Dewaterability of Anaerobic Digested Sludge with Cations and Chitosan as Dual Conditioners

  • S. W. Lau
  • S. H. Chong
  • H. M. Ang
  • T. K. Sen
  • H. B. Chua


Anaerobic digested sludge dewatering is very important in sludge management and disposal. In this study, flocculation and dewatering behaviour of anaerobic digested sludge were investigated using metal cations (sodium, magnesium, calcium, ferric and aluminium salts) and chitosan as dual conditioners. The trivalent ferric and aluminium ions were found to be more effective than the monovalent and divalent cations in improving sludge dewaterability as measured by capillary suction time (CST). Post-addition of chitosan into the sludge pre-coagulated with metal cations further enhanced the sludge dewaterability. This study suggests that pre-destabilisation of sludge by coagulation with metal cations followed by chitosan addition as polymeric flocculant may improve the dewaterability of anaerobic digested sludge.


Total Dissolve Solid Extracellular Polymeric Substance Sludge Sample High Molecular Weight Polymer Anaerobic Digested Sludge 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The authors would like to acknowledge Physics Department at Curtin Perth for the image analysis. Dominique Dodge-Wan proofreads this chapter.


  1. APHA (2005). Standard methods for the examination of water and wastewater. 21st edn. Washington, DC, American Public Health Association, American Water Works Association, and Water Environment Federation.Google Scholar
  2. Ayol, A. (2005). Enzymatic treatment effects on dewaterability of anaerobically digested biosolids-I: Performance evaluations. Process Biochemistry, 40(7), 2427–2434.CrossRefGoogle Scholar
  3. Chen, Y. G., Yang, H. Z., & Gu, G. W. (2001). Effect of acid and surfactant treatment on activated sludge dewatering and settling. Water Research, 35(11), 2615–2620.PubMedCrossRefGoogle Scholar
  4. Chitikela, S., & Dentel, S. K. (1998). Dual-chemical conditioning and dewatering of anaerobically digested biosolids: Laboratory evaluations. Water Environment Research, 70(5), 1062–1069.CrossRefGoogle Scholar
  5. CST Equipment Manual (1998). Essex: Triton Electronics Ltd.Google Scholar
  6. Dentel, S. K. (2010). Chemical conditioning for solid-liquid separation processes. Drying Technology, 28(7), 843–849.CrossRefGoogle Scholar
  7. Fu, J., Jiang, B., & Cai, W. (2009). Effect of synthetic cationic surfactants on dewaterability and settleability of activated sludge. International Journal of Environment and Pollution, 37(1), 113–131.CrossRefGoogle Scholar
  8. Hogg, R. (1999). The role of polymer adsorption kinetics in flocculation. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 146, 253–263.CrossRefGoogle Scholar
  9. Mikkelsen, L. H., & Keiding, K. (2002). Physico-chemical characteristics of full scale sewage sludges with implications to dewatering. Water Research, 36, 2451–2462.PubMedCrossRefGoogle Scholar
  10. Ozkan, A., & Yekeler, M. (2004). Coagulation and flocculation characteristics of celestite with different inorganic salts and polymers. Chemical Engineering and Processing: Process Intensification, 43(7), 873–879.CrossRefGoogle Scholar
  11. Pevere, A., Guibaud, G., van Hullebusch, E. D., Boughzala, W., & Lens, P. N. L. (2007). Effect of Na+ and Ca2+ on the aggregation properties of sieved anaerobic granular sludge. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 306, 142–149.CrossRefGoogle Scholar
  12. Renault, F., Sancey, B., Badot, P. M., & Crini, G. (2009). Chitosan for coagulation/flocculation processes—an eco-friendly approach. European Polymer Journal, 45(5), 1337–1348.CrossRefGoogle Scholar
  13. Rose, G. R. & ST. John, M. R. (2010). Encyclopedia of polymer science and technology. (2nd edn., Vol 7. pp. 211–233). Nalco Chemical Company.Google Scholar
  14. Sanin, F. D., Vatansever, A., Turtin, I., Kara, F. & Durmaz, B. (2006). Operational conditions of activated sludge: Influence on flocculation and dewaterability. Drying Technology 24(10), 1297–1306.Google Scholar
  15. Saveyn, H., Meersseman, S., Thas, O., & van der Meeren, P. (2005). Influence of polyelectrolyte characteristics on pressure-driven activated sludge dewatering. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 262, 40–51.CrossRefGoogle Scholar
  16. Spellman, F. R. (2003). Handbook of water and wastewater treatment plant operations. London: Lewis Publishers.CrossRefGoogle Scholar
  17. Turovskiy, I. S. & Mathai, P. K. (2006). Wastewater sludge processing. New Jersey: Wiley.Google Scholar

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • S. W. Lau
    • 1
  • S. H. Chong
    • 2
  • H. M. Ang
    • 2
  • T. K. Sen
    • 2
  • H. B. Chua
    • 1
  1. 1.Department of Chemical Engineering, School of Engineering and ScienceCurtin University Sarawak MalaysiaMiriMalaysia
  2. 2.Department of Chemical Engineering, Faculty of Science and Engineering, School of Chemical and Petroleum EngineeringCurtin UniversityPerthAustralia

Personalised recommendations