660030_RFI response_20230103

Smithfield
Good food. RDtb11°
PO Box 856
Warsaw, NC 28398
January 3, 2023
Ms. Christine Lawson
Water Quality Permitting Section
Animal Feeding Operations Program
1636 Mail Service Center
Raleigh, NC 27699-1636
Re: Additional Information Request
Application No. ADS660030
Farms 27-30
Washington County
Dear Ms. Lawson:
Smithfield Hog Production appreciates your review of our application for permit under the Digester General Permit. In
response to your October 17, 2022 request for additional information; we are submitting the included responses to your
questions. I have included your original questions in bold and our responses are below each question
This package is being submitted for permit plan approval by NCDWR for the proposed covered lagoon digesters. The
following items are included in this package:
• Updated CAWMP
o Updated Nutrient Management Plan
o Updated Irrigation Plan
o Odor Control Checklist
o Insect Control Checklist
o Mortality Management Checklist
o Emergency Action Plan
• 2022 Sludge Survey
• Updated Engineering Drawings
Thank you for taking the time to review this project. Please contact me at [phone] or [e-mail]
if you have any questions or need additional information.
Sincerely,
Jason E. Olmstead, P.E.
Engineering Project Manager

• Page 2 January 3, 2023
1. Freeboard — NC NRCS Standard 366 — Anaerobic Digester requires a minimum of 2 feet of
freeboard in the covered digester. Please provide clarification that both digesters meet minimum
freeboard requirements.
"Provide a minimum of 2 feet of freeboard above the digester design water surface; if rainfall is
included in determining the operating volume, only 1 foot of freeboard is required. The digester
storage volume does not need to account for rainfall for completely covered digesters."
Per the NRCS 366 Anerobic Digester standard rainfall was included in determining the operational
volume of the digesters. The NOAA Atlas 14 30yr normal rainfall data for the area was used to
determine the 25-year, 24-hour rainfall on the digester. With this data the operational volume for the
digester designs at this site are based on 12-inches of structural freeboard plus 7-inches for the 25-
year, 24-hour rainfall event to determine the 19-inches of freeboard for the digesters.
This allows the covered lagoon digester at farm 8527 to operate with the existing freeboard. For
proposed digester at farm 8529 this allows the top of dike and freeboard to be the same as the
exiting lagoons. This allows equalization of the lagoons if necessary, during large storm events,
which mitigates risk.
2. Stormwater Outlet — Please provide a typical detail for outlet for stormwater removed from digester
covers. Please also indicate stormwater outlet location(s) for each digester.
The stormwater removal outlet locations have been added to the site plan(s) and a detail of the outlet
added to construction plan set.
3. Biogas Use as a Renewable Energy Resource — Please provide information for the intended onsite
and/or offsite use of the biogas. Please include expected timeline regarding completion of digester
system and utilization of gas as a renewable energy resource.
The biogas produced at the site will be cleaned on -site to pipeline quality and trucked to a natural gas
pipeline insertion point off -site to be used as renewable natural gas. The anticipated digester
completion is Q2 2023 with utilization of the gas in Q4 2023.
4. Gas Generation Estimate — Please submit an estimate for the daily volume of biogas to be generated
by the proposed Digester.
The estimated total annual RNG generated at this facility is 52,840 dekatherms. The annual average
daily RNG produced from each digester would be +/-72 dekatherms (50 scfm)
5. Emergency Flare — Please provide location/identification for the emergency flare(s).
An emergency vent/flare connection location has been added to the site plans along with an updated
detail. The plan is to us a mobile/moveable "candle stick" flare that will be kept on -site for use on an
as needed basis for both digesters.
6. Slam Gate/Secondary Containment — Please indicate location of new slam gates/secondary
containment associated with proposed digesters, if applicable.
Per the site visit discussion, a secondary containment with valve has been added at the Farm 8529
digester adjacent to the level control station.
7. Influent/Effluent Sampling — Please indicate location for sampling of influent to and effluent from each
digester.
At Farm 8529 the influent sample(s) will be taken at the farm lift station(s) and the Effluent sample at
the digester level control station.
At Farm 8527 the influent sample(s) will be taken from the gravity pipeline clean -out nearest the
digester and the Effluent sample at the digester level control station.

• Page 3 January 3, 2023
8. Odor Control Checklist — The Odor Control Checklist was not included in the application. Please
provide as a required component of the CAWMP. Please use the updated form, attached.
See attached Swine Odor Control Checklist.
9. Insect Control Checklist — The Insect Control Checklist was not included in the application. Please
provide as a required component of the CAWMP.
See attached Swine Insect Control Checklist
10. Mortality Management Checklist — The Mortality Management Checklist was not included in the
application. Please provide as a required component of the CAWMP.
See attached Swine Mortality Management Checklist
11. Emergency Action Plan — The Emergency Action Plan was not included in the application. Please
provide as a required component of the CAWMP.
See attached Swine Emergency Action Plan
12. Sludge Survey — Please provide a copy of the most recent sludge survey for the existing Primary
Lagoon at Farm 27 (proposed Digester Cell 1).
See attached sludge survey for 2022. It is planned that approximately 2-3 feet of sludge from the
8527 primary will be removed and transferred into the new digester at Farm 8529. After transfer a
new sludge survey will be preformed for the 8527 primary.
13. Land application — Fields A, B, C, D, and E meet land application setback requirements; however,
these fields are near the road/neighbors. Please provide any information regarding additional BMPs
(example hose -drag vs travelling gun) in these areas used to improve protections and further reduce
risk of off -site impacts.
Land application BMP's:
• Fields A & B: Land Application by Airway application
• Fields C & D: Land Application by Airway application
• Field E: Land Application by Airway application
14. Air Quality Permitting — Please provide general information regarding any Air Quality permits, and/or
applicability determinations regarding this project. Please provide information about if applications
have been filed, permits (if issued), and/or results of an applicability determination.
A determination of non -applicability was issued by NCDAQ on February 22,2022. Applicability
Determination No. 3758.