(Adopted July 8, 2011) 

RULE 1133.3 EMISSION REDUCTIONS FROM GREENWASTE 

COMPOSTING OPERATIONS 

(a) Purpose 

The purpose of this rule is to reduce fugitive emissions of volatile organic 

compounds (VOC) and ammonia occurring during greenwaste composting 

operations. 

(b) Applicability 

This rule applies to the operator of all new and existing greenwaste composting 

operations that produce active or finished compost from greenwaste by itself or 

greenwaste in combination with manure or foodwaste, unless otherwise exempted 

under subdivision (g) of this rule. 

(c) Definitions 

For the purposes of this rule, the following definitions shall apply: 

(1) ACTIVE COMPOST means material that is in the process of being 

rapidly decomposed and is biologically unstable. Active compost is 

generating temperatures of at least 122 degrees Fahrenheit during 

decomposition. Active compost includes, but is not limited to, pathogenreduced mulch. 

(2) ACTIVE PHASE means the phase of the greenwaste composting process 

that begins when organic waste materials are mixed together for 

composting and lasts a minimum of 22 days under controlled conditions or 

until the compost has a Solvita Maturity Index of five or greater measured 

pursuant to subparagraph (e)(4)(A). 

(3) BACKYARD COMPOSTING means composting conducted by a 

household including, but not limited to, single family residences, 

condominiums, duplexes, or apartment buildings. 

(4) BASELINE EMISSION FACTORS mean the uncontrolled emission 

factors for greenwaste composting operations for VOC and ammonia. 

(5) COMMUNITY COMPOSTING means composting conducted by a 

residential neighborhood association using feedstock generated within the 

residential neighborhood to produce compost for the neighborhood’s use. 

1133.3 – 1 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

(6) COMPOSTING means a process in which solid organic waste materials 

are decomposed in the presence of oxygen through the action of bacteria 

and other microorganisms. 

(7) COMPOST OVERS mean the oversized woody materials that do not 

decompose in a typical composting cycle and are screened out of finished 

product at the end of composting. Compost overs have been through the 

pathogen reduction process outlined in Title 14, Section 17868.3 of the 

California Code of Regulations. 

(8) CURING PHASE means the phase of the greenwaste composting process 

that begins immediately after the end of the active phase of composting 

and lasts a minimum of 40 days or until the compost has a Solvita 

Maturity Index of seven or the product respiration rate is below ten 

milligrams of oxygen consumed per gram of volatile solids per day as 

measured by direct respirometry, pursuant to subparagraph (e)(4)(B). 

(9) EXISTING GREENWASTE COMPOSTING OPERATIONS mean all 

greenwaste composting operations that have begun operations on or before 

July 8, 2011. 

(10) FINISHED COMPOST means a humus-like material and/or compost 

overs that result from the controlled biological decomposition of organic 

waste materials and is biologically stable. Both the active and curing 

phases of the greenwaste composting are required to achieve this product. 

(11) FOODWASTE means any pre- or post-consumer food scraps collected 

from the food service industry, grocery stores, or residential food scrap 

collection. Foodwaste also includes food scraps that are chipped and 

ground. 

(12) GREENWASTE means any organic waste material generated from 

gardening, agriculture, or landscaping activities including, but not limited 

to, grass clippings, leaves, tree and shrub trimmings, and plant remains. 

(13) GREENWASTE COMPOSTING means composting of greenwaste by 

itself or a mixture with foodwaste, or with up to 20 percent manure, per 

pile volume basis. 

(14) NEW GREENWASTE COMPOSTING OPERATIONS mean greenwaste 

composting operations that have not started operations as of July 8, 2011. 

(15) NURSERY COMPOSTING means composting conducted at a nursery to 

produce compost for on-site use. 

1133.3 – 2 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

(16) ORGANIC WASTE means any organic waste material that includes 

foodwaste, greenwaste, woodwaste, or manure, or a mixture thereof. 

