### ARB Emissions Inventory Methodology for Composting Facilities

This C omposting Methodology w as dev el oped with the

as s istance and

r eview from

t he f ollowing

Ai r Po lluti on Co ntrol Distric ts (APCD) or Ai r Qu ality Ma nagement Di stricts (AQMD) : Bay

Ar ea AQMD, B utte

C ounty A QMD, I mperial

C ounty A PCD, Sacramento Metro AQMD, San Joaquin Valley A PCD, S an Luis Obispo County A PCD, S anta Barbara County A PCD, S hasta

C ounty AQMD

, S outh

C oast A QMD, V

entura C ounty A PCD, and

Yolo -S olano AQMD

.

I. B ackground and Applicability

Th e purpose of this document is to describe a methodology for estimating emissions

from California composting facilities. The methodology provides procedures for estimating volatile organic compound (VOC) and a mmonia (NH 3 ) emissions from composting operations. Composting facilities are also sources of greenhouse gases such as methane, nitrous oxide, and carbon dioxide; however, a separate methodology

that eval uates the complete lifecycle emissions for GHG emissions is warranted and is

not included in this document

.

Th ese facilities are typically subject to the regulations of the California Department of Resources, Recycling & Recovery (CalRecycle) , the State Water Resource Control

Board , and the local air districts

. CalRecycle permits the facility siting, pathogen destruction, and general operation standards for composting facilities. The State Water Resource Control Board ensures compliance with state water protection requirements to ensure that wastewater from composting facilities is properly handled onsite. The local air districts permit composting facilities under New Source Review and in some cases have source specific regulations. They also receive odor complaints from local

residents and refer them to CalRecycle or the delegated local enforcement agency.

Th is me thodology can be used to estimate emissions from c ompostable m aterial

h andling o peration f acilit ies (compost facility). A composting facil ity is an operation or facility that processes, transfers, or stores compostable materials for the purposes of controlled biological decomposition. Compostable materials include: grass clippings,

woodwaste

, manure, biosolids, digestate, and food waste. The methodology is applicable to facilities that process organic materials via a n open windrow composting or aerated static pile processes

. T his methodology assume s that material is s tockpile d prior to composting for up to 14 days before the active phase initiated . A ctive composting and curing is assumed to take approximately 8 to 9 week s

. Emissions from the composting, drying, or land application of organic wastes generated on farms and used to fertilize farm crops

, as well as backyard composting and un intentional composting

, are not addressed in this methodology.

Thi s emission inventory methodology addresses composting facilities with feedstocks that include greenwaste, co- composting ( greenwaste combined with biosolids and /or

1 3/2/2015manure) and foodwaste mixed with greenwaste

. This methodology only applies to a composit ing mixtures with no more than 15 % by weight foodwaste, biosolids (by volume) , or manure (by volume) and mixtures with no less than 85 % by weight greenwaste.

The emission calculations fro m this m ethodology apply to facilities that are identified by the following Category of Emission Source (CES) code and Reconciliation Emission Inventory Code (REIC):

CES REIC Description

89490 199

- 170

- 0260

- 0000 Composting Waste Disposal

II. Source Category Description

a. Process Description

Composting is a process that involves the biological break down of organic matter into products that generally can be used in an agricultural application. Compost application to agricultural fields increases soil health wh ile providing multiple co

- benefits. Compost application can reduce the amount of synthetic fertilizer needed, reduce the amount of water used, decrease soil erosion, increase soil carbon storage

, and reduce the use of

herbicides.

Compostable organic was te feedstock can come from many sources including but not

limited to the following:

• Biosolids

- organic material resulting from the treatment of wastewater or sewage sludge

.

• Animal waste (manure)

- non

- human animal excretions and waste, including, but

not limited to, dried solids and urine from cows or swine.

• Poultry litter

- poultry excretions and waste, including, but not limited to, dried solids and urine from chickens, turkeys, geese, or ducks.

• Greenwaste

- leaves, grass clippings, plants, tree pruni ngs, branches, and woody material such as large trees and stumps

, arising from domestic, agricultural, commercial or municipal activities.

• Pomace

- the solid remains of grapes, olives, or other fruit after pressing for juice or oil. It contains the skins, pulp, seeds, and stems of the fruit

• Foodwaste

- any food scraps collected from the food service industry, grocery stores, or residential food scrap collection. Foodwaste also includes food material that is chipped and ground. Food packaging material may be included with the foodwaste and depending on the material will need to be separated or ground into the composting pile.

