Simple AIR CONTAMINANT DISCHARGE PERMIT REVIEW REPORT Department of Environmental Quality Northwest Region

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1 Page 1 of 7 Simple AIR CONTAMINANT DISCHARGE PERMIT REVIEW REPORT Department of Environmental Quality Northwest Region Source Information: SIC 4911 NAICS Source Categories (Table 1 Part, code) Public Notice Category B 27 II Compliance and Emissions Monitoring Requirements: FCE Source test [date(s)] Compliance schedule COMS Unassigned emissions CEMS Emission credits Ambient monitoring Special Conditions Within 180 days after start-up Reporting Requirements Annual report (due date) Quarterly report (due dates) 15 Feb Monthly report (due dates) Excess emissions report Other (specify) Air Programs Synthetic Minor (SM) SM -80 NSPS (list subparts) NESHAP (list subparts) Part 68 Risk Management CFC JJJJ ZZZZ NSR PSD RACT TACT Other (specify)

2 Page 2 of 7 TABLE OF CONTENTS PERMITTING...3 SOURCE DESCRIPTION...3 COMPLIANCE...4 SPECIAL CONDITIONS...5 EMISSIONS...5 MAJOR SOURCE APPLICABILITY...6 ADDITIONAL REQUIREMENTS...6 SOURCE TESTING...7 PUBLIC NOTICE...7

3 Page 3 of 7 PERMITTING PERMITTING ACTION 1. The proposed permit is a new permit for a new source. OTHER PERMITS 2. No other permits have been issued by the Department of Environmental Quality for this source. The application states that handling of wastes at the facility will be regulated by the Oregon Department of Agriculture and a solid waste permit is not needed from DEQ. ATTAINMENT STATUS 3. The source is located in an attainment area for all pollutants. SOURCE DESCRIPTION OVERVIEW 4. The permittee proposes to construct a new anaerobic manure digester and produce electricity from the resulting biogas near Tillamook. The facility will accept some clean food waste, up to 20% of the total feedstock. Food waste would be delivered by truck. The facility will receive manure by truck or through a pipeline from nearby dairies. Naturally occurring anaerobic bacteria will reduce the raw material and produce methane-rich biogas. The biogas will be combusted in a large (1100 kw) generator to produce electricity. Liquid wastes from the process will be returned to the farms for use as a liquid fertilizer. Waste solids will also be sold as fertilizer. Waste heat from the generator, in the form of hot water, will be used for process heating requirements. The manufacturer s recommended maintenance schedule will be followed to assure continuous maximum efficiency of the generator. A flare will be installed at the facility to combust the biogas when the engine is down for maintenance, or when biogas is produced in quantities larger than the generator can safely process. The production of biogas varies, depending up the composition of the process feedstock at any given time. 5. The applicant does not foresee a problem with odors for the area. The facility will be located in an area where there are many dairy farms. Other than the transport of raw materials, the process should decrease odors. Upon receipt, the raw materials will be stored in an underground tank. Liquid waste products will be returned to farms via pipeline. Waste solid products will be less odorous than the original material. The anaerobic process is normally airtight; however, safety vents are included in digester design to safely address system overpressure events.

