Evaluation of different types of anaerobic seed sludge for the high rate anaerobic digestion of pig slurry in UASB reactors

Carlos Rico; Jesús A Montes; José Luis Rico

doi:10.1016/j.biortech.2017.04.014

Evaluation of different types of anaerobic seed sludge for the high rate anaerobic digestion of pig slurry in UASB reactors

Bioresour Technol. 2017 Aug:238:147-156. doi: 10.1016/j.biortech.2017.04.014. Epub 2017 Apr 7.

Authors

Carlos Rico¹, Jesús A Montes², José Luis Rico³

Affiliations

¹ Department of Water and Environmental Science and Technologies, University of Cantabria, Avda. Los Castros, s/n, 39005 Santander, Spain. Electronic address: ricoc@unican.es.
² Department of Water and Environmental Science and Technologies, University of Cantabria, Avda. Los Castros, s/n, 39005 Santander, Spain.
³ Department of Chemical and Process Engineering Resources, University of Cantabria, Avda. Los Castros, s/n, 39005 Santander, Spain.

PMID: 28433902
DOI: 10.1016/j.biortech.2017.04.014

Abstract

Three different types of anaerobic sludge (granular, thickened digestate and anaerobic sewage) were evaluated as seed inoculum sources for the high rate anaerobic digestion of pig slurry in UASB reactors. Granular sludge performance was optimal, allowing a high efficiency process yielding a volumetric methane production rate of 4.1LCH₄L^-1d^-1 at 1.5days HRT (0.248LCH₄g^-1COD) at an organic loading rate of 16.4gCODL^-1d^-1. The thickened digestate sludge experimented flotation problems, thus resulting inappropriate for the UASB process. The anaerobic sewage sludge reactor experimented biomass wash-out, but allowed high process efficiency operation at 3days HRT, yielding a volumetric methane production rate of 1.7LCH₄L^-1d^-1 (0.236LCH₄g^-1COD) at an organic loading rate of 7.2gCODL^-1d^-1. To guarantee the success of the UASB process, the settleable solids of the slurry must be previously removed.

Keywords: Anaerobic sewage sludge; Granular sludge; Supernatant; Thickened digestate; Volumetric methane production rate.

MeSH terms

Anaerobiosis
Animals
Bioreactors*
Digestion
Methane*
Sewage*
Swine

Substances

Sewage
Methane