Effect of temperature on bio-hythane production and bioremediation of recalcitrant dye by means of two anaerobic processes

Abstract

A series of batch experiments were carried out to investigate the effect of temperature on the improvement of bio-hythane production, thermodynamic characteristics, and decolorization efficiency of anaerobic degradation of C.I. acid red 88 containing wastewater. The maximum accumulated bioH2 gas reached 0.43 l/g VS under 65 °C and the target dye was hydrolyzed with a 98% color removal. Under mesophilic temperature, bio-hydrogen production was unstable due to growing unfavorable mixed microflora. The methanogenesis bacteria activity showed better performance under temperatures ranging from 45 to 65 °C. The maximum chemical oxygen demand (COD) degradation was reached 70.2% under 45 °C, with the highest methane bioconversion that was recorded. Our results confirmed that temperature is a significant factor in improving biogas production and treated wastewater’s quality for reuse. The activation energy for hydrogen and methane is determined using regression (R2, 0.95 and 0.96) to be 102.3 and 97.4 kJ/mol, respectively. Graphical abstract: [Figure not available: see fulltext.]