University of Oulu

Vali N, Combres A, Hosseinian A, Pettersson A. The Effect of the Elemental Composition of Municipal Sewage Sludge on the Phosphorus Recycling during Pyrolysis, with a Focus on the Char Chemistry—Modeling and Experiments. Separations. 2023; 10(1):31.

The effect of the elemental composition of municipal sewage sludge on the phosphorus recycling during pyrolysis, with a focus on the char chemistry : modeling and experiments

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Author: Vali, Naeimeh1; Combres, Aurélie1; Hosseinian, Aida2;
Organizations: 1Swedish Centre for Resource Recovery, University of Borås, 501 90 Borås, Sweden
2Water, Energy and Environmental Engineering Research Unit, Faculty of Technology, University of Oulu, 90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 6.3 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2023
Publish Date: 2023-02-28


The present study investigates how the original sewage sludge characteristics influence the composition of sewage sludge-based chars for land applications. Sewage sludge from two different wastewater treatment plants in Sweden was pyrolyzed at 500, 700, and 900 °C, and the resulting chars were analyzed. Thermodynamic equilibrium calculations (TEC), together with chemical fractionation, were implemented to simulate the char after the pyrolysis process at different temperatures. The results showed that, in general, for both the municipal sewage sludge (MSS), phosphorus (P) was significantly retained in the char at various temperatures. However, no specific correlation could be found between the pyrolysis temperature and the amount of P remaining. With regard to the heavy metals removed from the char after the pyrolysis reaction, the concentrations of copper, chromium, lead, nickel, zinc, and cadmium were below the limits of the Swedish regulations for farmland application.

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Series: Separations
ISSN: 2297-8739
ISSN-E: 2297-8739
ISSN-L: 2297-8739
Volume: 10
Issue: 1
Article number: 31
DOI: 10.3390/separations10010031
Type of Publication: A1 Journal article – refereed
Field of Science: 218 Environmental engineering
116 Chemical sciences
Copyright information: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (