After reading coverage of the connection between wastewater treatment plants and the excess concentrations of phosphorus and nitrogen in the Bay that led to the ongoing toxic algal bloom and talking with scientists at the SF Baykeeper, it seemed important to submit last week’s blog as an editorial opinion to the San Francisco Chronicle.
We are pleased that the Chronicle published it yesterday with this provocative headline: A toxic algae bloom has made it obvious the Bay Area needs to recycle its wastewater.
A few things were changed form the blog. First, we added the role of phosphorus – it and nitrogen are both harmful in these large doses. We also decreased the emphasis on San Francisco’s southeast plant, as there are nine water treatment plants south of the Bay Bridge – all of which are culprits to varying degrees (see chart).
Not also that such an algal bloom has been predictable as noted in “Nutrient Status of San Francisco Bay and Its Management Implications (James E. Cloern et al, 2021): “… our assessment includes reasons for concern: nitrogen and phosphorus concentrations higher than those in other estuaries impaired by nutrient pollution, chronic presences of multiple algal toxins, a recent increase of primary production, and projected future hydroclimatic conditions that could increase the magnitude and frequency of algal blooms.”
Please consider signing the Baykeeper’s petition to San Francisco Mayor London Breed, asking that she pursue water recycling. We have signed and will be encouraging other communities to do so as well.
There are many reasons that San Francisco, like other water agencies, will be fundamentally changing in years to come. Recycling, made possible with advanced technology including nanofiltration, provides reliable supplies and reduces pollution. It’s time has come.
Recycling will also reduce San Francisco’s reliance on the Tuolumne River and could replace the water storage function of Hetch Hetchy Reservoir. The time has also come to give Yosemite’s Hetch Hetchy Valley back to the people.