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Sonoma County Waste Management Agency

Municipal composting


Steaming Composting piles

Accepted in the green cart:

  • Fruit & peelings
  • Vegetables & peelings
  • Pasta & rice
  • Bread
  • Tea bags
  • Coffee grounds & filters
  • Eggshells
  • Wood ashes (cold)
  • Landscape prunings
    (maximum 4 feet long)
  • Grass clippings,
    leaves & weeds
  • Tree trunks & branches
    (maximum 4 inches
    in diameter by
    4 feet long)

Not accepted in the green cart:

  • Plastic bags, including compostable plastic bags
  • Poison oak
  • Cactus
  • Palm fronds
  • Pampas grass
  • Bamboo /li>
  • Meat
  • Cooking oil & liquid waste
  • Bones
  • Dairy & cheese
  • Plastic bags including
    compostable plastic bags
  • Poison oak
  • Cactus
  • Palm fronds
  • Pampas grass
  • Bamboo
  • Sudden Oak Death
    infested material
  • Dirt or rocks
  • Sod
  • Animal waste
  • Tree stumps
  • Other refuse

Download a .pdf fact sheet About Central Disposal Site (PDF: 60 KB)

Municipal composting program operations

The municipal composting program is operated by Sonoma Compost Company under contract with the Sonoma County Waste Management Agency. Sonoma Compost Company is responsible for processing all yard debris and vegetative food waste collected from Refuse Disposal sites and from weekly pick up of residential curbside green waste. Activities occur on a 25-acre portion of the Central Disposal Site between Cotati and Petaluma.

How is the material processed?
The yard debris is hand-sorted to remove unacceptable materials such as plastic bags and other non-organic items and then ground, and placed in windrows for about 10-12 weeks to produce a soil amendment. Specialty soil products are created by adding chicken feathers from local poultry processors, rice hulls and duck manure.

Municipal compost is OMRI “Organic” listed
OMRI Logo - Organic Meterials Review Institute Compost produced in the municipal program is listed as an allowed material by the Organic Materials Review Institute (OMRI) for use in the production of organic food and fiber. Because of this listing, compost produced by Sonoma Compost Company is used on a number of California Certified Organic Farms (CCOF).

How much material is processed?
In 2008, 92,000 tons of yard debris was transformed into a valuable soil amendment.

Where to purchase compost?
Sonoma Compost Company
500 Mecham Road
Petaluma, CA 94952
(707) 664-9113

Sonoma County Waste Management Agency ● 2300 County Center Drive, Suite B-100 ● Santa Rosa, CA 95403