ATTACHMENT F 

SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT 

Draft Final Staff Report 

Proposed Rule 1133 – Composting and Related Operations – General 

Administrative Requirements 

Proposed Rule 1133.1 – Chipping and Grinding Activities 

Proposed Rule 1133.2 – Emission Reductions from Co-Composting 

Operations

January 10, 2003 

Deputy Executive Officer 

Planning, Rule Development and Area Sources 

Elaine Chang, DrPH 

Assistant Deputy Executive Officer 

Planning, Rule Development and Area Sources 

Laki T. Tisopulos, Ph.D., P.E. 

Planning and Rules Manager 

Planning, Rule Development and Area Sources 

Zorik Pirveysian 

Authors: Tuyet-Le Pham – Transportation Specialist

Ricardo A. Rivera – Air Quality Specialist 

Reviewed By: Barbara Baird - District Counsel 

Frances Keeler - Senior Deputy District Counsel 

 

Contributions: Jay Chen - Sr. Air Quality Engineer Manager 

Shah Dabirian – Air Quality Specialist 

Mike Garibay – Sr. Air Quality Engineer 

David Jones - Air Quality Analysis & Compliance Supervisor 

Julia Lester, Ph.D. - Program Supervisor 

Charles Tupac - Sr. Air Quality Engineer 
SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT 

GOVERNING BOARD

CHAIR: WILLIAM A. BURKE, Ed.D. 

Speaker of the Assembly Appointee 

 

VICE CHAIR: S. ROY WILSON, Ed.D. 

Supervisor, Fourth District 

Riverside County Representative 

MEMBERS: 

MICHAEL D. ANTONOVICH 

Supervisor, Fifth District 

Los Angeles County Representative 

HAL BERNSON 

Councilmember, City of Los Angeles 

Cities Representative, Los Angeles County, Western Region 

JANE W. CARNEY 

Senate Rules Committee Appointee 

WILLIAM CRAYCRAFT 

Councilmember, City of Mission Viejo 

Cities Representative, Orange County 

BEATRICE LAPISTO-KIRTLEY 

Councilmember, City of Bradbury 

Cities Representative, Los Angeles County, Eastern Region 

RONALD O. LOVERIDGE 

Mayor, City of Riverside 

Cities Representative, Riverside County 

FRED AGUIAR 

Supervisor, Fourth District 

San Bernardino County Representative 

LEONARD PAULITZ 

Mayor Pro Tem, City of Montclair 

Cities Representative, San Bernardino County 

JAMES W. SILVA 

Supervisor, Second District 

Orange County Representative 

CYNTHIA VERDUGO-PERALTA 

Governor's Appointee 

EXECUTIVE OFFICER: 

BARRY R. WALLERSTEIN, D.Env. 
Table of Contents 

PR 1133, 1133.1, and 1133.2 i January 2003 

TABLE OF CONTENTS 

Executive Summary ................................................................................................ 1 

Background ............................................................................................................. 4 

Industry Profile ........................................................................................... 5 

Chipping and Grinding Activities ............................................................. 7 

Co-Composting Operations ....................................................................... 8 

Regulatory Background ............................................................................ 11

Other Issues Facing the Composting Industry ......................................... 14

Emissions Inventory and Reductions .................................................................... 17 

Control Methods ..................................................................................................... 18

Cost Effectiveness ................................................................................................... 19 

Summary of Proposed Rules ................................................................................. 21

Environmental Assessment..................................................................................... 27 

Socioeconomic Assessment ..................................................................................... 27 

Comparative Analysis ............................................................................................. 28 

Draft Findings ......................................................................................................... 28 

Conclusions .............................................................................................................. 29 

Comments and Responses ...................................................................................... 29 

List of Figures and Tables 

Figure 1 Composting Phases ......................................................................... 10 

Table 1 Composting and Related Operations Industry ............................ 6 

Table 2 Composting Facilities by County ................................................... 6 

Table 3 Emissions Inventory and Reductions for Existing 

Co-Composting Operations ............................................................ 17 

Table 4 Co-Composting Annualized Costs and Cost-Effectiveness 

Analysis ($/ton)................................................................................. 20 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 1 January 2003 

EXECUTIVE SUMMARY 

The proposed rules for composting and related operations are presented here as three separate 

rules: Proposed Rule 1133 – Composting and Related Operations - General Administrative 

Requirements; Proposed Rule 1133.1 – Chipping and Grinding Activities; and Proposed Rule 

1133.2 – Emission Reductions from Co-Composting Operations. The proposed rules are 

designed to regulate and reduce emissions from composting and related operations, which for 

the most part are currently not subject to specific District regulations. The purpose of these 

proposed rules is three fold: 1) establish a registration and annual reporting program for 

composting-related facilities to better characterize the emissions and operations of this 

industry and keep track of activity levels (PR 1133); 2) develop holding and processing time 

requirements for chipping and grinding activities in order to prevent inadvertent 

decomposition of greenwaste and foodwaste (PR 1133.1); and 3) reduce VOC and ammonia 

emissions from co-composting operations (PR 1133.2). 

The proposed rules would in part implement Control Measure WST-02 – Emission 

Reductions from Composting, which was included in the 1994 and 1997 AQMPs as well as 

in the 1999 Amendment to the 1997 Ozone State Implementation Plan for the South Coast 

Air Basin. The control measure called for the development of an emissions inventory as well 

as identification of technically and economically feasible control options for composting 

operations. Accordingly, a technology assessment was conducted by staff, which provided 

the industry profile and background information on composting operations, developed an 

estimated emissions inventory, identified and evaluated various control methods, conducted 

cost-effectiveness analysis, and provided recommendations for rule development. The 

technical assessment was presented to and approved by the AQMD’s Governing Board in 

April 2002. The information presented in this staff report is based on the technical 

assessment report as well as additional or new information obtained and developed since 

April 2002 (Attachment A to the Draft Final Staff Report). 

The three primary categories of the composting and related operations industry include cocomposting, greenwaste composting, and chipping and grinding which contribute to 

significant amounts of VOC and ammonia emissions in the South Coast Air Basin (Basin). 

VOCs and ammonia are precursors to ozone and PM10 emissions for which ambient air 

quality standards are currently exceeded in the Basin. Although emissions from greenwaste 

composting operations are significant (i.e., 4.4 approximately 5 tons of VOC and 1 ton of 

ammonia per day) and control options for these operations could result in significant 

reductions, the affordability analysis presented in the technology assessment demonstrated 

that the cost impact for this industry would be substantial at this time. Therefore, specific 

control requirements are not proposed for greenwaste composting operations at this time. 

Staff would continue to work with all stakeholders including the California Integrated Waste 

Management Board (CIWMB), sanitation districts and local municipalities to seek funding 

sources and identify feasible control methods for greenwaste composting operations. For cocomposting operations, however, based on the technology assessment report prepared by 

staff, control methods (e.g., enclosures, forced aeration, in-vessel systems, and biofilters) are 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 2 January 2003 

available which can significantly reduce emissions from these operations in a cost-effective 

manner. 

PR 1133 would require composting and chipping and grinding facilities to register with 

AQMD and provide their facility and throughput information (e.g., type and amount of 

feedstock and products, process description, etc.). These facilities will also be required to 

provide annual updates to AQMD on their registration information. Specific exemptions are 

provided for small scale operations such as nurseries; community, agricultural, recreational 

and backyard composting; and wood waste and portable chipping and grinding activities. 

PR1133.1 would establish holding and/or processing time requirements for greenwaste and 

foodwaste chipping and grinding activities in order to prevent inadvertent decomposition 

occurring during stockpiling greenwaste and/or foodwaste for extended periods of time. 

Stockpiling greenwaste (or foodwaste) for extended periods will cause the organic materials 

to decompose anaerobically and generate VOC and NH3 emissions (as well as odors) based 

on source tests conducted by District and CIWMB. High temperature and VOC monitoring 

data recorded during District staff site visits also demonstrate that these piles are in the 

process of decomposing. Inadvertent decomposition refers to decomposition of greenwaste 

(or foodwaste) which is not associated with normal chipping and grinding operations. 

Therefore, the proposed rule requires the removal or processing (i.e., on-site applications) of 

foodwaste and greenwaste received by facilities for chipping and grinding purposes within 

specified timeframe upon receipt. Specifically, foodwaste is required to be removed or used 

on-site for composting within 2 days of receipt. Curbside greenwaste such as household 

grass clippings and leaves is required to be chipped and ground or removed from the facility 

within 3 days of receipt. Non-curbside greenwaste, which is mainly composed of tree 

trimming and landscaping greenwaste, is required to be chipped and ground or removed from 

the facility within 14 days of receipt. Mixed greenwaste, that contains both curbside and 

non-curbside greenwaste, is required to be chipped and ground or removed from the facility 

within 7 days of receipt. All of the holding/processing time requirements stated above 

exclude state and federal holidays as well as rainy days and wet weather conditions following 

a rainy day (up to 10 days) which impede normal chipping and grinding operations. Chipped 

and ground curbside greenwaste are also required to be removed from the facility or used for 

on-site applications within a period of 3 days (unless the moisture content is less than 30%). 

The requirements for curbside greenwaste are different from non-curbside greenwaste since 

non-curbside greenwaste tend to decompose at slower rate compared with curbside 

greenwaste due to the lower moisture content of non-curbside greenwaste. 

PR1133.2 would require new co-composting operations to enclose their active co-composting 

operations and use forced-air aeration system for their curing part of the operations. Both the 

air exhaust from the enclosure and the aeration system are to be vented to an emission control 

system with a control efficiency of at least 80 percent for VOC and ammonia emissions. As 

an alternative to enclosing the active phase and aeration system for curing phase, new cocomposting operations may employ any combination of composting and control methods to 

achieve an overall control efficiency of 80 percent by weight for VOC and ammonia 

emissions from both the active and curing phases of the composting process. This optional 

method of compliance would also require the submittal of a compliance plan at least one year 

prior to start of operations. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 3 January 2003 

It should be noted that the recommendations in the Technology Assessment report for cocomposting operations only included requirements for new co-composting operations (with 

100,000 tons or more of throughput) because of potential cost impact on existing and smaller 

new facilities. However, at the April 2002 Board meeting as well as subsequent Stationary 

Source Committee meetings, the Board members directed staff to re-evaluate the cost of 

controlling emissions from existing as well as new facilities, in addition to large new 

facilities, because costs need not necessarily be borne by the facility, but may be passed on as 

a fee to waste disposal customers. Based on staff's analysis, the compliance cost for all 

existing co-composting operations will represent only a nominal increase of $0.25 per month 

per household assuming that the cost would be passed onto the Basin households. For a new 

co-composting facility, the compliance cost will be $0.004 per month per household for every 

10,000 tons of throughput using the same assumption. Therefore, emission reductions from 

existing and new smaller facilities are also feasible (in addition to larger new facilities) 

assuming the cost would be passed through to households in the Basin. These facilities are 

included in PR1133.2 for the Board's consideration. 

Under PR 1133.2, existing co-composting operations will be required to demonstrate an 

overall control efficiency of 70 percent for VOC and ammonia emissions based on 

implementation of any combination of composting and control methods. Existing cocomposting operations would also be required to submit a compliance plan at least one year 

prior to their effective date of compliance. The compliance date for new co-composting 

operations is as of the date of adoption of this rule (i.e., prior to start-up). Existing cocomposting operations compliance dates range from the year 2007 to 2009 depending on the 

size of their operations. 

Compliance with PR 1133.2 can be demonstrated based on a comparison of the cocomposting baseline emission factors, developed by the District, with the controlled 

emissions. The baseline emission factors, included in the proposed rule, were based on 

source tests conducted on existing co-composting operations (i.e., 1.78 pounds of VOC and 

2.93 pounds of ammonia per ton of throughput). The proposed rule also allows cocomposting operators to develop their facility-specific baseline emission factors to 

demonstrate that the reduction requirements are met. 

