Food Scraps and Yard Debris Compost vs. Biosolids

The city of San Francisco is a dynamic place. On the one hand it’s an international city that attracts dreamers, business people, and techies from around the world. On the other hand, it’s a small community where people know their neighbors, say hello to the grocery store owners, garbage men, and dog walkers.

San Francisco is also a place where experimentation is welcome. Sometimes that experimentation results in positive innovation, and sometimes it ends up on the front page of the San Francisco Examiner. The controversy around the San Francisco Public Utilities Commission‘s decision to comingle biosolids with food and yard debris and give it away to urban gardeners has caused a minor stir. The issues are the use and definition of the word “organic” in this context, the standards set by the Environmental Protection Agency, and public perception.

What’s in sewage sludge? According to the Australia and New Zealand Biosolids Partnership:

Biosolids are mainly a mix of water and organic materials that are a by-product of the sewage treatment processes. Most wastewater comes from household kitchens, laundries and bathrooms. Biosolids may contain:

  • Macronutrients, such as nitrogen, phosphorus, potassium and sulphur and
  • Micronutrients, such as copper, zinc, calcium, magnesium, iron, boron, molybdenum and manganese

Biosolids may also contain traces of synthetic organic compounds and metals, including arsenic, cadmium, chromium, lead, mercury, nickel and selenium. These contaminants limit the extent to which biosolids can be used, with all applications regulated by appropriate government authorities in each State and federally. Australia has one of the strictest regulatory regimes for biosolids production and application in the world.

Although sewage sludge or “biosolids” is technically organic (i.e. contains carbon), in the United States the sludge also contains pharmaceuticals that people ingest, and along with everything else, gets flushed down the toilet. Pharmaceuticals are often synthetic chemicals that have been manufactured to diagnose, cure, prevent or delay a disease.  They may be persistent chemical compounds that don’t break down or decay during the total 151 days of high-temperature sludge treatment. The “organic” waste may then become a problem in the human food chain if the synthetics are absorbed by plants (such as tomatoes grown in urban gardens) that are then consumed by anyone participating in the “home gardening revolution“.

For many years, Recology has warned against the improper disposal of medicine, and has been very careful in this area. We do not comingle biosolids with the food scraps and yard debris we compost for this reason. Our compost comes from two sources: food scraps generated from restaurants, hotels, markets, and coffee shops in the Bay Area, and from yard trimmings generated north of San Francisco. Closing the loop on compost is a creative process, suitable for an innovative environment like one found in the city of San Francisco. Unfortunately, the SFPUC has taken it a little too far.

3 Responses to “Food Scraps and Yard Debris Compost vs. Biosolids

  • orkut scraps
    11 years ago

    nice post…..thnks a lot…

  • GozarGirl
    11 years ago

    I’m surprised there are very little options for safe disposal of prescribed and over the counter medications. From one hospital, I received the following information:

    Member Service Representative said, “I’m sorry, but I don’t have that information. The pharmacy does not accept medications.”

    Person answering advice line said, “Just put them down the drain or flush them.”

    The volunteer in the lobby said, “That’s a very good question. They don’t recommend you flush them anymore.”

    Another member services representative said to put them in a plastic bag and tie a tight not before throwing them out.

    So Recology Staff, help me out. Other than “RAMP”, what do you recommend?

    • The short answer is:

      We buy mail-back envelopes for waste drugs and mail them back to SF residents who can fill them up and mail them to Texas for disposal.

      This is from the RSF website:

      Expired Medications–New Interest In An Old Problem
      In the last few years, many newspapers and television stations have reported about the disposal of expired medications. For decades the public was advised to either flush medications down the toilet or put them in the trash. Until recently, scientists have determined that when medications are disposed of in the trash or down the drain, the residual medications find their way into our waterways, and have a negative impact on fish and other aquatic life, including having caused deformities in the sexual development of frogs and fish. Therefore, sewer and trash disposal are no longer recommended.

      Proper Disposal
      San Francisco currently has no pharmacies that accept expired or unwanted medication from residents.

      Government agencies are hoping to set up “take back” programs at pharmacies so that you can return medications to where you purchased them. Unfortunately establishing these programs is not easy. In addition to concerns about space, there is concern that some medications, namely controlled substances such as barbiturates, opiates and anti-depressants, will tempt some people to steal and/or sell them illegally.

      SF Mail-In Program – The City of San Francisco is currently piloting a mail-in program for San Francisco residents only. These pre-paid envelopes can hold both liquid and solid medicine and can be picked up at the following locations:

      Department of the Environment
      11 Grove Street, San Francisco, CA 94102
      (415) 355-3700

      Recology San Francisco
      501 Tunnel Avenue, San Francisco, CA 94134
      (415) 330-1400

      Contact the Household Hazardous Waste Collection Facility at (415) 330-1300 for more information.

      If you would like to be involved with setting up a take back program at a San Francisco pharmacy, please call the San Francisco Department of the Environment at (415) 355-3700.

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