• Liquid waste

– some facilities use liquid waste from various sources which may include: brewery waste, soda waste, restaurant wastewater, or wastewater
residue.

2The following descriptions provide a general overview of the composting process at a facility and common types of composting processes that are currently being used.

Stockpile

Organic waste is generally transported by truck for processing at composting facilities. The material is dumped in piles to wait for incorporation into a n active composting pile. Material may be held in t h ese pre

- processing stockpile s for a few hours up to several days. During the stockpile pha se, the composting process may begin and create

emissions that are uncontrolled.

Grinding and Screening

In most cases, the materials in the stockpile will be ground and screened before they

are placed in the windrows. An electric or diesel powered grinder is generally used for this purpose. The material may also be sent through a screening plant to sort out debris and garbage from the process.

Once the materials have been processed through the grinding and screening phase, it

is then place d in piles or windrows to start the active and curing phases of the composting process. B rief description s of common composting methods used in
California are listed below.

Static Piles

Static piles are the simplest form of composting and require little management and equipment. Once established, it is very difficult to adjust moisture, and static piles tend to go anaerobic in the center. Aerobic conditions can be achieved if the initia l pile porosity is high (>60%) and there is a high proportion of bulking materials to keep pores open for air exchange. In general, product is kept on site for a t least 15 days prior to

sale to meet CalRecycle’s pathogen reduction requirements and is only turned if temperature warrants

. Currently this composting method is not addressed by the air

district rules and is not addressed in this methodology

. Upon further analysis and additional data availability, emissions from static piles may be add ressed at a later date.

Windrow Composting

Windrow is the general term for an elongated pile of stacked raw materials. Piles need to be small (3

- 6’) and porous enough for air to pass through t hem over a long period of

time. A turned windrow is one that is mechan ically turned using a bucket loader, manure spreader or a windrow turner. Turning the windrow remixes the materials, allowing all the raw materials to be colonized by microorganisms in the warmer, more active internal part of the compost pile. Turning re introduces o xygen and allows heat, water vapor

, and gases to escape. The most important reason for turning the pile is to reestablish porosity allowing air to get into the pile.

3Passively aerated windrow system (PAWS)

PAWS includes perforated pipes plac ed at the base of each windrow to promote convective airflow throughout the pile. The key to this system is thorough premixing of feedstocks before placing over the perforated pipes. Also, passively aerated windrows need to be insulated with finished compost to ensure that temperatures at the outer edges of the windrow are sufficient for pathogen destruction

.

Forced Aerated Static Piles

Forced aerated static piles are similar to PAWS piles, but blowers are installed at the ends of perforated pipes or air ducts. Air flow can be adjusted by changing the frequency and duration of the blower. Usually, blowers are set to turn on when the compost reaches a maximum temperature (e.g., 150F). Aerated static piles can be either positively or negatively aerated. (UW, 2002)

b. Emission s from Composting Windrows (VOCs, NH 3, )

This emissions methodology addresses VOC and NH3 emissions resulting from composting of organic materials

. A brief description for each of these is presented

below.

VOCs: V olatile organic compounds are emitted when organic waste is composted

. VOCs are emitted as a result of decomposition of organic material within the composting windrow and also directly from the feedstock. Whether the waste organic materials are composted or handled otherwise, they continue to emit a variety of VOCs. These VOCs are biogenic in origin; thus, they are biodegradable. Since these are biogenic and biodegradable compounds, any measure that would promote active biological processes will decrease their emissions. The key factors that need to be controlled to optimize the biological process of composting are oxygen content, moisture content, pH, and c arbon: n itrogen (C:N) ratio. Furthermore, since the VOC compounds emitted are biodegradable , water soluble (to some extent), and have adsorptive potential, there are an array of mitigation alternatives including pseudo

biofilter cap available to control their emissions. (SJV, 2010)

CalRecycle and UC Dav is conducted a study in 2011 to determine what VOCs are emitted from composting piles and the reactivity of the VOCs detected. More than 100 VOCs were detected and quantified in this study, including aliphatic alkanes, alkenes, aromatic hydrocarbons, bioge nic organics, aldehydes, ketones, alcohols, furans, acids, esters, ether, halogenated hydrocarbons and dimethyl disulfide (DMDS). Alcohols were found to be the dominating VOC in the emissions from a compost pile regardless of age, with the highest emissions coming from the younger composting windrows. (CalRecycle, 2011)

