Successful Application of High-Rate Clarification, UF, GAC and Ion Exchange Technologies to Meet Stringent NPDES Permit Limits for Stormwater Overflows

An industrial complex located on Ventura County, California requires to provide adequate treatment to stormwater overflows originated during heavy rain events, when. These stormwater overflows occur when the storage capacity of a series of ponds located at the site is exceeded, and the stormwater is discharged into receiving streams. This operation is subject to stringent permits that limit the concentration of a series of constituents, including heavy metals and trace organics. Treatment using conventional filtration, granular activated carbon, and ion exchange was not successful, since the target constituents were found to attach strongly to particles of small size that passed through the filters. However, when other processes such as high rate clarification and ultrafiltration were incorporated into the treatment train, the constituents were successfully removed at levels that met the permit limits.