PERMIT REVIEW SUMMARY

Permit Writer:	Carla Brown		Date:	August 2, 2022

Company Name:	Renewable Wood Solutions LLC

Facility Location:	State-Wide
			P.O. Box 233
			Crystal Springs, MS 39059

Permit Number:	0600-00076

County: 		State-Wide

FACILITY DESCRIPTION
Renewable Wood Solutions, LLC (RWS) proposes to operate one or more portable air curtain incinerators (ACIs) for purposes of reducing wood waste at permitted solid waste management facilities, as well as at locations at where RWS harvests purchased timber. The remaining ash produced following combustion will be stored and managed by RWS. Operation of the ACIs will fall under the Standard Industrial Classification (SIC) code of 4953 for “Refuse Systems” and NAICS code 562213 for “Solid Waste Combustors and Incinerators.” The ACIs are equipped with a firebox, which will be loaded with wood waste. The wood waste is ignited and a fan powered by a diesel engine that blows a curtain of air across the top of the waste such that the air circulates within the firebox to promote more complete combustion and minimize smoke. The ash is routinely removed once it reaches a certain height in the firebox. The following sketch depicts the ACI design.

Source: Air Burners Inc. (https://airburners.com/resource-center/sketches/)  
PROJECT/PERMIT ACTION DESCRIPTION
RWS proposes to operate one or more portable ACIs at locations across the State of Mississippi on a temporary basis for the purpose of incinerating wood waste. In order to comply with federal regulations for ACIs, the ACIs will only be allowed to burn (1) wood waste, (2) clean lumber, or (3) yard waste, or a combination of these three waste streams. Each term is defined in the proposed permit. 11 Miss. Admin. Code Pt. 2, R. 2.1.D(5). allows the Mississippi Department of Environmental Quality (MDEQ) to issue a state-wide permit for portable facilities that will be located only temporarily at a site or sites throughout the state. Therefore, the proposed Permit to Construct addresses installation of one or more ACIs on a temporary basis at specified locations across the state. See the “Applicable/Proposed Permit Limitations” section for more details. 

In order to allow for commercial operation of the ACIs for purposes of waste disposal, the ACIs must be operated at solid waste management facilities holding a solid waste permit issued by MDEQ pursuant to 11 Miss. Admin. Code Pt. 4, Ch. 1. Therefore, RWS will ensure each ACI is located at a permitted solid waste management facility, such as a Class I or II Rubbish Site. It is also the responsibility of the permitted solid waste management facility to ensure disposal of wood waste by incineration is allowed by their Plan of Operation. 

EMISSIONS SUMMARY
RWS is not considered one of the 28 categorical facilities listed in 40 CFR 52.21(b)(1)(i)(a); therefore, the Prevention of Significant Deterioration (PSD) threshold for a major source is 250 tons per year (tpy) of any regulated NSR pollutant. Since emissions may occur simultaneously from one or more ACIs located at one or more solid waste management facilities across the state, potential emissions were evaluated as the sum of emissions from all ACIs operated by RWS state-wide. This results in a conservative evaluation of potential emissions. 

Emissions of air pollutants result from the combustion of wood waste and were calculated using the proposed maximum amount of wood waste combusted on an annual basis and emission factors developed by the San Joaquin Valley Air Pollution Control District in California. Each ACI is equipped with a diesel-fired engine to operate the fan; however, because the permit requires the ACI not remain in a single location more than 12 months, the associated engine is considered a nonroad engine rather than a stationary source. Therefore, potential emissions from the engines are not included in the evaluation of emissions. The removal, handling, and storage of the resulting ash may also result in emissions of particulate matter, which were estimated based on 5% of the total wood waste combusted remaining as ash.  

With no restrictions on throughput, RWS has the potential to emit more than 250 tpy of carbon monoxide, a regulated NSR pollutant. To ensure RWS does not exceed the PSD major source threshold, the proposed Permit to Construct limits the annual wood waste combusted to 175,000 tons per year and requires each ACI be guaranteed by the manufacturer to meet those emission factors represented in the permit application. The emission factors are also incorporated as limits in the proposed Permit to Construct. As a result, RWS will be considered a moderate stationary source under 11 Miss. Admin. Code Pt. 2, Ch. 2. Based on the proposed permit limits, the potential emissions from state-wide operation of the ACIs and ash handling are as follows:

Pollutant	Emissions (tpy)1	
Particulate Matter 
(including PM10/PM2.5)	117.03	
Sulfur Dioxide	8.75	
Nitrogen Oxides	87.50	
Carbon Monoxide	227.50	
Volatile Organic Compounds	78.75	
Total Hazardous Air Pollutants	9.78	
1 Based on 175,000 tons per year wood waste combusted and 5% ash.