NH 3 : The presence of excess nitrogen in the form of ammonium carbonate or ammonia can be traced to the microbial metabolism of protein or other sources of nitrogen. If the
C : N ratio is t oo low, the energy source (carbon or carbohydrates) may be less than that required for converting all the available nitrogen into microbial cells. In such an event

, the organisms make full use of available carbon and the excess nitrogen combines with

4hydr ogen and is emitted as ammonia. If excess nitrogen in a decomposing mass is too great, ammonia may be formed in amounts sufficient to be toxic to the microbial population in the compost and will be emitted into the atmosphere as well

.

c. Available Emission s Test Data

E mission s test data available for developing emission factors used in this methodology are presented in Tables II

- 1 through II

- 3 below. The emissions test data was compiled to determine emission factors for greenwaste (including foodwaste up to 15% of feedstock) and biosolids/manure co

- composting. A more detailed summary of the

available emission factor sources can be found in the attached A ppendix A

.

Table II

- 1: Summary of Available Active Composting Greenwaste Emission s Test Data

Site VOC (lbs VOC /wet ton) Ammonia (lbs NH3 /wet ton)

SCAQMD Inland 1.56 0.26
SCAQMD Inland 2.25 0.63 CIWMB (Modesto) 0.85 N/A CIWMB (Modesto)* 1.95 N/A

Site X 6.30 2.34 Jepson Prairie 5.65 0.24 Northern Recycling (Zamora) 10.03 0.45 City of Modesto 1.50 N/A City of Modesto* 2.20 N/A
Average 3.58 0.78

*Source test contained 15% by weight foodwaste

Table II

- 2 : Summary of Available Active Co

- Composting Greenwaste with

Biosolids /Manure Emission s Test Data

Site VOC (lbs VOC /wet ton) Ammonia (lbs NH3 /wet ton)
Recyc Inc. 0.53 2.7 EKO System 1.7 3.28 San Joaquin Composting, Inc. 3.12 2.81 Average 1.78 2.93

Table II

- 3 : VOC Stockp ile Greenwaste Emissions Test Data

Site VOC EF (lb

- VOC/wet ton

- day) Northern Recycling Zamora 0.13

NorCal Jepson Prairie (Vacaville) 0.42

SCAQMD Inland 0.10
SCAQMD Inland 0.13 Average 0.20

5d. VOC and Ammonia Emission Control Techniques

A number of control techniques are available to facilities to control the emissions from composting activities. These control techniques reduce both VOCs and ammonia

emissions

. The first technique is aerated static piles (ASP) . In aerated static pile composting, organic waste is mixed together in one large pile instead of rows. To aerate the pile, layers of loosely pil ed bulking agents (e.g., wood chips, shredded newspaper) are added so that air can pass from the bottom to the top of the pile. The piles also can be placed over a network of pipes that deliver air into or draw air out of the pile. Often a ir blowers are activated by a timer or a temperature sensor. The air is run through a biofilter to control the emissions from the windrow. ASP systems can incorporate covers over the windrow to increase the capture efficiency. Examples of these types of systems includ e the Gore cover, Engineered Compost System (ECS), or AgBag.

Finished compost can be used as a pseudo

- biofilter. Finished compost can be applied in a thick layer over the surface of the windrow. Facilities may apply the finished compost for differing dur ations of time to reduce emissions. 90% of the VOC emissions happen in the active phase of composting and as a result compost covers are most effective during this active phase. (SJV, 2010) SJVAPCD and SCAQMD’s regulations are designed to get the most re ductions early on in the active phase and require a 22

- day compost cover (60% reduction of VOCs) and 15

- day compost cover (40% reduction of VOCs), respectively.

Finally

, one of the most effective ways to reduce emissions is to operate at an indoor

facili ty or use a fully enclosed system

. Indoor facilities are generally located in large

warehouse s and the indoor air is ducted through a biofilter. Fully enclosed systems may use drums, silos, or other types of sealed containers to capture the air and direc t it through a biofilter. Facilities can achieve 80% or more emissions reductions using these types of emission control devices

.

e. Emission Control Demonstrations

A number of studies have analyzed the use of emission control devices on composting

windrows. The most common types in California involve the use of compost as a cover for the windrows or an aerated static pile that passes the exhaust gas through a biofilter.

Table II

- 4 shows the most common emission control devices with their respective

aerati on types (positive or negative), emission control methods (compost cap, biofilter, etc.), and cover material (biofilter, membrane, plastic, etc.). Detailed s ummaries of the

sources can be found in the attached A ppendix A

.

