Grown in Marin
University of California
Grown in Marin

Frequently Asked Questions

1.  Compost Biochemistry:  What happens during the composting process?

Compost biochemical processes result in the destruction of pathogenic organisms and the transformation of nutrients in manure into more stable forms that are less mobile and thus less available for contamination of surface water. The compost environment is extremely complex, but the aerobic composting process consists of 3 basic phases: an ambient temperature phase; a high temperature phase, and a maturation phase. The process begins with materials assembled in proper proportions, with carbon/nitrogen ratio being paramount, along with a pile moisture of about 60%.  Microbial activity in the pile results in temperatures rising from ambient to up to 175 F. During this high temperature phase, (over 131 F), which can last for weeks, the pile is turned at least 5 times to expose all materials to the high temperatures in the pile interior to insure pathogenic organisms and weed seeds are killed. Eventually, readily available microbial food sources are consumed and biological activity, and temperature, decline.  The compost then enters the maturation phase, where it is allowed to sit for a period of 30 to 90 days prior to use.

2.  How does the compost project work?

The Project includes five components: the processing of 1) green waste, 2) equestrian waste and 3) dairy manure, 4) marketing and outreach to the horticultural and agricultural community and the general public and 5) use of the project as an educational resource for the agricultural community, and the general public.

1) Green Waste Processing
The green waste drop site will be open to the public five days per week on an appointment only basis, and will be staffed at all times during open hours. West Marin green waste would be collected by waste management and delivered to the site. A drop-off fee will provide essential long-term financial support for the Project. Weekly, in accordance with California Integrated Waste Management Board (CIWMB) and Marin County Environmental Health requirements, a grinder will grind all assembled green waste, which will then be hauled to the dairy composting facility at a rate of 1-2 50-yard capacity trucks per week.

2) Equestrian Waste Processing
For a fee, the project operator will provide participating equestrian facilities with a roll-off dumpster for used bedding and manure. Empty dumpsters will be dropped off at the horse facilities, and full ones will be hauled directly to the composting facility on the dairy (not to the quarry grinding site) at a rate of up to two deliveries per day.

3) Dairy component
Each week, using a front end loader owned and operated by Lunny Grading and Paving (LGP), manure solids from the Lafranchi Dairy's manure separators will be combined with approximately equal volumes of green and equestrian wastes and formed into windrows on the composting pad. Any runoff from the compost area will flow to the dairy's liquid waste storage ponds. Windrows will be managed in accordance with US Environmental Protection Agency (EPA) and USDA National Organic Program (NOP) guidelines to reduce pathogens and weed viability to negligible levels. A mechanical screen will be used to separate finished compost into three components: fines for use as a soil amendment; coarse material for reintroduction to the composting process; and medium materials for use as dairy bedding material. Final compost volume will be approximately 60% of the total initial volume of raw materials.

4) Marketing and Outreach to the Farming Community and General Public
Marin Organic will market the product to the agricultural community. They represents more than 95% of the certified organic growers and producers in Marin County, totaling more than 30 farms and ranches on over 12,000 acres, including increasing numbers of organic dairies. Compost is vital to organic farming, and as the number of organic acres in Marin County continues to grow, so does the need for organic soil amendments.

5) Education
As Project partners, UC Cooperative Extension (UCCE) and the Marin Agricultural Commissioner's office will help develop the Project as an educational resource for the agricultural and natural resource management sectors.

3. Why do you need greenwaste to compost with manure?

Dairy manure is a wet, dense material that does not compost well on its own. By mixing green waste and equestrian waste with dairy manure, the ideal carbon/nitrogen ratio, moisture level and bulk density can be achieved for perfect aerobic composting conditions. The quality of the finished product will also be enhanced by co-composting the three waste streams.

4. How is the dairy's manure incorporated into the composting process?  How will it be different than how the dairy currently handles their manure?

Manure solids will be mixed with equestrian waste and green waste at the beginning of the composting process. Liquid dairy waste will be used to moisten the initial compost mix.  Currently, the dairy spreads liquid and solid manure directly on pastures during the summer and fall.

5. How much greenwaste will be accepted? How much volume is reduced from the chipping of greenwaste?

The typical volume of green waste delivered will be approximately 300 yards per week and the chipped and ground volume will be about 75 yards per week Grinding/chipping of green waste typically reduces volume by 50-75%.

6.  Will Nicasio residents be able to bring greenwaste to the site?

Yes, by appointment. Appointments are necessary to insure that currently permitted traffic limits are not be exceeded. Periodic free green waste drop off days for the Nicasio community will be made available.

