Characteristics of a solid carbonaceous product of microwave torrefaction of sewage sludge

article in a collection out of WoS and Scopus

English

The aim of this work is to present results of characterization of the dried sewage sludge (SS) and produced solid carbonaceous product (SCP) of microwave torrefaction (MT) for combustion energy and agricultural use. The tests reflected several variables influencing pyrolysis such as mixing SS with additives, pelletization process, pyrolysis residence time, process temperature and parameters such as yield of SCP, yield of pyrolysis oil, yield of pyrolysis gas, content of heavy metals (HMs), calorific value, Corg, pH, EC, and SBET. The product of pretreatment is feedstock (FS) for MT process which can directly be used for energy or agricultural use. Mixing and pelletizing process improve the FS qualitative parameters for the certification of solid alternative fuel and the subsequent certification of biochar or the soil amendment substances. For certification of biochar or soil amendment substances, it is necessary to prepare mix of raw dried SS with additives to improve the feedstock qualitative parameters for the subsequent certification of biochar/soil amendment substances to increase organic matter or to improve other properties such as Corg, SBET etc. We conclude that slow MT with SCP represents an eco-friendly way of SS disposal, which belongs among the important strategies of circular economy.

sludge management, microwave torrefaction, sewage sludge, solid carbonaceous product

RAČEK, J.; CHORAZY, T.; KOMENDOVÁ, R.; KUČERÍK, J.; HLAVÍNEK, P.

26. 6. 2019

National Technical University of Athens, School of Chemical Engineering, Unit of Environmental Science & Technology

Athens, Greece

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