California Code of Regulations
Title 14 - Natural Resources
Division 7 - Department of Resources Recycling and Recovery
Chapter 3.2 - In-Vessel Digestion Operations and Facilities Regulatory Requirements
Article 6 - Digestate Handling Standards
Section 17896.61 - Physical Contamination Limits

(a) Compost produced at an in-vessel digestion facility (pursuant to section 17896.57(a)(2)) shall not contain more than 0.5% by dry weight of physical contaminants greater than 4 millimeters; no more than 20% by dry weight of this 0.5% shall be film plastic greater than 4 millimeters. Compost that contains physical contaminants in excess of either one or both of these limits shall be designated for additional processing, disposal, or other use as approved by local, state and federal agencies having appropriate jurisdiction. Verification of physical contamination limits shall occur prior to the point where compost is removed from the site or beneficially used on-site. Test results of samples must be received by the operator prior to removing compost from the in-vessel digestion facility where it was produced.

(b) The operator of an in-vessel digestion facility with an on-site aerobic compost process shall sample every 5,000 cubic-yards of compost produced and determine the percentage of physical contaminants greater than 4 millimeters in the sample using a method that provides accurate results and has been approved by the EA. If the in-vessel digestion facility produces less than 5,000 cubic-yards of compost in a 12 month period, the operator shall analyze at least one composite sample of compost produced every 12 month period.

(c) If the EA has reason to believe, based on the EA's visual observation or otherwise, that a determination of percent physical contaminants made pursuant to section 17896.61(b) is not accurate, the EA may require an operator of an in-vessel digestion facility to take a composite sample of compost in the presence of the EA and send the sample to a laboratory at which physical contaminants greater than 4 millimeters shall be collected and weighed to determine the percentage of physical contaminants by dry weight using the following protocol:

(d) Any sampling conducted to comply with this section shall require a composite sample. A composite sample shall be representative and random, and may be obtained by taking twelve (12) mixed samples as described below.

(e) Alternative methods of compliance to meet the requirements of this section may be approved by the EA if the EA determines that the alternative method will ensure the physical contaminant requirements of this section are met.