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

Wednesday, May 21, 2025

8:30 AM – 8:45 AM Alaska Daylight Time (AKDT)

Room: Cook Hall

Author(s)

K. Majid Sadeghi, Ph.D., P.E., BC.WRE

Env. Eng
City of Los Angeles, California, United States
Sheri Symons, P.E.

Sr. Env Eng
LA Sanitation & Environment - City of Los Angeles, California, United States
Shahrouzeh Saneie, Ph.D., P.E.

Sr. Env Eng
LA Sanitation & Environment - City of Los Angeles, California, United States
Nicole McIntosh, P.E.

Acting Civil Eng
LA Sanitation & Environment - City of Los Angeles, California, United States
Kenneth Pham, P.E.

Enn Eng
LA Sanitation & Environment - City of Los Angeles, California, United States
Stephen Opot, Ph.D., P.E.

Env Eng
LA Sanitation & Environment - City of Los Angeles, California, United States
Joel Jimenez

Env Eng Assoc
LA Sanitation & Environment - City of Los Angeles, California, United States
Octavio Murillo

Env Eng Assoc
LA Sanitation & Environment - City of Los Angeles, California, United States

Co-Author(s)

Hugo A. Loaiciga, Ph.D., P.E., B.C. WRE, P.H., F.EWRI

Distinguished Professor
University of California and Consulting Hydrologist, California, United States
Ali Sharbat, PhD, PE

Professor
California State Polytechnic University, Pomona, California, United States
Steve Gonzales

Murray Company, California, United States

Co-Author(s)

Sean Trainor
Gary Sutch
Ron Kuehne

Co-Author(s)

Daniela Zayas

Hyperion Water Reclamation Plant, LA Sanitation & Environment - City of Los Angeles
Austin Milo

Hyperion Water Reclamation Plant, LA Sanitation & Environment - City of Los Angeles

Abstract Submission: 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 system are refurbished with new installation: all internal packing, metering pump motors, spray internal nozzles, mist eliminators, recirculation pumps motors, 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.

Learning Objectives/Expected Outcome (Optional) : Primary and secondary water treatment, advanced water purification system, primary treatment tanks cover, refurbishment of primary treatment chemical scrubbers, contain and treat foul air stream [hydrogen sulfide (H2S)], chemical (sodium hypochlorite/sodium hydroxide) scrubber’s. Chemical scrubber system: internal packing, metering pump motors, spray internal nozzles, mist eliminators, recirculation pumps motors, pH and ORP sensors, butterfly drain valves, motor soft starters, and others. Operations, maintenance, and performance data at primary treatment and clarifier, air emissions measures, advancements of odor control systems.