Resource Innnovation for a Sustainable Environment (RISE)

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Cutting Edge Wastewater Management

Since 1954, OC San has been an industry leader in wastewater treatment and management, pioneering innovative technologies and approaches. Through our new program, Resource Innovation for a Sustainable Environment (RISE), we highlight our efforts that go beyond meeting regulations by anticipating future needs and building for tomorrow. Alongside our ongoing sustainability initiatives—such as Source Control, Beneficial Reuse & Recycling, the Groundwater Replenishment System, and Dry Weather Urban Runoff—we’re advancing research to enhance operations with cutting-edge processes and equipment that support enhancements in Water, Solids, Energy, and Air.

Water

Solids

Energy

Air

Water

Urban Runoff Optimization Study Salinity Green Acres Project (GAP) Past Research Initiatives

Urban Runoff Optimization Study

Upstream Perspective of the
Santa Ana Deli Diversion

Building on OC San’s existing Dry Weather Urban Runoff Diversion program success, a new study is underway to identify opportunities where additional runoff may be captured to increase water recycling and improve downstream water quality throughout the county and at our beaches. OC San is collaborating with the Orange County Water District and County of Orange on this important effort to optimize existing and identify new diversions by June 30, 2025.

Salinity

OC San partners with the Orange County Water District (OCWD) and Santa Ana Watershed Project Authority (SAWPA) to protect potable water quality by managing salt disposal through our existing infrastructure. OC San accepts OCWD’s reverse osmosis concentrate free of charge for ocean disposal via our Ocean Outfall and collects unreclaimable flows from SAWPA’s Inland Empire Brine Line through the Santa Ana River Interceptor for treatment at Plant No. 2 in Huntington Beach. OC San remains committed to environmentally responsible disposal of dissolved solids, balancing the benefits of water reclamation and reuse with minimizing the impact of higher salt concentrations on the ocean environment.

Green Acres Project (GAP)

For decades, OC San has partnered with the Orange County Water District (OCWD) to provide recycled water for landscape irrigation at parks, schools and golf courses; industrial uses such as carpet dying; and power generation cooling through the Green Acres Project (GAP). As part of GAP, OC San sends secondary treated wastewater effluent to OCWD, where flows are treated to a tertiary level by mixing in coagulant, passing though flocculation paddles, filtration through dual-media beds (sand and anthracite), and finally spending time in a chlorine contact chamber before being discharged to a storage reservoir. GAP water is currently distributed to approximately 100 different locations, including OC San, and local water retail agencies.

Diverting wastewater to OCWD for GAP provides numerous benefits, including reducing demand for higher quality drinking water, decreasing the amount of water extracted from the groundwater basin, lowering reliance on imported water, and mitigating the risk for potential seawater intrusion into local supplies. This collaborative effort supports sustainability by maximizing water reuse and promoting long-term water reliability for the region.

Past Research Initiatives

Cell-Based Bioassay

In 2019, OC San partnered with the Southern California Coastal Water Research Project on a case study to examine the applicability of cell bioassays as a novel tool to measure contaminant bioactivity in wastewater and the coastal receiving environment. The results demonstrated that cell bioassays have potential as a screening tool for assessing the efficacy of certain wastewater treatment processes. However, as there was no significant bioactivity in any of the seawater samples, cell bioassays are not useful in receiving environments with good water quality such as OC San’s monitoring area.

Solids

Supercritical Water Oxidation Deep Well Injection Past Research Initiatives

Supercritical Water Oxidation

One of our research initiatives has led to a demonstration project of a Supercritical Water Oxidation facility at our Fountain Valley plant. This new system includes new treatment methods that address constituents of emerging concern such as PFAS or per- and polyfluoroalkyl substances. This process uses water at a high temperature and pressure to oxidize complex compound materials into more basic and benign compounds. The system is planned to be online in 2025.

