Enhanced coagulation for satisfying the arsenic maximum contaminant level under variable and uncertain conditions

Dominic L. Boccelli, Mitchell J. Small, David A. Dzombak

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


This study evaluated the effects of influent variability and model parameter uncertainty when utilizing enhanced coagulation modification to bring existing treatment plants into compliance with a stricter arsenic regulation. Enhanced coagulation modification options include: (1) increased ferric chloride dose, (2) addition of an acid dose, and (3) a combination of the individual options. Arsenic removal is described by adsorption to hydrous ferric oxide with a surface complexation model and subsequent removal through sedimentation and filtration. The least-cost modification for reliably satisfying the arsenic regulation is determined using an optimization algorithm that explicitly includes variability and uncertainty. The ferric chloride only modification is always the least-cost treatment modification. The ferric chloride and acid modification could be the least-cost option when considering waste handling processes due to a tradeoff between modification cost and sludge production. By inclusion of variability and uncertainty, the relative importance of individual parameter distributions for determining whether the arsenic regulation is reliably satisfied is assessed. Influent arsenic concentration variability is always critical, while variability in the influent pH and sulfate concentrations and uncertainty in the filter removal efficiency and equilibrium adsorption constant for the ≡FesOHCa2+ surface species are critical or important, depending on influent conditions.

Original languageEnglish (US)
Pages (from-to)6501-6507
Number of pages7
JournalEnvironmental Science and Technology
Issue number17
StatePublished - Sep 1 2005
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry


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