7.  How will you ensure the product does not contain toxics? How can you stop residents from putting unwanted waste into collection bins?

It is illegal to put toxins into greenwaste cans or dispose of them in any but an approved toxic waste facility.  Each load will be inspected as it is off-loaded; contaminated loads will not be accepted; if contaminants are found following off-loading, the driver will be required to immediately reload and remove the material from the site.  As indicated in Question #9 below, State guidelines require testing of compost for sale on a regular basis.

8.  How will water be provided for the compost piles in drought years? Can the piles catch on fire?

The ideal moisture content of a compost pile is 50-60%. Compost piles can catch on fire if moisture and temperature are not properly monitored. Most of the water for the process will be come from liquid manure added at the beginning of the composting process.  Subsequent waterings, if needed, will use clean water from the Lafranchi Ranch. It may be necessary to truck in water in drought years. Dairy loafing barn roof catchment systems may also be used for additional fresh water storage.

9.  How will site be monitored? Who performs the monitoring?

The County of Marin Department of Health Services will regulate both the greenwaste and composting sites in accordance with CIWMB and Marin County guidelines.  Ongoing water quality monitoring in creeks flowing through the participating dairy will continue under the direction of UC Cooperative Extension.

10.  Why does the drop-off site have to be at the quarry? Why can't it be at the dairy where the composting occurs?

County regulations require the green waste drop-off site to have a full-time site attendant and restroom facilities.  The quarry site meets these requirements, while the dairy does not.  The quarry site is a significant match to the project cost.  There is not sufficient funding in the grant to establish these facilities at another site, nor is there the time available that would be required for the County to permit such facilities prior to the grant period running out.  There are also significant biosecurity and privacy issues at the dairy that must be respected.

11.  Why would agricultural producers want to spread compost onto pastures instead of liquid manure? Will the producers really use it?

Because finished compost is a dry material (typically less than 40-50% moisture at maturity, it is much less costly to spread than wet manure (typically 75-95% water). Finished compost is odorless and much less mobile under rainfall conditions than manure; in fact, compost is often used as an erosion control material to help prevent soil movement on disturbed sites. Properly composted material does not contain viable weed seeds, which liquid manure often does, so spreading compost does not encourage thistles or other weeds.

12.  Where are the greenwaste, dairy manure, and equine waste coming from?

Only green waste from West Marin will be accepted at the site; haulers will be required to present identification and report the origin of their load. Tipping fees will be comparable to other green waste drop off sites in the region to avoid any incentive for hauling green waste into West Marin from outside of the area. The problem may also be addressed by inflating tipping fees for outside users. The dairy waste will be limited to that produced on the Lafranchi dairy only. Equine waste will be limited to West Marin equestrian facilities only.

13.  How can we ensure we aren't getting equine waste etc. from outside this area?

Equine waste will be delivered to the compost site in roll off dumpsters hauled from horse facilities by the compost site operator; no material will be imported from outside West Marin.

14.  What truck trips are already happening as a result of hauling bedding, hauling away horse manure, hauling greenwaste through town?  Will there be fewer?

Hauling of bedding material into the dairy currently involves 2 to 3 transfer loads per week from the Central Valley.  Horse manure is currently being hauled out of the area but the exact number of truck trips in not known.  Greenwaste is currently being hauled through Nicasio on its way to San Rafael, Redwood, or Sonoma for disposal.

15.  Describe the magnitude of project truck trips.

While the precise number of truck loads is not known, it is certain that total vehicle hours on West Marin roads will decline significantly, due to local handling of materials now being hauled out of the area. No significant increase in traffic through Nicasio is anticipated. To insure no significant increase in traffic volume, the drop off site will be accepting green waste only by appointment and is designed to not exceed permitted traffic limits currently imposed on the quarry (average of 25 daily trips). It is estimated Waste Management will deliver 3-4 truck trips per week to the drop-off site.

16.  How will you keep people from showing up without an appointment?

Haulers showing up for the first time without an appointment will have the policy explained and warned that their load will not be accepted in the future without an appointment.

17. Describe the magnitude of noise limits

The drop-off site will use a grinder 1-2 hours per week and will be operational only during normal business hours.  The noise associated with the grinder will not exceed limits currently imposed on the quarry.

18. Will this project expand? Who keeps track of the amount of green waste that is dropped off?

The project is designed around the volume of manure produced by the dairy and the maximum volume of compost that can be held on site under state guidelines.  The project will operate under what is known as the "notification tier" in accordance with State regulations. No expansion is planned and none would be possible without complete regulatory review. This project therefore cannot expand; however, as indicated in Question #9, the site will be monitored by the County of Marin Environmental Health on a quarterly basis to ensure compliance.

