Solid Waste Disposal Site Permits

Risk and Performance-Based Composting Facility Permitting

DEQ’s composting rules are structured such that the type of permit issued is based on the level of risk posed by a composting facility and anaerobic digesters to public health or the environment.
Composting rule highlights:
  • The rules establish a base of performance standards for any facility, addressing protection of public health and the environment.
  • The rules allow site operators the flexibility in site design, construction and operation to meet those standards.
  • The rules exempt, from permit requirements, lower-risk facilities that comply with performance standards.
  • Site screening criteria, established in rule, are used to determine the level of environmental and public health risk posed by a proposed facility, based on site-specific features of the facility.
  • The rules establish a tiered permitting system. Facilities not exempt from permitting but considered low-risk, after screening, would operate under a different type of permit than a facility that poses a higher environmental risk.
  • Permitting fees are structured so that facilities posing a greater threat and taking more DEQ oversight pay greater amounts.
​DEQ’s composting rules contain performance-based standards that all composting facilities must meet, including anaerobic digesters and facilities that are exempt from permitting requirements. These performance standards set a base level of facility performance and provide DEQ flexibility to exempt low-risk facilities from permitting requirements.

The performance standards address:
  • Proper management of stormwater, process water, leachate and liquid digestate to prevent pollution.

  • Odor minimization - to not create foul odors that affect neighbors

  • Prevention of vector propagation - eliminate conditions that attract flies, rodents and other pests

  • Protection of groundwater through facility design and operations, particularly if some facility liquids will be managed through soil infiltration.

  • Standards for pathogen reduction to protect public health and the environment, including for digestate.

For Anaerobic Digesters:

  • Appropriate collection and storage of biogas in order to minimize risk of explosion and fire.

  • Adequate storage capacity for liquid digestate for several reasons:

    • to store through Oregon’s wet winter months, when land application can cause water quality problems

    • to meet pathogen-reduction standards for time and temperature.

Feedstock Definitions

Feedstocks are the organic ingredients of composting processes, such as yard debris, animal manures and food scraps. Feedstock definitions also include the solid and liquid by-products of anaerobic digestion, called digestate. DEQ staff use a lot of information, including the type and amount of feedstocks, to determine if a permit is needed and what type of permit.

Feedstock types (common examples):

  • Type 1: yard and garden wastes, wood wastes, agricultural crop residues, wax-coated cardboard, vegetative food wastes; digestate from Type 1 feedstocks

  • Type 2: manure and bedding; also digestate from Type 2 feedstocks

  • Type 3: source-separated mixed food waste, meat, eggs, dairy products, mortality; also, digestate from Type 3 feedstocks

  • Type X: specified risk material from bovine animals that can be source of prions that can cause Bovine Spongiform Encephalitis. Type X is neither intended nor expected to be a normal composting facility feedstock. The idea is to specifically identify this material for special management.

When does a site need a composting facility permit?

The type and amount of feedstock composted is used to establish criteria for determining when a composting facility permit is required and when a facility is exempt from permitting requirements. Exempt facilities still need to maintain compliance with environmental performance standards. For facilities that do require a composting facility permit, the type of permit is determined based on site-specific physical characteristics, design characteristics and operations.

A permit is required if:

  • Type 1 and 2 Feedstocks: The facility receives > 100 tons of feedstocks per year

  • Type 3 Feedstocks: The facility receives > 20 tons of feedstocks per year -OR- the facility receives > 40 tons of feedstocks per year when using an in-vessel system

Obtaining a composting facility permit

According to DEQ rules, a composting facility is considered a solid waste disposal site. Composting facilities that need a permit must submit an application for a solid waste disposal site; applicants should check the “Composting Facility” box. DEQ will process the “complete” application, conduct a site and facility environmental risk screening to determine the type of permit required, conduct a public comment period on the drafted permit and issue the permit, barring a complicating issue. The table below outlines the permitting process and includes links to necessary application materials. 

The composting facility/anaerobic digester permitting process

Step 1 - Application

Operator of proposed composting facility gathers information and submits “complete” application to DEQ. Application materials include:

Step 2 - Completeness Review

Application received and reviewed for completeness; DEQ permit writers work with applicant to obtain complete application

Step 3 - Environmental Risk Screening

DEQ permit writer conducts environmental risk screening, makes a risk determination based on potential risk the site poses to pollute ground and surface water, soil or create nuisance odors that will negatively affect neighbors. DEQ contacts the applicant informing of the determination and sends an evaluation letter. If the site poses a risk, an individual permit and Site Operations Plan is required. If DEQ staff determine the site poses a low-risk, then a Registration permit will be required.

Step 4 - Draft Permit and Public Notice

DEQ permit writer drafts permit, permit evaluation report, public notice document, cover letter and puts draft out for public notice/comment period.

  • For Registration permit – 30-day comment period
  • For Individual composting facility permit – 35-day comment period

Step 5 - Comment Period Ends

DEQ permit writer responds to comments, alters permit as necessary and issues the permit. Note: An Individual composting facility permit may require a public hearing if at least 10 people or someone representing 10 people request one. A public hearing usually prolongs the permit issuance timeframe.

Step 6 - Length of time to Issue a Composting Facility Permit

Once DEQ receives a complete application (all required application materials) it takes roughly four to six months to issue a composting facility permit. Complex permits may take longer to issue.


For additional information, contact Bob Barrows, Composting Program Lead, at 541-687-7354.