The emissions inventory for co-composting operations is estimated to be 1.67 and 2.74 tons 

per day of VOC and ammonia, respectively. The proposed rule is expected to reduce VOC 

and ammonia emissions by 70 percent (1.17 tons of VOC per day and 1.92 tons of ammonia 

per day) from existing co-composting operations. Depending on the control method selected, 

the cost-effectiveness would vary for co-composting facilities. For new co-composting 

facilities, the cost effectiveness is estimated to be about $24,000 to $27,000 per ton of VOC 

reduced or $11,000 to $12,000 per ton of VOC and ammonia reduced based on fabric or 

concrete type of enclosure for the active phase of composting and forced aeration system for 

the active and curing phases of operations vented to a biofilter. For existing co-composting 

facilities, the cost effectiveness would vary based on the composting/control methods 

selected. Three scenarios are presented in the cost-effectiveness section for existing cocomposting facilities. Depending on the type of enclosure for active phase and forced 

aeration system for curing phase both vented to a biofilter, the cost-effectiveness would range 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 4 January 2003 

from approximately $8,700 to $10,000 per ton of VOC and ammonia reduced or $23,000 to 

$26,500 per ton of VOC reduced. Assuming that forced aeration system in combination with 

other methods (e.g., process controls, biofilters) for both active and curing phases (without 

building enclosure) could achieve the required reductions (i.e., 70% VOC and 70% 

ammonia), the cost-effectiveness could be as low as $6,500 per ton of VOC and ammonia 

reduced or about $17,000 per ton of VOC reduced. Forced aeration systems in combination 

with methods such as optimized process controls and optimized feedstock ratios could result 

in significant emission reductions. 

Facilities affected by PR1133 will be subject to a one-time registration fee equivalent to the 

plan submittal fee in Rule 306 - Plan Fees which is currently $89.59. PR1133.1 would also 

result in minimal cost to affected facilities for recordkeeping. There are no additional cost 

associated with compliance with PR1133.1 since emission reductions are not claimed under 

PR1133.1 for the chipping and grinding activities and the rule establishes holding/processing 

time requirements for greenwaste (and foodwaste) to prevent inadvertent decomposition 

associated with stockpiling greenwaste (and foodwaste) for extended periods of time. Based 

on information provided by the industry and through CTAC, chipping and grinding activities 

subject to the rule are already processing their greenwaste within the time frame proposed in 

PR1133.1, and therefore, emission reductions, and additional costs, if any, are not expected 

to be significant. The objective of establishing these standard holding/processing time 

requirements is to prevent emissions from increasing for chipping and grinding activities. 

BACKGROUND 

The 1994 and 1997 AQMPs as well as the 1999 amendments to the 1997 AQMP Ozone State 

Implementation Plan (SIP) for the South Coast Air Basin included the proposed Control 

Measure WST-02 – Emission Reductions from Composting. The control measure was 

proposed to be implemented in two phases. Under Phase I, an emissions inventory of 

composting operations would be developed based on additional source tests and improved 

test protocols. Depending on the significance of these emissions, Phase II would identify 

specific control options to reduce emissions (VOC and ammonia) from composting activities. 

In order to implement the proposed control measure, AQMD staff conducted a technical 

assessment for composting and related operations. The technology assessment provided the 

composting industry’s profile, estimated emissions inventory, evaluated various composting 

methods and control technologies, and conducted cost-effectiveness analysis. 

At its April 5, 2002 Board meeting, the Governing Board of the South Coast Air Quality 

Management District (AQMD) conducted a Pre-Hearing on controlling VOC and ammonia 

emissions from composting and related operations and received staff’s Technology 

Assessment Report. Based on the Technology Assessment Report (April 2002), significant 

VOC and ammonia emissions are attributed to the composting and related operations. The 

baseline emissions inventory for this industry (i.e., co-composting and greenwaste 

composting only) is estimated at 6.8 and 4.7 tons per day for VOC and ammonia, 

respectively. The technology assessment also identified and evaluated a number of feasible 

control technologies for co-composting operations. (For more details on the composting 

industry, emissions inventory estimation, control technology assessment, and cost-
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 5 January 2003 

effectiveness analysis, refer to the Technology Assessment Report (Attachment A to the Draft

Final Staff Report). Accordingly, the Governing Board directed AQMD staff to proceed with 

rulemaking and to develop a series of proposed rules to address each sector of the composting 

and related operations industry independently. Also, according to the AQMD Governing 

Board’s direction, a Composting Technical Advisory Committee (CTAC) was established to 

oversee the on-going technical studies of cost-effective composting control technologies and 

assist AQMD staff during rule development. In addition, a Co-Composting subcommittee to 

CTAC was subsequently formed to further evaluate specific issues related to controlling 

emissions from co-composting operations. Board members also directed staff to evaluate the 

feasibility of controlling emissions from existing and smaller new facilities. 

Industry Profile 

The AQMD developed an inventory of facilities involved in composting operations and/or 

chipping and grinding activities based on information obtained from the California Integrated 

Waste Management Board (CIWMB) permit database, AQMD permit system, AQMDconducted surveys, facility inspections and comments from the public. Through this process, 

277 facilities were identified that represent the composting and related operations industry. 

For the purpose of rule development, these facilities are classified into four categories: 1) cocomposting facilities; 2) greenwaste composting facilities; 3) chipping and grinding facilities; 

and, 4) exempt facilities. 

Co-composting facilities include composting facilities that use putrescible materials, such as, 

biosolids and/or manure in combination with greenwaste or foodwaste to produce compost 

products. Greenwaste composting facilities are composting facilities that use green-waste as 

raw feedstock materials or greenwaste with small amount of amendments such as manure. 

Chipping and grinding facilities are facilities dedicated to the size reduction of greenwaste or 

wood waste to be used in composting, as alternative daily cover (ADC) for landfills, as 

feedstock for waste-to-energy facilities, or for producing mulch. Finally, exempt facilities are 

those facilities that are proposed to be categorically exempt from the proposed rules because 

of the type of operation (e.g., nurseries, community composting, and portable 

chipping/grinding activities, agricultural composting). Table 1 provides a breakdown of the 

composting-related facilities as well as their estimated annual throughput. 

 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 6 January 2003 

Table 1 - Composting and Related Operations Industry 

Category 

Number 

of 

Facilities 

Throughput 

(tons/year) 

Co-Composting 9 6833701

Greenwaste-composting 18 867,618a

Chipping/Grinding 47 3,033,092 b

Exempt Facilities 203 237,356

 

Total 277 4,821,436 

a Four facilities have unknown throughputs. 

b Twenty-one facilities have unknown throughputs. Note that a portion of the chipped/ground 

greenwaste could be used for greenwaste and co-composting operations. 

The geographical distribution of the facilities for the composting and related operations 

industry, by county, is approximately 42, 20, 22 and 16 percent for Los Angeles, Orange, 

Riverside, and San Bernardino counties, respectively. Table 2, Composting Facilities by 

County, provides information of the number of facilities in each of the counties by industry 

sector. 

Table 2 

Composting Facilities by County 

Category 

Number of Facilities by County

Los Angeles Orange Riverside San Bernardino

Co-Composting 3 0 1 1 2 5 3

Greenwastecomposting6 5 4 3

Chipping/Grinding 20 9 13 5

Exempt Facilities 87 39 26 51

Total 116 54 45 62

 

1

Throughput includes both putrescible materials and bulking agents (i.e., greenwaste). 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 7 January 2003 

Chipping and Grinding Activities 

For the purpose of proposed rules 1133 and 1133.1, chipping and grinding is defined as an 

activity that mechanically reduces the size of greenwaste, woodwaste or food waste, using 

chippers and/or tub grinders. Chipping and grinding can be a stand-alone operation, or part 

of a landfill or a composting operation. 

Chipping and grinding facilities process greenwaste, which is mostly, collected from 

landscapers or from cities’ curbside collection programs. Curbside greenwaste is collected 

from receptacles designated for residential household greenwaste, and is mainly composed of 

succulent materials such as grass clippings and weeds. Curbside greenwaste tends to 

decompose quickly under high temperature and moisture conditions, and may also contain 

other putrescible wastes (i.e., foodwaste). Non-curbside greenwaste is greenwaste that is not 

collected from curbside programs and mainly contains tree trimmings and other landscaping 

greenwaste. Non-curbside greenwaste is expected to decompose at a much slower rate due to 

its low moisture content. 

At chipping and grinding facilities, curbside greenwaste is usually separated from other waste 

contaminants such as food, glasses, cans, or paper waste, prior to being chipped or ground. 

In some facilities, in order to maintain a low moisture level needed for certain end products, 

curbside greenwaste is kept separately from non-curbside greenwaste, or is sorted to separate 

grassy greenwaste material from woody material. Also, in order to obtain fine or coarse 

products, chipping and grinding facilities may also screen greenwaste either before or after 

the chipping and grinding activity. Generally, curbside greenwaste is chipped/ground and 

transferred to customers or used for on-site applications within 2 to 3 days of receipt of 

greenwaste (except for holidays or extreme circumstances). There is a broad market for 

chipped and ground curbside greenwaste where they can be utilized as alternative daily cover 

(ADC) at landfills, mulch, feedstock for greenwaste composting, and bulking agents for 

manure and/or sewer sludge composting. 

Stockpiling greenwaste, especially those from curbside collection, for an extended period of 

time (under favorable moisture and temperature conditions), will cause anaerobic 

decomposition of greenwaste and will result in VOC and ammonia emissions. High 

temperature readings and VOC emissions data obtained from greenwaste piles at chipping 

and grinding facilities are strong indicators of the greenwaste decomposition. District's 

recent source tests for curbside and non-curbside greenwaste have also confirmed that VOC 

and ammonia emissions occur from greenwaste piles. Chipping and grinding activities are 

required to comply with PR 1133.1, which establishes holding or processing time 

requirements for foodwaste, curbside and non-curbside greenwaste in order to prevent 

inadvertent decomposition of greenwaste and foodwaste. 

Chipping and grinding activities could also generate significant amounts of particulate matter 

(PM) emissions when wood waste or greenwaste is mechanically ground and shredded, 

screened, and when chipped and ground greenwaste is stored outdoor or loaded into trucks. 

These activities are currently required to comply with AQMD Rule 403 – Fugitive Dust. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 8 January 2003 

Co-Composting Operations 

Composting is a biological process where organic materials (e.g., grass clippings, tree 

trimming, leaves, biosolids, manure, food waste) are decomposed by microorganisms under a 

controlled environment to create a soil-like material called compost. While decomposition 

occurs naturally anywhere plants grow, the process has also been industrialized to produce 

compost products under controlled conditions. In co-composting operations, putrescible 

materials such as biosolids and/or manure are combined with bulking agents to produce 

compost. 

Composting is an important component of the solid waste industry. It provides resource 

conservation through source reduction, recycling, and reuse. However, as with other 

industrial processes, composting produces air emissions that are currently uncontrolled. In 

terms of air quality, composting is an exothermic process that releases carbon dioxide, water 

vapor, and other organic and inorganic gases such as ammonia, methane, VOCs, amines, and 

sulfides. 

From an industrial perspective, composting is a three-stage process that begins as soon as 

appropriate materials are combined and piled together. The initial stage of the process is 

referred to as active composting followed by curing or finishing, and storage and/or 

processing of composted products. During the composting process microorganisms such as 

bacteria, fungi, and actinomycetes, consume oxygen while feeding on organic material such 

as green/wood waste, food-waste, livestock manure, biosolids (the semisolid residue of 

domestic sewage treatment processes) and other putrescible materials. The microbial activity 

results in the decay of the initial mixture and at the completion of the composting cycle 

wastes are transformed into a stable, pathogen-free composted material. 

The microorganisms that contribute to the composting process contain both thermophilic and 

mesophilic species. Thermophilic and mesophilic microorganisms are microorganisms that 

can sustain life under high (110-150 oF) and low (50–105 oF) temperatures, respectively. The 

type of microbial activity present may characterize the active and curing stages of the 

composting process. However, for the purpose of Proposed Rule 1133.2, active cocomposting has been defined as the phase of the composting process that begins when 

organic materials are mixed together for composting purposes and lasts at least 22 days. 