6Table II

- 4 : Control Techniques for Composting Operations

Control Type Aeration Control Method Cover Material

**Windrow**

Static Pile

– No Biofilter Passive None None Managed Windrow

– No Biofilter Passive None None Water Management Requirements 1 Passive Watering None Static Pile/Passively Aerated Windrow

covered 15 days with a biofilter 2 Passive At least 6 inches of Compost Cover Finished Compost or Compost Overs Static Pile/Passively Aerated Windrow

covered 22 days with a biofilter 1 Passive At least 6 inches of Compost Cover Finished Compost or Compost Overs **Aerated Static Pile (ASP)** Negative ASP with Biofilter (classic) 3 Forced, Negative

Air At least 6 inches of Compost Cover (optional),

Biofilter Bed Finished Compost or Compost Overs

Positive ASP with Biofilter Cover Forced, Positive Air At least 6 inches of Compost Cover Finished Compost or Compost Overs

**Enclosed Aerated Static Pile** Enclosed, Negative ASP with Biofilter (e.g., ECS) Forced, Negative

Air Biofilter Bed Engineered Cover Tarp

Negative ASP with Biofilter (indoor) 3 Forced, Negative

Air Biofilter Bed Building

Enclosed, Positive ASP (e.g., GORE Cover) Forced, Positive Air None Engineered Cover

Membranes Ag Bag Forced, Positive Air None Thick Mill Plastic Bag

General Enclosed Pile vented through

a Biofilter Forced Vented through biofilter Finished Compost or Compost Overs

1 Requires compliance with p ile management and /or watering requirements in SJVAPCD’s rule 4566.

2 Requires compliance with p ile management and /or watering requirements in SCAQMD’s rule 1133.3

. 3 These composting types can be conducted at the indoor setting venting indoor air to a biofiltration control system.
(SC, 2011a) (NRAES, 1992) (Paul & Geesing, 2009)

7III. Recommended Emission Estimation Approaches

This methodology describes two approaches for estimating emissions. The first is based on actual emission testing and the second approach relies on industry averaged

data emission factors from composting facilities. These two approaches are described

below.

a. Facility S pecific Data (Emission Testing)

Conducting on

- site emissions testing to determine s ite specific emission factors is one approach for estimat ing emissions from a given facility. It is recommended to use the testing methods listed in the South Coast Air Quality Management District ( SCAQMD )

or San Joaquin Valley Air Pollution Control District (SJV A PCD ) composting rules.
SCAQMD lists thei r testing requirements and protocols in SCAQMD Rule 1133.3(e).

SJVAPCD list s their testing requirements in SJVAPCD Rule 4566(6.4). This data can be combined with the facility throughput, control technology factors etc. as described in

b. below to estimat e the annual emissions for the facility.

b. Composting Emission Factor An alternative approach is to use emission factors developed based on the results of emission tests or studies performed at one or more facilities. This approach is

described below. Us e of the following emission factors are subject to the approval of the local air districts who permit the composting facilities. 1 Additional testing may be necessary to demonstrate emission control efficiency factors or emissions from a composting facility.

i. Data Requirements

For each facility

, the following information would be needed to calculate the emissions for the facility using a recommended emission factor :

• Facility throughput (wet tons)

o Annual amount of organics processed at the facility . Wet tons is defined

as the mass of greenwaste, co

- composting , and foodwaste th at is processed at the facility, excluding any screen w aste that does not go through the composting process.

• Feedstock Composition (e.g. greenwaste, foodwaste, co

- composting )

o This emission factor is appropriate for greenwaste only or a mixture of greenwaste with foodwaste or co

- composting up to 15 % by weight o f total.

• Control Tech nology Efficiency (ASP, biofilter )

o It is necessary to determine the control technology emission reduction efficiency. This can be done with source testing or using the standard

recommended values in Table III

- 3

.

• Average Stockpile Time

1 The local air pollution control districts or air quality management districts may have established emission factors and/or regulation approved for use in their corresponding air basin. Contact the local air district

for more information.

