Characterization of floc size, strength and structure in various aluminum coagulants treatment

Wang, Yan; Gao, Baoyu; Xu, Xiu-Ming; Xu, Weiying; Xu, Guiying

doi:10.1016/j.jcis.2009.01.002

Cited by 157 publications

(64 citation statements)

References 22 publications

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“…A higher D f normally corresponds to a more compact interior floc structure (Wang et al, 2009). An increased value of S f indicates flocs that are better able to withstand shear and thus should be considered stronger than a floc with lower value.…”

Section: Characterization Of Morphological Properties Of Sludgementioning

confidence: 99%

Wastewater sludge dewaterability enhancement using hydroxyl aluminum conditioning: Role of aluminum speciation

et al. 2016

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a b s t r a c tChemical conditioning is one of the most important processes for improve the performance of sludge dewatering device. Aluminum salt coagulant has been widely used in wastewater and sludge treatment. It is generally accepted that pre-formed speciation of aluminum salt coagulants (ASC) has an important influence on coagulation/flocculation performance. In this study, the interaction mechanisms between sludge particles and aluminum salt coagulants with different speciation of hydroxy aluminum were investigated by characterizing the changes in morphological and EPS properties. It was found that middle polymer state aluminum (Al b ) and high polymer state aluminum (Al c ) performed better than monomer aluminum and oligomeric state aluminum (Al a ) in reduction of specific resistance to filtration (SRF) and compressibility of wastewater sludge due to their higher charge neutralization and formed more compact flocs. Sludge was significantly acidified after addition Al a , while pH was much more stable under Al b and Al c conditioning due to their hydrolysis stability. The size of sludge flocs conditioned with Al b and Al c was small but flocs structure was denser and more compact, and floc strength is higher, while that formed from Al a is relatively large, but floc structure was loose, floc strength is relatively lower. Scanning environmental microscope analysis revealed that sludge flocs conditioned by Al b and Al c (especially PAC 2.5 and Al 13 ) exhibited obvious botryoidal structure, this is because sludge flocs formed by Al b and Al c were more compact and floc strength is high, it was easy generated plentiful tiny channels for water release. In addition, polymeric aluminum salt coagulant (Al b , Al c ) had better performance in compressing extracellular polymeric substances (EPS) structure and removing sticky protein-like substances from soluble EPS fraction, contributing to improvement of sludge filtration performance. Therefore, this study provides a novel solution for improving sludge dewatering property by controlling aluminum speciation.

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Section: Characterization Of Morphological Properties Of Sludgementioning

confidence: 99%

Wastewater sludge dewaterability enhancement using hydroxyl aluminum conditioning: Role of aluminum speciation

et al. 2016

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“…The floc strength is dependent upon the interparticle bonds between the components of the aggregates. As reported by Wang et al (2009), the Al m species can complex with HA to form large and strong flocs while the Al 13 species react with HA to form small and unstable flocs. Those two HAAl flocs can be joined together by adsorption and bridging due to larger polymer and solid-phase Al(OH) 3 , resulting in larger flocs.…”

Section: Floc Formation Breakage and Regrowthmentioning

confidence: 61%

Novel ferromagnetic nanoparticle composited PACls and their coagulation characteristics

Zhang

Xiao

et al. 2012

Water Research

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“…In addition, the inflow and out flow tubes were placed opposite one another at a depth just above the impeller in the holding ports. More detail has been reported in full in other paper [26].…”

Section: On-line Measurement Of Floc Sizementioning

confidence: 94%

Evaluation of enhanced coagulation coupled with magnetic ion exchange (MIEX) in natural organic matter and sulfamethoxazole removals: The role of Al-based coagulant characteristic

Wang

et al. 2016

Separation and Purification Technology

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Characterization of floc size, strength and structure in various aluminum coagulants treatment

Cited by 157 publications

References 22 publications

Wastewater sludge dewaterability enhancement using hydroxyl aluminum conditioning: Role of aluminum speciation

Wastewater sludge dewaterability enhancement using hydroxyl aluminum conditioning: Role of aluminum speciation

Novel ferromagnetic nanoparticle composited PACls and their coagulation characteristics

Evaluation of enhanced coagulation coupled with magnetic ion exchange (MIEX) in natural organic matter and sulfamethoxazole removals: The role of Al-based coagulant characteristic

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