19.  How will the product be sold?

Product will be sold in bulk and delivered by operator. A small amount of compost will be available for retail purchase at the green waste drop-off site.

20.  Will there be a review period if a permit is granted?

This is currently open for discussion.  Regardless of review periods stipulated in the permit, both the drop-off site and compost site will be inspected by Marin Department of Environmental Health Services for compliance at least quarterly.

21.  How can we be sure the project will work?

The project goals are to improve community water and air quality by diverting local waste materials from landfills, long distance hauling and environmentally inappropriate disposal and storage. Establishing the drop-off and composting sites will achieve these objectives.  The long-term economic viability of the project is dependent upon tipping fees associated with green waste and equestrian drop off and the value of the finished compost to the dairy as a bedding material. Thus, as long as the target waste streams are available, the project will be viable. If the waste streams were to cease to exist, the project would no longer be necessary.

22. Who is contributing matching in-kind dollars to the project?

LGP is contributing $393,000 in construction labor and equipment. The West Marin Compost Coalition is contributing $110,000 in consulting expertise. Other partnering agencies and organizations are contributing $100,000 in outreach, education and permitting assistance.

23.  What are the advantages for the Nicasio Community?

  • Residents have access to free (on designated days), local greenwaste drop off site.
  • Residents have access to local site for compost pick up.
  • Equestrian facilities have local outlet for manure drop off.
  • Dairy has access to local source of bedding material.
  • Improved watershed health. Reduction of untreated equestrian manure stockpiles and dairy manure applications and the addition of compost on land lead to improved soils and improved water quality in Nicasio Creek and tributaries.

24.  What are the environmental advantages of doing this project?  For the local community, for the greater community?

The project will have the following benefits:

  • Local production of a much-needed dairy bedding material. Dairy producers will be assisted through production of a much-needed, low-pathogen, cost-competitive, local alternative to sand for bedding.
  • Improved Water Quality Compliance with water quality regulations. There will be a significant improvement in water quality and nutrient balancing at the Project partner dairy due to the spreading of composted, rather than raw manure, on pastures.  Equestrian operations will benefit from the Project as a manure management tool. Most horse operations currently stockpile manures before hauling off site; this can lead to nutrient and pathogen-laden runoff to surface waters, as identified by the RWQCB.  Project implementation will eliminate these stockpiles and the threat they pose to water quality. Overall, there will be a significant reduction in non-point source pollution into nearby streams due to proper handling of 1,000's of cubic yards of equestrian and dairy waste.
  • Improved air quality, traffic safety and reduced vehicle impacts on County roadways. Average trucking time for West Marin greenwaste haulers will be reduced by 1.5 hours.  Hundreds of west Marin truck loads annually will be diverted from traveling to East Marin and beyond, saving hundreds of hours of trucking time and associated fuel, traffic impacts and road wear each year. Hauling of equestrian waste will be similarly reduced, representing a significant savings of fuel and trucking time on West Marin roads annually.
  • Enhancement of Marin County's air quality and contribution to atmospheric carbon sequestration. The project will assist in reducing production of global-warming atmospheric gases through the transportation fuel savings noted above, and by providing a local, organic alternative to the thousands of tons of fossil fuel-derived fertilizers applied annually to Marin's rangelands and agricultural lands. Under rapidly evolving global carbon-trading scenarios, the diversion of methane and carbon dioxide-producing materials to the soil carbon pool as compost represents a potentially significant asset to the regional agricultural economy.
  • Decreased soil erosion and increased water infiltration. Natural resources and ecosystem processes in West Marin will benefit through increased utilization of soil quality improving compost and reduction of inorganic commercial fertilizer use.  Compost produced at the Project site will be made available to organic and non-organic producers on a wholesale basis. Compost of known quality will be readily available for use by the Marin RCD in on-farm erosion control projects in accordance with US EPA guidelines for use of compost as an erosion control material for biotechnical slope stabilization.
  • Economic sustainability. By processing west Marin's organic waste stream for re-use within West Marin, the community will save an estimated 1,500 hours of trucking at $80.00 per hour, or roughly $120,000.00 per year.  This also represents a savings of approximately 15,000 gallons of fuel annually.  The project will also make local, organic compost available to West Marin producers with associated savings in truck charges over imported material.  A significant community waste stream will be converted to a valuable product for reuse within the community. Local dollars will be retained through conservation, diversion and reuse of economic and natural resources within the community.
  • Increased life expectancy for the East Marin Redwood landfill.  Diversion of West Marin organic waste materials away from landfill disposal to reuse within West Marin will benefit all Marin residents.



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