(17) OPERATOR means any person that operates a greenwaste composting 

operation. 

(18) PILE means compostable material that is heaped together. 

(19) RECREATIONAL FACILITY COMPOSTING means composting 

conducted at parks, arboretums and other recreational facilities using 

feedstock generated on-site to produce compost for on-site use. 

(20) SOLVITA MATURITY INDEX means an index that defines the stage 

where compost exhibits resistance to further decomposition, as tested by 

the Solvita Maturity Test®. 

(21) START-UP means the first day of active greenwaste composting 

operations at the facility. 

(22) THROUGHPUT means the mass of manure, foodwaste, or greenwaste in 

tons per year as received by the facility and processed through 

composting, excluding recycled materials. 

(23) TMECC means Test Methods for the Examination of Composting and 

Compost published by the US Composting Council Research and 

Education Foundation. 

(24) WOODWASTE means lumber, and the woody material portion of mixed 

demolition and construction wastes. Woodwaste also includes large wood 

materials of curbside greenwaste or mixed greenwaste that is screened or 

unscreened, such as tree trimmings, branches, tree trunks, stumps, and 

limbs exceeding two inches in any dimension. 

(d) Requirements 

(1) Effective July 8, 2011, the operator of greenwaste composting operations 

shall comply with the following requirements: 

(A) Chip or grind, as necessary, and use greenwaste for on-site 

composting as allowed by the Local Enforcement Agency. 

(B) Use foodwaste for on-site composting within 48 hours of receipt or 

cover foodwaste with screened or unscreened finished compost 

until used, unless otherwise required by the Local Enforcement 

Agency. 

(2) Effective upon start-up for new greenwaste composting operations and 

effective November 8, 2011 for existing greenwaste composting 

1133.3 – 3 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

operations, the operator of greenwaste composting operations processing 

greenwaste only or up to 20 percent manure, by volume, or up to 5,000 

tons per year of foodwaste throughput shall comply with the following 

requirements: 

(A) Cover each active phase pile with screened or unscreened finished 

compost within twenty-four hours of initial pile formation such 

that the top is at least six inches thick and the pile shall not be 

turned for the first seven days of the active phase of composting, 

unless subparagraph (d)(2)(D) applies. 

(B) For the first fifteen days after initial pile formation for the active 

phase period of composting, within six hours before turning, apply 

water as necessary to the surface area of each active phase pile 

such that the top one half of the pile is wet at a depth of at least 

three inches. Alternatively, the operator may apply water during 

turning using a windrow turner which is equipped with water 

spraying technology during the entire windrow turning process. 

(i) For the purpose of this subparagraph, “wet” shall be 

determined by means of a squeeze ball test or an alternative 

approved by the Executive Officer, California Air 

Resources Board, and the United States Environmental 

Protection Agency. The ball test shall be conducted by 

taking a sample of the compostable material from the top 

half of the pile, at least three inches below the outer 

surface. The material should be squeezed into a ball using 

hand pressure and wearing a protective glove. There 

should be at least enough water to form a ball when 

compressed, but the ball may break when tapped. If the 

ball crumbles upon release of the hand pressure, apply 

additional water to the windrow prior to turning until the 

material passes the ball test. 

(C) If a rain event occurs prior to watering the pile within six hours 

before turning and the pile is wet to a depth of three inches, the 

operator may turn the pile without adding additional water. If the 

top half of the pile is dry to the three inch depth, apply additional 

water to the pile pursuant to subparagraph (d)(2)(B). 

1133.3 – 4 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

(D) If the pile needs to be turned within the first seven days for 

managing temperature or pathogen reduction pursuant to Title 14 

Division 7, Chapter 3.1, Section 17868.3 of the California Code of 

Regulations, the operator does not need to re-apply the screened or 

unscreened finished compost cover and shall apply water pursuant 

to subparagraph (d)(2)(B) for the first fifteen days of the active 

phase. 