Because the proposed emissions of particulate matter less than 10 microns and less than 2.5 microns (PM10 and PM2.5, respectively) and emissions of carbon monoxide exceed 100 tpy, RWS is considered a major stationary source under the Title V regulations of 11 Miss. Admin. Code Pt. 2, Ch. 6. Additionally, the federal regulations applicable to the ACIs (i.e., 40 CFR Part 60, Subpart CCCC) require the owner/operator maintain a Title V Operating Permit for the ACIs. Therefore, a Title V Operating Permit is being proposed for issuance concurrently with the Permit to Construct. 

APPLICABLE/PROPOSED PERMIT LIMITATIONS
Below, each permit condition proposed under MDEQ’s authority in 11 Miss. Admin. Code Pt. 2, R. 2.2.B(10). is summarized, including the basis for each. The monitoring, recordkeeping, and reporting requirements demonstrating compliance with these limitations and standards are addressed in the Title V Operating Permit.

•	Condition 3.1: Only install and operate an ACI and associated ash handling equipment at a permitted solid waste management facility approved to incinerate wood waste or a location at which RWS harvests purchased timber. This condition is intended to ensure each ACI is operated in accordance with MDEQ’s Nonhazardous Solid Waste Management Regulations in 11 Miss. Admin. Code Pt. 4, Ch. 1. This condition is not intended to preclude RWS from operating portable ACI at other temporary locations for the combustion of debris from declared emergencies or disasters as long as such operation is in accordance with applicable Federal and State regulations.
•	Condition 3.2: Meet 150-foot buffer zone requirements. Buffer zone requirements apply to each ACI and all air emissions equipment under 11 Miss. Admin. Code Pt. 2, Ch. 2.
•	Condition 3.3: Limit the annual throughput of waste combusted to 175,000 tons per year. This annual limit, calculated on a 12-month rolling basis, ensures emissions of carbon monoxide are below the PSD major source threshold of 250 tpy. 
•	Condition 3.4: Only conduct burning in each ACI between sunrise and 6:00 p.m. This condition is intended to ensure the operator can clearly observe the operating condition of the ACI and to minimize combustion during hours when atmospheric mixing (or dispersion) is not ideal. 
•	Condition 3.5: Meet the emission standards for PM, NOx, CO, and VOC used in the application, expressed as pounds of pollutant per ton of wood waste burned (lb/ton). These emission standards, in combination with the annual throughput limit in Condition 3.3, are intended to ensure RWS avoids applicability to the PSD regulations.
•	Condition 3.6: The permittee shall not locate and operate an ACI and associated engine at the same location for more than 12 consecutive months. This condition ensures that the intent of the State regulation regarding operation of portable sources on a temporary basis is met, in addition to ensuring the engine used to power the ACI fan is not considered a stationary source and, otherwise, regulated by MDEQ and certain federal standards.
•	Condition 4.1: Operate and maintain the ACI according to the manufacturer’s written instructions. To ensure the ACI is operated in the manner under which the emissions guarantees were determined, it should be operated according to the manufacturer’s instructions.
•	Condition 4.2: Do not store combustible materials within 100 feet of the ACI, and not operate the ACI according to setbacks recommended by the manufacturer for given wind speeds. These operating criteria are based on the Operator’s Manual for the proposed ACIs and are included to prevent dangerous conditions and/or nuisance conditions from occurring as a result of ACI operation.
•	Condition 4.3: Use only clean oils to ignite a start-up fire. Do not use highly volatile accelerants and minimize the amount of accelerant needed to ignite a start-up fire. This condition is intended to prevent dangerous conditions during startup, as well as minimize emissions of volatile organic compound (VOC). 
•	Condition 4.4: Comply with work practice standards regarding ash removal, storage, and transfer. These work practice standards are intended to prevent excess PM, or dust, from being generated and also ensure the ash is handled as a potential product for beneficial reuse.
The remaining permit conditions regard applicable Federal and State standards and are addressed in the following sections.

