UNITED STATES ENVIRONMENTAL PROTECTIONAGENCY REGION IX 75 Hawthorne Street San Francisco, CA 94105
July 20,2010
George Heinen San Joaquin Valley Air Pollution Control District 1990East Gettysburg Avenue Fresno, CA 93726 Subject: Dairy Menus in June 17,201 0 Revised Proposed Version of SJVAPCD Rule 4570 Dear Mr. Heinen: We greatly appreciate SJVAPCD's Governing Board and staff support in helping us better understand the opportunities and implications of further VOC controls for confined animal facilities. We know that Board members greatly value timely adoption of rule improvements and we appreciate their agreement to delay consideration of rule revisions from June until October 2010 partly in response to our June 1,2010request. Since that decision, we have had several discussions with District staff as well as larger meetings with District staff and the dairy industry, environmental and community groups, and technical experts. As promised in Deborah Jordan's June 1 1 email, we are providing comments below regarding the dairy components of the draft rule. We intend to provide comments on other parts of the rule by August 13. The comments below focus on menus in the rule regarding dairy feed, silage, freestall barns and corrals after February 201 1. Based on SJVAPCD's most recent draft emission factors, these menus address 90% ofthe VOC emissions fiom dairies in the Valley. While we support SJVAPCD efforts to further reduce VOC emissions fiom other dairy activities as well, these four menus present much larger opportunities for long term emission reductions than the menus in effect before 201 1 and other menus that address significantly smaller VOC emissions. We are also not addressing economic and technical feasibility for add-on control devices such as biofilters at this time. On May 19, the District agreed to provide a more expansive feasibility analysis ofbiofilters that considers dairies larger than 500 head. We strongly encourage the District to complete this analysis so that we and other stakeholders can review it and provide comments if appropriate before the October Board hearing. Economic and Technical Feasibility The District needs to demonstrate that Rule 4570 implements RACT by requiring those measures that are economically and technically feasible. Towards this end, during our April 22 meeting, SJVAPCD agreed to explain in the rule's staff report why voluntary measures are not mandatory. District staff have provided such explanations for somemeasures in the June 17, 2010 draft staffreport. The measures listed below are the ones that we believe need further justification.District staff have provided verbal justifications for why the following measures are not economically or technically feasible in discussions over the last few months. Please document thesejustifications in the staff report: i Dairy Feed Menu (section 5.6.1 .A): For medium and large dairy CAFs, measure A.3. Dairy Silage Menu (section 5.6.1.B): For medium and large dairy CAFs, measure B. 1.g. Dairy Freestall Barn Menu (section 5.6.1.D): For medium and large dairy CAFs, measure D.5. Dairy Corrals Menu (section 5.6.1.E): For medium and large dairy CAFs, measure E. 10. Please provide a more detailed analysis of whether the following measures are economically and technically feasible for broad classes of sources. Where individual measures or sets of measures (e.g., all large dairies can implement either measure 

### X or measure 

### Y, which have similar results) are feasible, please make them mandatory. For justifications related to economic feasibility, please provide or reference quantitative analysis. Dairy Feed Menu (section 5.6.1 .A): For medium dairy CAFs, measures A. 1 and A.2. For large and medium dairy CAFs, measures A.4 through A.8. Dairy Silage Menu (section 5.6.1.B): For both large and medium dairy CAFs, measures B. 1.e and B. 1.f. Dairy Freestall Barn Menu (section 5.6.1.D): For both large and medium dairy CAFs, measures D.2 through D.4, D.6, D.7, and D.9. Dairy Corrals Menu (section 5.6.1.E): For medium dairy CAFs, measures E.2 through E.4. For large and medium dairy CAFs, measures E.5 through E.9. Dairy Feed Menu
We understand that District staff believe the National Research Council (hTRC) feed guidelines reduce starch in manure which lowers VOC emissions. As a result, draft section 5.6.1.A.1 requires large dairy CAFs to feed according to NRC guidelines. However, the NRC guidelines are extremely complex and we are unclear which sections reduce starch. To clarify section 5.6.1 .A.1,please add a reference to the section in the NRC guidelines that reduces starch. Also, please further describe the relationship between reduced starch in manure and VOC emissions in the staff report. Several measures are designed to reduce emissions by removing uneaten feed from various areas within 1 

### - 14 days (sections 5.6.1.A.4,5 and 

### 7). However, we now understand that these menu options may be relatively ineffective because VOC emissions from silage are mostly emitted within 12hours of removal from the silage pile. Other measures are intended to reduce VOC emissions by minimizing spoilage in feed wet by rain (sections 5.6.1.A.6 and 8). These options may also be ineffective in areas that get little rain. In light of the large estimated emissions from dairy feed, please consider whether section 5.6.1.A can be revised to further reduce VOC emissions by revising or eliminating potentially low-effectivemeasures 4-8. Please also consider whether it would be feasible to require partially enclosed feedbunks to reduce VOC emission losses from total mixed rations. The following terms are used in measure 5.6.1.A.3: "high moisture corn," "steam-flaked corn," "steam-flaked cereal grains," and "dry rolled corn." Please define them in the rule. Dairy Silage Menu Based on the information we have gathered from recent meetings and literature reviews, we understand that minimizing silage exposure to oxygen can greatly reduce VOC emissions while simultaneously preventing feed related economic losses to dairymen. The comments below relate to how to minimize this exposure. Please evaluate whether the following control measures are economically and technically feasible and whether adding them as requirements or options to section 5.6.1 .B.1.d will help improve pile compaction: o Having silage piles that can be completely driven over with a tractor. o Having silagepiles with side walls. Dairies complying with section 5.6.1 .B.1.amust cover silage piles with a plastic tarp. Please consider also requiring that the tarp be weighed down to ensure close contact with the pile, thus minimizing silage exposure to air.
We understand that the District intends to require sections 5.6.1 .B.1.a (cover silage with tarp) and 5.6.1.B.1.d.iv (cover silage within 72 hours of last delivery) of all silage piles. Section 5.6.1.B.1.d.i requires that corn silage be harvested at 265% moisture, which we believe means that dry matter must be 

### 5 35%. However, the table under 1.d.ii currently allows 34-37% dry matter content for processed corn. For clarity, please either adjust the % moisture in Section 5.6.1.B.I .d.i or the range of dry matter content for processed corn in the table under 1.d.ii.
Because of the large emissions estimated from silage, please consider limiting selection of section 5.6.1.B.1.e.ii to sources above a certain geographic size. Please also consider whether editorial revisions are appropriate to prevent a source from claiming compliance with section 5.6.1 .B.1.e.ii while having one silage pile with 2,150-4,300 square feet exposed surface area and a second fully closed pile. Please consider if it is feasible to revise section 5.6.1.B.2 to require covering the open face of AG-bags when not removing silage. Please also consider whether it is feasible to require inspecting AG-bags periodically for holes, with appropriate action taken to patch them.
The following terms are used in the table under 5.6.1 .B.1.d.ii: "hard kernel" and "soft kernel." Please define them in the rule. Dairy Freestall Barn Menu
To improve clarity, please specify how frequently sources need to vacuum manure if selecting measure 5.6.1

### .D.9.

### I hope these comments are helpful, and we look forward to working with you in the next few weeks regarding other portions of the rule. Sincerely,

~ndrew Steckel Rules Office Chief cc: Mike Guzzetta, California Air Resources Board