High-rate anaerobic co-digestion of kraft mill fibre sludge and activated sludge by CSTRs with sludge recirculation

Eva-Maria Ekstrand; Marielle Karlsson; Xu-Bin Truong; Annika Björn; Anna Karlsson; Bo H Svensson; Jörgen Ejlertsson

doi:10.1016/j.wasman.2016.06.034

High-rate anaerobic co-digestion of kraft mill fibre sludge and activated sludge by CSTRs with sludge recirculation

Waste Manag. 2016 Oct:56:166-72. doi: 10.1016/j.wasman.2016.06.034. Epub 2016 Jul 21.

Authors

Eva-Maria Ekstrand¹, Marielle Karlsson², Xu-Bin Truong³, Annika Björn⁴, Anna Karlsson⁵, Bo H Svensson⁶, Jörgen Ejlertsson⁷

Affiliations

¹ Department of Thematic Studies, Environmental Change, Linköping University, 581 83 Linköping, Sweden. Electronic address: eva-maria.ekstrand@liu.se.
² Scandinavian Biogas Fuels AB, Holländargatan 21A, 111 60 Stockholm, Sweden. Electronic address: marielle.karlsson@scandinavianbiogas.com.
³ Scandinavian Biogas Fuels AB, Holländargatan 21A, 111 60 Stockholm, Sweden. Electronic address: xubin.truong@scandinavianbiogas.com.
⁴ Department of Thematic Studies, Environmental Change, Linköping University, 581 83 Linköping, Sweden. Electronic address: annika.bjorn@liu.se.
⁵ Scandinavian Biogas Fuels AB, Holländargatan 21A, 111 60 Stockholm, Sweden. Electronic address: anna.karlsson@scandinavianbiogas.com.
⁶ Department of Thematic Studies, Environmental Change, Linköping University, 581 83 Linköping, Sweden. Electronic address: bo.svensson@liu.se.
⁷ Department of Thematic Studies, Environmental Change, Linköping University, 581 83 Linköping, Sweden; Scandinavian Biogas Fuels AB, Holländargatan 21A, 111 60 Stockholm, Sweden. Electronic address: jorgen.ejlertsson@scandinavianbiogas.com.

PMID: 27453288
DOI: 10.1016/j.wasman.2016.06.034

Abstract

Kraft fibre sludge from the pulp and paper industry constitutes a new, widely available substrate for the biogas production industry, with high methane potential. In this study, anaerobic digestion of kraft fibre sludge was examined by applying continuously stirred tank reactors (CSTR) with sludge recirculation. Two lab-scale reactors (4L) were run for 800days, one on fibre sludge (R1), and the other on fibre sludge and activated sludge (R2). Additions of Mg, K and S stabilized reactor performance. Furthermore, the Ca:Mg ratio was important, and a stable process was achieved at a ratio below 16:1. Foaming was abated by short but frequent mixing. Co-digestion of fibre sludge and activated sludge resulted in more robust conditions, and high-rate operation at stable conditions was achieved at an organic loading rate of 4g volatile solids (VS)L(-1)day(-1), a hydraulic retention time of 4days and a methane production of 230±10NmL per g VS.

Keywords: Activated sludge; Anaerobic digestion; Fibre sludge; High-rate CSTR; Pulp and paper; Sludge recirculation.

MeSH terms

Anaerobiosis
Bioreactors*
Industrial Waste / analysis*
Paper
Waste Disposal, Fluid / methods*

Substances

Industrial Waste