(E) The operator may implement an alternate mitigation measure that 

will be based on a test protocol approved by the Executive Officer, 

California Air Resources Board, and the United States 

Environmental Protection Agency and that demonstrates emission 

reductions by at least 40 percent, by weight, for VOC and emission 

reductions by at least 20 percent, by weight, for ammonia for 

combined screened or unscreened finished compost cover and 

water application. 

(3) Effective July 8, 2011, the operator of greenwaste composting operations 

processing greater than 5,000 tons per year of foodwaste throughput shall 

comply with the following requirements, for the purpose of regulatory 

compliance: 

(A) Any active phase of composting containing more than 10 percent 

foodwaste, by weight, shall be conducted using an emission 

control device designed and operated with an overall system 

control efficiency of at least 80 percent, by weight, each for VOC 

and ammonia emissions. 

(B) The operator may implement a control alternative if the alternative 

is approved by the Executive Officer, California Air Resources 

Board, and the United States Environmental Protection Agency, to 

achieve VOC and ammonia reductions that are greater than or 

equal to the reductions required pursuant to subparagraph 

(d)(3)(A). 

(C) For new greenwaste composting operations that intend to compost 

greater than 5,000 tons per year of foodwaste throughput, a permit 

shall be obtained for an emission control device, as specified in 

subparagraph (d)(3)(A) or (d)(3)(B), prior to construction. 

The annual throughput calculation may exclude any non-putrescible 

materials, including, but not limited to paper, woody, other low-water, 

1133.3 – 5 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

high cellulose materials, and non-compostable contaminants and green 

waste that are separated either before or after composting and shipped offsite for disposal provided they are quantified and appropriate records are 

maintained for. 

(4) No later than October 10, 2011, for existing greenwaste composting 

operations that, as of July 8, 2011, process or plan to process greater than 

5,000 tons per year of foodwaste throughput, the operator shall file a 

permit application for an emission control device and fully implement the 

emission control device in accordance with subparagraphs (d)(3)(A) or 

(d)(3)(B) within six months upon approval of the permit application. 

(5) The overall control efficiency required in subparagraph (d)(3)(A) shall be 

demonstrated by a source test within three months after implementation of 

the emission control device, or within nine months of permit approval, 

whichever occurs sooner, and every three years thereafter. For the 

purpose of this rule, the baseline emission factors to be used shall be 4.25 

pounds of VOC per ton of throughput and 0.46 pounds of ammonia per 

ton of throughput for the active phase of composting only. The Executive 

Officer may approve the use of alternate baseline emission factors, if the 

operator demonstrates through the approved source test that alternate 

baseline emission factors are representative of uncontrolled operations for 

that facility 

(6) All emission control devices shall be installed, operated, and maintained in 

accordance with the manufacturer’s operation and maintenance manual or 

other similar written materials supplied by the manufacturer or distributor 

of such equipment to ensure that the system remains in proper operating 

conditions. Such documentation shall be made available to the Executive 

Officer upon request. 

(7) All records, including application of screened or unscreened finished 

compost and water, operation and maintenance of an emission control 

device, and source tests, shall be kept and maintained at the facility 

pursuant to subdivision (f). 

(e) Test Methods and Protocol 

(1) For a greenwaste composting operation subject to paragraphs (d)(3) 

through (d)(5), the operator shall conduct all required source and 

laboratory tests in accordance with an Executive Officer approved test 

1133.3 – 6 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

protocol developed in accordance with the guidelines provided in 

Attachment A of this rule. 

(2) For a greenwaste composting operation subject to paragraphs (d)(3) 

through (d)(5), the operator shall use a District approved laboratory in 

accordance with the Attachment A of this rule. 

(3) The following methods shall be used to determine compliance with this 

rule: 

(A) SCAQMD Method 207.1 – Determination of Ammonia Emissions 

from Stationary Sources. 

(B) SCAQMD Method 25.3 – Determination of Low Concentration 

Non-Methane Non-Ethane Organic Compound Emissions from 

Clean Fueled Combustion Sources. 

