Size and structure effects on centrifugal dewatering of digested sewage sludge
The application of light scattering over small angles for the determination of digested sludge floc size and structure and its relationship with dewaterability is investigated. It appears that improved dewatering corresponds with lower floc fractal dimension (a more open structure) and a smaller pro...
| Publié dans: | Water science and technology : a journal of the International Association on Water Pollution Research. - 1986. - 44(2001), 2-3 vom: 01., Seite 427-35 |
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| Auteur principal: | |
| Autres auteurs: | , |
| Format: | Article |
| Langue: | English |
| Publié: |
2001
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| Accès à la collection: | Water science and technology : a journal of the International Association on Water Pollution Research |
| Sujets: | Journal Article Polymers Sewage Water 059QF0KO0R |
| Résumé: | The application of light scattering over small angles for the determination of digested sludge floc size and structure and its relationship with dewaterability is investigated. It appears that improved dewatering corresponds with lower floc fractal dimension (a more open structure) and a smaller proportion of fine particles. The initial increase in fractal dimension with increasing polymer dose for the digested sludge is most likely due to more efficient aggregation of the finer particles and the resulting formation of denser particle aggregates. A large colloidal fractal of the digested sludge (< 10 microm) appears to be less negative than the bulk digested sludge. This suggests that the fine particles will react differently and possibly less aggressively to the cationic polymer than the larger and more negative particles. The higher negative charge associated with the larger particles might be related to greater levels of highly negatively charged extracellular polysaccharides (EPS) adsorbed to the flocs or could result from the association of FeS with the finer fraction. The appearance of much greater levels of fine particles after digestion suggests that the flocs have undergone disintegration. Whether this is due to reduced biological efficiency within the digestor or iron reduction under the anaerobic conditions is not known for certain, although no indication of prolonged stress in the digesters could be found from plant performance data |
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| Description: | Date Completed 17.01.2002 Date Revised 21.11.2013 published: Print Citation Status MEDLINE |
| ISSN: | 0273-1223 |