8o It is necessary to average the time that the incoming organics are stockpiled before incorporation into the composting piles.

ii. Estimating Emissions from a Facility

Total Annual Emissions = (CP EF x (1

- CE) x TP ) + (SEF x SD X TP) ;

• Where

o CP EF = Composting Process Emission Factor (lbs/wet

- ton)

o SEF = Stockpile Emission Factor (lbs/wet ton

- day)

o SD = Average number of days material is stockpiled (days)

o CE = Control Efficiency (Percentage)

o TP = Total annual facility throughput (wet

- tons)

Table III

- 1: Recommended Emission Factor s for Greenwaste and Foodwaste 1

Pollutant Stockpile (lbs /wet ton

- day) Composting Process (lb s /wet ton)

VOC 0. 20 3.58

NH3 N/A 0.78

Table III

- 2 : Recommended Emission Factor s for Greenwaste Mixed with Animal
Manure, Biosolids, or Poultry Litter ( Co

- Composting 1 )

Pollutant Co

- Composting Process (lbs/wet ton)

VOC 1.78

NH3 2.93

1 Foodwaste, biosolids, and manure can be a maxi mum of 15% by weight of the total mixture with greenwaste.

9Table III

- 3: Control Techniques for Composting Operations

Control Type Aeration VOC Control Efficiency NH3 Control Efficiency

**Windrow**

Static Pile

– No Biofilter Passive 0% 0% Managed Windrow

– No Biofilter Passive 0% 0% Water Management Requirements 1 Passive 19% 19% Static Pile/Passively Aerated Windrow

covered 15 day s with a biofilter 2 Passive

40% 20% Static Pile/Passively Aerated Windrow

covered 22 day s with a biofilter 1 Passive

60% 20% **Aerated Static Pile (ASP)** Negative ASP with Biofilter (classic) Forced, Negative

Air 26% 23%
Positive ASP with Biofilter Cover Forced, Positive Air 80%

- 98 % 53 %

**Enclosed Aerated Static Pile** Enclosed, Negative ASP with Biofilter (e.g., ECS) Forced, Negative

Air 80%

- 98 % 70%

- 7 8 % Negative ASP with Biofilter (indoor) Forced, Negative

Air 80%

- 98 % 80%

- 99 % Enclosed, Positive ASP (e.g., GORE Cover) Forced, Positive Air

80% 70% Ag Bag Forced, Positive Air 80% 70%
General Enclosed Pile vented through

a Biofilter Forced 80% 70%

1 Requires compliance with p ile management and /or watering requirements in SJVAPCD’s rule 4566.

2 Requires compliance with p ile management and /or watering requirements in SCAQMD’s rule 1133.3

.

10Data Sources

(CalRecycle, 2011) Volatile organic compound emissions from green waste composting:

Characterization and ozone formation

(CalRecycle, 2013) Greenwaste Compost Site Emissions Reductions from Solar

‐ powered Aeration and Biofilter Layer

(Colorado, 2012) Composting: VOC Emissions & Best Management Practices, Colorado Department of Public Health and Environment

(Elsevier, 2009) A methodology to determine gaseous emissions in a composting plant

, Composting Resear ch Group, Department of Chemical Engineering , Barcelona, Spain

(NRAES, 1992) NRAES, On

- Farm Composting Handbook, June 1992.

(Paul & Geesing, 2009) John Paul and Dieter Geesing, Compost Facility Operator Manual, 2009.

(SC, 2011) RULE 1133.3 EMISSION REDUCTI ONS FROM GREENWASTE

COMPOSTING OPERATIONS

(SC, 2011a) SCAQMD, Final Staff Report for Proposed Amended Rule 1133.1 and Proposed Rule 1133.3, July 2011.

(SDSU, 2012) Full

- Scale VOC Emissions from Green And Food Waste Windrow Composting , Fatih Büyüksönmez, De partment of Civil, Construction and Environmental Engineering, San Diego State University

(SJV, 2011) RULE 4566 ORGANIC MATERIAL COMPOSTING OPERATIONS,

SJVAPCD

(SJV, 2010) Compost VOC Emission Factors , SJVAPCD

(UW, 2002) The Art and Science of Composting, Leslie Cooperband, University of

Wisconsin

- Madison

(Yolo, 2012) ECS AC Composter Pilot Facility, Air Emissions Source Test, Thomas R. Card, P.E., Charles E. Schmidt, PhD.

11

### Appendix A to ARB Recommended Emissions Inventory Methodology for Composting Facilities

A. Overview

This appendix provides a summary of available California facility composting emissions

data and an overview of a recent study conducted on effectiveness of emission control

sy stems

.