(C) SCAQMD Method 1.1 – Sample and Velocity Traverses for 

Stationary Sources. 

(D) SCAQMD Method 1.2 – Sample and Velocity Traverses for 

Stationary Sources with Small Stacks and Ducts. 

(E) SCAQMD Method 2.1 – Determination of Stack Gas Velocity and 

Volumetric Flow Rate (S-Type Pitot Tube). 

(F) SCAQMD Method 2.2 – Direct Measurement of Gas Volume 

through Pipes and Small Ducts. 

(G) SCAQMD Method 2.3 – Determination of Gas Velocity and 

Volumetric Flow Rate from Small Stacks or Ducts. 

(H) SCAQMD Method 4.1 – Determination of Moisture Content in 

Stack Gases. 

(4) Triplicate samples shall be taken for the following test methods: 

(A) TMECC 05.08-E – Solvita Maturity Index (April 7, 2002). 

(B) TMECC 05.08-A – Specific Oxygen Uptake Rate (April 7, 2002). 

(f) Recordkeeping 

Records shall be kept in a format approved by the Executive Officer. All 

operational records and information recorded pursuant to the provisions of this 

rule shall be maintained for the prior five years of operation, with the most recent 

two years retained at the facility, which shall be immediately available upon 

request by the Executive Officer. The remaining three years of records shall be 

made available to the Executive Officer within one week of request. 

1133.3 – 7 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

(g) Exemptions 

(1) Composting facilities subject to Rule 1133.2 – Emission Reductions from 

Co-Composting Operations, are exempt from the provisions of this rule. 

(2) If the operator of any greenwaste composting operation installs an 

emission control device, in accordance with paragraphs (d)(3) through 

(d)(6), the provisions of paragraph (d)(2) do not apply. 

(3) The following types of facilities and operations are exempt from the 

requirements of this rule, provided that the operation is not subject to the 

Local Enforcement Agency Notification or Permit regulations pursuant to 

Title 14 Division 7, Chapter 3.1, Section 17857.1 of the California Code 

of Regulations: 

(A) Community composting; 

(B) Nursery composting; 

(C) Backyard composting; and 

(D) Recreational facility composting. 

1133.3 – 8 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

ATTACHMENT A 

GUIDELINES FOR THE DEVELOPMENT OF SOURCE TEST 

PROTOCOLS FOR VOC AND AMMONIA EMISSIONS FROM 

GREENWASTE COMPOSTING OPERATIONS 

Source test protocols are to consist of testing plans to measure VOC and ammonia 

emissions due to the composting process. When used for determining the control device 

efficiency requirement specified for new and existing facilities, the measurements shall 

consist of lb/hr measurements at the inlet and exhaust of the control device and are 

subject to the applicable requirements that follow. When used for determining the overall 

emission reduction requirements as compared to the baseline emissions factors, emissions 

are to be reported as % reductions for the active phase composting in terms of pounds of 

emissions per ton of throughput (total raw material as received) and are subject to the 

applicable requirements that follow. The following are general requirements for all 

testing as well as specific requirements for the rule sections for each facility-specific 

protocol which must be prepared by the source test contractor and approved by the 

SCAQMD prior to testing. 

1. Alternative Test Methods 

The reference test methods for ammonia, VOC, and flow rate cited in this 

guideline shall be used to determine compliance with this rule. Alternative test 

methods may be used if they are determined to be equivalent and approved in 

writing by the Executive Officer, the California Air Resources Board, and the 

U.S. Environmental Protection Agency. For the source test protocols, as defined 

as the manner in which the reference test methods are employed to obtain a 

measurement of the emissions, alternatives to the procedures cited in this 

guidelines may be used if they are determined to be equivalent and approved in 

writing by the Executive Officer. 

