Synthetic sludge: A physical/chemical model in understanding bioflocculation

Sanin F. D. , Vesilind P.

WATER ENVIRONMENT RESEARCH, vol.68, no.5, pp.927-933, 1996 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 68 Issue: 5
  • Publication Date: 1996
  • Doi Number: 10.2175/106143096x127938
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.927-933
  • Keywords: alginate, sludge, bioflocculation, calcium, extracellular polymers, ACTIVATED-SLUDGE, FLOCCULATION, POLYMERS


We postulate a mechanism for flee formation and demonstrate its feasibility by building synthetic sludge flocs. In this work, polystyrene latex particles of a size similar to bacteria are used to simulate individual bacteria; alginate, a polysaccharide, is used to simulate microbial extracellular polymers; and calcium ions are used as the bridging cations. Calcium and alginate are added at typical concentration ranges relative to the amount of microorganisms existing iii wastewater treatment biological sludges. Flocs are formed almost instantly by the addition of calcium ions and are observed to be remarkably similar to the activated sludge flocs in physical appearance. Roc formation is faster at higher calcium concentrations. Higher alginate and calcium concentrations always ensure lower turbidities indicating better flee forming abilities.