Pilot plant evaluation of PFS from coal-fired power plant waste

Pilot plant studies were conducted to evaluate the performance of a polymeric ferric sulfate (PFS) coagulant synthesized from waste SO2. Aluminum sulfate (alum), ferric sulfate and ferric chloride were compared with PFS. Preliminary jar tests were performed to determine coagulant dose range and expected turbidity removal. The studies were conducted at the City of Savannah Industrial and Domestic (I&D) Water Treatment Plant in Port Wentworth, GA. The raw water source, a tributary of the Savannah River, was high in organic content. Due to its proximity to the coast, the tributary is tidally affected resulting in continuous water quality changes. Of the three iron-based coagulants tested, all provided nearly 10% greater reductions in total organic carbon when compared to alum. The pH ranges using the iron-based coagulants were much lower than those experienced with alum. Turbidity removal was approximately 100% for all coagulants. Ferric sulfate required the highest average dosage for proper coagulation/flocculation with efficient turbidity removal at 110 ppm. The performance of the PFS was comparable to that of ferric sulfate.