Last reviewed: September 2026
Ferric sulfate is an iron-based inorganic coagulant used to help destabilize suspended and colloidal material in water. During treatment, ferric species hydrolyze and form ferric hydroxide floc that can capture particles for clarification and filtration.
Ferric Sulfate
Ferric Sulfate Coagulation and Process Control
Common applications
- Coagulation and floc formation in drinking water treatment
- Clarification and solids removal in wastewater and industrial systems
- Process programs where iron-based coagulation is suited to the raw-water chemistry
Process and handling considerations
Ferric sulfate performance is influenced by pH, alkalinity, temperature, raw-water quality, mixing, settling, and filtration conditions. Coagulant addition can consume alkalinity and affect pH, while the resulting floc contributes to residuals and sludge volume. Jar testing and plant monitoring should be used to establish and refine the feed rate for a specific treatment train.
Compare ferric sulfate and aluminum sulfate for coagulation.
Contact WSU about ferric sulfate availability and delivery.
Source: U.S. EPA, Water Treatment Plant Model Version 2.0 User’s Manual.
