TY - JOUR
T1 - Changes imposed by pyrolysis, thermal gasification and incineration on composition and phosphorus fertilizer quality of municipal sewage sludge
AU - Thomsen, Tobias Pape
AU - Sárossy, Zsuzsa
AU - Ahrenfeldt, Jesper
AU - Henriksen, Ulrik B
AU - Frandsen, Flemming J
AU - Müller-Stöver, Dorette Sophie
N1 - Copyright © 2017 Elsevier Ltd. All rights reserved.
PY - 2017/8/1
Y1 - 2017/8/1
N2 - Fertilizer quality of ash and char from incineration, gasification and pyrolysis of a single municipal sewage sludge sample were investigated by comparing composition and phosphorus (P) plant availability. A process for post oxidation of gasification ash and pyrolysis char was developed and the oxidized materials were investigated as well. Sequential extraction with full elemental balances of the extracted pools as well as scanning electron microscopy with energy dispersive X-ray spectroscopy were used to investigate the mechanisms driving the observed differences in composition and P plant availability in a short-term soil incubation study. The compositional changes related mainly to differences in the proximate composition as well as to the release of especially nitrogen, sulfur, cadmium and to some extent, phosphorus (P). The cadmium load per unit of P was reduced with 75-85% in gasification processes and 10-15% in pyrolysis whereas no reduction was observed in incineration processes. The influence on other heavy metals was less pronounced. The plant availability of P in the substrates varied from almost zero to almost 100% of the plant availability of P in the untreated sludge. Post-oxidized slow pyrolysis char was found to be the substrate with the highest P fertilizer value while ash from commercial fluid bed sludge incineration had the lowest P fertilizer quality. The high P fertilizer value in the best substrate is suggested to be a function of several different mechanisms including structural surface changes and improvements in the association of P to especially magnesium, calcium and aluminum.
AB - Fertilizer quality of ash and char from incineration, gasification and pyrolysis of a single municipal sewage sludge sample were investigated by comparing composition and phosphorus (P) plant availability. A process for post oxidation of gasification ash and pyrolysis char was developed and the oxidized materials were investigated as well. Sequential extraction with full elemental balances of the extracted pools as well as scanning electron microscopy with energy dispersive X-ray spectroscopy were used to investigate the mechanisms driving the observed differences in composition and P plant availability in a short-term soil incubation study. The compositional changes related mainly to differences in the proximate composition as well as to the release of especially nitrogen, sulfur, cadmium and to some extent, phosphorus (P). The cadmium load per unit of P was reduced with 75-85% in gasification processes and 10-15% in pyrolysis whereas no reduction was observed in incineration processes. The influence on other heavy metals was less pronounced. The plant availability of P in the substrates varied from almost zero to almost 100% of the plant availability of P in the untreated sludge. Post-oxidized slow pyrolysis char was found to be the substrate with the highest P fertilizer value while ash from commercial fluid bed sludge incineration had the lowest P fertilizer quality. The high P fertilizer value in the best substrate is suggested to be a function of several different mechanisms including structural surface changes and improvements in the association of P to especially magnesium, calcium and aluminum.
KW - Journal Article
U2 - 10.1016/j.jenvman.2017.04.072
DO - 10.1016/j.jenvman.2017.04.072
M3 - Journal article
C2 - 28478348
SN - 0301-4797
VL - 198
SP - 308
EP - 318
JO - Journal of Environmental Management
JF - Journal of Environmental Management
IS - Part 1
ER -