Based on source tests conducted by District staff, 80% of VOC and 50% of NH3 emissions 

occurred during the first 22 days of the composting operations, which is considered the active 

phase of the composting for the purpose of the rule. The active phase of composting is where 

the thermophilic microorganisms’ population is usually the highest. This stage is 

characterized by high temperatures, high level of oxygen demand and high evaporation rates 

due to temperature. 

Conversely, the curing stage of the process is where the mesophilic microorganism 

population is the highest and the need for oxygen and the evaporation rates decreases. For 

the purpose of Proposed Rule 1133.2, the curing phase has been defined as a period that 

begins immediately after the active phase and lasts 40 days or until the compost exhibits a 

Solvita Maturity Index® of 7, or the product respiration rate is below 10 milligrams of 

oxygen per gram of volatile solidsthroughput per day as measured by direct respirometry. The 

Solvita Maturity Test® is a widely recognized test that gives a maturity index for compost 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 9 January 2003 

(maturity means resistance to further decomposition). The test measures the carbon-dioxide 

respiration and ammonia volatility simultaneously. There is also a linkage between the 

microbial activity and the VOC emissions profile from composting operations. Specifically, 

emissions can be correlated to the activity of these microorganisms in that the emissions are 

generally higher during thermophilic temperatures and lower during mesophilic temperatures. 

Figure 1 illustrates the oxygen demand and microbial profile of the various composting 

stages. This figure can be used to illustrate the corresponding VOC emissions primarily 

occurring during active and curing phases of composting. 

Proposed Rule 1133.2 includes control requirements for co-composting operations in order to 

achieve VOC and ammonia emission reductions. Co-composting are composting operations 

where biosolids and/or manure are mixed with bulking agents to produce compost. 

Of the nine co-composting facilities in the Basin, seven facilities use the windrow method of 

composting, one uses a forced aeration system in combination with a biofilter and one uses 

the in-vessel composting technology where the composting operations are confined within a 

building and emissions are vented to a biofilter. Of the seven co-composting facilities that 

are not equipped with any control methods, three have annual throughputs greater than 

100,000 tons, two have throughputs between 10,000 and 100,000 tons and two have less than 

10,000 tons of throughput per year. These composting methods are described in detail in the 

Technical Assessment report on composting and related operations. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 10 January 2003 

Figure 1 

Composting Phases

OXY

G

E

N

DEM

AND

R

A

T

E, *

C

ARBON

DIOXID

E

EVO

L

UTION

SCREENING COMPOSTING CURING 

TIME 

THERMOPHILIC 

MESOPHILIC 

COMPOST IS 

STABLE 

PHASES DURING COMPOSTING

This graphic was provided by Eliot Epstein, Ph.D. Chief 

Environmental Scientist, Tetra Tech, Inc. 

*VOC emissions are expected to follow the similar profile as 

oxygen demand. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 11 January 2003 

As stated before, it is the ability to control the physical and chemical characteristics of the 

process that makes composting a viable industrial process. The main physical and chemical 

characteristics that are optimized in an industrial composting process include: carbon-tonitrogen ratio (C:N), moisture content, oxygen, temperature, PH, particle size, pile structure, 

and type of feedstock. These characteristics are described in detail in the Technical 

Assessment for Composting and Related Operations, dated April 2002, Attachment A to the 

Draft Final Staff Report. 

Regulatory Background 

Following is a summary of the regulatory programs that are applicable or pertinent to the 

composting and related operations industry. 

Federal Programs 

The federal Clean Air Act requires the AQMD to adopt an AQMP that identifies a control 

strategy to demonstrate compliance with the federal ambient air quality standards. To 

address this federal mandate, the 1994 and 1997 AQMPs and 1999 Amendments to the 1997 

Ozone State Implementation Plan for the SCAB included Control Measure WST-02 – 

Emission Reductions from Composting. The U.S. EPA approved these plans making this 

control measure federally enforceable. In addition to air quality issues, there are other federal 

requirements that apply to composting operations. Specifically, the federal requirements 

focus mainly on water and solid waste (i.e., sewage sludge) issues. The following is a brief 

summary of these requirements. 

Resource Conservation and Recovery Act 

In 1976, Congress enacted the Resource Conservation and Recovery Act (RCRA), an 

amendment to the 1965 Solid Waste Disposal Act. RCRA calls for conservation of energy 

and natural resources, waste reduction, and environmentally sound waste management 

practices. In addition, RCRA encourages states to develop plans for non-hazardous industrial 

solid waste and municipal solid waste (MSW) management, sets criteria for MSW landfills, 

as well as for other solid waste disposal facilities, and prohibits the opening dumping of solid 

waste. Congress delegated authority to U.S. EPA to develop specific regulations to 

implement the requirements of RCRA. Solid waste regulations have been promulgated in the 

Code of Federal Regulations under Title 40, Chapter I, Subchapter I, Parts 240-282 (40 CFR 

Parts 240-282). As a result of RCRA’s prohibition on open dumping of solid waste other 

disposal alternatives for sewage sludge has been pursued including land spreading (treated 

sludge is spread over crop land as fertilizer), aerobic digestion, and composting. 

National Pollutant Discharge Elimination System

The National Pollutant Discharge Elimination System (NPDES) is an EPA-implemented 

program that requires permits for discharging pollutants from facility operations into water2. 

Even though the NPDES program focuses on water pollution from all types of industries, 

NPDES also applies to owners or operators of facilities that treat and handle sewage sludge, 

including composting with sewage sludge. The criteria and standards for NPDES are quite 

extensive and have been promulgated in several parts of the Code of Federal Regulations 

 

2

40 CFR Part 122, §122.1 (b). 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 12 January 2003 

under Title 40, Chapter I, Subchapter D, Parts 122, 123, 124 and 125 (40 CFR Parts 122–

125). 

Sewage Sludge Disposal Standards

EPA promulgated standards for the use or disposal of sewage sludge in Title 40, Chapter I, 

Subchapter O, Part 503 of the Code of Federal Regulations (40 CFR Part 503). 40 CFR Part 

503 contains requirements for the control of pathogens, vectors, and heavy metal for sludge 

composting operations. In particular, to qualify as Class A compost Appendix B to Part 503-

Pathogen Treatment Processes, generally requires Processes to further reduce pathogens 

(PFRP). PFRP requires that open windrow composting maintain the temperature of the 

compost to be 550 C or higher for 15 days or longer, and during this time there must be a 

minimum of 5 turnings of the windrows. For in-vessel or aerated static pile (ASP) 

composting, the PFRP requires the active pile temperature be at least 550 C or higher for 3 

days. 

State Programs 

State law also requires the AQMD to adopt an AQMP that identifies a control strategy to 

demonstrate progress towards achieving the state ambient air quality standards. The 1994 

and 1997 AQMPs and 1999 Amendments to the 1997 Ozone State Implementation Plan for 

the SCAB that included Control Measure WST-02 – Emission Reductions from Composting, 

was also submitted to the CARB to comply with state law. These air plans identified 

composting as a source of ammonia, PM10, and VOC emissions. As such, Control Measure 

WST-02 required the development of control to reduce the emissions from this industry by 

2003. In addition to air quality requirements, there are several other state requirements that 

may apply to chipping and grinding and composting operations. Specifically, these state 

requirements focus on air, water and solid waste (i.e., sewage sludge) issues. The following 

is a summary of these requirements. 

California Air Resources Board

In addition to reviewing and approving the AQMP, CARB's permitting requirements can 

affect composting and chipping and grinding operations that use portable equipment. Under 

the CARB’s “Statewide Portable Equipment Registration Program”, registered portable 

engines and equipment can be operated throughout California without the need to get 

individual permits from local air pollution control districts, such as the AQMD. Therefore, it 

is common for composting and chipping and grinding facilities to have equipment (i.e., 

portable engines associated with wood chippers, tub grinders, trommel screens) registered 

under the State Program. 

California State Legislature: California Integrated Waste Management Act 

Recognizing landfill limitations (i.e., capacity and siting) and the need for integrated waste 

management practices, in 1989, the California state legislature passed Assembly Bill (AB) 

939 – California Integrated Waste Management Act into law, which was incorporated into 

the California Public Resources Code, Division 30. Accordingly, cities and counties are 

mandated to achieve a total waste diversion of 25 percent by 1995 and a total waste diversion 

of 50 percent by 2000 based on the 1990 baseline. As a result, recycling, reuse, and source 

reduction have been widely promoted to achieve these goals. Based on the California 

Integrated Waste Management Board’s (CIWMB) report, statewide diversion rate in the year 

of 2000 reached a 42 percent benchmark. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 13 January 2003 

California Integrated Waste Management Board

In June 1995, the CIWMB promulgated a set of regulations governing composting operations 

and facilities. The CIWMB currently regulates approximately 87 composting facilities 

operating in California in accordance with the California Code of Regulations, Title 14, 

Division 7, Chapter 3.1 – Composting Operations Regulatory Requirements (Chapter 3.1). 

Depending on the type of composting materials and the throughputs, affected facilities are 

required to obtain a Registration Permit, a Standardized Composting Permit, or a Full Solid 

Waste Facilities Permit (Full Permit). Full Permits require the preparation of an 

Environmental Impact Report (EIR) and are issued by CIWMB while Registration and 

Standardized Permits are issued through local enforcement agencies (LEAs), such as the 

environmental health departments. According to the CIWMB database, sixteen of the 

twenty-seven facilities in the AQMD’s jurisdiction are identified as having a CIWMB permit. 

The CIWMB is currently developing amendments to the California Code of Regulations, 

Title 14, Division 7, Chapter 3.1 – Composting Operations Regulatory Requirements 

(Chapter 3.1) to include chipping and grinding and other operations that handle compostable 

organic materials. These facilities would be subject to both permitting and operational 

requirements. In addition, to address increasing number of odor complaints, the CIWMB is 

also proposing a requirement of an Odor Impact Minimization Plan (OIMP) which must be 

developed by each facility. However, the proposed regulation at this time does not establish 

odor control requirements for these operations. Instead, the adequacy of an OIMP would be 

determined through public complaints. 

Regional Water Quality Control Board

The Regional Water Quality Control Board (RWQCB) enforces EPA-issued National 

Pollutant Discharge Elimination System (NPDES) permits. In addition, the RWQCB focuses 

on wastewater generation, water demand, the capacity of existing or planned stormwater 

drainage systems and potential new sources of polluted run-off, and potential depletion of 

groundwater supplies or interference with groundwater recharge. In the case of composting 

and chipping/grinding facilities, the RWQCB has required various composting and chipping 

and grinding sites to be graded, paved, and surrounded by berms and other drainage-related 

protections to prevent run-off and the leaching of chipped and ground materials into the 

groundwater. 

Local Programs 

There are several local requirements that may apply to chipping/grinding and composting 

operations. Specifically, these requirements focus on air, land use and solid waste (i.e., 

sewage sludge) issues. The following is a summary of these requirements. 

AQMD Rule Requirements

Currently, operators of chipping/grinding facilities located in the district are required to 

comply with AQMD Rule 402 – Nuisance, Rule 403 – Fugitive Dust, and Rule 203 – Permit 

to Operate for equipment that require permits (composting facilities are subjected to Rules 

403 and 203). However, none of these rules establish specific control requirements to reduce 

VOC and ammonia emissions from greenwaste at composting and chipping and grinding 

facilities. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 14 January 2003 

Local Enforcement Agency Requirements

There are several different local (i.e., city or county) enforcement agencies or LEAs that act 

as the either the permitting or enforcement division of the CIWMB, depending on the 

throughput and type of compostable materials. For example, the local department of health 

services, on behalf of the CIWMB, issues Registration and Standardized permits and enforces 

the requirements in these permits for facilities with lower throughputs. However, for 

facilities that have throughputs that require a Full Permit issued by the CIWMB, the LEA is 

only responsible for enforcing the requirements in the Full Permit. For either type of permit 

scenario, the LEAs are responsible for handling and investigating complaints from 

composting and chipping/grinding operations. Pursuant to Section 41705, composting 

operations are exempt from AQMD odor regulations; AQMD must refer odor complaints to 

the LEA. 

