Threats to Organic Recycling Programs

Emissions Reduction from Composting & Related Facilities

Background

The South Coast Air Quality Management District (AQMD) is responsible for implementing emission reduction requirements to achieve clean air standards. AQMD targeted emissions from chipping and grinding and composting operations in the development of Rule 1133. 

In August 2001, the AQMD proposed one rule that would have required all composting facilities to be enclosed with emissions vented to a biofilter; AQMD scheduled adoption of the rule for November 2001. The proposed rule would have been a cost-prohibitive solution for many compost processors and subsequently would have had serious impacts on the ability of local jurisdictions to meet their waste diversion mandates. 

Based on further technical assessment and on subsequent input from stakeholders, including industry, local government, and CIWMB, the AQMD instead adopted three rules—rather than a single rule—with significant modifications to the originally proposed rule language that includes alternative control strategies.

Adopted Rules

On January 10, 2003, the AQMD adopted the following rules on emissions reductions from composting and related facilities.

• Rule 1133—Reporting and Registration
• Rule 1133.1—Chipping and Grinding Activities
• Rule 1133.2—Co-Composting Operations

In addition, AQMD plans to develop an additional Proposed Rule (PR) 1133.3 for greenwaste composting.

• PR 1133.3—Greenwaste Composting

Rule 1133—Reporting and Registration

Chipping and grinding activities and composting facilities will be required to register by 7/1/03 and to renew their registration annually. The registration process requires submittal of facility information including:

• Types and amounts of materials received.
• Design and actual throughput.
• Published tipping fees.
• Enforcement actions issued by the local enforcement agency (LEA) and CIWMB for the preceding year.

Exemptions are provided for portable chipping and grinding; wood-waste chipping and grinding; and community, agricultural, nursery, recreational, and backyard composting.

Rule 1133.1—Chipping and Grinding Activities

Chipping and grinding activities have holding time restrictions by material type: 2 days for food waste, 3 days for curbside greenwaste, 14 days for noncurbside greenwaste, and 7 days for mixed greenwaste. Rule 1133.1 also includes considerations for wet weather conditions and a moisture content exemption on chipped and ground greenwaste of 30 percent. Exemptions are provided for the following chipping and grinding activities: portable, agricultural, land clearing, wood waste, and palm.

Rule 1133.2—Co-Composting

Green highlighted words indicate definitions and links to the glossary.

Co-composting facilities are required to meet 80 percent emission reductions for new facilities and 70 percent emission reductions for existing facilities for both volatile organic compounds (VOC) and ammonia. Rule 1133.2 now provides more flexibility in acceptable control methods through submittal of a compliance plan that includes options of feedstock mix, process controls, best management practices, and/or a combination of methods, in addition to the original choices of enclosure, aeration, and biofiltration. Also, greenwaste composting can include up to 20 percent manure before it is considered co-composting and subject to Rule 1133.2.

PR 1133.3—Greenwaste Composting

AQMD may consider development of another proposed rule to control emissions from greenwaste composting facilities (PR 1133.3). Currently, it appears that AQMD may work on developing PR 1133.3 in 2005 and will consider using best management practices as emissions reduction control strategies.

Best Management Practices (BMP)

CIWMB completed emissions tests on greenwaste composting at Tierra Verde Industries in Irvine in November 2002. The tests were designed to evaluate emission reductions that could be achieved by controlling feedstock mixtures and aeration techniques. Specifically, two blends of feedstock were used, a woody blend (high carbon:nitrogen ratio) and a grassy blend (low carbon:nitrogen ratio). Two levels of aeration were evaluated as well: static windrows (natural convection only) and mechanically turned windrows using a Scarab. 

The results from the emission tests indicated that ammonia emissions were non-detect or extremely low and should not be an issue of concern for greenwaste composting. The emission results for volatile organic compounds (VOC) indicate that controlling feedstock blends can effectively reduce VOC emissions. The results associated with aeration techniques show different emission profiles over time; however it is difficult to conclude whether aeration techniques can lower total emissions without conducting a life cycle assessment. Overall, the Tierra Verde tests supported the concept of using best management practices, that are affordable operating strategies requiring minimal technology, to lower emissions.

The CIWMB has subsequently funded a research project with San Diego State University to conduct life cycle assessment studies on effective best management practices to lower emissions from greenwaste composting. This project will provide further definition for a menu of BMPs, the conditions under which they should be used, and the anticipated emission reductions that can be realized. The research project includes a field demonstration of the most promising BMPs. The project also includes an evaluation of baseline emissions for naturally occurring organic materials. The CIWMB anticipates the findings from this research to be essential supporting information in the AQMD’s development of PR 1133.3 for greenwaste composting.

CIWMB Contact: Bob Horowitz

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Last updated: August 01, 2008