B. California Air District Emission Factors

T wo sets of emission factors have been adopted by local air quality management

districts . The San Joaquin Air Pollution Control District (SJVAPCD) published their

emission factor in 2010

. SJVAPCD adopted Rul e 4565 : Biosolids, Animal Manure, and Poultry Litter and Rule 4566 : Organic Material Composting Operations for composting

facilities in March of 2007 and August of 2011 , respectively

. The South Coast Air Quality Management District ( SCAQMD ) adopted their Rule 1133. 2 : Emission
Reductions from Co

- Composting Operations in January 2003 and Rule 1333.3 : Emission Reductions from Greenwaste Composting Operations in July 2011

. SCAQMD published the following emission factor s as part of the 2011 rulemaking process. Table

A

- 1 list the factors for each district

. As can be seen, SJV APCD has an emission factor
for VOC emissions and SC AQMD has emission factors for both VOCs and a mmonia. The following Tables A

- 2 through A

- 5 present the underlying emissions source test d ata

that were used in developing the approved emission factors for each district.

Table A

- 1: Summary of Composting Emission Factors Approved b y SJVAPCD &
SCAQMD

Compost Type Stockpile (lb

- VOC/wet

- ton

- day) Windrow EF Per Composting Cycle

(lb

- VOC/wet ton) Windrow EF (lb NH3/wet ton)

SJVAPCD SCAQMD SCAQMD SCAQMD SCAQMD
Greenwaste, Foodwaste, Grape Pomace 0.2 N/A 5.71 4.67 0.71

Co

Composting N/A N/A 1.78 1.78 2.93

1Table A

- 2 : SJVAPCD VOC Stockpile Greenwaste Emissions Testing Data

Site Length of Time the Material Stays in the Stockpiles (day) Season Samples

Taken EF (lb

- VOC/wet ton

- day)

Northern Recycling

Zamora 90 Spring 0.126

NorCal Jepson Prairie (Vacaville) 7 Summer 0.422

SCAQMD

Inland 9 Winter 0.101

SCAQMD

Inland 21 Fall 0.133

Average 0.196

Table A

- 3 : SJVAPCD VOC Windrow Greenwaste Emission s Testing Data

Site Sampling Age of

Material Season Samples

Taken EF (lb

- VOC/wet ton) CIWMB (Modesto) Over the Active + Curing Phase (days

not sampled were interpolated) Fall 0.85 *

Site X Spring 6.30 NorCal Jepson Prairie (Vacaville) Summer 5.65

Northern Recycling (Zamora) Spring 10.03

Average 5.71
*1.54 was identified in the green waste report after a recalculation to better represent other sites; however, 0.85 was the actua l value reported from this test site and will be used in the EF

determination.

Table A

- 4 : SCAQMD Greenwaste VOC & Ammonia Emission s Testing Data

Site Sampling age

of material Season samples

were taken Throughput (tons/day) VOC (lbs/wet ton) Ammonia ( lbs/wet ton)

Inland Over the static

and windrow phase Winter 307 1.56 0.26

Inland Fall 350 2.25 0.63

Modesto Over the active and curing phase (days

were not sampled were interpolated) Fall 103 0.85 N/A

Site X Spring 200 6.30 2.34

JPO Summer 163 5.65 0.24

Zamora Spring 319 10.03 0.445

Weighted average emission factors 4.67 0.66

2Table A

- 5 : SCAQMD & SJVAPCD Co

- Composting Uncontrolled VOC & Ammonia

Emission s Testing Data

Facilities VOC E.F. (lb/ton mix) NH3 E.F. (lb/ton mix)

RECYC Inc. (Corona, 1995) 0.53 2.7 EKO System (Corona, 1995) 1.7 3.28 San Joaquin Composting, Inc. (Lost Hills, 1996) 3.12 2.81

Average 1.78 2.93

As shown in Table A

- 4, SC AQMD used the same emission source data as SJVAPCD

. H owever, they included two additional source tests from the Inland facility in the

calculation to determine the emissions factor . This caused the weighted emission factor to decrease by approximately 1 lb/wet ton. At the time of the SJVAPCD’s emission factor development, SJVAPCD chose not to use these source tests because they

believed that the facility was small and did not accurately reflect the size of the facilities

in their district. Because there is a limited subset of data, we have included the Inland

s ource test information. While t he data may not be representative of the sites in SJVAPCD, it is representative of many sites throughout the state and is included in this methodology.

