Influence of the operating conditions of the intermediate thermal hydrolysis on the energetic efficiency of the sludge treatment process

Israel Díaz; Alina Díaz-Curbelo; Kevin Ignacio Matute; María Fdz-Polanco; Sara Isabel Pérez-Elvira

doi:10.1016/j.biortech.2021.125114

Influence of the operating conditions of the intermediate thermal hydrolysis on the energetic efficiency of the sludge treatment process

Bioresour Technol. 2021 Aug:333:125114. doi: 10.1016/j.biortech.2021.125114. Epub 2021 Apr 6.

Authors

Israel Díaz¹, Alina Díaz-Curbelo¹, Kevin Ignacio Matute¹, María Fdz-Polanco¹, Sara Isabel Pérez-Elvira²

Affiliations

¹ Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain.
² Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain. Electronic address: sarape@iq.uva.es.

PMID: 33894446
DOI: 10.1016/j.biortech.2021.125114

Abstract

The application of steam explosion between two stages of anaerobic digestion may improve energy recovery from sludge while increasing organic matter removal. The influence of the operating conditions of the thermal process: temperature (130-210 °C), retention time (5-45 min) and TS concentration (5.4-10.8%), on the efficiency of VS removal, the biochemical methane potential of hydrolysed sludge and the kinetic constant of the degradation were evaluated using a Taguchi design. Increasing temperature and time increased the removal of VS and the potential of methane production but the kinetic constant was higher at lower temperatures. An optimal operating scheme was found at 170 °C (6 barg), 25 min at the greatest TS concentration in the feeding. Under such conditions, the thermal energy obtained from biogas combustion in a CHP covered the requirements for vapour generation and a profit of 3.54 € m^-3 of sludge was estimated.

Keywords: High solids digestion; Intermediate thermal hydrolysis; Sludge treatment; Techno-economic analysis; Wastewater treatment plant.

MeSH terms

Anaerobiosis
Biofuels
Bioreactors
Hydrolysis
Methane*
Sewage*
Waste Disposal, Fluid

Substances

Biofuels
Sewage
Methane