In addition, city or county offices in the jurisdiction where a facility is located, has the 

authority over land use issues and issuing conditional use permits to site composting 

facilities, transfer stations, et cetera. 

Sewage Sludge Ordinances

In addition to EPA’s federal requirements regarding the use or disposal of sewage sludge, 

there are local ordinances or restrictions throughout California and other states that ban the 

import and land use of certain grades of sewage sludge. For example, 14 counties within 

California, with Riverside county being the only one located within the AQMD’s jurisdiction, 

have passed ordinances or permitting requirements that either ban or restrict the application 

of certain grades of sewer sludge onto farmland3. In addition, recent litigation and 

regulations in both Kern and Kings counties have resulted in ordinances that ban the import 

of certain classes of sewage sludge starting early 2003. Other states such as Pennsylvania, 

Vermont, and New Hampshire, have also passed similar ordinances to ban or limit the 

application of sewer sludge onto land. These restrictions will likely force the water treatment 

plants within the AQMD’s jurisdiction, throughout California and the nation to further 

process the sewage sludge so that it can be recycled and used on farmland. 

Local Governments

Local government zoning ordinances determine where composting and chipping and grinding 

activities can occur. In addition, local governments grant conditional use permits if the 

jurisdiction has determined that special conditions and approvals are necessary. Local 

governments also contract with chipping and grinding facilities for chipping and grinding 

greenwaste collected from their curbside recycling programs. 

Other Issues Facing the Composting Operations 

Public Nuisance Issues 

Uncontrolled emissions, odors, and dust generated by windrow composting and chipping and 

grinding operations are often sources of public complaints. Emissions and odors can 

dramatically increase if the windrows are not maintained properly or chipped and ground 

 

3 County of Riverside Ordinance No. 744 – Regulating the Processing of Greenwaste. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 15 January 2003 

material is allowed to decompose. Feedstocks like food waste, dairy products, manure, sewer 

sludge, are odorous. Dust may also result from open feedstock preparation areas, chipping 

and grinding operations, and compost turning, curing, screening, storage, and loading. The 

problem can be worse during high winds. 

Over the last two years, thousands of odor and dust complaints have been filed with the 

AQMD and with local enforcement agencies (LEAs). In particular, between January 1, 2000 

and December 31, 2001, the AQMD received 470 public complaints regarding composting 

and chipping and grinding operations. The LEAs have received over 2,600 complaints 

regarding composting and chipping and grinding operations.4 The AQMD staff has issued 

notices to comply (NC) and notices of violation (NOVs). The AQMD does not have records 

of enforcement actions taken by the LEAs. The table presented below summarizes this 

information. 

2000-2001 Public Complaints/AQMD Enforcement Actions 

On Composting and Chipping and Grinding Operations 

Agency # of Complaints # of NCs/NOVs

AQMD 470 55 (30 NCs and 27 NOVs)

LEAs 2,600+ N/A

The AQMD’s role in addressing public complaints from these facilities has been affected by 

AB 59 that became law in 1995. Under this law, all air districts in California are to refer 

public complaints pertaining to odors from a composting facility that is subject to the 

CIWMB’s regulatory requirements, to the LEAs. Odors from non-composting activities, 

such as chipping and grinding activities, mulching, and ADC application, as well as non-odor 

related public complaints including dust or emissions-related nuisances are under the air 

districts’ jurisdictions. 

Waste Diversion (AB 939) 

The use of chipped and ground greenwaste as ADC is one of many integral methods of 

compliance with AB 939, which requires 50% waste diversion by the year 2000. However, 

actual quantity of waste diverted is not available at this time. Instead, the CIWMB 

determines compliance with AB 939 waste diversion goals by measuring the reduction in the 

amount of waste that a given jurisdiction disposes to the landfill. For each jurisdiction, a 

maximum allowable disposal amount is calculated, which represents a 50 percent reduction 

of disposed waste from 1990. To meet the diversion rate requirement, a jurisdiction may not 

dispose more than the maximum allowed amount. Each jurisdiction must also submit an 

annual report that includes information on all programs being implemented to divert waste 

disposal from a landfill. 

As mentioned earlier, the year 2000 statewide diversion rate is estimated at 42 percent; 

however, it is unknown how much each individual waste diversion program contributes to the 

overall waste diversion rate. 

 

4

This number underestimates the total number of complaints to LEAs because not all the LEAs maintain the data in 

a tabulated format and not all the composting and chipping and grinding facilities were included in the AQMD’s data 

request. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 16 January 2003 

Recent studies by the CIWMB show that many of the organic materials (i.e., foodwaste, 

grass, etc.) which are prevalent in the waste stream (35.1%) are associated with odors and 

emissions. 

Environmental Justice 

In California, environmental justice is generally considered to be a call for the fair treatment 

of people of all races, cultures, and incomes with respect to the development, adoption, 

implementation, and enforcement of environmental laws and polices. In October 1997, the 

AQMD Governing Board adopted an environmental justice policy. The four guiding 

principles are: 

• All basin residents have the right to live and work in an environment of clean air, free 

of airborne health threats; 

• Government is obligated to protect public health; 

• The public and private sectors have the right to be informed of scientific findings 

concerning hazardous and toxic emission levels, and to participate in the development 

and implementation of adequate environmental regulations in their communities; and 

• The (AQMD) governing board is to uphold the civic expectation that the public and 

private sectors of the basin will engage in practices that contribute to a health 

economy and truly livable environment." 

Environmental justice can be an issue in the siting of composting operations because of odors 

and dust impacts on neighborhoods from uncontrolled operations. The number of public 

nuisance complaints that the AQMD and LEAs have received regarding composting and 

related activities shows that these operations are having an impact on the surrounding 

community. As such, regardless of air quality regulations, environmental justice issues will 

affect the ability for future expansion of composting operations unless these issues can be 

adequately addressed. Controls to reduce emissions are expected to go a long way in 

addressing these impacts and would be consistent with the AQMD’s environmental justice 

policy. 

Regulatory Limits on Land-Application of Wastewater Sludge 

There are two classes of processed sludge. Class A sludge must undergo pathogen reduction 

to be below detectable levels; therefore, it can be used on edible vegetables and plants. Class 

B sludge must undergo pathogen reduction to ensure the pathogens are reduced to levels that 

are protective of public health and the environment. Class B sludge is only used on nonedible crops, forests, and reclamation sites. 

Currently, most Class B sewer sludge is trucked from this region to Kings and Kern Counties 

where it is spread on croplands. Public concerns over Class B sludge used on croplands in 

Kings and Kern Counties has resulted in these jurisdictions placing limitations on Class B 

sludge. As a result, additional options to deal with Class B sludge will need to be developed. 

This could include additional composting of sewer sludge in the region. Therefore, there is 

an increased need to resolve the environmental impacts issues associated with co-composting 

operations so that additional co-composting facilities can be sited in the AQMD’s 

jurisdiction. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 17 January 2003 

EMISSIONS INVENTORY AND REDUCTIONS 

The emissions inventory for co-composting operations was developed based on the 2001 

activity data (i.e., annual throughput) and baseline emission factors developed for these 

operations. The VOC and ammonia baseline emission factors were developed based on the 

AQMD source tests conducted in 1995 and 1996 for three windrow co-composting facilities. 

The baseline emission factors for VOC and ammonia are 1.78 and 2.93 lbs./ton of 

throughput (i.e., composting feedstock received at the facility), respectively. Emissions from 

co-composting operations are estimated by multiplying the facilities annual throughput by 

these facility-wide average emission factors. For chipping and grinding activities, emission 

reductions are not claimed under PR1133.1 since this rule establishes holding/processing 

time requirements for greenwaste to prevent inadvertent decomposition associated with 

stockpiling greenwaste (or foodwaste) for extended periods of time. Based on information 

provided by the industry and through CTAC, chipping and grinding activities subject to the 

rule are already processing their greenwaste within the time frame proposed in PR1133.1, and 

therefore, emission reductions, if any, are not expected to be significant. The objective of 

establishing these standard holding/processing time requirements is to prevent emissions 

from increasing for chipping and grinding activities. 

Table 3 provides the emissions inventory for co-composting operations as well as the level of 

reductions anticipated from the implementation of PR1133.2. As shown in Table 3, cocomposting operations generate significant amounts of VOC and ammonia emissions in the 

Basin. Emissions from co-composting operations place the composting and related 

operations industry as the largest unregulated stationary source category and the second 

largest stationary source category following the refinery category in the Basin. Using the 

baseline VOC emission factor, co-composting facilities with annual throughput of at least 

11,300 tons would also generate VOC emissions in excess of 10 tons per year, which is the 

threshold for major sources as defined in AQMD Rule 3001. The three largest cocomposting facilities in the Basin emit about 100 to 300 tons per of VOC and 150 to 500 tons 

per year of ammonia. 

Table 3 - Emissions Inventory and Reductions for 

Existing Co-Composting Operations

 

VOC NH3 

Emissions Inventory 

(tons/day) 

1.67 2.74 

% Reduction 70% 70% 

Emissions Reduction

(tons/day) 

1.17 1.92 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 18 January 2003 

CONTROL METHODS 

The technology assessment provided an analysis of several control methods available to 

industry including: windrow, enclosures, forced aeration systems, and in-vessel composting. 

Emissions from enclosures, forced aeration systems and in-vessel systems can also be vented 

to emission control equipment such as biofilters. Forced aeration and in-vessel systems can 

also be enclosed, with all emissions vented to control equipment. Also available are other 

composting methods that employ variations of in-vessel and forced-air aeration systems that 

may be considered as closed-loop systems capable of achieving very high capture and control 

efficiencies. In this region, with the exception of three facilities, the predominant method of 

co-composting is windrow composting. In windrow composting, materials are moved with 

front-end loaders into long piles called windrows. Aeration for this method of composting is 

achieved mechanically by the turning of the piles with front-end loaders or scarabs machines. 

The temperature and moisture are monitored to optimize and hasten decomposition. After 

two to four months in the windrows, the material becomes compost. Based on the analysis 

conducted in the technology assessment, technologies exist today that can significantly 

reduce emissions from co-composting operations. 

Currently, there are 118 operational composting facilities in the U.S. utilizing the forced 

aeration systems (e.g., ASP); one of them is located in the District. Nationwide, these 

facilities handle a daily throughput ranging from 0.1 to 300 dry tons. In addition, several 

groups in the District also consider forced aeration systems for their future co-composting 

facilities. There are also approximately 50 operational composting facilities in the U.S. 

utilizing the in-vessel technology; one of them is located in the District. The daily 

throughputs for these facilities range from 1 to 100 dry tons. A number of these forced 

aeration or in-vessel systems are enclosed with exhaust vented to the control equipment. 

Biofiltration is a well-established emission and control technology in Europe where over two 

hundred biofilters were in use as of 1984 and even more are expected today. In the United 

States, biofilters have been mainly utilized for the treatment of odors as well as VOCs in 

wastewater treatment plants. Biofilters have recently gained better acceptance by composting 

and other operations such as auto body shops, pharmaceuticals, and beer breweries. Based on 

the information collected so far on existing biofilter composting applications, control 

efficiencies of about 80% to 90% for VOC and 70% to over 90% for ammonia have been 

achieved (one of this composting applications reported an initial control efficiency of 65 

percent for VOC but was later improved to achieve an 80 percent control efficiency). This 

specific field example along with other available data presented in the Technology 

Assessment Report clearly demonstrates that a well-designed, well-operated, and wellmaintained biofilter is capable of achieving 80 percent control efficiency for VOC and 

ammonia. Biofilter manufacturers also emphasize that regular inspection and maintenance of 

the biofilter are key elements to achieve such control level. Furthermore, information from a 

well-known biofilter manufacturer indicate that VOC removal efficiencies of greater than 

90% are achievable. 

