Influence analysis for the behavior of dewaterability of excess sludge in a two-stage vermifilter

To improve excess sludge dewaterability, a two-stage vermifilter was developed to qualitatively and quantitatively analyze sludge physico-chemical properties (fractal dimension, zeta potential, extracellular polymeric substances (EPS), particle size distribution, etc.) and to correlate them with slu...

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Veröffentlicht in:Applied microbiology and biotechnology 2017-02, Vol.101 (4), p.1643-1652
Hauptverfasser: Xing, Meiyan, Li, Cenran, Jiang, Jinzhou, Wang, Yin, Yang, Jian
Format: Artikel
Sprache:eng
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Zusammenfassung:To improve excess sludge dewaterability, a two-stage vermifilter was developed to qualitatively and quantitatively analyze sludge physico-chemical properties (fractal dimension, zeta potential, extracellular polymeric substances (EPS), particle size distribution, etc.) and to correlate them with sludge dewatering characteristics (specific resistance to filtration (SRF) and capillary suction time (CST)). Results demonstrated that sludge dewatering performance was significantly improved after the primary vermifilter VF 1 and the second-stage vermifilter VF 2 . In addition, the further VF 2 treatment exhibited higher effects on sludge dewatering performance. The particle boundary of sludge after VF 2 treatment was clearer and smoother than VF 1 sludge (VF 1 S), apart from the fact that sludge morphological structure got denser and more compact. Comparing with VF 1 S, the fractal dimension D 1 calculated within 1D topological space was closer to 1 after VF 2 treatment, and the fractal dimension D 2 within 2D topological space closer to 2, indicating a better dewatering performance after VF 2 treatment. Additionally, the changes of sludge floc surface properties (such as zeta potential and EPS) resulted in small particles agglomerating into larger ones and then the increase of particle diameter. In summary, the two-stage vermifilter got a better sludge dewatering performance, and thus beneficial for subsequent processing of sludge.
ISSN:0175-7598
1432-0614
DOI:10.1007/s00253-016-7920-y