FULL-SCALE TESTING OF THE FIRST SSO BALLASTED FLOCCULATION SYSTEM

The Lawrence Wastewater Treatment Plant (WWTP) is being expanded and improved to accommodate the City of Lawrence, Kansas, future growth, maintain compliance with new regulatory requirements, and meet facility needs up through the design year 2020. To accommodate future projected storm flows or sanitary sewer overflows (SSO), an excess flow facilities consisting of a 40-mgd ballasted flocculation system will be constructed to be directly discharge to the Kansas River. During the full-scale testing of the ballasted flocculation system, several testing issues had to be resolved, including the development of a simulated storm flow for testing, which was 2.5 times greater than the normal plant flow. The peak flow was generated while maintaining a small flow to the existing plant process. During the optimization and process performance test, foam was generated at the plant's outfall, which discharged into the Kansas River casuing the testing to be halted. The foam was a result of the operation of the ballasted flocculation facilities and surfactants within Lawrence wastewater flow. This presentation will provide details on the development of the flow to the SSO facility for testing and the resolution of foaming issues associated with the operation of the excess flow facilities.