In order to comply with the requirements of PR1132, new co-composting facilities would be 

required to enclose their active phase of co-composting operations and use negative forcedair aeration system for the curing phase of operations. The exhaust from the enclosure and 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 19 January 2003 

the aeration system would also be required to be vented to a control equipment such as a 

biofilter with a control efficiency of at least 80 percent for VOCs and ammonia emissions. 

Based on source test data from two existing co-composting operations (Griffith Park and 

Philadelphia Biosolids Recycling Center ), properly-designed and maintained biofilters have 

demonstrated destruction efficiencies of over 90% for both VOC and NH3 emissions. 

However, because of concerns over the continuous effectiveness of biofilters in reducing 

emissions beyond 80%, a minimum of 80% control efficiency is required under the rule. 

Proposed Rule 1133.2 would require demonstration of compliance with these destruction 

efficiencies within 180 days of the start of operations and every two years thereafter. In 

addition, it is expected that biofilter control systems, as with any other control device, are 

maintained and operated in accordance with permit conditions. 

Alternatively, new co-composting operations would also have the option to utilize any 

combination of the composing and control methods to demonstrate an overall control 

efficiency of 80 percent for VOC and ammonia emissions from active and curing phases. 

Under PR1133.2, existing co-composting operations would be required to demonstrate an 

overall emission reduction of 70 percent for VOC and ammonia emissions (from active and 

curing phases) using any combination of composting and control methods. These facilities 

can comply with these requirements by enclosing their active co-composting and using forced 

aeration system for curing phase of operations (in combination with emission control 

equipment). Under this scenario, the enclosure will have a 100% capture efficiency for the 

active phase, the aeration system will have an control collection efficiency of at least 45% for 

VOC and 55% for NH3 emissions (based on test results from the recent Southern California 

Association of POTWs (SCAP) study), and a biofilter control system with a control 

efficiency of at least 80% for VOC and NH3. For ammonia emissions, the above 

combination in conjunction with optimized feedstock mix ratios (with at least 40% reduction 

efficiency) will also achieve the required reduction target. In addition, there are best 

management practices that can reduce emissions, which can be used as part of the compliance 

strategy provided such reductions are quantified following the guidelines specified in 

Attachment A of PR1133.2. 

Any combination of composting and control methods (e.g., enclosure, aeration system, invessel composting, biofiltration, process controls, optimized mix ratios, and best 

management practices) capable of achieving the required emission reductions may also be 

utilized by existing facilities or new facilities (under the alternative option) to comply with 

PR1133.2 (following the testing guidelines included in the rule). 

COST-EFFECTIVENESS 

Table 4 presents staff’s cost-effectiveness analysis for new and existing co-composting 

operations based on implementation of several possible scenarios. For new co-composting 

operations, the cost-effectiveness is estimated to be about $24,000 to $27,000 per ton of VOC 

reduced depending on the type of enclosure (fabric or concrete). However, if the VOC and 

ammonia emission reductions are considered, the cost-effectiveness would range from about 

$11,000 to $12,000 per ton of both VOC and ammonia reduced. This scenario assumes 

Formatted: Underline
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 20 January 2003 

enclosure and aeration system for active co-composting operations and aeration system for 

curing phase both vented to a biofilter. It should be noted that the use of aeration system 

inside the enclosure would significantly reduce the enclosure cost because of the reduced 

space requirements for the aeration system (compared to windrow composting). 

For existing co-composting operations, three scenarios were analyzed as presented in Table 4. 

Under scenario 2, assuming enclosure without an aeration system for active phase of 

composting and a forced aeration system for curing phase (both vented to a biofilter) and 

depending on the type of enclosure, the cost-effectiveness would range from $11,400 to 

$15,400 per ton of VOC and ammonia reduced , or $30,000 to $40,000 per ton of VOC 

reduced. However, as mentioned before, the use of a forced aeration system for active phase 

within an enclosure will significantly reduce the overall cost because of reduced space 

requirements, as indicated in scenario 3. Under scenario 3, using enclosure and aeration 

system for active phase, and aeration system for curing phase, both vented to biofilter (with 

efficiencies mentioned in previous section), the cost effectiveness would range from $8,700 

to $10,000 per ton of VOC and ammonia reduced or $23,000 to $26,500 per ton of VOC 

reduced (depending on the type of enclosure). Under scenario 4, assuming that forced 

aeration system (in combination with process controls, optimized feedstock mix ratios, and 

best management practices) for both active and curing phases (combined with a biofiltration 

system) could achieve the required reductions (i.e., 70% for VOC and ammonia), the costeffectiveness could be as low as $6,500 per ton of VOC and ammonia reduced or $17,000 per 

ton of VOC reduced. However, additional test data will be necessary to validate the 

efficiency of such control methods. The cost assumptions used in this analysis (capital and 

operating cost) are included in the Technology Assessment Report for PR1133 (Attachment 

A to the Draft Final Staff Report). 

Table 4 - Co-Composting Annualized Cost and 

Cost-effectiveness ($/ton) 

Facility 

Type Scenario 

Annualized Cost 

(Millions $) C-E for VOC Only 

C-E for VOC & 

Ammonia 

Concrete Fabric Concrete Fabric Concrete Fabric 

New 1 $4.45 $3.88 $27,287 $23,798 $12,345 $10,767

Existing 2 $22.7 $16.9 $40,677 $30,236 $15,373 $11,427

Existing 3 $14.8 $12.9 $26,508 $23,118 $10,018 $8,737

Existing 4 $9.6 $17,166 $6,487

Scenario 1. Enclosure+ Forced Aeration System (Open ASP) + Biofilter (80% ammonia, 80% VOC) for 

Active. Forced Aeration System +Biofilter (19% 20% ammonia, and 20% VOC) for Curing. 

Assuming 200,000 tons per year throughput. 

Scenario 2. Enclosure+ Windrow+ Biofilter for Active. Forced Aeration System +Biofilter for Curing. 

70% Overall Reduction for VOC and ammonia. The building cost for the enclosed windrow 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 21 January 2003 

is assumed to be three times higher than the building cost for an enclosed aeration system 

due to higher footage requirements. 

Scenario 3. Enclosure + Forced Aeration System + Biofilter for Active. Forced Aeration System + 

Biofilter for Curing, achieving 70% overall reductions for VOC and ammonia. 

Scenario 4. Forced Aeration System for Active and Curing, assuming that forced aeration system for 

both active and curing operations is capable of achieving 70% overall reductions for VOC 

and ammonia. 

For new and existing co-composting operations, compliance cost would represent an increase 

of about $22/ton of throughput (waste processed). For new co-composting facilities with a 

combined throughput of 200,000 tons per year, this cost would represent an additional $0.08 

per month per household in the Basin (or $0.004 per month per household for every 10,000 

tons of throughput) assuming that the cost would be passed onto the Basin households. The 

compliance cost for all existing co-composting facilities would represent an additional $0.25 

per month per household (under scenario 3 above) using the same assumption. 

Facilities affected by PR1133 will also be subject to a one-time registration fee equivalent to 

the plan submittal fee in Rule 306 - Plan Fees which is currently $89.59. Also, PR1133.1 

would result in minimal cost to affected facilities for recordkeeping. There are no additional 

cost associated with compliance with PR1133.1 because the holding/processing time 

requirements in the rule are based on the normal chipping and grinding activities which do not 

result in inadvertent decomposition (based on information provided through the Composting 

Technical Advisory Committee). 

SUMMARY OF PROPOSED RULES 

PR 1133, PR 1133.1, and 1133.2 would implement, in part, AQMD Control Measure WST02. These proposed rules were developed with the assistance and input from the Composting 

Technical Advisory Committee (CTAC) and the Co-Composting Subcommittee to CTAC. 

PR 1133 is an administrative rule, which is intended to obtain information from the 

Composting and Related Operations industry via a registration and annual update process. 

PR 1133.1 establishes holding time/processing requirements for chipping and grinding 

operators with the objective of preventing inadvertent decomposition from occurring at 

chipping and grinding facilities. PR 1133.2 requires emission reductions from cocomposting based on implementation of specific control methods. Following is a summary 

of the requirements of the proposed rules. 

Summary of Proposed Rule 1133 - Composting and Related Operations - 

General Administrative Requirements 

Applicability

PR 1133 applies to owners or operators of chipping and grinding, and composting facilities. 

The proposed rule applies to both existing and new facilities. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 22 January 2003 

Requirements

Effective July 1, 2003, PR 1133 would require existing chipping and grinding and 

composting facilities to register with the District by submitting a registration form. The 

registration data would include general business information, process and operations 

information, and number of air quality- and odor-related enforcement actions issued for the 

facility. The odor-related information is requested as part of the registration process because 

of the correlation between odor and emissions (e.g., ammonia). 

New chipping and grinding and composting facilities would also be are required to submit 

the registration form prior to the start of their operations (i.e., prior to facility's start-up). 

New facilities are also required to provide projected information when actual information is 

not yet available. 

Also, effective July 1, 2004, every year thereafter, chipping and grinding, and composting 

facilities would be required to provide an update to the information provided as part of the 

initial registration. 

Fees

Facilities subject to PR1133 will be subject to a one-time fee equivalent to the plan submittal 

fee in accordance with Rule 306 – Plan Fees at the time of registration. Based on the existing 

version of Rule 306, facilities subject to PR 1133 will be subject to a one-time fee of $89.59. 

Exemptions

The composting and related operations industry includes various processes and types of 

operations. PR 1133 specifically exempts from regulations the following seven types of 

operations: portable chipping and grinding operations; community composting; agricultural 

composting; nursery composting; recreational facilities composting; backyard composting; 

and wood waste chipping and grinding facilities. These operations or activities are defined 

within PR 1133. These operations are generally conducted in small scales or do not cause 

inadvertent decomposition. 

Summary of Proposed Rule 1133.1 - Chipping and Grinding Activities 

Applicability

PR 1133.1 applies to operators of chipping and grinding activities, unless otherwise 

exempted. In order to clarify the applicability of Rule 403 – Fugitive Dust to all chipping and 

grinding activities, language is provided in PR 1133.1 to reinforce this requirement.

Requirements

In order to clarify the applicability of Rule 403 – Fugitive Dust to all chipping and grinding 

activities, language is provided in PR 1133.1 to reinforce this requirement.

Effective July 1, 2003 , operators of chipping and grinding activities would be required to: 

1) remove foodwaste or use for on-site composting within a period of two days; 2) chip and 

grind, use on-site, or remove curbside greenwaste from the facility within three calendar days 

of receipt ; 3) chip and grind or remove non-curbside greenwaste from the facility within 14 

days of receipt; 4) chip and grind, use on-site, or remove mixed greenwaste within seven 

days of receipt; and 5) remove from the facility chipped and ground curbside greenwaste or 

use them on-site within three days of being chipped and ground (unless the moisture content 

is maintained below 30%, in which case the holding/processing time limit for chipped and 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 23 January 2003 

ground curbside greenwaste will not apply. All of the holding/processing times exclude state 

and federal holidays and may be extended to include rainy days and wet weather conditions 

(which could last up to 10 days after a rainy day) provided that records documenting wet 

weather conditions which impede normal operations are kept on-site. 

Non-curbside greenwaste as used in this proposed rule refers to greenwaste that is not 

collected from receptacles designated for residential household greenwaste. It also includes 

screened or sorted greenwaste containing only large woody materials, such as tree trimmings 

and branches that are larger than 3 inches in any dimension. Although these woody materials 

may also come from city’s curbside collection programs; they are generally separated from 

the grassy materials and processed separately. Greenwaste containing woody materials is 

expected to decompose at a slower rate (compared with grassy materials) due to their lower 

moisture content. On the other hand, curbside greenwaste refers to greenwaste that is 

collected from receptacles designated for residential household greenwaste. It also includes 

screened or sorted curbside greenwaste that contains only grass, leaves, and/or small twigs. 

