Pretreatment of wastewater: Optimal coagulant selection using Partial Order Scaling Analysis (POSA)

Eran Tzfati, Maya Sein, Angelika Rubinov, Adi Raveh, Amos Bick

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Jar-test is a well-known tool for chemical selection for physical-chemical wastewater treatment. Jar test results show the treatment efficiency in terms of suspended matter and organic matter removal. However, in spite of having all these results, coagulant selection is not an easy task because one coagulant can remove efficiently the suspended solids but at the same time increase the conductivity. This makes the final selection of coagulants very dependent on the relative importance assigned to each measured parameter. In this paper, the use of Partial Order Scaling Analysis (POSA) and multi-criteria decision analysis is proposed to help the selection of the coagulant and its concentration in a sequencing batch reactor (SBR). Therefore, starting from the parameters fixed by the jar-test results, these techniques will allow to weight these parameters, according to the judgments of wastewater experts, and to establish priorities among coagulants. An evaluation of two commonly used coagulation/flocculation aids (Alum and Ferric Chloride) was conducted and based on jar tests and POSA model, Ferric Chloride (100. ppm) was the best choice. The results obtained show that POSA and multi-criteria techniques are useful tools to select the optimal chemicals for the physical-technical treatment.

Original languageEnglish
Pages (from-to)51-59
Number of pages9
JournalJournal of Hazardous Materials
Issue number1-3
StatePublished - 15 Jun 2011
Externally publishedYes


  • Coagulation
  • Jar test
  • Management modeling
  • Multi-criteria decision
  • Partial order analysis
  • Treatment selection

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis


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