SF Bay Area Indymedia indymedia
About Contact Subscribe Calendar Publish Print Donate

San Francisco | Environment & Forest Defense

SF Biosolids Compost is Safe, Tested and Great for Plants!
by Tony Winnicker, SFPUC
Friday Sep 25th, 2009 12:20 PM
San Francisco's biosolids compost is safe, tested and great for plants. It is tested for metals and other contaminants and it meets or exceeds all standards, even EU standards! San Francisco's biosolids compost is high quality and safe.
compostlawnsign.jpg
compostlawnsign.jpg

The biosolids compost that the SFPUC gives out at our events is basically what you would find in a gardening store. Our goal with the program is to increase awareness about biosolids and expand our in-city reuse opportunities. The problem with claims by the Center for Food Safety is that they don't really address the fact that we have empirical lab data on the metals and other compounds found in San Francisco's biosolids. Their broad statements really have no foundation in San Francisco, where as with many of our other sustainable programs, we go above and beyond what is required by federal and state laws in testing.

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.

- 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 is mixed in with organic materials like wood chips or paper fiber. This is the process that allows us to designate the biosolids as compost.

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


Metals Levels / Other compounds of concerns (ie: 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 ahead of the curve. We have lab reports showing extremely low levels for all of these compounds in our biosolids. One of the few countries in the world that even has limits on endocrine disrupters is Denmark. Our levels of endocrine disrupters fall below what is required to meet even their reuse standards.

- The Center for Food Safety is correct that the EPA doesn't require testing, it doesn't really apply to San Francisco because we have tested.


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 get our great water pretty much from Sierra Nevada snowmelt 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 puts on the Big Blue Bucket event. We educate people and provide resources for people to do the right thing. At our first event last year, we collected more than 2 tons of old/expired medications for proper disposal. A few months ago SFE started a pilot drug mail-back that has been met with huge success.

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 and compounds into the wastewater system.

Earlier this year, the US EPA made news when it released a list of unregulated, untested, unmonitored chemicals, drugs and pharma it found in sewage sludge "biosolids".

http://www.beyondpesticides.org:80/dailynewsblog/?p=1196

"New Report Finds High Concentrations of Toxic Contaminants in Sewage Sludge
(Beyond Pesticides, January 28, 2009)

The U.S. Environmental Protection Agency’s (EPA) national sewage sludge survey identifies high concentrations of toxic contaminants with heavy metals, steroids and pharmaceuticals, including the antibacterials, triclocarban and triclosan. Despite the prevalence of these toxic chemicals in the environment and their potential adverse impacts to human health and the environment, EPA maintains that it is not appropriate to speculate on the significance of the results at this time."

San Francisco sludge compost is NOT tested for these toxic substances which are found in ALL sewage sludge "biosolids".

Included on EPA;s list are antibiotics, disinfectants, antimicrobials, steroids, endocrine disrupting chemicals and other anthropogenic drugs found in sludge biosolids which can be taken up by plants and cause great harm in the environment, particularly to aquatic biota.

http://www.epa.gov/waterscience/biosolids/tnsss-tech.pdf

Some users of Class A sludge biosolids compost have suffered serious health effects: http://www.sludgevictims.com/Class-A-sludge.html



Helane Shields, PO Box 1133, Alton, NH 03809 Sludge researcher since 1996 hshields [at] worldpath.net http://www.sludgevictims.com "H