Converting waste molasses liquor into biohydrogen via dark fermentation using a continuous bioreactor. (5th May 2021)

• Record Type: Journal Article
• Authors: Lee, Kuo-Shing; Chen, Shin-Liang; Lin, Chiu-Yue; Chang, Jo-Shu
• Is Part Of: International journal of hydrogen energy. Volume 46:Number 31(2021)
• Page Start: 16546
• Page End: 16554
• Publication Date: 2021-05-05
• Subjects: Biohydrogen production -- Dark fermentation -- Molasses -- Preheating treatment; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2021.02.101
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: This study investigated the effects of substrate concentration, HRT (hydraulic retention time), and pre-treatment of the substrate molasses on biohydrogen production from waste molasses (condensed molasses fermentation solubles, CMS) with a CSTR (continuously-stirred tank reactor). First, the hydrogen production was performed with various CMS concentrations (40–90 g COD/L, total sugar 8.7–22.6 g/L) with 6 h HRT. The results show that the maximal hydrogen production rate (HPR) occurred at 80 g COD/L substrate (19.8 g ToSu/L, ToSu: Total Sugar), obtaining an HPR of 0.417 mol/L/d. However, maximum hydrogen yield (HY) of 1.44 mol H2 /mol hexose and overall hydrogen production efficiency (HPE) of 25.6% were achieved with a CMS concentration of 70 g COD/L (17.3 g ToSu/L). The substrate inhibition occurred when CMS concentration was increased to 90 g COD/L (22.6 g ToSu/L). Furthermore, it was observed that the optimal HPR, HY, and HPE all occurred at HRT 6 h. Operating at a lower HRT of 4 h decreased the hydrogen production performance because of lower substrate utilization efficiency. The employment of pre-heating treatment (60 °C for 1 h) of the substrate could markedly enhance the fermentation performance. With 6 h HRT and substrate pre-heating treatment, the HPE raised to 29.9%, which is 18% higher than that obtained without thermal pretreatment. Highlights: Bioreactor strategies on dark H2 fermentation from waste molasses were developed. Best bioH2 production occurred at 70 g COD/L substrate concentration & 6 h HRT. Substrate preheating treatment markedly improved bioH2 production from CMS feedstock.