1133.2 - 1

(Adopted January 10, 2003) 

RULE 1133.2 EMISSION REDUCTIONS FROM COCOMPOSTING OPERATIONS 

(a) Purpose 

 The purpose of this rule is to reduce volatile organic compounds (VOC) and 

ammonia (NH3) emissions from co-composting operations. 

(b) Applicability 

 This rule applies to all new and existing co-composting operations. 

(c) Definitions 

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

(1) AERATION SYSTEM is a system where air is forced through organic 

materials being composted, through the use of fans or blowers. 

(2) AGRICULTURAL COMPOSTING is composting conducted in 

agricultural settings where the feedstock consists of wastes generated onsite by the production and processing of farm or agricultural products. 

(3) ACTIVE CO-COMPOSTING is the phase of the composting process that 

begins when organic materials are mixed together for composting and 

lasts a minimum of 22 days. 

(4) BASELINE EMISSIONS FACTORS are the non-controlled emission 

factors for co-composting operations for VOC and ammonia. 

(5) BIOFILTRATION is a pollution control technology that removes and 

oxidizes VOC and ammonia through the action of bacteria and other 

microorganisms. 

(6) CO-COMPOSTING is composting where biosolids and/or manure are 

mixed with bulking agents to produce compost. Co-composting includes 

both the active and curing phases of the composting process. 

(7) COMPOST is a product resulting from the controlled biological 

decomposition of organic materials. 

(8) COMPOSTING is a process in which solid organic waste materials are 

decomposed in the presence of oxygen under controlled conditions 

through the action of bacteria and other microorganisms. 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 2 

(9) CURING is the phase of the co-composting process that begins 

immediately after the end of the active phase of composting and lasts 40 

days or until the compost has a Solvita Maturity Index of 7 or the product 

respiration rate is below 10 milligrams of oxygen consumed per gram of 

volatile solids per day as measured by direct respirometry. 

(10) ENCLOSURE is a completely walled, floored, and roofed structure or 

vessel. 

(11) EXISTING CO-COMPOSTING OPERATIONS are all co-composting 

operations that have begun operations on or before the date of adoption of 

this rule. 

(12) GREENWASTE is 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 is composting of greenwaste by itself or 

greenwaste in combination with up to 20 percent manure, by volume. 

(14) NEW CO-COMPOSTING OPERATIONS are co-composting operations 

that have not started operations as of the date of adoption of this rule. 

(15) OPERATOR is the operator of a co-composting operation. 

(16) SOLVITA MATURITY INDEX is an index that defines the stage where 

compost exhibits resistance to further decomposition, as tested by the 

Solvita Maturity Test®. 

(17) START-UP is the first day of active co-composting operations at the 

facility. 

(18) THROUGHPUT is the mass of biosolids, manure, and greenwaste in tons 

per year as received by the facility and processed through composting 

excluding recycled materials. 

(19) WOODWASTE is lumber, and the woody material portion of mixed 

demolition wastes and mixed construction wastes. 

(20) WOODWASTE COMPOSTING is composting of woodwaste by itself. 

(d) Requirements 

(1) Operators of new co-composting operations shall: 

(A) Conduct all active co-composting within the confines of an 

enclosure which meets the following conditions: 

(i) The inward face velocity of air through each opening in 

which air can enter the enclosure shall be a minimum of 100 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 3 

feet per minute, unless the opening is equipped with a 

closure device that seals the opening in the event that the 

airflow direction changes. 

(ii) 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. 

(iii) 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. 

(iv) No measurable increase over background levels of 

ammonia or hydrocarbons 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 shall be used for these 

measurements. The portable ammonia analyzer shall be 

operated per manufacturer's instructions and calibrated with 

certified zero and 10 parts per million ammonia standards. 

The portable hydrocarbon analyzer shall be a flame 

ionization detector operated per manufacturer's instructions 

and calibrated with certified zero and 10 parts per million 

methane standards. 

(B) Conduct all curing using an aeration system that operates under 

negative pressure for no less than 90 percent of its blower(s) 

operating cycle; and, 

(C) Vent the exhaust from the enclosure and the aeration system to an 

emissions control system designed and operated with a control 

efficiency equal to or greater than 80 percent, by weight, for VOC 

emissions and 80 percent, by weight, for ammonia emissions. 

