This page provides information and resources for permitting an in-vessel digestion facility or operation.

Please note that other local, state, or federal agencies may also have regulatory authority over solid waste facilities.

What Is an In-Vessel Digestion Facility or Operation?

An “in-vessel digestion facility or operation” is a site that receives solid wastes for the purpose of digestion in an in-vessel digester.

  • Digestion” means, pursuant to Public Resources Code section (§) 40116.1, the controlled biological decomposition of organic solid wastes. Digestion includes: A) aerobic digestion; B) anaerobic digestion; and C) other controlled biological decomposition processes.
  • In-Vessel Digester” means the sealed container(s) or sealed structure in which the entire digestion process occurs.

Also see specific regulatory definitions in Title 14 of the California Code of Regulations (14 CCR) §17896.2.

Which Permit Is Required for In-Vessel Digestion Facilities or Operations?

The type of permit required for an in-vessel digestion facility or operation depends on the amount of material and type of feedstock being received.

Excluded TierEnforcement Agency Notification TierRegistration Permit TierFull Solid Waste Facility Permit
Refer to 14 CCR §17896.6Research In-Vessel Digestion Operations
14 CCR §17896.8
Medium-Volume In-Vessel Digestion Facilities
[average between 15 tpd (60 yd3) or 100 tpd, not to exceed 700 tpw (2,800 yd3)]
14 CCR §17896.12
Large-Volume In-Vessel Digestion Facilities
[average > 100 tpd, average > 700 tpw (2,800 yd3)]
14 CCR §17896.13
Dairy In-Vessel Digestion Operations
14 CCR §17896.9
Distribution Center In-Vessel Digestion Operations
14 CCR §17896.10
Limited Volume In-Vessel Digestion Operations
[average < 15 tpd (60 yd3), not to exceed 105 tpw (420 yd3)]
14 CCR §17896.11

A list of excluded activities that are not subject to the in-vessel digestion regulations can be found in 14 CCR §17896.6. Nothing in this section precludes the enforcement agency (EA) from inspecting an excluded activity to verify that the activity is being conducted in a manner that qualifies as an excluded activity or from taking any appropriate enforcement action.

What Permit Requirements Are Unique to In-Vessel Digestion Facilities or Operations?

  • All in-vessel digestion facilities and operations are required to comply with the state minimum standards set forth in Articles 1, 2, 3, 4, and 6, except as noted in 14 CCR §17896.1(a).
  • Article 5 set forth additional minimum standards that apply only to in-vessel digestion facilities.
  • A medium-volume in-vessel digestion facility is required to file with the enforcement agency (EA) an “In-Vessel Digestion Facility Plan” pursuant to 14 CCR §17896.14 and §18221.5.1.
  • An Odor Best Management Practice Feasibility Report may be required as specified in 14 CCR §17896.30.
  • A large-volume in-vessel digestion facility is required to file with the EA an “In-Vessel Digestion Report” pursuant to 14 CCR §17896.15 and §18221.6.1.
  • An Odor Minimization Plan is required for all in-vessel digestion operations and facilities as specified in 14 CCR §17896.31.

Pre-Existing Permits and Notifications

14 CCR §17896.3 describes the process and timelines for operators with pre-existing permits or EA notifications to apply for the proper tier.

Regulations Summary

Regulations Pertaining to In-Vessel Digestion Facilities and Operations
In-Vessel Digestion Regulatory RequirementsTitle 14, Chapter 3.2, Article 1
State Minimum StandardsTitle 14, Chapter 3.2, Articles 1, 2, 3, 4, and 6
Additional Minimum Standards for Facilities OnlyTitle 14, Chapter 3.2, Article 5
In-Vessel Digestion PlanTitle 14, §18221.5.1
In-Vessel Digestion ReportTitle 14, §18221.6.1
DefinitionsTitle 14, §17896.2
Pre-Existing Permits or Notifications Title 14, §17896.3
Regulatory Tier RequirementsTitle 14, Division 7, Chapter 5, Article 3.0

New Regulations Effective January 1, 2022:

The passage of SB 1383 resulted in changes to Title 14 CCR, Division 7, Chapter 3.2. The following is a brief summary of those changes:

  • Send digestate for additional processing or composting only to a transfer/processing facility or operations that meets the incompatible material limit or a composting facility or operation that demonstrates the percentage of organic waste sent to disposal are within organic fraction limits
New CalRecycle Standards Pertaining to Compostable Material Handling Facilities and Operations
Measuring Organic Waste in Material Sent to Disposal 14 CCR § 17869.44.1
Recordkeeping and Reporting Requirements14 CCR § 17896.45
Digestate Handling14 CCR § 17896.57(a)(3)(A)