This type of greenwaste is expected to decompose at a faster rate, and therefore, is proposed 

to be subject to a shorter holding or processing time requirement. Chipped and ground 

greenwaste products (form non-curbside type greenwaste) used for applications such as 

biomass fuel (i.e., meets specific biomass fuel specifications) are not subject to PR 1133.1 

holding time requirements because of the low moisture content requirements for these 

products thereby decreasing or eliminating the potential for inadvertent decomposition. 

The holding or processing time requirements for chipping and grinding activities are intended 

to prevent inadvertent decomposition of greenwaste, which is not associated with normal 

chipping and grinding operations. Therefore, these requirements are not intended to interfere 

with AB 939 diversion goals. For greenwaste categories subject to PR 1133.1, the proposed 

rule is not expected to result in any significant emissions reductions since the requirement for 

holding or processing time is in line with the normal practice of most chipping and grinding 

operations. However, the proposed rule would establish a uniform requirement for the 

removal, on-site use, or processing of greenwaste in a reasonable time frame to ensure that 

inadvertent decomposition associated with stockpiling greenwaste for an extended period of 

time would not occur. Compared to a performance-based approach (i.e., emission 

thresholds), which is not practical for chipping and grinding activities, or other requirements 

based on best management practices, which are not clearly defined, the holding/processing 

time requirements would streamline compliance for chipping and grinding facilities as well 

as enforcement for the District. 

In addition, the operator of a chipping and grinding activity would also be required to 

maintain the following records on-site for two years: 

• A copy of the facility’s AQMD registration and annual updates; and, 

• Records of date, type, and amount of greenwaste and/or foodwaste received; and, 

• Records of date, type, amount of greenwaste and/or foodwaste removed from the site, and 

location where they are transferred. 

• Records of dates of rainy days and wet weather conditions (i.e., conditions following 

rainy days that impede normal operations). 

• Records of moisture content measurements for chipped and ground curbside greenwaste 

(if applicable). 

• Records of dates and amount of curbside greenwaste chipped and ground.
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 24 January 2003 

Exemptions

PR 1133.1 provides exemption from the holding or processing time and record keeping 

requirements for the following: 

• Portable chipping and grinding operations, palm chipping and grinding, and woodwaste 

chipping and grinding activities. Woodwaste (i.e., lumber, woody portion of mixed 

demolition and construction wastes) mostly contain very low moisture levels generally 

not subject to decomposition. Palm is fibrous and bulky, and costly and difficult to grind 

quickly, and is not expected to decompose quickly. Also, portable chipping and grinding, 

defined as chipping and grinding utilizing equipment (with a manufacturer's rating of 170 

brake horsepower or less) where usually small amounts of greenwaste are processed and 

the piles are usually removed shortly after being chipped and ground is not subject to this 

rule. 

• Chipping and grinding activities of greenwaste and/or foodwaste derived from the site 

and used on-site, such as chipping and grinding activities at agricultural settings, 

nurseries, botanical gardens, etc. 

Summary of Proposed Rule 1133.2 Requirements 

Applicability

PR 1133.2 applies to the operators of new and existing co-composting operations. 

Requirements

PR 1132 establishes emission control requirements for new and existing co-composting 

operations. New facilities would have two options to comply with the rule requirements. 

Under the first option, new co-composting facilities would be required to enclose their active 

phase of the co-composting operations and use aeration system (that operates under negative 

pressure for no less than 90 percent of its blower(s) operating cycle) during the curing phase 

of their co-composting operations. Air exhaust from both the enclosure and aeration system 

are required to be vented to an emission control system with a control efficiency of at least 80 

percent for VOC and 80 percent for ammonia emissions. The required destruction (control) 

efficiency for VOC and ammonia emissions are based on the demonstrated effectiveness of 

existing emission control equipment or systems such as biofilters for co-composting 

operations. 

Because of the potentially large area of enclosure required for the active phase, and the need 

to have openings for brief periods (i.e., access or maintenance), the enclosure for active phase 

of composting must also meet the following criteria: 

1) The inward face velocity of air through each opening in which air can enter the enclosure 

shall be a minimum of 100 feet per minute, unless the opening is equipped with a closure 

device that seals the opening in the event that the airflow direction changes. 

2) The area of all openings in the enclosure through which air can enter the enclosure shall 

not exceed 2% of the surface area of the enclosure’s four walls, floor, and ceiling. 

3) The enclosure may be opened for brief time periods, not to exceed a total of 30 minutes 

per day for purposes of access or maintenance. These time periods do not need to be 

included in the face velocity determination or as an opening for the two percent criteria. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 25 January 2003 

4) No measurable increase over background levels outside the enclosure shall occur at any 

enclosure opening including any opening that occurs briefly for access or maintenance.

A portable ammonia or hydrocarbon analyzer that is calibrated in accordance with 

manufacturer's specifications shall be used for these measurements. 

5) These enclosure requirements are not to lessen the stringency of any applicable safety 

requirement.

As indicated in the rule, the active phase of composting that needs to be enclosed under this 

option is defined as the phase of the composting process that begins when organic materials 

are mixed together for composting and lasts a minimum of 22 days. Enclosure of this phase 

(lasting at least 22 days) would ensure that majority of emissions associated with composting 

operations will be captured and vented to the control device. 

Under the second option, new co-composting facilities would be required to achieve an 

overall reduction target of 80 percent by weight for VOC and 80 percent by weight for 

ammonia emissions from the active and curing phases of composting. This option would 

require facilities to submit a compliance plan at least one year prior to start of operations. 

Compliance with the 80% overall reduction target is expected to be achieved based on a 

combination of composting methods (such as optimized mix ratios, pile design, best 

management practices and aeration systems) in conjunction with control methods (e.g., 

biofilters). Staff has also received information that this level of reduction is achievable 

through the use of in-vessel composting with advanced aeration systems without the use of 

control equipment such as biofilters. For operators which select to use the enclosed in-vessel 

composting method, this option provides the flexibility to enclose a shorter period of the 

composting (since aeration accelerates composting time) and use aeration or other methods 

for curing in conjunction with control equipment as long as they can meet the overall 

reduction target. 

Existing co-composting operations will be required to employ any combination of 

composting and control methods to demonstrate an overall control efficiency of 70 percent 

for VOC and 70 percent for ammonia emissions (for both active and curing operations). 

Existing co-composting operations would also be required to submit a compliance plan at 

least one year prior to their effective date of compliance. The less stringent reduction target 

for existing facilities (i.e., 70% vs. 80%) is to accommodate the lesser flexibility for these 

facilities in designing and operating composting and control methods compared with new 

facilities. Compliance with the 70% overall target can be achieved by enclosing the active 

phase, using negative aeration system for the curing phase, and venting exhaust from the 

enclosure and aeration system to a biofilter capable of achieving at least 80% destruction 

efficiency for VOC and NH3. Based on recent tests conducted by SCAP on the Griffith Park 

co-composting facility, the aeration system has demonstrated an approximately 45% 

collection reduction for VOC emissions and about 55% collection reduction for ammonia 

emissions (prior to being vented to the biofilter). Therefore, the combination of an enclosure 

(with 100% capture efficiency) for active phase, aeration system for curing phase, and a 

biofilter will achieve the required VOC reductions. For ammonia emissions, the above 

combination in conjunction with optimized feedstock mix ratios (capable of achieving at 

least 40% reduction in NH3 emissions) will also achieve the required reduction for ammonia 

emissions. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 26 January 2003 

Compliance with the overall emission reduction targets for existing and new facilities will be 

demonstrated based on a comparison of the co-composting baseline emission factors, 

developed by the District, with the controlled emissions rates for VOC and NH3. The 

baseline emission factors, included in the proposed rule, were based on source tests 

conducted on existing uncontrolled co-composting operations (i.e., 1.78 pounds of VOC and 

2.93 pounds of ammonia per ton of throughput). The proposed rule also allows cocomposting operators to develop their facility-specific baseline emission factors to 

demonstrate that the reduction requirements are met (as part of the compliance plan process). 

Compliance plans required to be submitted by new facilities (under second option) and 

existing facilities must at least include the following data and information to be approved by 

District: a description and process diagram of the co-composting operation; a complete and 

detailed description of the control method(s) that will be used at the co-composting operation 

to meet the reduction requirements such as enclosure; aeration; biofiltration; feedstock 

component optimization mix or process controls; best management practices; or any 

combination of the methods listed in the rule here; or, any other method approved by the 

Executive Officer, California Air Resources Board, and the United States Environmental 

Protection Agency. 

In addition, the compliance plan must contain all data, calculations methodology, 

calculations, records manufacturer specifications and all other information necessary to 

determine that the composting methods and control methods will achieve the required 

emission reductions. Also, a methodology and calculations establishing the daily and annual 

VOC and ammonia emissions or projected emissions must be provided. Furthermore, for 

facilities that select to establish their own operation-specific baseline emission factors, a 

source test protocol must be submitted in accordance with the guidelines included in 

Attachment A of the rule (which includes guidelines for the development of source test 

protocols for VOC and ammonia emissions from co-composting operations). Finally, a 

source testing protocol must be developed to demonstrate compliance with the overall 

emission reductions following the guidelines in Attachment A of the rule. Facilities would 

also be required to identify all equipment that require District permit in this process. 

Following the interim approval of the compliance plan by the District, within 180 days of the 

effective compliance dates for existing and new co-composting operations, facilities are 

required to demonstrate compliance with the required reductions by submitting a compliance 

report which would include all the necessary source test and applicable data and obtain 

District's final approval of the compliance plan. 

Compliance Schedule 

New co-composting operations would be subject to the requirements of this rule on the date 

of adoption of this rule prior to the start of operations. Existing facilities, defined in the 

proposed rule as facilities that have begun operation as of the date of adoption of this 

proposed rule will be required to comply with the requirements of this rule based on the size 

of facility (i.e., design capacity). Facilities that have a design capacity of greater than 

100,000 tons per year or more will be required to comply with the requirements of this 

proposed rule by January 1, 2007. Facilities that have a design capacity greater than 10,000 

but less than 100,000 tons per year will be required to comply by January 1, 2008. Facilities 

that have a design capacity of less than 10,000 tons per year will be required to comply by 

January 1, 2009. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 27 January 2003 

Fees

Operators subject to compliance plans will be subject to plan submittals and evaluation fees 

in accordance with Rule 306. 

Exemptions

Proposed Rule 1133.2 provides and exemption from this rule for greenwaste composting 

operations, agricultural composting operations, woodwaste composting operations as well as 

co-composting operations that have a design capacity of less than 1,000 tons of throughput 

per year. In addition, the proposed rule also provides an exemption from the requirements of 

the proposed rule for new and existing co-composting operations that: 1) are equipped with 

an aeration system and the emissions are vented to a control device with a control efficiency 

of 80 percent, by weight, for VOC and 80 percent, by weight, for ammonia emissions; 2) are 

owned and operated by municipalities which compost wastes generated within the 

jurisdiction of the municipality; and, 3) process less than 5,000 tons of biosolids or manure, 

combined, per year. These facilities are however required to demonstrate the effectiveness of 

the control device (i.e., biofilters) in reducing VOC and NH3 emissions on January 1, 2007 

and every two years thereafter. 

In addition, because of cost considerations, the compliance date for an existing cocomposting operation with less than 3 years remaining under its non-renewable conditional 

use permit (beyond its effective compliance date) will be extended for up to three years 

provided that the operator submits a copy of the conditional use permit and a letter from the 

responsible agency verifying that the permit is non-renewable and the date when the permit is 

expired.

ENVIRONMENTAL ASSESSMENT 

Pursuant to the California Environmental Quality Act (CEQA) and SCAQMD Rule 110, the 

SCAQMD has prepared a Draft Environmental Assessment for Proposed Rules 1133, 1133.1, 

and 1133.2. The Draft EA has been released on October 16, 2002 for a 30-day public review 

and comment. The Draft EA can be obtained by calling the AQMD Public Information 

Center at (909) 396-3600.

