Challenge
The City of Los Angeles has long faced the dual challenge of protecting its coastal environment while reducing reliance on imported water. In 1977, the Los Angeles Regional Water Quality Control Board advised the city to cease the discharge of tertiary effluent from the Terminal Island Water Reclamation Plant (TIWRP) at LA Sanitation into Los Angeles Harbor.
This regulatory mandate, combined with the need to combat seawater intrusion in local aquifers and to build resilience against drought, made advanced water reuse a critical priority.
Water reclamation was determined to be the most cost-effective and sustainable alternative to deep-ocean outfalls, meeting discharge requirements, protecting the harbor, and providing a reliable water source for industrial users and groundwater recharge.
Solution
To meet regulatory and water security goals, the city developed the Advanced Water Purification Facility (AWPF) at Terminal Island. The phased approach began with 5 million gallons per day (MGD) of recycled water by 1999 and grew to 12 MGD by 2018, with plans for further expansion. Terminal Island provides comprehensive tertiary treatment through microfiltration (MF), reverse osmosis (RO), and advanced oxidation processes.
A key component of this treatment process is Xylem’s Wedeco UV system combined with hypochlorite. Highlighting the importance of pilot testing, Lance Thibodeaux, P.E., MBA, Division Manager of LA Sanitation and Environment at Terminal Island, noted, “the selection for Wedeco UV and hypochlorite was due to pilot performance results and Xylem customer service”.
Xylem worked closely with the city to resolve operational challenges. For example, when bromate formation emerged as a byproduct risk, the team optimized the process by adding ammonia dosing to produce harmless bromamine instead of bromate, ensuring compliance and water security.
Notably, Terminal Island became the first water reclamation plant to apply UV-hypochlorite AOP for advanced treatment of wastewater effluent. These measures, combined with the expertise of skilled operators and maintenance staff, ensure consistent compliance and dependable water reuse operations.
Results
Today, Terminal Island delivers advanced treated water to key users, including the Dominguez Gap Seawater Barrier, as well as industrial users in the harbor area. This recycled water helps prevent seawater intrusion and reduces demand for potable water supplies.
Key outcomes include:
- 12 MGD of advanced treatment capacity, doubling since the phase one launch and enabling indirect potable reuse, groundwater replenishment, and industrial processes.
- Regulatory compliance with the LA Regional Water Quality Control Board and full advanced treatment under California Code of Regulations Title 22.
- Operational reliability supported by advanced controls, preventative maintenance, and skilled operators.
- Resilient supply that maintains customer confidence, even during power or process disruptions.
- Reduced reliance on imported water, improving long-term water security.
Terminal Island also builds public trust through tours, community outreach, and participation in scientific publications and studies. Looking ahead, Los Angeles is preparing to expand its distribution infrastructure to serve additional end users and strengthen the region's long-term water resilience.
Conclusion
The Terminal Island Water Reclamation Plant demonstrates how regulatory drivers, innovative technology, and strong partnerships can transform a challenge into an opportunity for water security. With Xylem’s Wedeco UV solutions, Los Angeles has set a benchmark for sustainable water reuse, ensuring a cleaner harbor, a stronger local water supply, and a resilient future.
About Pure Water Los Angeles
Pure Water Los Angeles (PWLA) is a forward thinking water source program and partnership between LASAN and LADWP planned to produce up to 260 million gallons of purified recycled water daily at Hyperion Water Reclamation Plant, significantly adding to LA's local water supply by 2035.