California Treatment Agencies Prepare for Cannabis

“We don’t know what we don’t know,” is the way Riverside Senior Environmental Compliance inspector Michael Placencia describes the situation wastewater treatment agencies may soon face as cannabis-related discharges start showing up in their collection systems. 

 In his city, the commercial cultivation and production of cannabis aren’t allowed, but that doesn’t keep him from thinking about the potential ramifications of cannabis on sewer systems, following the passage of California Proposition 213.  

“There are issues from a treatment perspective,” he says. “The industry has sort of emerged from the shadows. It’s not like other industries which have growers’ associations and manufacturing standards.” 

Excessive pesticides or fertilizers could be applied, or cannabis products could be washed in an inappropriate manner, producing contaminants of concern at the local level, Placencia points out.  And, wastewater plants need to be prepared about the indirect discharge of THC and CBD into sanitary sewers from consumers. 

Placencia notes that in his city, the University of California-Riverside has only just begun to develop testing protocols and technically based limits for the concentration of THC and CBD in water, including the fate of these materials as they leave the human body. The results will allow treatment authorities to establish local limits and restrict discharges, he says.  

At East Bay MUD. 

In the Bay Area, wastewater agencies are already beginning to experience the presence of cannabis cultivation and manufacturing in their service areas.  At East Bay MUD, Director of Wastewater Eileen White and her team have developed a detailed plan for permitting and managing cannabis discharges. 

The agency has compiled a table which lists the local cannabis regulations and potential cultivation and manufacturing operations in each of the eight  jurisdictions in its service area.  Two—Albany and Piedmont—have banned all cannabis businesses. 

The EBMUD plan requires Industrial Wastewater Discharge permits for any cannabis operation generating more than 25,000 gallons of wastewater a day or having a cannabis cultivation canopy greater than 10,000 square feet, and Best Management Practice-based Pollution Prevention Permits for operations discharging less. 

At this writing, 6 facilities have submitted discharge applications to East Bay MUD, but the agency is expecting up to hundreds more based on information from the cities, including Oakland. 

White has faith in the process and the outcome. “Our job is not to get in the way of the cannabis business,” she says. “Our goal is to be a responsible wastewater utility. We are treating the cannabis applications like we would any other new industrial permit application.” 

White says her agency is on the lookout—not so much for THC or CBD—but for pesticides, nutrients, fungicides, solvents, extractions, and fats-oil-grease produced by the cannabis industry.  

Looking ahead. 

Back in Riverside, Placencia is confident his new 26-mgd Membrane Bioreactor plant is capable of treating cannabis related pollutants, even if his city should decide to allow cannabis cultivation and processing facilities in the future.  

And White remains optimistic, as well, even as she anticipates a substantial increase in cannabis businesses with her district. 

“We’re encouraging the industry to talk with us,” she says. “We both have much to learn, but I’m not thinking there’s going to be a problem. We’ll know more in a year.” 



Michael Placencia, Riverside

Eileen White, EBMUD

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