Touring Orange County’s Largest Wastewater Plant

Have you ever wondered what happens to Fullerton’s wastewater after it goes down the drain? When we flush the toilet, shower, or wash our dishes, the water flows down residential drains and pipes to the city’s sewer system. City pipes connect to the Orange County Sanitation District’s (OC San) regional sewer pipe network, which collects local wastewater and transports it from the city to one of the county’s two wastewater treatment plants. I recently had a chance to tour Orange County’s largest treatment plant, in Fountain Valley, with Jon Bradley, Operations Manager, and April Frost, Chief Plant Operator, to learn about how the county provides wastewater treatment services for Fullerton and other North Orange County communities.

The OC San is a public agency that provides wastewater collection, treatment and recycling services for roughly 2.6 million people in central and northern Orange County, according to the organization’s website. The agency operates two facilities – Reclamation Plant No. 1 in Fountain Valley and Treatment Plant No. 2 in Huntington Beach – treating more than 180 million gallons of wastewater daily. According to Rebecca Long, Senior Public Affairs Specialist at the OC San, OC San is the third largest regional wastewater agency west of the Mississippi River.

Rebecca said via email, “Wastewater flows from Fullerton via gravity or a pump station. In total, there are five parallel trunk sewer systems to get to OC San’s Reclamation Plants in Fountain Valley and Huntington Beach.”

Jon Bradley explained that trunk sewer systems are a network of large-diameter pipes that act as the main arteries of a sewage collection system, gathering wastewater from smaller local sewer lines and transporting it to a wastewater treatment plant. He said, “Essentially, they are the primary conduits for large volumes of wastewater within a community, similar to how major arterial roads function in a city.”

Rebecca Long, Jon Bradley & April Frost at OC San’s Reclamation Plant No. 1

Driving down Euclid Street and following the Euclid pipeline, I eventually arrived at OC San’s Headquarters in Fountain Valley. A bridge connects the agency’s headquarters to Reclamation Plant No. 1. I checked in with security, received a visitor ID badge, and met with April, Jon, and Rebecca, who gave me a hard hat and a vest, before we walked across the bridge to the treatment plant across the street.

Our first stop was the “Headworks” area, which serves as a convergence point where all the various trunk lines from the different sewers arrive. I learned from April Frost that it plays an important part in the preliminary treatment process, helping to meter and divert flows if necessary.

Following Jon and April down a set of steps into the plant’s tunneling system, I saw six massive underground pipes that bring wastewater into the plant’s system and a seventh pipe that serves as a diversion line that connects to Reclamation Plant No. 2 in Huntington Beach. Jon explained that “Headworks” also screens out heavy debris that affects downstream equipment.

“You noticed we were standing on the Euclid trunk line, which conveys some of the flows from the Fullerton area, and you can see that here. This is where we would also measure the flow coming into our treatment plant,” said Jon. “We also monitor for conductivity and pH levels in this area.”

Massive pipes at the Euclid Trunk Line in the Headworks area of OC Sanitation District’s wastewater treatment plant in Fountain Valley

In addition to the odors normally associated with wastewater, I learned that hydrogen sulfide is formed in sewer pipes while being transported to the treatment plants. The OC San prevents the potential release of these odors with control measures such as covering treatment areas and sealing utility hole covers, as well as biological, activated carbon, and chemical air scrubbers to eradicate odors.

April added, “Throughout the facility, we have several different odor control scrubbers, where we pull foul air off the different processes, make sure that it stays contained, and then treat it through scrubber systems. Up at our Headworks, we have two different styles: one’s a biological scrubber, which uses microorganisms to treat the odor-causing bacteria, and chemical scrubbers that treat the foul air coming off of our primary processes.”

Moving forward, Jon and April showed me how screening and grit chambers remove larger objects and materials that clog up downstream processes, which can include anything from rags and dental floss to coffee grounds. I learned that at this point in the treatment process, the water still includes biodegradable solids and dissolved organics.

The wastewater then flows into large settling tanks where the remaining solids sink to the bottom. Jon said, “Within the primary clarification process, we use chemicals to enhance the settling in them to clarify the wastewater. We use chemicals such as polymers and ferrics; this aids in settling. Within a primary clarifier, whatever settles, settles, and what will float, floats. The material that floats is scraped off, and the material that settles is also scraped off through a series of paddles and collectors, and then that material is pumped to our digestion process.”

April explained that the remaining sludge is sent to digesters to undergo anaerobic digestion, which converts sludge to energy and fertilizer. OC San then sends partially treated wastewater to aeration basins or trickling filters for further treatment. Microorganisms feed on the remaining organic materials in the wastewater. After microorganisms and secondary sludge are removed, the treated water is sent to the Groundwater Replenishment System for recycling or released into the Pacific Ocean.

To learn more about Orange County’s water recycling and wastewater treatment processes, visit http://www.ocsan.gov. For Fullerton residents interested in a public tour of the wastewater treatment plant in Fountain Valley, visit www.ocsan.gov/tours/.