Conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis

In this study, the conditioning effect of cationic polyacrylamide (CPAM) with different charge densities on raw sludge (RS) and thermo-hydrolyzed sludge (HS) pretreated with or without ferric salt is studied through orthogonal experiments. In addition, this paper uses the principles of rheology and...

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Autores principales:	Liqiang Duan, Zhen Zhou, Xiaohu Dai
Formato:	article
Lenguaje:	EN
Publicado:	IWA Publishing 2021
Materias:	cationic polyacrylamide dewatering performance morphological orthogonal experiments thermal hydrolysis Environmental technology. Sanitary engineering TD1-1066
Acceso en línea:	https://doaj.org/article/57727f6b434f49f788ce9c5aa5406f9c
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spelling	oai:doaj.org-article:57727f6b434f49f788ce9c5aa5406f9c2021-11-06T10:54:07ZConditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis0273-12231996-973210.2166/wst.2021.051https://doaj.org/article/57727f6b434f49f788ce9c5aa5406f9c2021-04-01T00:00:00Zhttp://wst.iwaponline.com/content/83/7/1566https://doaj.org/toc/0273-1223https://doaj.org/toc/1996-9732In this study, the conditioning effect of cationic polyacrylamide (CPAM) with different charge densities on raw sludge (RS) and thermo-hydrolyzed sludge (HS) pretreated with or without ferric salt is studied through orthogonal experiments. In addition, this paper uses the principles of rheology and morphology to analyze and clarify the conditioning mechanism of RS and HS, and reveals the mechanism of thermal hydrolysis to improve the dewatering performance of sludge. Compared with the RS, the HS has smaller particle size, better filterability, stronger fluidity and more obvious thixotropy. However, due to the influence of filter pressing time, ferric salt should be added before conditioning. The orthogonal experiment shows that the optimal conditioner is CPAM with charge density of 60, and the specific resistance to filtration and capillary suction time of the adjusted thermo-hydrolyzed sludge are reduced to (1.11 ± 0.07) × 1012 m/kg and 16.1 ± 1.8 s; the particle size increased from 61.2 to 253.5 μm. The moisture content of the sludge cake is about 48%. The structural strength and thixotropy of HS are higher than those of the RS, and can be greatly improved by adding ferric salt. Morphological analysis confirms that thermal hydrolysis can lyse microbial cells in sludge, and the sludge treated with ferric salt will have more porous structure and stronger flocculation strength. HIGHLIGHTS Effects of CPAM on conditioning of raw sludge and thermal hydrolysis sludge were studied.; Thermal hydrolysis treatment will improve sludge dewatering capacity and fluidity.; Ferric salt treatment enhanced structural strength and thixotropy of conditioned thermal hydrolysis sludge.; Rheological analysis can be used as a new tool to reflect the dewatering capacity of sludge.;Liqiang DuanZhen ZhouXiaohu DaiIWA Publishingarticlecationic polyacrylamidedewatering performancemorphologicalorthogonal experimentsthermal hydrolysisEnvironmental technology. Sanitary engineeringTD1-1066ENWater Science and Technology, Vol 83, Iss 7, Pp 1566-1577 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	cationic polyacrylamide dewatering performance morphological orthogonal experiments thermal hydrolysis Environmental technology. Sanitary engineering TD1-1066
spellingShingle	cationic polyacrylamide dewatering performance morphological orthogonal experiments thermal hydrolysis Environmental technology. Sanitary engineering TD1-1066 Liqiang Duan Zhen Zhou Xiaohu Dai Conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis
description	In this study, the conditioning effect of cationic polyacrylamide (CPAM) with different charge densities on raw sludge (RS) and thermo-hydrolyzed sludge (HS) pretreated with or without ferric salt is studied through orthogonal experiments. In addition, this paper uses the principles of rheology and morphology to analyze and clarify the conditioning mechanism of RS and HS, and reveals the mechanism of thermal hydrolysis to improve the dewatering performance of sludge. Compared with the RS, the HS has smaller particle size, better filterability, stronger fluidity and more obvious thixotropy. However, due to the influence of filter pressing time, ferric salt should be added before conditioning. The orthogonal experiment shows that the optimal conditioner is CPAM with charge density of 60, and the specific resistance to filtration and capillary suction time of the adjusted thermo-hydrolyzed sludge are reduced to (1.11 ± 0.07) × 1012 m/kg and 16.1 ± 1.8 s; the particle size increased from 61.2 to 253.5 μm. The moisture content of the sludge cake is about 48%. The structural strength and thixotropy of HS are higher than those of the RS, and can be greatly improved by adding ferric salt. Morphological analysis confirms that thermal hydrolysis can lyse microbial cells in sludge, and the sludge treated with ferric salt will have more porous structure and stronger flocculation strength. HIGHLIGHTS Effects of CPAM on conditioning of raw sludge and thermal hydrolysis sludge were studied.; Thermal hydrolysis treatment will improve sludge dewatering capacity and fluidity.; Ferric salt treatment enhanced structural strength and thixotropy of conditioned thermal hydrolysis sludge.; Rheological analysis can be used as a new tool to reflect the dewatering capacity of sludge.;
format	article
author	Liqiang Duan Zhen Zhou Xiaohu Dai
author_facet	Liqiang Duan Zhen Zhou Xiaohu Dai
author_sort	Liqiang Duan
title	Conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis
title_short	Conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis
title_full	Conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis
title_fullStr	Conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis
title_full_unstemmed	Conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis
title_sort	conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis
publisher	IWA Publishing
publishDate	2021
url	https://doaj.org/article/57727f6b434f49f788ce9c5aa5406f9c
work_keys_str_mv	AT liqiangduan conditioningofrawsludgeandthermallyhydrolyzedsludgebyferricsaltandcationicpolyacrylamiderheologicalanalysis AT zhenzhou conditioningofrawsludgeandthermallyhydrolyzedsludgebyferricsaltandcationicpolyacrylamiderheologicalanalysis AT xiaohudai conditioningofrawsludgeandthermallyhydrolyzedsludgebyferricsaltandcationicpolyacrylamiderheologicalanalysis
_version_	1718443730153766912

Conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis

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