(2) In lieu of complying with the requirements of paragraph (d)(1), operators 

of new co-composting operations may submit a compliance plan, for the 

approval of the Executive Officer, that demonstrates an overall emission 

reduction of 80 percent, by weight, for VOC emissions and 80 percent, by 

weight, for ammonia emissions from the baseline emission factors. 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 4 

(3) Operators of existing co-composting operations shall submit a compliance 

plan, for the approval of the Executive Officer, that demonstrates an 

overall emission reduction of 70 percent, by weight, for VOC emissions 

and 70 percent, by weight, for ammonia emissions from the baseline 

emission factors. 

(4) The baseline emission factors to be used under paragraphs (d)(2) and 

(d)(3) shall be 1.78 pounds of VOC per ton of throughput and 2.93 pounds 

of ammonia per ton of throughput. The Executive Officer may approve 

the use of operation-specific baseline emission factors in lieu of the 

baseline emission factors, if the operator requests the use of such baseline 

emission factors as part of the compliance plan submittal and 

demonstrates that the operation specific baseline emissions factors are 

representative of noncontrolled operations. 

(5) The operator of a co-composting operation shall submit the compliance 

plan required pursuant to paragraphs (d)(2) or (d)(3) at least one year prior 

to the start of operations for new co-composting operations and at least 

one year prior to the effective date of compliance for existing cocomposting operations. 

(6) The control efficiency required under subparagraphs (d)(1)(C) and 

(j)(2)(A) for new co-composting operations shall be demonstrated by a 

source test conducted as part of the permit application process and every 

two years thereafter. 

(7) The control efficiency required under subparagraph (j)(2)(A) for existing 

co-composting operations shall be demonstrated by a source test 

conducted on or before January 1, 2007, and every two years thereafter. 

(8) Within 180 days after the effective date of compliance and every two 

years thereafter, the operator of a co-composting operation shall perform 

all necessary tests and provide a certification of compliance report that 

includes all source test data and all other applicable information to 

demonstrate compliance with the emission reduction requirement of 

paragraphs (d)(2) or (d)(3). 

(e) Compliance Plan 

(1) Compliance plans required under paragraphs (d)(2) and (d)(3) shall 

contain all the following elements: 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 5 

(A) The name(s), address(es), and telephone number(s) of the 

person(s) responsible for the preparation, submittal and 

implementation of the compliance plan; 

(B) The name, address, and telephone number(s) of the facility for 

which the compliance plan is being prepared; 

(C) A description and process diagram of the co-composting operation; 

(D) A complete description of the control method(s) that will be used 

at the co-composting operation to meet the requirements under 

paragraphs (d)(2) or (d)(3). The description shall be in sufficient 

detail to demonstrate compliance with paragraphs (d)(2) or (d)(3). 

The acceptable control methods include, but are not limited to: 

(i) enclosure design or technology; 

(ii) aeration system design and operation; 

(iii) biofiltration; 

(iv) scrubber; 

(v) feedstock component optimization; 

(vi) biosolids thermal pre-treatment; 

(vii) enclosed material mixing and thermal stripping; 

(viii) staged active pile construction and aeration; 

(ix) feedstock ratio optimization; 

(x) process controls; 

(xi) best management practices; or, 

(xii) any combination of the methods listed above; or, 

(xiii) any other method approved by the Executive Officer, 

California Air Resources Board, and the United States 

Environmental Protection Agency. 

(E) All data, calculations methodology, calculations, records, 

manufacturer specifications and all other information necessary to 

determine that the composting methods and control methods 

proposed in subparagraph (e)(1)(D) will achieve the required 

emission reductions. 

(F) A methodology and calculations establishing the daily and annual 

VOC and ammonia emissions or projected emissions; 

(G) If applicable, a source test protocol developed in accordance with 

the requirements of subdivision (g), to establish operation-specific 

baseline emission factors. 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 6 

(H) A source testing protocol developed in accordance with the 

requirements of subdivision (g) to demonstrate compliance with 

the overall emission reductions specified in paragraph (d)(2) or 

(d)(3). 

(I) An identification of all equipment needing permits to construct and 

operate. 

(2) In evaluating the plan, the Executive Officer may require tests and 

sampling as necessary to determine the adequacy of the plan and the 

likelihood of compliance with the emission reduction requirements of 

paragraphs (d)(2) or (d)(3). 

(3) The Executive Officer may approve operation-specific baseline emissions 

factors provided the baseline emissions factors are substantiated with 

source test data obtained in accordance with subdivision (g) of this rule 

and the composting method(s) and mixture is representative of normal 

operations. 

(4) The Executive Officer shall provide interim approval of the compliance 

plan provided the operator submits all of the information required under 

paragraph (e)(1) and the Executive Officer verifies that, by design, the 

plan will meet the requirements of paragraph (d)(2) or (d)(3), as 

applicable. 

