Impact of Temperature-Dependent Reaction Rates on Methane Yields in Intermittently Fed Mesophilic Sludge Digestion

Abstract

Efficient anaerobic digestion (AD) of sludge is crucial for the overall energy balance, minimization of carbon footprint, and the economy for most wastewater-treatment plants (WWTPs). In recent years, intermittent feeding (IF) has become increasingly interesting because it has been shown to better condition the digester microbiology for overloading events. Additionally, IF is required when AD facilities move toward being active players in grid balancing via on-demand delivery and storage of green energy (i.e., power-to-gas). In this study, six laboratory-scale IF digesters were operated at 34, 37, and 40 degrees C in a 300-day experiment to determine the impact of temperature on methane yield and long-term stability at typical conditions for conventional WWTP sludge digestion. The results show that IF led to no significant differences in methane yield observed among tested temperatures at an organic loading rate of 3 kg VS m(-3) days(-1) and a hydraulic retention time of 16 days. However, in an on-demand energy-delivery scenario, increased temperature could be interesting because of significantly increased methane production in the first hours following feeding. (C) 2017 American Society of Civil Engineers.

Keywords

Anaerobic digestion; Mesophilic; Temperature; Primary sludge; Energy optimization; Intermittent feeding

Published in

Journal of Environmental Engineering
2018, volume: 144, number: 1, article number: 04017085
Publisher: ASCE-AMER SOC CIVIL ENGINEERS

SLU Authors

• Nordberg, Åke

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

Global goals (SDG)

SDG6 Clean water and sanitation

UKÄ Subject classification

Water Treatment

Publication identifier

• DOI: https://doi.org/10.1061/(ASCE)EE.1943-7870.0001301

Permanent link to this page (URI)

https://res.slu.se/id/publ/93289