Waste Water Treatment Plant Air Quality

The City of Mill Valley and the staff of the Waste Water Treatment Plant located on Sycamore Avenue have received notice of concern from a parent of a Middle School student regarding air quality issues related to the plant. Staff has heard from some parents regarding their concerns and questions, and have been in dialog with the school over many years regarding odors.

“We thank you for contacting us with your concerns,” Lew Kious, Board President, said. “We want to share that the Sewerage Agency of Southern Marin Board and staff are committed to protecting the health and safety of residents, and promoting a healthy natural environment.”

We have met with Bay Area Air Quality Management District (BAAQMD) inspectors to evaluate plant odors and have scheduled a supplemental meeting next week to further investigate the concerns. After this meeting, we will follow-up to share the results and further the dialog about addressing community concerns.

Background and Additional Resources
The Waste Water Treatment Plant is undergoing a major improvement project to ensure reliable treatment of wastewater, as well as compliance with regional, State and Federal regulations. As part of the planning for the project, SASM hired a consultant to study the emissions from the plant. The conclusions are summarized in an Odor Evaluation Report. The study found that the plant’s emissions are not negatively impacting public health, within the plant or at the nearby Middle School.

Based on this report, SASM’s design consultant, Carollo Engineers, designed a new odor scrubbing system to replace the approximately 40-year-old air scrubbing system. The SASM Board specifically prioritized that this component be included in the first phase of the improvement project. This new system was initially projected to be activated by the Spring of 2019. Staff is working toward accelerating this schedule, and hope to start up the new system before the end of 2018.

City and plant officials will continue to work with school administrators and community members to communicate our plans and be available to answer questions on an ongoing basis.

Questions or comments may be directed to Mark Grushayev, Waste Water Treatment Manager at (415) 388-2402 or email