C. Composting Facility Emissions Test Data

a. Modesto Composting Facility

CalRecycle sponsored a study in 2012 by San Diego State University. The study was conducted at the Modesto Composting Facility operated by the City of Modesto. Samples were collected with United States Environmental Protection Agency (U.S. EPA) isolation flux chambers for 59 days and analyzed according to the SC AQMD

Method 25.3. Two separate composting windrows were tested in this study . The first

windrow was comprised of greenwaste only and the second windrow was a mixture of 85% greenwaste and 15% foodwaste. Emission factors were determined to be 1.4 g/kg

- d ry

- weight (dw) (1.5 lb s VOC/wet ton 1 ) and 2.2 g/kg

- dw (2.2 lb s VOC/wet ton 1 ) for green waste and greenwaste combined with foodwaste composting, respectively. (SDSU, 2012)

b. Composting Outside of California

The Colorado Department of Public Health and Environment published a memo titled

“ Composting: VOC Emissions & Best Management Practices ” in 2012. In the memo, they cited the SJVAPCD emission factor as “the most robust and technically sound study currently available .” However, they did not use the stockpile emission factor as they assumed that the climate differences would impact the emissions from the stockpile. This was not a concern for the active composting emission factor as the

1 Conversion to wet tons was done using the initial blend moisture content.

3moisture content, temperature, an d turning requirements should create a windrow with similar characteristics. (Colorado, 2012)

D. Summary of Composting Emission Sources

The following tables A

- 6 through A

- 7 present a summary of the available source testing

results for composting facilities wh ose test results were used to develop the emission factors in the proposed composting emission inventory methodology.

Table A

- 6 : Summary of Available Active Composting Greenwaste Emissions Test

Data

Site VOC (lbs VOC /wet ton) Ammonia (lbs NH3 /wet ton)

Inland 1.56 0.26

Inland 2.25 0.63 CIWMB (Modesto) 0.85 N/A CIWMB (Modesto)* 1.95 N/A

Site X 6.30 2.34 Jepson Prairie 5.65 0.24 Northern Recycling (Zamora) 10.03 0.45 City of Modesto 1.50 N/A City of Modesto* 2.20 N/A
Average 3.58 0.78

*Source test contained 15% foodwaste

Table A

- 7 : Summary of Available Active Co

- Composting Greenwaste with

Biosolids/Manure Emissions Test Data

Site VOC (lbs VOC /wet ton) Ammonia (lbs NH3 /wet ton)
Recyc Inc. 0.53 2.7 EKO System 1.7 3.28 San Joaquin Composting, Inc. 3.12 2.81 Average 1.78 2.93

4F. Emission Reduction Technology Assessments

The following section provides a brief overview of the sources that were used to develop the proposed emission reduction (control efficiency) factors in the emission inventory methodology.

a. CalRecycle: Greenwaste Compost Site Emissions Reductions from Solar

Powered Aeration and Biofilter Layer

CalRecycle and SJVAPCD sponsored a test project that monitored emissions from a solar powered aerated static pile s ystem (eASP)

. The eASP utilized ambient air blown into the pile from the bottom; the blowers were powered by photovoltaic panels and

associated batteries. The eASP had a biofiltration layer added to the surface as an air pollution control measure. A series of compost wind rows were built concurrent with the eASP using the same feedstock. The air emissions from the eASP were compared to

the on

‐ site measured air emissions of the current industry standard windrow composting

method.

Table A

- 8 provides a summary of the emission s from the windrow over the 22

‐ day active composting period, as specified by SJVAPCD Rule 4566. VOC reductions of 98.8% were achieved when compared to the control windrows. Reductions in ammonia emissions were 83% using tubes in the field, and 53% from t he laboratory, when the eASP was compared to the control windrows. Reductions in emissions of greenhouse gases ranged from 13% for methane up to nearly 89% for N 2 O for the eASP system when compared to the controls. (CalRecycle, 2013)

Table A

- 8 : Results of eASP Study (lbs pollutant/wet ton)

b. Colorado Department of Public Health and Environment: Composting:

VOC Emissions & Best Management Practices

Colorado cited the October 31, 2007 report “Emissions Testing of Volatile Organic Compounds from Greenwaste Composting at the Modesto Compost Facility in the San Joaquin Valley” published by the California Integrated Waste Management Board and

used 75% con trol efficiency for biofilter/compost cover that is used for the entire process. They used a 56.25% control efficiency when the biofilter/compost cover is used only in the first two weeks.

5Table A

- 9 : Summary of Control Efficiencies from Colorado Department of Public

Health and Environment

G. Regulatory Requirements for Emission Controls

SJVAPCD and SCAQMD both specify in their regulations the minimum requirements for composting facilities emission control devices. The requirements of the regulati ons are summarized in the following tables.

