The San Francisco Public Utilities Commission (SFPUC)

Thank you for contacting the San Francisco Public Utilities Commission (SFPUC) regarding the safety of our City’s biosolids compost and the use of the term “organic” in signs and literature promoting our compost give away events.

The SFPUC has been giving away biosolids compost yearly since 2007. The SFPUC shares your concerns regarding the safety of biosolids compost – that is why we test our biosolids for contaminants, and make those test results available to the public. We are constantly re-evaluating our pilot giveaways and have no immediate plans for our next event.

The SFPUC’s previous use of the term “organic” in signs and literature regarding our biosolids compost was intended to communicate its high carbon content in a manner akin to the term “organic chemistry”. To prevent confusion with what is labeled as “Organic” by the United States Department of Agriculture (USDA), the SFPUC has since removed any reference to the term from all of its signage and literature.

San Francisco is a city that prides itself on its sustainability and being at the forefront of new environmental and public health initiatives. Just as in many of our other initiatives, our biosolids program goes above and beyond what is required by federal and state laws. Although no law requires it, the SFPUC tests for contaminants and we have found extremely low levels of contaminants in our biosolids. One of the few countries in the world that has limits on endocrine disrupters is Denmark. Our levels of endocrine disrupters fall below what is required to meet even their reuse standards.

I hope you will take the time to learn more about our San Francisco biosolids program by reading the accompanying text. In addition, you can also find more documentation along with tests results on our website at http://www.sfsewers.org

Sincerely,

Tommy Moala
Assistant General Manager for the Wastewater Enterprise
San Francisco Public Utilities Commission
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Background: What are Biosolids? What is Biosolids Compost?
* Biosolids are the treated nutrient-rich solid waste removed from sewage at every wastewater treatment plant. In San Francisco, biosolids treated in an anaerobic environment (in an environment devoid of oxygen) and heated for about 20 days at 95 degrees Fahrenheit in a series of tanks at our treatment plants. Methane gas is collected from the biosolids and used to produce renewable energy that powers our operations.

* Biosolids Compost undergoes further aerobic treatment for 3-4 weeks (oxygen-based environment) and kept at temperatures exceeding 131 degrees Fahrenheit at a composting facility in Merced. At the facility, the biosolids are mixed in with organic materials like wood chips or paper fiber. This is the process that converts the biosolids to compost.

* The sustained and serial anaerobic and aerobic treatment substantially reduces many compounds of concern.

Metals Levels / Other compounds of concerns (i.e.: endocrine disrupters, triclosan, etc.)
* Metals - We have very low concentration of metals in our biosolids. Our levels are not only far below the current EPA standards, but below the more stringent European Union standards as well. In fact, if you line up our biosolids compost with the same compost you would purchase at your typical gardening store, the metals concentrations would be about the same, in other words, very low.

Other compounds of concerns
* Although we aren't required to, the SFPUC has conducted tests on these compounds because we want to be ahead of the curve. We have extremely low levels for all of these compounds in our biosolids. One of the few countries in the world that has limits on endocrine disrupters is Denmark. Our levels of endocrine disrupters fall below what is required to meet even their reuse standards.

The Term “Organic”
* The San Francisco Public Utilities Commission’s (SFPUC) former use of the term “organic” referred to the scientific definition of organic matter as in containing significant amounts of organic carbon. To prevent confusion with what is labeled as “Organic” by the United States Department of Agriculture (USDA), the SFPUC has since removed any reference to the term from all of its signage and literature.

Why are the metals/other compounds low?
- There are a couple of reasons why:
1) The SFPUC provides drinking water from an enclosed, protected tap water supply. There is no contamination of our water from wastewater dischargers into our water source. We receive our great water pretty much straight from snowmelt off the Sierra Nevada to our taps.

2) San Franciscans are very educated and environmentally conscious. Part of that is due to the great work of SF Environment and the SFPUC. People know they shouldn't be dumping their motor oil down the drain or dumping dangerous chemicals down the toilet. After all, where does all that end up - straight to our wastewater treatment plants.

This is also part of the reason the SFPUC has sponsored an Eco-Fair two years in a row, the Big Blue Bucket event. We educate people and provide resources. For example, at our events, we collected more than 2 tons of old/expired medications for proper disposal.

The SFPUC also has an aggressive, and award winning water pollution prevention program. In the past 8 years, we've eliminated mercury runoff from dentist's offices and are constantly sampling our major dischargers to make sure they are in compliance.

3) San Francisco is primarily a residential city. There are no major industries in the City that would serve as a large contributor of metals, chemicals and compounds into the wastewater system.