Learn more about OC San's Supercritical Water Oxidation Facility:

Deep Well Injection

OC San is currently conducting a feasibility study on the implementation and benefits of Deep Well Injection (DWI) of biosolids. The proposed DWI project presents an innovative approach to managing biosolids, eliminating the need for long-haul truck transportation, thereby cutting down carbon emissions and associated costs. DWI would also provide a forever home for these carbon and nutrient-rich residuals which contain trace amounts of harmful substances like PFAS (per- and polyfluoroalkyl substances), microplastics, and pharmaceuticals.

The DWI project intends to inject biosolids 5,400 feet below OC San’s treatment plant in a sand layer sandwiched between layers of rock thousands of feet below the aquifer. This naturally warm sand layer becomes an anaerobic digester converting the biosolids into methane and carbon dioxide. This DWI will keep the biosolids and the gases they become completely separate from the groundwater basin and provide a forever home for forever chemicals. The study is slated for completion in summer 2025.

Learn more about Deep Well Injection:

Fact Sheet

Past Research Initiatives

Enertech

One option explored as part of the Biosolids Management Program was Enertech, a process that used heat and pressure to remove excess water from biosolids, dried the resulting material into a pellet, and used that pellet to be contracted to cement kilns to burn as an alternative to coal. The pellets had less nitrogen oxide than coal making them beneficial to the environment and were certified as a renewable energy by State of California. Enertech was the first method used to create an energy source from our biosolids. Due to the private funding stabilization of Enertech, this effort was terminated in 2012.

Energy

Battery Storage System Mass Timber Headquarters Building Food Waste Diversion Past Research Initiatives

Battery Storage System

In 2019, OC San installed the world’s largest behind-the-meter battery storage facility – utilizing the latest energy technology to offset almost the entire Plant No. 1 demand during peak power. Doing so eliminated the need to operate OC San’s third central generator on natural gas. The battery storage system also provides OC San a long-term solution that reduces the overall impacts of increased energy costs. This system continues to be operational.

Mass Timber Headquarters Building

Completed in the spring of 2024, OC San’s new Headquarters incorporates many environmental components. The building design features the most environmentally friendly features and materials, including a hybrid of mass timber columns and decking combined with exposed steel-braced framing. Mass timber is made of compressed layers of wood which is engineered for high strength like concrete and steel but significantly lighter in weight.

In addition to using mass timber, the Headquarters uses hot water from Reclamation Plant No. 1 for heating, achieves net-zero energy, and is LEED (Leadership in Energy and Environmental Design) Gold certified.

Food Waste Diversion

The State of California has issued limits on the volume of organic waste that is diverted to landfills. To aid in this effort, OC San is working with the County of Orange, other local agencies, and waste haulers to find ways to beneficially reuse food waste, a type of organic waste, to assist cities in our service area in meeting their diversion requirements while increasing OC San’s energy production. An agreement with the County and other digester owners has been made, and funding is available for infrastructure at OC San. Once a process for sorting food waste has been established by others, OC San will build the infrastructure. This is an active effort.

Past Research Initiatives

Hydrogen Fueling Station

In 2011, OC San partnered with UC Irvine and the National Fuel Cell Research Center to launch the world’s first experimental fuel cell, converting wastewater into hydrogen fuel, electricity, and heat. The project enabled hydrogen car refueling with sewage-derived fuel at 70 miles per gallon. Designed by UCI, FuelCell Energy, and Air Products & Chemicals, it was funded by federal and state agencies. While the research was successful, it was not beneficial for a regional wastewater agency the size of OC San and was thus terminated.

Air

Fleet Electrification Regional Odor Control Biological Treatment Methods for Odor Control Engine Emmissions Reduction Digester Gas System Integrity Inspection Program Past Research Initiatives

Fleet Electrification

OC San relies on mobile equipment for daily operations and is committed to adopting the cleanest available technologies, including electric vehicles. Our desire to transitioning our mobile fleet to zero emissions depends on availability, cost, reliability, and regulatory compliance. Recently, OC San procured a 65-foot hybrid-powered research vessel, designed by All American Marine, with a plug-in hybrid system that can be upgraded to full electric if needed, to meet potential zero emission standards of the California Air Resources Board. Expected for delivery in September 2027, this vessel aligns with OC San’s commitment to sustainability and zero-emission goals. As an industry pioneer in sustainability, our dedication to a green fleet strengthens our ongoing efforts to achieve zero emissions.

