Compost Facility Frequently Asked Questions (FAQs)

The questions and answers below may help you find the information you’re looking for. This page will be updated as the project progresses, so check back now and then for new information. If you have a question and don’t see the answer below, please use the project comment form to send it to staff for a response.

What is compost/composting?

Composting is the process of organic materials, like leaves and food scraps, breaking down or decomposing into a nutrient rich product.

Finished compost is an end product of the composting process. Finished compost can be applied to dirt as a soil amendment to improve its health, increase its water holding ability, and sequester carbon.

What materials will the facility accept and where will those materials come from?

The county is focused on a facility that could accept both yard waste and food scraps from residents, businesses, and farmers. Examples of sources and types of materials that will be explored for acceptance include:

Residential yard waste (tree trimmings, brush, grass, weeds, etc.)
Residential and commercial food scraps
Commercial yard waste (from landscaping operations, arborists, and garden centers)
Crop residue and vegetative materials from agricultural operations
Vegetative and woody materials from municipal and county wildfire mitigation and Parks and Open Space Department operations

What about certified compostable packaging, certified compostable bags, paper towels, napkins, coffee filters, and tea bags?

We’re working to understand if these types of materials can be accepted without creating a contaminated finished product. Acceptance of compostable packaging and other paper products will be analyzed as a part of this initial project phase.

What about biosolids?

The project team has decided to not consider biosolids as a feedstock at a potential compost facility.

Biosolids as defined by the Environmental Protection Agency (EPA) are “a product of the wastewater treatment process.” They are a stabilized solid organic matter final product that are nutrient-rich and contain valuable ingredients for crop growth and improving soil conditions. Biosolids are overseen, tested, and regulated by state and federal agencies to ensure consumer safety. Currently, biosolids are being applied to land across the state, but they can also be added to composting processes to add nutrients.

Where will the facility be located?

Boulder County DOES NOT currently have a site selected. We do know that it will not be at the previously explored Rainbow Nursery site on US 287 near Lookout Road in eastern Boulder County. Potential site analysis is part of the initial phase of this project.

Will the site be on Boulder County Parks & Open Space land?

Boulder County is not exploring using Boulder County Parks & Open Space land for a compost facility.

How large will the facility be?

Currently, about 48,000 tons of food scraps and yard waste from Boulder County residents and businesses are collected and sent to A1 Organic’s private processing facility in Keenesburg, CO. Boulder County is considering a facility that would be large enough to process this amount locally as well as additional organic material, generated within the county, that is currently being landfilled. The county is looking for a 10 to 20 acre site.

Who will operate the facility and how will material be processed?

Operational aspects, like the processing equipment and the operator, will be evaluated as part of the initial phase of assessments.

What about odors from a facility and from the finished compost?

Finished compost smells earthy and not noxious. Correctly finished compost smells earthy and not noxious. Bad smells from finished compost indicates a processing issue where there is not enough oxygen within the organic material. When there is not enough oxygen, the composting microorganisms shift from aerobic (oxygen needing) to anaerobic (non-oxygen needing). Anaerobic microbes create smells as byproducts of them processing materials.

Odors are controlled and eliminated in compost facilities through proper site design and process management. Examples of odor elimination techniques include enclosing compost operations inside a building, using air filtration systems, and covering piles of material daily. Boulder County staff will explore all operational best practices. Additionally, impacts from compost facilities Colorado Department of Public Health and Environment (CDPHE) regulates compost facilities and their impacts, such as odors.

What about contamination in the finished compost? PFAS? Microplastics?

Boulder County will analyze which input materials to accept along with the best processing techniques and technologies to produce the highest quality finished compost products. The county understands that the finished compost product must meet the highest standards to be useable by customers.

What about water quality around a facility? Traffic caused by a new facility? Other impacts?

Potential impacts are site specific and addressed during the site design and permitting process. The county has not chosen facility location but will engage with the community to understand concerns.

For any commercial compost facility to be built in Boulder County, the facility operator – whether County or another party – would need to apply for and be issued a Special Use permit through the Boulder County Community Planning & Permitting Department. Additionally, all facilities in Colorado also need to be permitted through the Colorado Department of Public Health and Environment (CDPHE). These permits require comprehensive site design, engineering review, operation review, traffic, and environmental impact studies. The mitigation of impacts is required prior to the issuance of permits.