Vallejo wastewater maintenance causing rotten odor miles away

VALLEJO – Recent maintenance work by the Vallejo Flood and Wastewater District has caused an unpleasant smell wafting up from the waterfront sewage treatment plant into south and central Vallejo in recent months and led to a flurry of complaints to government officials. The district now expects that residents and visitors in Vallejo will have to endure the odors for months longer.

District Operations Superintendent Orlando Cortez said the district underestimated both the range of odors that would be released during the maintenance work, and the duration of the problem. On March 14 the district sent a letter to customers within a half-mile radius of the facility, warning that unpleasant odors may be noticeable until the middle of May. 

Cortez said the district now estimates the odor could last until November and that in the future the district will expand its notification range to two miles. He said that more than 60 to 70% of the majority of odor complaints came from the Heritage District, a mile to the north of the treatment plant between Solano Avenue and Ryder Street on the South Vallejo waterfront.

The district issued a new letter to the community about the problem on Monday. “We want to emphasize that the unpleasant odors are not a regular occurrence,” the letter, signed by management analyst Eddy Castillo Gomez, said. “The odor problems are due to the ongoing construction work at the District Treatment Plant in combination with the unusually hot weather this summer. We want to assure the community that the unpleasant odors are not toxic and do not pose any risk to the community’s health.”

May Castro, who lives outside of the initial notification rage, noticed a strong odor that she said initially smelled like rotting fish in March. Castro said that she and her husband have lived in Vallejo for 18 years. “The odors were never a problem before the new project,” she said. “The bad smells continue to this day. Whatever technology they were using before we did not have the odors! They smell gassy like a sewer. Others have complained it's like fecal matter.”

Other people claim that bad odors from the plant have been occurring since well before the March 2024 filter replacement project.

Some residents have circulated a petition that states that residents living near Monterey Street and Curtola Parkway have experienced an intolerable and pervasive foul smell for the past year, and that the situation has significantly deteriorated and is severely impacting quality of life and raising serious health concerns.

One of the many posts found on social media complaining about the issues states “Another Summer in the Heritage District, unable to be outside without ammonia poisoning from tank fumes. Vallejo Water, you (literally) stink.”

Cortez said that the strong smells residents noticed in March were likely emitted from the south biofilter tower, when a project began to replace filter media that was installed in 1988. 

Wastewater that would normally be treated in the south tower is being treated in the north tower while the filters are being replaced. The two biofilter towers handle a much greater volume of water during the rainy season, so the north tower was thought to have the capacity during the dry season to handle the total amount of sewage during work on the south tower.

Cortez said that the north tower is stressed, and that they didn’t anticipate that it would be a source of smells. “We definitely underestimated this as far as the duration that we would have probably unpleasant odors,” Cortez said, adding that summertime heat can contribute to odors from the plant. 

Cortez described the district’s aerobic treatment process as completely non-toxic. The bio towers are filled with plastic mesh filters, also known as trickling filters, that are coated with a living slime called a zoogleal mass. Tiny microorganisms in that slime eat suspended solids that remain in the water. 

The biosolids that are separated from the water then are mixed with lime and made into a fertilizer that is used to grow oats and hay for livestock. Cortez said that this unique, environmentally friendly process eliminates the problems that Richmond and Crockett wastewater treatment plants recently had with hydrogen sulfide gas being released into the atmosphere. He said he understands why people may have health concerns about smells from the Vallejo plant. “Unpleasant, yes. Toxic, no,” Cortez said.

The district recently installed six fans that blow a product called Ecosorb into the air around the site to help mitigate some of the unpleasant odors.

Cortez said he understands the public’s frustration. He said that he likes to open his windows when the sun goes down at 8 p.m. instead of running his air conditioner. “I live in this community myself. I love Vallejo,” he said. “We want to do the best possible job.”

But Vallejo residents who’ve been through months of frustration about the smells may not be satisfied with the district’s explanation. Castro said she noticed what she considered a mild smell when she arrived at her home on the evening of July 8. “Then my brother stopped by and immediately noticed it and complained,” she said. “I guess I am getting used to it! That's probably what they want! For us to get used to it and just live with it.”

Castro also expressed concern that the prevalent bad smells could lower her home value.

Vallejo Mayor Robert McConnell, who is also President of the Wastewater District Board of Trustees, said during a Board of Trustees meeting on July 9  that he and other elected officials have been getting more and more complaints about odors. “But we don't really have any information to respond to those complaints with,” he said. 

Gomez said they reached out directly to the community rather than going to the City Council or the Board of Trustees because they assumed that the odors from maintenance work would only reach a very small radius. “Had we known that the reach was going to be higher than that we would at least do an informational report,” he said.

“If anything,” Gomez said, “what we learned from this is that we need to ramp up our communication.” He said that in the future they’ll publish more on the district website and on social media. He said that the public can email or call the district “and we'll be transparent about what's going on.”

The strength and range of odors emitted from site are not apparent from the ground at the plant. The open tops of the bio towers are three stories high, and the prevailing south winds blow the fumes overhead toward downtown Vallejo.

The district is asking for the public’s help to identify odors coming from the plant. This will help them determine which activities and weather conditions contribute to the bad smells. “We do like to know if there's something that we're doing, for instance, if we're loading a biosolids truck, a sledge truck during the day, okay, can we change that,” Cortez said.

The public can report odor problems by email at admin@vallejowastewater.org, use the online odor complaint form, or call (707) 644-8949. Include the specific date and time and nature of the odor (i.e. rotten egg) to help the district identify the source.