Regional Odor Control

OC San has developed a comprehensive odor control program to address public concerns about odors from wastewater facilities and collection systems. The program integrates optimized chemical treatment, continuous dosing control, and mechanical abatement techniques.

OC San manages 380 miles of sewers and 15 pump stations, utilizing liquid-phase odor control to maintain hydrogen sulfide levels below 25 parts per million. Traditional chemicals like ferrous chloride and magnesium hydroxide are used, but OC San developed Alkaline-Enhanced Iron (AE-Fe) to enhance odor control while reducing costs. The innovative and patented use of AE-Fe increases wastewater pH to improve iron sulfide precipitation, while minimizing gaseous hydrogen sulfide emissions. This process reduces both chemical use and the amount of waste going to treatment plants.

Chemical Dosing Station at
Westside Pump Station in Rossmoor

Biological Treatment Methods for Odor Control

In 2022, OC San conducted a study on the effectiveness of various biological media technologies for treating raw foul air from incoming wastewater. A pilot unit tested five biological treatment methods—two bioscrubbers and three biofilters—to remove odors such as rotten egg, rotten vegetables, and fecal smells. Results showed that biofilters, especially those using lava rock media, were the most effective in reducing odors and harmful emissions. This study led to the optimization of air treatment technologies, enhancing air quality around OC San facilities and contributing to a cleaner environment for the community.

Engine Emmissions Reduction

Central Generation engines are the largest sources of air emissions at OC San. They emit both criteria pollutants (NOx, CO, VOC, particulates, SOx) and air toxics. In 2007, OC San partnered with the South Coast Air Quality Management District (SCAQMD) on the pilot demonstration of an engine emissions reduction project with the goal to evaluate and test technologies to reduce emissions from the engines to address future compliance with SCAQMD rules. Based on the favorable results of the technical evaluation and field demonstration, in 2015 OC San implemented the dual Selective Catalytic Reduction /Catalytic Oxidizer System across all eight engines at Plant Nos. 1 and 2. This post‐combustion technology has proven effective for controlling NOx, CO, and VOC emissions well below the regulatory limits adopted by SCAQMD.

Digester Gas System Integrity Inspection Program

In 2022, OC San proactively implemented the Digester Gas System Integrity Inspection Program using optical gas imaging cameras for the detection of fugitive methane emissions. Process Engineers certified to handle and evaluate the findings perform comprehensive field walks of each plant on a semi-annual frequency. This multifaceted program has proved effective in helping the Operations division detect and mitigate fugitive emission leaks.

Past Research Initiatives

Ammonia Slip Emissions Monitoring Technology

OC San, in partnership with CEMTEK, conducted a demonstration of the Unisearch LasIR Tunable Diode Laser (TDL) ammonia monitoring system. This project, done for SCAQMD, tested the system’s ability to measure real-time ammonia emissions from an engine using urea injection and a dual SCR/Oxidation Catalyst system.

The pilot study provided valuable insights into how well this technology works in real-world conditions, highlighting its strengths and limitations. The findings will help improve ammonia monitoring technology and guide future air quality regulations.

Resource Innnovation for a Sustainable Environment (RISE)

Cutting Edge Wastewater Management

Urban Runoff Optimization Study

Salinity

Green Acres Project (GAP)

Cell-Based Bioassay

Supercritical Water Oxidation

Deep Well Injection

Enertech

Battery Storage System

Mass Timber Headquarters Building

Food Waste Diversion

Hydrogen Fueling Station

Fleet Electrification

Regional Odor Control

Biological Treatment Methods for Odor Control

Engine Emmissions Reduction

Digester Gas System Integrity Inspection Program

Ammonia Slip Emissions Monitoring Technology

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Resource Innnovation for a Sustainable Environment (RISE)

Cutting Edge Wastewater Management

Urban Runoff Optimization Study

Supercritical Water Oxidation

Battery Storage System

Fleet Electrification

About OC San

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