NEW SOURCE PERFORMANCE STANDARDS (NSPS) APPLICABILITY
Standards of Performance for Commercial and Industrial Solid Waste Incineration (CISWI) Units – 40 CFR Part 60, Subpart CCCC
Because the ACIs would be operated by a commercial entity at solid waste management facilities receiving municipal, commercial, and/or industrial solid waste, the ACIs were determined to be CISWI units. The permit requires the permittee only operate an ACI for which construction commenced after June 4, 2010, or reconstruction or modification commenced after August 7, 2013. (See Permit Condition 3.7.) Therefore, each ACI will be considered a new incineration unit subject to Standards of Performance for Commercial and Industrial Solid Waste Incineration (CISWI) Units in 40 CFR Part 60, Subpart CCCC. Subpart CCCC contains limited requirements for ACIs that burn only wood waste, clean lumber, and/or yard waste. “Wood waste” and “clean lumber” are defined in Subpart CCCC. “Yard waste” is defined in the similar NSPS Subpart EEEE and incorporated for clarity. 

Under Subpart CCCC, each ACI is subject to an opacity standard of ≤ 10%, except during startup periods which shall not exceed 35% opacity. Subpart CCCC requires an initial and annual opacity test to demonstrate compliance with the standard. 

Standards of Performance for Small Municipal Waste Combustion Units – 40 CFR Part 60, Subpart AAAAA
Although the ACIs will operate at sites that may accept municipal solid waste, the ACIs are not considered municipal solid waste incinerators under the Standards of Performance for Municipal Waste Combustion Units in 40 CFR Part 60, Subpart AAAA. The definition of a municipal solid waste in 40 CFR 60.1465 does not include clean wood or wood waste, as defined in Subpart CCCC; therefore, the ACIs are no considered small municipal waste combustion units under Subpart AAAA.

Standards of Performance for Other Solid Waste Incineration (OSWI) Units – 40 CFR Part 60, Subpart EEEE
The Standards of Performance for Other Solid Waste Incineration (OSWI) Units in 40 CFR Part 60, Subpart EEEE were also evaluated. Because operation of the ACIs will only take place at permitted solid waste management facilities and will not combust waste produced by RWS, the ACIs may be classified as OSWI units per 40 CFR 60.2888. However, since the proposed ACIs may burn up to 13 tons per hour of wood waste, clean lumber, and/or yard waste, they would not clearly fall under the 35 ton per day threshold in Subpart EEEE. Therefore, Subpart EEEE does not apply to the proposed ACIs. 

Standards of Performance for Compression Ignition Internal Combustion Engines – 40 CFR Part 60, Subpart IIII
The only other potentially applicable NSPS is related to operation of the diesel-fired engines mounted with the ACI, which may be addressed under the Standards of Performance for Compression Ignition Internal Combustion Engines in 40 CFR Part 60, Subpart IIII. However, as specifically addressed in the permit, each engine shall meet the definition of a “nonroad engine” in 40 CFR 1068.30, since it may not remain at the same location for more than 12 consecutive months. Therefore, the engines are not subject to Subpart IIII per the definition of “stationary internal combustion engine” in 40 CFR 60.4219.    
 
NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS (NESHAP) APPLICABILITY
RWS is considered an area source of hazardous air pollutants (HAPs). Therefore, only NESHAP applicable to area sources were evaluated. There were no NESHAP identified as potentially applicable to the ACI. With regards to the diesel-fired engines associated with the ACIs, these engines will not be considered “stationary reciprocating internal combustion engines (RICE)” under the NESHAP for Stationary RICE in 40 CFR Part 63, Subpart ZZZZ, because they will meet the definition of a “nonroad engine” in 40 CFR 1068.30. 

PUBLIC PARTICIPATION
The 30-day public notice period begins on August 10, 2022, and ends September 9, 2022, with the publication of a notice in three papers commonly used for general permits and regulations which apply state-wide – The Clarion Ledger, Sun Herald, and Northeast Mississippi Daily Journal.  

RECOMMENDATION
The staff has preliminarily decided to recommend issuance of the permit to the Mississippi Environmental Quality Permit Board as shown in the draft permit. However, the staff recommendation to the Board will be made only after a thorough consideration of all public comments.