Table A

- 1 0 A : SJVAPCD Rule 456 5 Co

- Composting Emission Control Device Requirements

Facility Size Emission Control Device Alternative to Emission
Control Device Less than 20,000 tons/year Implement at least 3 of t he Class One mitigati on measures listed in Table 2 **OR** implement at least 2 Class One mitigation measures in addition to 1 Class Two mitigation measure for active composting listed in Table

A

- 10B

. 20,000 to 100,000 tons/year Implement at least 4 of the Class One mitigation

measures listed in Table 2 OR implement at least 3 Class One mitigation measures in addition to 1 Class Two mitigation measure for active composting listed in Table

A

- 10B

. Greater than 100,000 tons/year Implement at least 4 Class One mitigation measures in addition to 1 Class Two mitigation measure for active composting **OR** Implement at least 2 Class One mitigation measures, in addition to 1 Class Two mitigation measure for active composting and 1 Class Tw o mitigation measure for curing composting listed in Table A

- 10B.

6Table A

- 10B

– SJVAPCD Rule 4565 Co

- compostin g Facility Mitigation Measures Class One Mitigation Measures

1. Scrape or sweep, at least once a day, all areas where compostable material is mixed, screened, or stored such that no compostable material greater than one inch (1”) in height is visible in the areas scraped or swept immediately after scraping or sweeping, except for compostable material in process piles or storage piles.

2. Maint ain a minimum oxygen concentration of at least five percent (5%), by volume, in the free air space of every active and curing compost pile.

3. Maintain the moisture content of every active and curing compost pile between 40% and 70%, by weight.

4. Manage every active pile such that the initial carbon to nitrogen ratio of every pile is at least twenty (20) to one (1).

5. Cover all active compost piles within 3 hours of each turning with one of the following: a waterproof covering; at least six (6) inches of finished compost; or at least six (6) inches of soil.

6. Cover all curing compost piles within 3 hours of each turning with one of the following: a waterproof covering; at least six (6) inches of finished compost; or at least six (6) inches of soil.

7

. Implement an alternative Class One mitigation measure(s) not listed above that demonstrates at least a 10% reduction, by weight, in VOC emissions. Class Two Mitigation Measures

8. Conduct all active composting in aerated static pile(s) vented to a VOC emission control device with a VOC control efficiency of at least 80% by weight.

9. Conduct all active composting in an in

- vessel composting system vented to a VOC emission control device with a VOC control efficiency of at least 80% by weight.

10. Conduct all curing composting in aerated static pile(s) vented to a VOC emission control device with a VOC control efficiency of at least 80% by weight.

11. Conduct all curing composting in an in

- vessel composting system vented to a VOC

emission control d evice with a VOC control efficiency of at least 80% by weight.

12. Implement an alternative Class Two mitigation measure(s) not listed above that demonstrates at least 80% reduction, by weight, in VOC emissions.

Table A

- 1 1 : SJVAPCD Rule 4566 Greenwaste and Foodwaste Emission Control Device Requirements

Facility Size Emission Control Device Alternative to Emission
Control Device
Less than 200,000 tons/year Watering System Requirements 19% Reduction of VOC

emissions
200,000 to 750,000 tons/year Watering System Requirements and Finished Compost Cover 60% Reduction of VOC

emissions

Greater than 750,000 tons/year 80% Reduction of VOC

emissions 80% Reduction of VOC

emissions

7Table A

- 1 2 : S CAQMD Rule 1133.2 Co

- Composting Emission Control Device Requirements

Facility Size Emission Control Device Alternative to Emission
Control Device Any new facility with greater

than 20% manure , by

volume Enclosed Emission Control

Device with a control efficiency of 80% reduction
of VOC and Ammonia

Emissions 80% Reduction of VOC and

Ammonia emissions

Table A

- 1 3 : S CAQMD Rule 1133.3 Greenwaste Emission Control Device Requirements

Facility Size Emission Control Device Alternative to Emission
Control Device New facility with less than 20% manure or 5,000 tons
foodwaste Cover w indrow with finished compost and watering requirements 40 % Reduction of VOC

emissions and 20%
reduction of A mmonia

emissions New facility with greater
than 20% manure , by volume, or 5,000 tons and greater than 10%

foodwaste , by weight 80% Reduction of VOC and

ammonia emissions 80% Reduction of VOC and

Ammonia emissions

8