City of Seal Beach Lampson Wellhead Treatment and Sewer Siphon

Seal Beach, CA

PACE was contracted by the City of Seal Beach to evaluate treatment alternatives and provide designs to efficiently reduce H2S concentration levels in the Lampson Water Well. The well is one of the City’s four water wells, capable of providing up to 4,000 gallons per minute to support local water demand. However, the well has historically operated at low flow rates to avoid odor complaints caused by high hydrogen sulfide (H2S) concentration levels, necessitating a solution to allow for more consistent supply.

On-site pilot testing was employed to evaluate the viability of a biological treatment process using granular activated carbon (GAC), with and without plastic media, under various operating conditions. The pilot testing allowed for troubleshooting and refinement, which led to selection of the biological activated carbon (BAC) process. The final system design effectively removes H2S odors, reduces chlorine chemical dosage using four 12-foot diameter steel pressure vessels, and allows for the incorporation of PFAS treatment.  Additionally, PACE designed an inverted sewer siphon to increase flow capacity through an existing choke point to allow for periodic filter vessel backwashing and wastewater discharge to the existing sewer system. The treatment system design is powered and controlled by a new distribution system and control panels.

Key Features:

• 4,000 gpm biological treatment system
• Wellhead treatment system added to an existing groundwater well
• Treatment pilot study to determine the feasibility of a biological treatment process using GAC
• Four 12-foot steel pressure vessels
• Invert siphon for backwash discharge to the existing sewer system
• Designed valves and piping for future simultaneous removal of PFAS and H2S
• Updated distribution switchboard and control panels
• California Title 24 Compliant Lighting Systems