Process water properties from hydrothermal carbonization of chemical sludge from a pulp and board mill

Mikko Mäkelä; Julia Forsberg; Christer Söderberg; Sylvia H Larsson; Olli Dahl

doi:10.1016/j.biortech.2018.05.044

Process water properties from hydrothermal carbonization of chemical sludge from a pulp and board mill

Bioresour Technol. 2018 Sep:263:654-659. doi: 10.1016/j.biortech.2018.05.044.

Authors

Mikko Mäkelä¹, Julia Forsberg², Christer Söderberg³, Sylvia H Larsson⁴, Olli Dahl⁵

Affiliations

¹ Aalto University, School of Chemical Engineering, Department of Bioproducts and Biosystems, PO Box 11000, 00076 Aalto, Finland; Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, Division of Biomass Technology and Chemistry, Skogsmarksgränd, 90183 Umeå, Sweden. Electronic address: mikko.makela@aalto.fi.
² RISE Processum AB, Hörneborgsvägen 10, 89122 Örnsköldsvik, Sweden.
³ Iggesund Paperboard AB, Iggesund Mill, Development Department, PO Box 15, 82580 Iggesund, Sweden.
⁴ Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, Division of Biomass Technology and Chemistry, Skogsmarksgränd, 90183 Umeå, Sweden.
⁵ Aalto University, School of Chemical Engineering, Department of Bioproducts and Biosystems, PO Box 11000, 00076 Aalto, Finland.

PMID: 29776721
DOI: 10.1016/j.biortech.2018.05.044

Abstract

Hydrothermal carbonization (HTC) can be used to break down sludge structure and generate carbonaceous hydrochar suitable for solid fuel or value-added material applications. The separation of char and the reaction medium however generates a filtrate, which needs to treated before potential discharge. Thus, this work determined filtrate properties based on HTC temperature and sludge moisture content and estimated the discharge emissions and the potential increase in analyte loads to an industrial wastewater treatment plant based on derived regression models. Direct discharge of HTC filtrate would significantly increase effluent emissions at the mill, indicating the filtrate treatment is crucial for the future implementation of HTC at pulp and paper mills. Recycling the HTC filtrate to the wastewater plant would lead to only a nominal increase in effluent flow, but would increase the suspended solids, BOD, COD and total nitrogen loads by 0.1-0.8%, 3.8-5.3%, 2.7-3.1% and 42-67%, respectively, depending on HTC temperature.

Keywords: Biosolids; Experimental design; Hydrothermal treatment; Multiple linear regression; Principal component analysis; Wastewater treatment.

MeSH terms

Carbon / chemistry*
Industrial Waste
Refuse Disposal*
Temperature
Wastewater
Water

Substances

Industrial Waste
Waste Water
Water
Carbon