2. LAP Requirements 

The sampling, analysis, and reporting shall be conducted by a laboratory/source 

test firm that has been approved under the SCAQMD Laboratory Approval 

Program (LAP) for the cited SCAQMD reference test methods, where LAP 

approval is available. For SCAQMD reference test methods for which no LAP 

program is available, the LAP approval requirement shall become effective one 

year after the date that the LAP program becomes available for that SCAQMD 

reference test method. 

3. Operating Conditions 

The testing must be conducted under representative operating conditions with 

respect to seasonal conditions, compost composition, process throughput, 

1133.3 – 9 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

processing of the materials, and pile geometries. The following operating 

parameters shall be recorded during testing and reported with the test results: 

a) A thorough description of the composting process and process diagram of 

each processing area and including residence times in each of the composting 

process areas. 

b) Process throughput as determined by facility’s billing scales or other 

calibrated measuring device that represents the tons of the material as received 

that is present at the facility during the time of the testing. When using the 

District Baseline Emission Factors, the process throughput is to include all of 

the raw organic materials that are composted excluding material that is 

recycled from previous similar processing. Several throughputs may be 

necessary if applicable to the different processing areas or pile ages. 

c) Compost composition (percent and type of materials i.e. manure, greenwaste, 

foodwaste, etc...). 

d) Age of all piles that were tested and all piles present at the facility during 

testing. 

e) Detailed dimensions of all piles or the biofilter so that a surface area for each 

pile type can be calculated. 

f) A description of the biofilter system, including a process diagram and type of 

biofilter media. 

g) Age of the biofilter media. 

h) A thorough description of the humidification and moisture maintenance 

system for the biofilter. 

i) Identification of peripheral monitoring equipment, such as moisture or 

temperature sensors, and data from them during testing. 

4. Ammonia Sampling 

SCAQMD Method 207.1 shall be used to obtain the ammonia samples from each 

source of emissions to be tested. When sampling from a flux chamber, a sample 

line of minimal length should be connected to a midget sampling train consisting 

of; two midget impingers each filled with 15 ml of 0.1N Sulfuric Acid, an empty 

bubbler, and a bubbler filled with tared silica gel. The samples shall be analyzed 

for ammonium content as ammonia by ion chromatography or ion selective 

electrode. 

5. VOC Sampling 

Duplicate integrated gas samples shall be taken from each source of emissions to 

be tested using SCAQMD Method 25.3. The Method 25.3 apparatus should be 

connected to sample directly inside the flux chamber or duct as applicable. 

Compost emissions are considered as water soluble sources where the 50 ppm 

applicability limit of Method 25.3 does not apply. 

1133.3 – 10 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

6. Specific Requirements for Testing Greenwaste Composting Operations Control 

Equipment Performance 

For surface types of emissions, such as with open faced biofilter exhausts, the 

exhaust emission rate shall be determined as in the following Section (8). 

For a control device inlet or exhaust that is vented through a testable duct, the gas 

velocity within the duct shall be measured according to SCAQMD Methods 1.1, 

2.1, and 3.1. The flow rate shall also be corrected to dry standard conditions using 

the moisture content as determined by SCAQMD Method 4.1. This flow rate may 

then be used to determine mass emission rates. 

The overall destruction efficiency is calculated as follows: 

ODE = 100 x (1 – (E / I)) (Equation 1) 

Where: 

ODE = Overall Destruction Efficiency (%) 

E = Total Exhaust Emission Rate (lb/hr) 

I = Total Inlet Emission Rate to Control Device (lb/hr) 

7. Specific Requirements for Existing Greenwaste Composting Operations and New 

Greenwaste Composting Operations (Overall Emissions Reduction) 

A proposed measurement from the active greenwaste composting process, 

including but not limited to surface emissions of all piles where the materials are 

composted, and outlets (vents or surfaces) of control devices must be included in 

the protocol. If the emissions are vented to atmosphere from a vent stack such as 

from an otherwise uncontrolled aerated static pile or other vent to atmosphere, 

then the stack concentration, determined using methods specified in Sections (4) 

and (5) and flow rate measurements as specified in the previous Section (6) are 

required. From all surface types of emissions such as from compost piles and 

biofilter surfaces, the procedure for measuring surface emissions as in Section (8) 

is required. A measurement for fugitive emissions from aerated static pile 

surfaces must also be included. 

