Chemical Treatment Systems

Description
Chemical treatment involves adding chemicals to improve the treatment of target constituents. The key treatment processes are either sedimentation or disinfection, depending on the chemical added. Addition of coagulants stimulates floc formation, which increases the settling velocity of particles, and improves sedimentation. The primary constituents removed by the addition of coagulants are total suspended solids (TSS), total nitrogen and phosphorus, total and dissolved metals, microbiological constituents, and litter. The addition of other chemicals, such as hypochlorous acid (liquid form) or ozone (gaseous form), can disinfect stormwater by inactivating microbiological constituents.

Experience
Caltrans Tahoe Basin Small-Scale Pilot Studies – Chemical Treatment
Caltrans Small-Scale Studies on Low-Intensity Chemical Dosing (LICD) for Treatment of Highway Runoff
Caltrans Aquatic Toxicity Testing
Caltrans Disinfection Reconnaissance Study