Pursuant to the California Environmental Quality Act (CEQA) Guidelines Section 15252 and 

the AQMD’s Certified Regulatory Program (Rule 110), staff has prepared an Environmental 

Assessment (EA) for the proposed Rules 1133, 1133.1. and 1133.2. The Draft EA, which 

was made available for a 30-day review period, concluded that the proposed rules would not 

have any significant adverse affects on environment. Responses to comments received on the 

EA have been prepared and are part to the Final EA, which is included as part of the attached 

package for the public hearing on the proposed rules.

SOCIOECONOMIC ASSESSMENT 

The socioeconomic assessment and the incremental cost-effectiveness analysis for the 

proposed rules have been prepared and are presented as an addendum to the staff report. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 28 January 2003 

PR 1133 affects a total of 74 facilities, including 18 greenwaste, 47 chipping and grinding, 

and 9 co-composting facilities. PR 1133.1 would impact 18 greenwaste and 47 chipping and 

grinding facilities. PR 1133.2 would impact seven co-composing facilities. The total 

compliance cost for the 74 facilities affected by PR 1133 would be $6,630 for a one-time 

registration fee. PR 1133.1 would result in minimal cost to affected facilities. The average 

annual cost of the PR 1133.2 is estimated at $14.80 million. It is estimated that an average of 

155 jobs could be forgone annually in the local economy as a result. However, considering 

the two existing facilities' plan to move to an enclosed facility (vented to biofilter) despite the 

proposed rule and one facility's potential extension of compliance date (i.e., due to its nonrenewable conditional use permit), the compliance cost and regional economic impact 

associated with PR1133.2 will be about 10% of these estimates.

COMPARATIVE ANALYSIS 

As required by Health and Safety Code Section 40727.2, the purpose of this analysis is to 

identify and compare any other AQMD or federal regulations that apply to the same 

operations or source type. Currently, there are no existing federal regulations or AQMD 

requirements that apply to composting and related operations with regards to VOC emissions 

and ammonia emissions, however, other federal state and local requirements have been 

summarized on pages 9-13. 

DRAFT FINDINGS 

Before adopting, amending or repealing a rule, the AQMD shall make findings of necessity, 

authority, clarity, consistency, non-duplication, and reference, as defined in Health and Safety 

Code Section 40727. The draft findings are as follows: 

Necessity - The AQMD Governing Board finds and determines that Proposed Rule 1133 – 

Composting Operations – General Administrative Requirements, Proposed Rule 1133.1 – 

Requirements for Chipping and Grinding Activities, and Proposed Rule 1133.2 – Emissions 

Reductions from Co-Composting Operations, are necessary in order to implement a control 

measure of the 1999 Amendment to the 1997 Ozone SIP, and to reduce PM10 and its 

precursors. 

Authority - The AQMD Governing Board obtains its authority to adopt, amend or repeal 

rules and regulations from Health and Safety Code §§39002, 40000, 40001, 40440, and 

40702. 

Clarity - The AQMD Governing Board finds and determines that Proposed Rule 1133 – 

Composting Operations – General Administrative Requirements, Proposed Rule 1133.1 – 

Requirements for Chipping and Grinding Activities, and Proposed Rule 1133.2 – Emissions 

Reductions from Co-Composting Operations, are written and displayed so that the meaning 

can be easily understood by persons directly affected by it. 

Consistency – The AQMD Governing Board finds and determines that Proposed Rule 1133 

– Composting Operations – General Administrative Requirements, Proposed Rule 1133.1 – 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 29 January 2003 

Requirements for Chipping and Grinding Activities, and Proposed Rule 1133.2 – Emissions 

Reductions from Co-Composting Operations are in harmony with, and not in conflict with or 

contradictory to, existing statutes, court decisions, or federal or state regulations. 

Non-Duplication – The AQMD Governing Board has determined that Proposed Rule 1133 – 

Composting Operations – General Administrative Requirements, Proposed Rule 1133.1 – 

Requirements for Chipping and Grinding Activities, and Proposed Rule 1133.2 – Emissions 

Reductions from Co-Composting Operations do not impose the same requirements as any 

existing state or federal regulation, and the extent they overlap with NESHAP requirements 

are necessary to carry out the duty to adopt rules implementing the AQMP. 

Reference - In adopting these proposed rules, the AQMD Governing Board references the 

following statutes which AQMD hereby implements, interprets or makes specific: Health and 

Safety Code Sections 40001 and 40440. 

CONCLUSIONS 

The proposed rule reflects reasonable available control technology for the reduction of VOC 

and ammonia emissions from the co-composting operations. The implementation of the rule 

as proposed is estimated to reduce 1.2 tons and 1.9 tons of VOC and ammonia emissions, 

respectively at an overall cost-effectiveness of approximately $8,700 to $10,000 per ton of 

VOC and ammonia reduced (or $23,000 to $26,500 per ton of VOC reduced), to be passed to 

waste disposal customers at a cost of between $0.004 and at least $0.25 per month per 

household, assuming that the cost would be passed onto the Basin households.

COMMENTS AND RESPONSES 

PR1133

Comment 1-1: Definitions in PR1133, 1133.1 and 1133.2 should be consistent for the 

same terms. 

Response 1-1: The definitions used throughout the proposed rules were made 

consistent. 

 

Comment 1-2: The date of compliance for registration is too stringent. 

 

Response 1-2: The compliance date for Proposed Rule 1133 has now been extended 

from February 1, 2003 to July 1, 2003. 

 

Comment 1-3: The registration process should be streamlined by providing a checklist 

on the registration form. 

 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 30 January 2003 

Response 1-3: The registration form will include a checklist that facilitates compliance 

with the requirements of the proposed rule (i.e., submittal of registration 

information). 

 

Comment 1-4: The proposed rule exempts nurseries, residential neighborhoods, 

agricultural composting operations and other types of operations from 

the registration requirements of this rule; however, the definitions 

describing these operations are too restrictive in that they do not allow 

the sale of products derived from this type of operations. This limitation 

on sale of products should be eliminated from these definitions. 

 

Response 1-4: The definitions have been changed and no longer limit the sale of 

products derived from the exempted sources.

Comment 1-5 Does the definition of community composting include any limits of 

compost sold?

Response 1-5. The definition of community composting does not include any limits of 

compost sold; however, it clearly states that this activity is conducted by 

a residential neighborhood association using feedstock generated by the 

neighborhood to produce compost for the neighborhood’s use.

 

PR 1133.1

Comment 1-1 Definitions of curbside and non-curbside greenwaste should be 

combined since curbside loads often include non-curbside greenwaste. 

Response 1-1 A new definition for mixed greenwaste is added to the rule to define 

greenwaste that contains both curbside and non-curbside materials. 

However, there are different holding/processing time requirements for 

curbside and non-curbside greenwaste so both definitions are necessary. 

Specific holding/processing time for mixed greenwaste is also 

established. 

Comment 1-2 Definition of alternative daily cover refers exclusively to greenwastederived materials. It could also include woodwaste. 

Response 1-2 Under the revised rule language, the holding/processing time 

requirements are proposed for chipped and ground curbside greenwaste 

instead of ADC or composting feedstock (i.e., 3-days). Exemption is 

also provided for chipped and ground curbside greenwaste provided that 

the moisture content is less than 30%. Because of this revision, the 

definition for ADC is removed. 

Comment 1-3 Definition of mulch should also refer to the use of mulch below the 

surface of soil as well as on top of soil. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 31 January 2003 

Response 1-3 Under the revised rule language, the holding/processing time 

requirements are proposed for chipped and ground curbside greenwaste 

instead of ADC (including mulch) or composting feedstock (i.e., 3-

days). Exemption is also provided for chipped and ground curbside 

greenwaste provided that the moisture content is less than 30%. Because 

of this revision, the definition for mulch is removed. 

Comment 1-4 Agricultural chipping and grinding should be exempt from the holding 

time requirements of the rule. 

Response 1-4 Rule language is revised to exempt agricultural chipping and grinding 

from the holding/processing time and recordkeeping requirements. 

Comment 1-5 PR 1133.1 should have a provision to address equipment breakdown. 

Response 1-5 Equipment breakdown is covered under Rule 430 – Breakdown 

Provisions, which includes reporting procedures and specific timeframe 

for equipment repair, as well as the allowance for emergency variance 

for equipment that would need additional repair time. 

Comment 1-6 PR 1133.1 should allow additional holding time during and after rainy 

days. 

Response 1-6 PR 1133.1 is revised so that holding/processing time may be extended to 

allow time for rainy days (defined as any day with a minimum of 0.05 

inches of rain reported by the National Weather Service or a cooperative 

weather reporting station for the site closest to the chipping and grinding 

operations) and wet weather conditions defined as weather conditions 

following a rainy day that would impede normal operations (not to 

exceed 10 days) provided that records documenting these conditions are 

kept on-site. 

Comment 1-7 Palm chipping and grinding activity should be exempt from PR 1133.1 

Response 1-7 PR 1133.1 is revised to exempt palm chipping and grinding activity from 

the holding/processing time and recordkeeping requirements because of 

its bulkiness and difficulty in grinding quickly as well as due to its slow 

decomposition rate. 

Comment 1-8 Holding/processing times are too strict, especially for non-curbside 

greenwaste. 

Response 1-8 PR 1133.1 is revised to include various holding times for unprocessed 

greenwaste received as well as for processed (curbside chipped and 

ground) greenwaste. In particular, the holding/processing time for 

unprocessed non-curbside greenwaste is revised to be 14 calendar days 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 32 January 2003 

(from receiving date), excluding official federal and state holidays as 

well as rainy days and wet weather conditions, and the holding time for 

chipped and ground curbside greenwaste is 3 calendar days. There is no 

holding time requirement for chipped and ground non-curbside 

greenwaste such as those used for biomass fuel. 

The holding/processing time requirements are revised to be in-line with 

normal chipping and grinding operations while preventing inadvertent 

decomposition. 

Comment 1-9 PR 1133.1 should prohibit chipping and grinding of foodwaste. 

Response 1-9 Instead of prohibiting foodwaste chipping and grinding, PR 1133.1 

requires foodwaste to be removed from the site or used for on-site 

composting within 2 calendar days of receipt. 

Comment 1-10 The holding/processing time requirements of PR 1133.1 may negatively 

impact AB 939 (i.e., waste diversion from landfills). 

Response 1-10 The holding/processing time requirements are intended to prevent 

inadvertent decomposition associated with stockpiling of greenwaste for 

extended periods of time, which is not supposed to be a normal practice 

at chipping and grinding facilities. Therefore, these requirements do not 

adversely impact AB 939 goals.

Comment 1-11. Landclearing activity should be exempt from PR 1133.1.

Response 1-11. PR 1133.1 is revised to exempt landclearing activity from the 

holding/processing time and recordkeeping requirement since the 

activity is conducted offsite and is associated with non-curbside 

greenwaste chipping and grinding.

Comment 1-12. ASTM Test Method E 871 – Standard Method for Moisture Analysis of 

Particulate Wood Fuels should be an additional method to measure 

moisture content.

Response 1-12. PR 1133.1 is revised to add the above ASTM method.

PR1133.2

 

Comment 1-1: An aeration system within an enclosure is discretionary; therefore it 

should not be constrained by the 90 percent negative pressure operating 

requirement. 

 

Response 1-1: Proposed Rule 1133.2 does not require the use of aeration systems 

within enclosures. The proposed rule language has been modified to 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 33 January 2003 

clarify that the requirement for an aeration system (a forced-air aeration 

system that operates under negative pressure for at least 90 percent of the 

blower operating time) is only for curing phase of composting under the 

method of compliance specified in paragraph (d)(1), for new facilities. 

 

Comment 1-2: The definition of the term “active co-composting” contradicts the 

definition of the California Integrated Waste Management Board 

(CIWMB) (i.e., 122oF). The use of a range of temperatures does not 

work for this definition. Alternative ways to define this term should be 

considered. 

 

Response 1-2: This definition has been modified and is now based on time (number of 

days) instead of temperature. As revised, the definition clearly defines 

the active phase and does not contradict the CIWMB definition for 

active composting. For air quality purposes, defining active cocomposting based on the number of days is more representative, since up 

to 80 percent of VOC and 50 percent of ammonia emissions occur in this 

phase. 