(5) Following the interim approval of the plan, the Executive Officer shall 

approve the compliance plan provided the operator submits, no later than 

180 days after the effective date of compliance, a certification of 

compliance report that includes all source test data, and the Executive 

Officer verifies that the emissions from the co-composting operations 

comply with the requirements of paragraphs (d)(2) or (d)(3), as applicable. 

(6) The Executive Officer may impose conditions necessary to ensure that the 

co-composting operation complies with the compliance plan and all 

applicable AQMD rules. 

(7) The Executive Officer may require the operator to maintain records 

consistent with the compliance plan necessary to demonstrate compliance 

with the plan. 

(8) Compliance with the provisions of the approved plan does not exempt an 

operator from complying with the requirements of the California Health 

and Safety Code, or any other AQMD rule. 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 7 

(f) Compliance Schedule 

(1) The effective dates of compliance for paragraphs (d)(1), (d)(2), and (d)(3) 

of this rule shall be as follows: 

(A) Upon start-up for new co-composting operations. 

(B) January 1, 2007 for existing co-composting operations with a 

facility design capacity of 100,000 tons of throughput per year or 

more. 

(C) January 1, 2008 for existing co-composting operations with a 

facility design capacity greater than or equal to 10,000 but less 

than 100,000 tons of throughput per year. 

(D) January 1, 2009 for existing co-composting operations with a 

facility design capacity less than 10,000 tons of throughput per 

year. 

(2) The Executive Officer shall extend for up to three years the compliance 

date for an existing co-composting operation which, at the time of rule 

adoption and at least one year prior to the effective compliance date, has 

less than 3 years remaining under a non-renewable conditional use permit 

beyond its effective compliance date. By June 1, 2003, the operator of 

such an operation must submit to the Executive Officer 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. 

(g) Testing Protocol 

(1) The operator of a co-composting operation shall conduct all required 

source and laboratory tests in accordance with an Executive Officer 

approved test protocol developed in accordance to the guidelines provided 

in Attachment A of this rule. 

(2) The operator of the co-composting operation 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. 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 8 

(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 or 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. 

(h) Recordkeeping 

The operator shall, at a minimum, maintain operation’s records for a period of at 

least two years, or five years for facilities subject to Title V Permit Requirements, 

and make them available to the Executive Officer upon request. 

(i) Plan Fees 

Operators subject to a compliance plan submittal pursuant to paragraphs (d)(2) 

and (d)(3) shall be assessed, as applicable, filing and evaluation fees pursuant to 

Rule 306. 

(j) Exemptions 

(1) The provisions of subdivisions (d) through (i) of this rule shall not apply 

to agricultural composting operations, greenwaste composting operations, 

woodwaste composting operations, co-composting operations with a 

design capacity of less than 1,000 tons of throughput per year, and 

existing co-composting operations with a design capacity of less than 

35,000 tons of throughput per year containing no more than 20 percent 

biosolids, by volume. 

(2) Except for paragraphs (d)(6) and (d)(7), the provisions of subdivisions (d) 

through (i) shall not apply to new and existing co-composting operations 

that: 

(A) Conduct co-composting operations using an aeration system that is 

vented to an emission control device with a control efficiency of 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 9 

80 percent, by weight, for VOC emissions and 80 percent, by 

weight, for ammonia emissions; and, 

(B) Are owned and operated by a municipality which composts waste 

generated within the jurisdiction of the municipality; and, 

(C) Process less than 5,000 tons of biosolids or manure per year, 

combined. 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 10 

ATTACHMENT A 

GUIDELINES FOR THE DEVELOPMENT OF SOURCE TEST 

PROTOCOLS FOR VOC AND AMMONIA EMISSIONS FROM COCOMPOSTING 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 facilities, the measurements shall consist of 

lb/hr measurements at the inlet and exhaust of the control device as well as a verification 

of the enclosure 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 cocomposting and curing phases 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. 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 11 

3. Operating Conditions 

The testing must be conducted under representative operating conditions with 

respect to seasonal conditions, compost composition, process throughput, 

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. biosolids, manure, 

greenwaste, etc...). 

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

testing. 

e) Detailed Dimensions of all piles so that a surface area for each pile type can 

be calculated. 

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. 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 12 

6. Specific Requirements for Testing Co-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 Co-Composting Operations and New CoComposting Operations (Overall Emissions Reduction) 

A proposed measurement from the active and curing co-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). 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 13 

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 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 are 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 are 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: 
Rule 1133.2 (cont.) (Adopted January 10, 2003) 

1133.2 - 14 

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.