Surfactant-mediated settleability and dewaterability of activated sludge

The activated sludge process is widely used for wastewater treatment, and the settleability and dewaterability of activated sludge are crucial to the operation of wastewater treatment plants. In this study the surfactant-mediated settleability and dewaterability of activated sludge were investigated...

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Bibliographic Details
Published in:Chemical engineering science 2014-09, Vol.116, p.228-234
Main Authors: Wang, Long-Fei, Wang, Ling-Ling, Li, Wen-Wei, He, Dong-Qin, Jiang, Hong, Ye, Xiao-Dong, Yuan, Hai-Ping, Zhu, Nan-Wen, Yu, Han-Qing
Format: Article
Language:English
Subjects:
Activated sludge
Dewaterability
Dewatering (separation process)
Dosage
EPS
Extracellular polymeric substances (EPS)
Laser light scattering
Settleability
Sludge
Sodium dodecyl sulfate
Surfactant
Surfactants
Wastewater treatment
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Summary:The activated sludge process is widely used for wastewater treatment, and the settleability and dewaterability of activated sludge are crucial to the operation of wastewater treatment plants. In this study the surfactant-mediated settleability and dewaterability of activated sludge were investigated. It is found that dose of anionic surfactant sodium dodecyl sulfate (SDS) caused substantial release of extracellular polymer substances (EPS), especially proteins, from sludge. Laser light scattering (LLS) results reveal that the released EPS became stretched and more expanded when the SDS dosage was increased. The sludge dewaterability was significantly deteriorated at a dosage of 2.084g/L SDS, and meanwhile the capillary suction time (CST) and specific resistance of filtration (SRF) increased by 6.3 and 5.1 times, respectively, than the raw sludge. The correlations between the EPS contents and the sludge properties, i.e., CST, SRF, moisture content of filter-cake and sludge volume index, were evaluated and the significant roles of proteins in governing the EPS properties as well as the settleability and dewaterability of sludge were further confirmed. This study elucidates how the settleability and dewaterability of activated sludge were affected by surfactants via changing the properties and structure of the released EPS from sludge. [Display omitted] •The impact of SDS on the settleability and dewaterability of activated sludge was investigated.•Dose of anionic SDS caused a significant deterioration in settleability and dewaterability of sludge.•The mechanism for the SDS-induced settleability and dewaterability of activated sludge was clearly elucidated.
ISSN:0009-2509
1873-4405
DOI:10.1016/j.ces.2014.05.014