 

Comment 1-3: The use of the word “throughput” in the definition of the term “baseline 

emission factors” is inconsistent with how emissions factors were 

developed. 

 

Response 1-3 The proposed rule now contains a definition for the term “throughput.” 

Adding this definition clarifies the rule and eliminates the 

inconsistencies. 

 

Comment 1-4 The definition of the term “co-composting operations does not mention 

any greenwaste or bulking agents. Co-composting cannot be conducted 

without bulking agents. 

 

Response 1-4: The co-composting definition has now been modified to state that cocomposting operations are "composting operations where biosolids 

and/or manure are mixed with bulking agents to produce compost. Cocomposting operations include both the active and curing phases of the 

composting process." 

 

Comment 1-5: The use of the word “collection” in the definition of composting is 

incorrect since the collection aspect does not have anything to do with 

composting. 

 

Response 1-5: The definition of the term “composting” has been modified and does not 

include collection. 

 

Comment 1-6: The definition of the term “curing” in terms of temperature is 

burdensome. It is recommended that the definition be changed to a 

microbial-activity based definition. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 34 January 2003 

Response 1-6: The definition of the term “curing” has been changed and it now contains 

a time element (i.e., 40 days) and a microbial-activity based definition

based on the Solvita test or oxygen consumption (respirometry). 

 

Comment 1-7: There are greenwaste composting operations that process or use manure 

and/or foodwaste in their composting process. These types of operations 

should not be considered to be co-composting since they are truly 

greenwaste composting operations. It is recommended that definition of 

the term “co-composting” be changed to exclude greenwaste composting 

operations that handle small amounts of manure. 

 

Response 1-7: Proposed Rule 1133.2 has been modified and it now includes a 

definition of greenwaste composting, defined as greenwaste composting 

operations where bulking agents can include up to 20 percent manure. 

The proposed rule specifically exempts greenwaste composting from the 

requirements of Proposed Rule 1133.2. Furthermore, the definition of 

co-composting has been modified and foodwaste as a feedstock is not 

included in that definition, and therefore, foodwaste composting is not 

regulated under the Proposed Rule 1133.2 at this time. 

 

Comment 1-8: The most likely add-on control technology that would be used to comply 

with rule is biofiltration. Given the limited source tests data on VOC 

reduction efficiency with this type of control technology, it is requested 

that the proposed rule provide some flexibility in demonstrating 

compliance with the destruction efficiency of biofilters since the 

demonstration on a continuous basis may be difficult. 

 

Response 1-8: The proposed rule has been revised to address this issue by providing 

flexibility in demonstration of the destruction efficiency of biofilters 

such that compliance demonstration must be done initially as part of the 

permit application process and every two years thereafter. Guidelines 

for source test protocols to determine compliance are provided in 

Attachment A of PR1133.2. 

 

Comment 1-9 Previous version of the rule contained exemptions for small composting 

operations. Please consider adding an exemption for small composting 

operations: 

 

Response 1-9: The proposed rule includes an exemption for small co-composting 

operations that handle less than 1,000 tons of throughput per year. 

Comment 1-10: A 100 percent capture efficiency is too restrictive and may be difficult to 

be met. 

 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 35 January 2003 

Response 1-10: The rule is revised to include specific criteria for an enclosure to provide 

for access as well as brief periods of openings (refer to section 

(d)(1)(A)(i) through (d)(1)(A)(iv)). 

 

Comment 1-11 The baseline emission factors that AQMD has developed represent only 

the active phase of composting. 

 

Response 1-11: Staff disagrees. The baseline emission factors were based on source tests 

conducted on both the active and curing phases of co-composting 

process (including and up to the 62 days of composting). 

 

Comment 1-12: There is insufficient data on biofilter performance with respect to 

controlling VOCs. 

 

Response 1-12: Based on the available data on existing biofilter applications, VOC 

destruction efficiencies of between 80 65% and 90% have been 

demonstrated. Based on available information, the 80 percent reduction 

efficiency required for emissions control equipment for new facilities 

(under d(1)) is achievable by optimally maintained and operated 

biofilters or other control equipment capable of achieving equivalent 

reductions, while providing some compliance margin to address 

potential performance variations. 

 

Comment 1-13: Small municipally-owned co-composting operations that have already 

invested in control technologies should be exempt from Proposed Rule 

1133.2. Furthermore, this type of exemption should also be provided to 

other municipalities whose operations are not for profit and would have 

difficulty in meeting the financial demands to comply with the main 

requirements of the proposed rule. 

 

Response 1-13: The proposed rule has been revised and now includes an exemption for 

co-composting operations that meet all of these conditions: 1) the cocomposting operation is equipped with a forced-air aeration system and 

the emissions from the forced-air aeration system are vented to a control 

device that has a destruction efficiency equal or greater than 80 percent 

for VOC and ammonia, by weight; and, 2) the co-composting operation 

is used to compost wastes generated within the jurisdiction of the 

municipality, and 3) the co-composting operation does not handle more 

than 5,000 tons per year or biosolids or manure, combined. 

 

Comment 1-14: The proposed rule should exempt existing co-composting operations that 

have a non-renewable and limited conditional use permit. Facilities that 

would only operate for three years beyond the compliance schedule of 

this rule should be exempt, since it would be impossible to amortize the 

required investment to comply with the proposed rule. 
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 36 January 2003 

Response 1-14: The District is proposing this rule to protect public health by reducing air 

pollutants. The District rule establishes a percentage control for existing 

facilities, but leaves the method of control to the individual facility. This 

would enable a facility to choose the most cost effective controls for its 

operation. Furthermore, Proposed Rule 1133.2 includes a provision to 

extend the effective date of compliance for up to three years for an 

existing facility that has less than 3 years remaining under a nonrenewable conditional use permit (beyond its effective compliance date) 

provided such facility submits a copy of their conditional use permit and 

a letter from the responsible agency confirming that the permit has an 

expiration date and it is non-renewable. The District has a variance 

procedure for facilities that cannot comply with rules for reasons beyond 

their control.

Comment 1-15: The proposed rule is technology limiting and discriminates against other 

viable technologies. 

Response 1-15: The proposed rule, in fact, provides flexibility for new and existing cocomposting operations to demonstrate compliance using any 

combination of composting and control methods. 

Comment 1-16: Alternatives to flux chamber method of testing for VOC emissions 

should be allowed because of the high cost of testing. 

Response 1-16: Attachment A of PR 1133.2 is revised to allow for alternative test 

protocols to be submitted to the District for approval. 

Comment 1-17: Method 207.1 for measuring ammonia is a draft method and specifies 

outdated analytical techniques. 

Response 1-17: Attachment A of PR 1133.2 is revised to specify the use of ion 

chromatography or ion specific electrode analytical methods under 

Method 207.1. 

Comment 1-18: The requirement for the use of Laboratories approved under District's 

Laboratory Approval Program (LAP) is too restrictive and costly. 

Annual renewal of certificates is also required. 

Response 1-18: The use of approved laboratories is common to all District regulations 

and is intended to provide data quality assurance and equity. This is a 

responsible alternative to using District resources solely. The annual 

renewal fee is minimal ($100).

Comment 1-19. Manure should be excluded from the definition of co-composting.
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 37 January 2003 

Response 1-19. From an emissions standpoint, manure is included in the definition of 

co-composting since manure is a putrescible organic matter that 

generates ammonia and VOC emissions. The concern that by including 

manure in the co-composting definition, greenwaste composting would 

be included in PR 1133.2 is addressed by adding a definition for 

greenwaste composting that includes up to 20 percent manure. 

Greenwaste composting is exempt from the requirements of Proposed 

Rule 1133.2.

Comment 1-20. PR 1133.2 should provide flexibility to achieve the required emissions 

reduction by the use of process control and/or best management 

practices, (i.e., pile geometry, mixture composition optimization).

Response 1-20. Proposed Rule 1133.2 provides a compliance option whereby a facility 

may comply with the requirements of the proposed rule by employing 

any combination of composting and control methods, including, but not 

limited to, process controls and/or best management practices.

Comment 1-21: The requirements for enclosures openings should be based on either face 

velocity or emission measurements, not both.

Response 1-21. To ensure that enclosures are well designed in terms of their ability to 

capture emissions, both tests are required and are independent of each 

other.

Comment 1-22 Does a compliance plan supersede a permit?

Response 1-22. Compliance plan submittals are required as part of the rule for existing 

co-composting facilities and for new facilities that elect to comply with 

the overall emission reduction target through a compliance plan process. 

These plans are independent of any permits that may be required to site a 

new facility or modify an existing facility. A compliance plan does not 

supersede a permit or vice versa. Also for facilities that may be able to 

comply with the requirements of the rule solely by process controls or 

best management practices, the plan then becomes the enforcement tool 

since there may not be a permit associated with that type of composting 

method (i.e., without control equipment or basic equipment).

Comment 1-23. Demonstration of control efficiency should not be limited to source 

testing.

Response 1-23. Source testing is the only acceptable procedure to demonstrate control 

efficiency of control equipment. The rule also allows overall control 

efficiency demonstration through source testing. However, alternative 

test methods are also allowed provided that they are determined to be 

equivalent and approved by the AQMD, ARB and U.S. EPA.
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 38 January 2003 

Comment 1-24. Source testing requirement should not be included in the compliance 

plan since it is part of the permit applications.

Response 1-24. Source testing requirements are included in compliance plans in order to 

demonstrate compliance with required emission reductions, especially in 

the event that permits are not required. When both permits and a plan 

are required, District staff will ensure that conditions of any plan and any 

required permit requirements are consistent with each other.

Comment 1-25. Clarify baseline emissions.

Response 1-25. Baseline emissions are emissions generated from the existing 

uncontrolled setting and/or practices of the composting operations, 

where emissions control equipment or methods are not in-place.

Comment 1-26. Why is interim plan approval necessary?

Response 1-26. Interim plan approval is a necessary procedure to ensure that the 

proposed compliance method would achieve the overall emission 

reduction targets prior to a facility beginning construction and incurring 

costs. Following the construction of the new or modified facility, the 

operator is then required to demonstrate by source testing that the 

proposed method of control demonstrates compliance.

Comment 1-27. The definition of curing should include product respiration rate in terms 

of oxygen uptake.

Response 1-27. The proposed rule language is revised to also include the suggested 

oxygen uptake as option in defining the end of the curing phase of the 

composting process.

Comment 1-28. The control efficiency requirements for control equipment is bothersome 

since there may be insufficient data regarding biofilter’s control 

efficiency.

Response 1-28. It is important that the rules achieve intended emission reductions. 

Without specifying a control efficiency, reductions may not be achieved. 

Manufacturers can design biofilters to meet the control efficiency. 

Based on the literature review and the available source test information, 

control efficiencies of 80% to 90% for VOC and 70% to over 90% for 

ammonia have been achieved in practice. Biofilter 

manufacturers/designers also emphasize that biofilters have to be welldesigned, well-operated, and well-maintained to achieve such control 

levels.
Final Staff Report for Proposed Rules 1133, 1133.1, and 1133.2 

PR 1133, 1133.1, 1133.2 39 January 2003 

Comment 1-29. The unit of the emission factors are not consistent between source test 

reports and rule language (lb emissions/ton compost mix vs. lb 

emission/ton throughput). Does throughput include recycled materials?

Response 1-29. The proposed rule language has been made consistent throughout. A 

definition of the term “throughput” has also been included for 

clarification which does not include recycled materials. Throughput 

only includes the amount of compost feedstock plus bulking agents 

and/or amendment.

Comment 1-30. Clarify the number of existing co-composting facilities in the inventory.

Response 1-30. Based on the previous definition of co-composting, District staff had 

identified 12 co-composting facilities, which included small facilities as 

well as facilities that compost small percentage of manure along with 

greenwaste. However, under the current definition of co-composting,

there are 9 co-composting operations identified under PR 1133.2. Please 

note that staff also considered two operations conducted by two 

independent operators at the same location as two individual facilities.