Proposed Air Quality Permit 6886-SC-R2 – Source Category Permit to Construct and Operate Temporary Portable Crushers, Screens, and Conveyors

PUBLIC NOTICE

Proposed Air Quality Permit 6886-SC-R2 – Source Category Permit to Construct and Operate Temporary Portable Crushers, Screens, and Conveyors at various locations in the District of Columbia

Notice is hereby given that, pursuant to 20 DCMR §210, the Air Quality Division (AQD) of the Department of Energy and Environment (DOEE), located at 1200 First Street NE, 5th Floor, Washington, DC, intends to issue a source category permit covering a subset of temporary portable crusher/screen/conveyor operations in the District of Columbia. This source category permit will be designated Permit No. 6886-SC-R2.

This source category permit will cover only portable crushers, screens, and conveyors processing nonmetallic minerals only, that will be in operation at a given site for no more than six months. This permit covers only units that are controlled with wet suppression (i.e. water spray) and that will operate for less than twelve hours per day. Engines associated with the equipment are required to operate using only gasoline or ultra-low sulfur diesel fuel.

 

The proposed overall emission limits for the equipment are as follows:

1. Emissions of dust shall be minimized in accordance with the requirements of 20 DCMR 605 and the “Operational Limitations” of this permit.
2. The emission of fugitive dust from any material handling, screening, crushing, grinding, conveying, mixing, or other industrial-type operation or process is prohibited. [20 DCMR 605.2]

c.     Emissions from the engine powering the crusher/screen/conveyor shall not exceed those achieved by proper operation of the equipment in accordance with manufacturer’s specifications and those specified in the applicable U.S. Environmental Protection Agency (EPA) non-road engine emission standards.

d.    Visible emissions shall not be emitted into the outdoor atmosphere from the crusher/screen/conveyor and any associated engine except that discharges shall be permitted for two (2) minutes during any startup, cleaning, adjustment of combustion or operational controls, or regeneration of emission control equipment, provided that such discharges shall not exceed twenty-seven percent (27%) opacity (unaveraged). [20 DCMR 606.1(a)(2), 606.2(a)(2), and 606.2(f)]

e.     In addition to Condition (d), emissions from grinding mills, screening operations, bucket elevators, transfer points on belt conveyors, bagging operations, storage bins, enclosed truck or railcar loading stations shall not exceed 7% opacity. Emissions from crushers shall not exceed 12% opacity. Truck dumping of nonmetallic minerals into any screening operation, feed hopper, or crusher is exempt from the requirements of this condition. Compliance with these standards shall be determined based on the average of five consecutive 6-minute averages over a 30-minute period, as measured in accordance with 40 CFR 60, Appendix A-4, Method 9. [40 CFR 60.672(b), 40 CFR 60.672(d), 40 CFR 60, Subpart OOO, Table 3, and 40 CFR 60.675(c)(3)]

f.     An emission into the atmosphere of odorous or other air pollutants from any source in any quantity and of any characteristic, and duration which is, or is likely to be injurious to the public health or welfare, or which interferes with the reasonable enjoyment of life or property is prohibited. [20 DCMR 903.1]

        Violation of the requirements of this condition that occur as a result of unavoidable malfunction, despite the conscientious employment of control practices, shall be an affirmative defense for which the owner or operator shall bear the burden of proof. A malfunction shall not be considered unavoidable if the owner or operator could have taken, but did not take, appropriate steps to eliminate the malfunction within a reasonable time, as determined by the Department. [20 DCMR 903.13(b)]

g.     Emissions of PM₁₀ from all sources at the site shall not exceed 25 tons during the duration of operations of the unit at the site.

h.   Emissions of NO_x from all sources at the site shall not exceed 25 tons during the duration of operations of the unit at the site.

Emissions Estimate:

Due to the different types of equipment available for coverage under this permit, emissions will vary depending on the age and power of the engines associated with the crusher/screen/conveyor and the throughput capacity of the units themselves. Inquiries indicated that the largest crusher used in the District would likely be a 400 ton per hour unit, though actual crushing would probably not exceed 100 tons per hour at any time. A unit this size would typically use about a 350 HP engine, but to be conservative for emission estimates, a 599 HP engine was assumed. 599 HP was used as engines with 600 HP or greater power outputs have lower emission factors per AP-42. To estimate worst case operating hours allowable under the proposed permit emission calculations assumed 2,190 hours per year of operation (12 hours per day, for six months). To be conservative, the higher emission factors for gasoline or diesel engines were used for each pollutant.

To estimate the worst case emissions from the actual crushing, screening, or conveying operation, the same 400 ton per hour highly conservative processing rate was used. Additionally, rather than using the lower crushing, standard screening, or conveyor transfer point  emission factors, the higher fines screening emission factor, available from AP-42, Section 11.19.2, was used.

 

The following represents an estimate of the maximum emissions expected from any crusher/screen/conveyor covered by this source category permit:

 

The draft revised permit and supporting documentation are available for public inspection at AQD and copies may be made available between the hours of 9:00 A.M. and 5:00 P.M. Monday through Friday. Interested parties wishing to view these documents should provide their names, addresses, telephone numbers and affiliation, if any, to Stephen S. Ours at (202) 498-8143 or [email protected]. Copies of the draft permit and related technical support memorandum are also available in the attachments section below.

Interested persons may submit written comments or may request a hearing on this subject within 30 days of publication of this notice. The written comments must also include the person’s name, telephone number, affiliation, if any, mailing address and a statement outlining the air quality issues in dispute and any facts underscoring those air quality issues. All relevant comments will be considered in issuing the final permit.

Comments on the proposed permit and any request for a public hearing should be addressed to:

Stephen S. Ours  
Chief, Permitting Branch - Air Quality Division

Department of Energy and Environment
1200 First Street NE, 5^th Floor
Washington DC 20002

[email protected]

No comments or hearing requests submitted after August 19, 2024 will be accepted.

For more information, please contact Stephen S. Ours at (202) 498-8143.