Odor control has always been a top priority during the planning and design phases of new facilities at the Southeast Treatment Plant. With the start of operations of the new Headworks Facility last summer, the San Francisco Public Utilities Commission (SFPUC) introduced cutting-edge technology that significantly reduces odors resulting from the wastewater influent, or sewage flow entering the plant, for both staff and the surrounding community.  

Major capital projects at the Southeast Treatment Plant have a commission-endorsed commitment for no odors past the fence line. Innovations, such as biotrickling filters and carbon adsorption, at the recently constructed headworks help to keep the plant’s stink at bay. This includes a two-stage odor control system to treat more than 90,000 cubic feet per minute (CFM) of airflow to minimize the smell of the wastewater influent as it enters the plant and through screening and grit removal treatment processes.   

“This system isn’t just a technical upgrade—it’s a direct response to what we’ve heard from our neighbors. For years, the community voiced concerns about persistent odors emanating from the Southeast Treatment Plant, and we listened,” said WWE Senior Engineer Nohemy Revilla. “The design and implementation of this advanced odor control system reflect our commitment to being a good neighbor. By incorporating community feedback into the project’s planning phase, we’ve created a solution that benefits everyone—inside and outside the fence line.”

So, how exactly do you capture and transform the stink from the wastewater treatment process?  

1. Eat it – Biotrickling filters are beds of materials, or media, that support odor-eating microbes. Odorous air is pushed through these biofilters, and microorganisms digest the smelly pollutants—turning stink into clean air.
2. Adsorb it – Next, the air passes through carbon filter stacks that trap any leftover odor causing pollutants that the microorganisms didn’t consume. These carbon filters act like sponges, soaking up anything the microbes missed.
3. Release it – Finally, the cleaned air is released through a stack, much like a chimney, odor-free and safe for the environment. 

This state-of-the-art technology doesn’t just clean the air—it transforms it. By reducing unpleasant odors at the first step of the treatment process, the SFPUC has created a cleaner, more comfortable environment for our operations staff and delivered a breath of fresh air to our neighbors. The headworks odor control system is not only designed to mitigate our operational impacts—it's also fully permitted and regulated by the Bay Area Air Quality Monitoring District, ensuring compliance with regional air quality standards. The smell from headworks operations may no longer be lingering in the surrounding community but the benefits of this project are definitely reaching further than just the fence line. 

This is the third article in our series about the new Headworks Facility and how it helps Southeast Treatment Plant look better, work better, and smell better. Check out the previous story about how the headworks is making the plant more efficient, reliable, and resilient.