Each type of pile must be tested. If the facility includes several identical piles, 

then only the largest pile need be tested. If the facility has more than three 

different age piles that are otherwise identical in processing and composition, then 

at a minimum three ages can be tested including newer, older, and middle aged 

piles. In any case, the surface area of all piles at the facility must be included in 

the determination of pile dimensions as recorded in Section (3). 

If the facility elects to use an alternative to the District’s baseline emissions 

factors, then a separate test must be conducted to establish this baseline on the 

1133.3 – 11 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

uncontrolled composting operation (e.g., windrow method) with the same 

compost mix. Following the source test to determine an alternative baseline, 

facilities would have the option to use the District’s baseline emissions factors or 

the alternative baseline emissions factors. 

Reduction of emissions shall be calculated as follows: 

% Reduction = 100 x (1-TE/B) (Equation 2) 

Where: 

TE = Total Active and Curing Phase Emissions (lb/ton throughput) 

B = District Baseline Emissions or Alternative Baseline Emissions if 

Tested (lb/ton throughput) 

8. Procedure for Measuring Surface Emissions 

The procedure for measuring surface emissions such as the compost pile and 

biofilter surfaces that cannot be tested by conventional methods through a stack or 

duct, is a modified form of the procedures found in the US Environmental 

Protection Agency’s (EPA) Measurement of Gaseous Emission Rates from Land 

Surfaces Using an Emission Isolation Flux Chamber User’s Guide (EPA Guide). 

The modification to the procedures in the EPA Guide is specified in the following 

requirements.

The flux chamber encompasses a fixed surface area of 1.4 ft2 and contains a 

sweep air system to obtain a homogeneous air sample by employing a mixing fan 

and sweep gas (10% He in air at 5 liters/min recommended). The sweep gas must 

contain a non reactive and non-present tracer such as the aforementioned 10% 

helium so that a correction for the contribution of the surface flow rate can be 

calculated. 

A minimum of ten (10) sample locations or a sufficient number at each 

pile/surface tested must be obtained in order to achieve a representative sample of 

the surface emissions. These locations can be composited for each pile/surface to 

reduce testing costs. For example, for one hour sampling, ten (10) random 

positions on the pile should be tested for 6 minutes each. Alternatively, a lesser 

number of sample locations may be sampled provided that an evaluation of spatial 

variation demonstrates that the number of sample locations is sufficient. 

The emissions must be reported in units of lb/hr-ft2

, lb/hr and lb/ton of 

throughput. The following calculations shall apply to the test results: 

Surface Flow Correction Factor = Ct / Cs (Equation 3) 

Where: 

1133.3 – 12 
Rule 1133.3 (Cont.) (Adopted July 8, 2011) 

1133.3 – 13 

Ct = Concentration of Tracer in Sweep Gas 

Cs = Concentration of Sweep Gas in Flux Chamber Sample 

Corrected Flux Chamber Results (lb/hr-ft2

) = UFC x SFCF (Equation 4) 

Where: 

UFC = Uncorrected Flux Chamber Results (lb/hr-ft2

) 

SFCF = Surface Flow Correction Factor 

lb/hr = lb/hr-ft2

 x Total Compost Surface Area in Category (Equation 5) 

lb/ton throughput = lb/hr x (24 hr/day) /PT (Equation 6) 

Where: 

PT = Process Throughput (total ton/day as received) 

Total Emissions (lb/ton throughput) = ∑ P (Equation 7) 

Where: 

P = Active and curing sources of the Facility Compost Emissions (lb/ton 

throughput) 

For a facility where not every age of pile was tested, the surface areas from each 

pile in the facility must be included and sorted into appropriate age and emissions 

categories from those that were measured.