene glycol; Saline wastewater.

MeSH terms

Anaerobiosis
Bioreactors
Hydrogen
Methane*
Wastewater*

Substances

Waste Water
Hydrogen
Methane