The New Primary Clarifier Tanks Cover Replacement and Refurbishment of Primary Treatment Chemical Scrubbers to Mitigate Foul Air at Hyperion Water Reclamation Plant in the City of Los Angeles, California

LA Sanitation & Environment (LASAN) operates Hyperion Water Reclamation Plant (HWRP) in the City of Los Angeles (City) with an average dry-weather capacity of 450 million gallons per day (MGD) and has been operating since 1892. LASAN core mission has championed the protection of public health and the environment. Separately from the primary and secondary water treatment, HWRP is currently planning an advanced water purification system with the goal to produce 100% recycled water called Pure Water Los Angeles (PWLA) Program ($4.8B). The new primary treatment tanks cover replacement are improvements at HWRP which was completed in June 2024 ($14.5M). In addition, the refurbishment of primary treatment chemical scrubbers was completed in September 2023 ($4.0M). These projects are designed to contain and treat foul air stream [hydrogen sulfide (H2S)] from the primary treatment system. Primary battery (27 tanks) have new aluminum cover installation and include launders, scum troughs, maintenance access hatches, sludge collection hoppers, and influent channel. All covers were installed in accordance with the manufacturer’s recommended installation procedures/relevant shop drawings. The OEM and the contractor has completed the reconditioning of all six chemical (sodium hypochlorite/sodium hydroxide) scrubber’s systems (air flow of 120,000 ft3/min for six fans in parallel), each is 20,000 ft3/min. All six chemical scrubber systems are refurbished with new installation: all internal packing, metering pump motors, spray internal nozzles, mist eliminators, recirculation pumps, pH and ORP sensors, butterfly drain valves, motor soft starters, and others. Results have been outstanding with the two projects and a reduction of H2S occurring in ambient air around the primary clarifier. The operations, maintenance, and performance data at primary treatment and clarifier, air emissions measures, advancements will be presented for LASAN’s odor control systems.