Dry Chemical Mixing

Dry Chemical Mixer

Processes involving the mixing of dry chemicals/materials emit air contaminants including particulate matter and potentially toxics. Dry chemical mixing requires a permit to operate unless the mixer has a rated working capacity of 0.5 cubic yards or less for dry material, 1 cubic yard or less for wet material not using volatile solvents or is otherwise exempt according to District Rule 11.

The information on this page will assist in the completion and submittal of an application for each dry chemical mixer/process. Each section of the page contains important information needed to submit an application.

Application Forms

Application forms tell us about your operation and allow us to permit your process. Accurate and complete information decreases processing time and helps avoid additional charges for unnecessary revisions. Please carefully review and complete the following forms. Also listed below are required attachments that need to be submitted with the application. You may contact the District with any questions.

General Application Word PDF

Dry Chemical Mixing Supplemental Forms Word PDF

Toxics Form Word PDF

Required Attachments:

    -Plot Plan including stack and/or other release point location(s) and nearby building dimensions

    -Equipment brochures/process flow diagram

    -Bag-house/filter specifications and control efficiency (if applicable)

    -BACT analysis (if applicable)

The general and equipment specific application forms along with required attachments must be submitted with each application packet. 

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Estimated Fees

The correct fee must be submitted with your application in order for it to be accepted. For this type of equipment, fees are determined based on the time and materials required to conduct the review, so a fee estimate must be obtained from the District prior to submittal. Please note that application fees are estimated and the final fee may be more or less than this amount based on time and materials spent processing the application. The District maintains work records for this purpose.

Before submitting an application, contact the District (see bottom of page) to obtain an application fee estimate for application submittal. Please note that an additional fee may also apply depending on the method of payment. A breakdown of how the application fee(s) are determined can be seen here. Additional information can be found in District Rule 40.

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How to Pay

These fees may be paid by check payable to "Air Pollution Control District" or by credit card (Visa, MasterCard, Discover, and American Express). 

If you choose to email or fax your application and intend on paying with a credit card, you must provide contact information (name and phone number) so that the District can complete payment.

Please note that credit card payments are assessed a transaction fee of 2.2% that is charged by the credit card provider.

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Best Available Control Technology

If a piece of equipment or a process emits more than 10 pounds per day of particulate matter (PM10), oxides of nitrogen (NOx), volatile organic compounds (VOC) or oxides of sulfur (SOx), the application must include a best available control technology (BACT) analysis. Please note that the 10 pounds per day threshold is based on emissions for the entire process line and may include emission points other than just the mixing location. 

The District has a BACT guide to assist with the analysis. If you have questions or need assistance reference the contact information at the bottom of this page. Please review District Rules 20.1 and 20.2

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Toxics

District Rule 1200 applies to any new, relocated, or modified emission unit which may increase emissions of one or more toxic air contaminant(s). The proposed project must comply with Rule 1200. Proposed equipment may require toxics best available control technology (TBACT) depending on the project. Please review District Rule 1200 for further details. 

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Trade Secret

District rules address how information that is submitted to the District is managed. District Regulation IX contains District rules 176 and 177. Please refer directly to these rules when submitting trade secret information. However, be aware that you will need to submit:

1.       A letter disclosing the proprietary information. This can be submitted electronically.

2.       A letter for the public record explaining why the information needs to be held as trade secret.

The inclusion of proprietary information can significantly delay permit applications. In an effort to expedite the permit application process it is recommended that you contact the manufacturer or vendor of any proprietary materials that are used in the process and prepare the required letters as part of your application submittal. 

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AB3205

In 1989, the California state legislature passed a law, AB 3205, designed to protect schoolchildren from hazardous air contaminants. The law, as currently written, requires the District to notify parents of schoolchildren, neighboring businesses and residents of all new or modified equipment that emits any hazardous air contaminant into the air which will be installed within 1,000 feet of a school site. The law also requires the District to consider any comments before authorizing construction. Please review your proposed location. If a school property boundary is located within 1,000 feet of the proposed emissions point, the AB3205 process will be initiated. This process requires a 30 day public comment period and the overall process will delay projects by at least six weeks.

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How to Submit Application Packet

Mail

SDAPCD

Permit Processing

10124 Old Grove Rd

San Diego, CA 92131-1649

Fax

(858) 586-2601

Select equipment type applications can now be submitted online through Citizen Access. Sign up today to get connected to your applications and permits. 

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Application Status

The District will act on complete applications as soon as possible but at most within 180 days. The engineer assigned to your application will review it and contact you within 30 days of receipt to confirm that it is complete or request additional information. Typically permits are issued in about 60 days. More complex processes will take longer.

Ensuring your application is complete is the best way to reduce processing time. Complete emissions data is the most important factor in minimizing application processing time and iterative information requests. If you have any questions about what information is required, please contact the District using the information at the bottom of this page. Learn more about the rules that govern application processing time. 

Sign up for Citizen Access to get up to date information on the status of your application.

Learn more about the application process and what to expect. 

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NESHAP/NSPS/ATCM

Dry chemical mixing is not subject to any of these rules.

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District Rules

Several District rules may apply to your equipment. General rules that may apply to dry chemical mixing including Rules 505152, and 54.

There are no equipment specific rules for dry chemical mixing. A complete listing of the District's rules can be found here.

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Calculation Procedures and Additional Resources

The District has not prepared default emission calculation procedures for dry chemical mixing processes. To obtain assistance identifying a procedure or emission factors for calculating emissions, contact the District.

If available, manufacturer provided equipment specific emission data or source test results should be utilized before using default emission factors. Sources of all emission data used must be included as attachments to the application.

AP-42 - An alternative compilation of emission factors and calculation procedures prepared by the EPA that may be utilized by the District in some situations for some equipment types. 

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Obtain Assistance

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Need Help? Have Questions?

Email the District or call (858) 586-2600 and ask for the duty engineer.

More in depth help and site visits can be performed by the District Small Business Assistance Program Coordinator who can be reached at (858) 586-2656.

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