Abstract

Requirement of a long hydraulic retention time (HRT) for efficient degradation restrains the anaerobic digestion of hydrothermal pretreated sludge. Shortening the HRT can increase the treatment capacity of a plant but may also induce digester instability. This study investigated the impact of HRT on process performance and microbial community by consecutively operating a reactor for 145 days. The HRT was gradually decreased from 20 to 10, 5, and 3 days. The methane yield declined from 0.28 to 0.12 L/g-VSin with this shortening, and acetate concentration increased from 38 to 376 mg/L. Methanoculleus (58%) dominated methanogens at a 20 days HRT. However, the methanogenic structure shifted toward an increased level of Methanospirillum, representing 95% of the total archaea at a 3 days HRT. Microorganisms were almost washed out at the end of experiment. Conclusively, shortening HRTs is a feasible strategy to increase treatment capacity and produce more biogas at existing plants.

Keywords

Methanogenic communities; Process performance; Anaerobic digestion; Thermal hydrolyzed sludge; Hydraulic retention times

Published in

Bioresource Technology
2019, Volume: 272, pages: 180-187
Publisher: ELSEVIER SCI LTD

SLU Authors

• Westerholm, Maria

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

Associated SLU-program

Food Waste


Sustainable Development Goals

Ensure access to affordable, reliable, sustainable and modern energy for all


UKÄ Subject classification

Water Treatment
Energy Systems


Publication identifier

DOI: https://doi.org/10.1016/j.biortech.2018.10.023

Permanent link to this page (URI)

https://res.slu.se/id/publ/97912