Effect of thermal hydrolysis pretreatment on volatile fatty acids production in sludge acidification and subsequent polyhydroxyalkanoates production

Dandan Zhang; Houlin Jiang; Jing Chang; Jiao Sun; Weiming Tu; Hui Wang

doi:10.1016/j.biortech.2019.01.077

Effect of thermal hydrolysis pretreatment on volatile fatty acids production in sludge acidification and subsequent polyhydroxyalkanoates production

Bioresour Technol. 2019 May:279:92-100. doi: 10.1016/j.biortech.2019.01.077. Epub 2019 Jan 21.

Authors

Dandan Zhang¹, Houlin Jiang¹, Jing Chang², Jiao Sun¹, Weiming Tu¹, Hui Wang³

Affiliations

¹ State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
² Beijing Drainage Group Co. Ltd (BDG), Beijing, China; Beijing Engineering Research Center (NO:BG0113), Beijing 100124, China.
³ State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: wanghui@tsinghua.edu.cn.

PMID: 30711757
DOI: 10.1016/j.biortech.2019.01.077

Abstract

The study compared the differences in VFAs production between raw sludge and thermal hydrolyzed sludge (TH-sludge) at different temperature (35 °C and 55 °C) in four semi-continuous acidification reactors. Optimal VFAs yield was obtained from TH-sludge at 35 °C (0.22 gVFA_COD/gVS), 44.6% higher than raw sludge at 35 °C, since the advantage of TH-sludge in SCOD solubilization overcame its disadvantage of lower carbon biodegradability. Moreover, high temperature (55 °C) was proved to aid the acidification of raw sludge by 15.7% (in Y_VFAs), but inhibit that of TH-sludge by 12.2%, mainly due to the suppressed microbial activities under heat. Microbial community analysis showed that TH-sludge had a larger proportion of acidogenic microbes than raw sludge, mainly attributing to the increase of Selenomonadales (37.3% vs. 3.7%); high temperature enriched thermophilic proteolytic microbes, Anaerobaculum and Coprothermobacter. Finally, optimal acidified liquid from TH-sludge at 35 °C was applied for PHAs production and achieved a competitive yield of 34.6% PHAs/DCW.

Keywords: Acidification; Acidogenic microbes; Polyhydroxyalkanoates (PHAs) production; Thermal hydrolysis; VFAs production.

MeSH terms

Bacteria, Anaerobic / metabolism
Carbon / metabolism
Fatty Acids, Volatile / biosynthesis*
Hot Temperature
Hydrogen-Ion Concentration
Hydrolysis
Polyhydroxyalkanoates / biosynthesis*
Sewage*

Substances

Fatty Acids, Volatile
Polyhydroxyalkanoates
Sewage
Carbon