4 Page 4 of 7 6. The process of anaerobic digestion produces hydrogen sulfide (H 2 S). H 2 S is a colorless, flammable gas that, in its raw state is poisonous and smells of rotten eggs. During combustion, the H 2 S in biogas is chemically converted to SO 2 (sulfur dioxide), an air contaminant that is likewise produced when fossil fuels are combusted. The application presumes 500 ppm H 2 S in the fuel prior to combustion. Other manure digestion facilities in production have realized H 2 S as a constituent in the biogas from 500 to 2500 ppm or more. Weekly measurement of the H 2 S content of the fuel is required in the permit. 7. Emissions are calculated using the heating value of the biogas fuel, in million Btu (MM Btu). During combustion, most of the H 2 S will be converted to SO 2. At an inlet concentration of 500 ppm, H 2 S emissions from the generator will be pounds per MM Btu; SO 2 emissions will be pounds per MM Btu. Similarly, flare emissions will be pounds H 2 S per MM Btu and pounds SO 2 per MM Btu. The complete calculations are available in the source file. 8. The applicant has developed a process to address odor complaints received at the facility, to include site visits, review of operations at the time of the complaint, and a tracking system for resolution and reporting. 9. The proposed site of the facility is adjacent to a dairy farm in Tillamook County. The applicant will be required to advise the Department if another site is selected. Construction is planned to begin in spring 2011 and be complete in autumn PROCESS AND CONTROL DEVICES 10. Air contaminant sources at the facility will consist of the following: a. Gauscor SFGM-560 supercharged 4 cycle, 16-cylinder, inter-cooled, lean burn, piston internal combustion engine with spark ignition and a maximum mechanical load of 1341 hp (1000 kw) b. Back-up flare, currently in the design stage, to include a thermocouple and visible alarm connection in case of equipment malfunction CONTINUOUS MONITORING DEVICES 11. Equipment at the facility will be equipped with automatic recorders that will capture the engine power output, biogas flow, engine operating parameters, and biogas flow in the flare. Manual back-up procedures will be in place. Weekly readings of the H 2 S content of the gas will be taken with a Draeger tube or similar device. COMPLIANCE 12. The facility will be inspected by Department personnel to ensure compliance with the permit conditions.

5 Page 5 of 7 SPECIAL CONDITIONS 13. Equipment selections were not confirmed at the time of application. Technical specifications of the biogas flare must be submitted to the Department prior to start-up. Should the applicant choose a different make/model of generator, it is required to notify DEQ of the equipment chosen, using forms available from the Department for that purpose. EMISSIONS 14. Proposed PSEL information: Netting Basis Plant Site Emission Limits (PSEL) Pollutant Baseline Emission Rate Previous Proposed Previous PSEL Proposed PSEL PSEL Increase SO NO x CO VOC a. The proposed PSELs for all pollutants are equal to the Generic PSEL in accordance with OAR (4)(b) and the netting basis is zero in accordance with OAR (2). b. All PM emissions are assumed to be PM 10 from combustion. The emission factors for PM 10 were taken from AP-42, Sections 3.2 and 2.4. PM/PM 10 emissions were estimated at less than one ton/year and are not included in the PSEL. c. Emission factors for all other pollutants were based on engineering estimates from vendor information. d. The application included an emissions estimate for PM 2.5. At the time of this permit action, Oregon did not have regulatory authority to include a PSEL for PM 2.5 in the permit. e. Maximum actual emissions were estimated based on 82,862 MM Btu/year for the operation of the generator and 4,143 hours of operation for the flare and are estimated at 0.3 tons PM 10, 28.8tons NO X, 32.9 tons CO, 10 tons VOC per year, and 6.3 tons SO 2. The SO 2 emissions estimate is based on 500 ppm H 2 S in the biofuel. At 2500 ppm, SO 2 emissions could be 32 tons per year. f. H 2 S emissions are estimated at 0.16 tons/year. This item is included only for informational purposes.

6 Page 6 of 7 g. The original proposed emission factors for the engine generator set were in pounds per million Btu. The heating value of biogas is highly variable. The emission factors were changed to pounds per brake horsepower-hour to provide more correct data without having to monitor, daily, the Btu content of the fuel. h. The PSEL is a federally enforceable limit on the potential to emit. SIGNIFICANT EMISSION RATE ANALYSIS 15. For each pollutant, the proposed Plant Site Emission Limit is less than the Netting Basis plus the significant emission rate, thus no further air quality analysis is required. MAJOR SOURCE APPLICABILITY CRITERIA POLLUTANTS 16. A major source is a facility that has the potential to emit 100 tons/yr or more per year of any criteria pollutant. The conservative emissions estimates included in the application were based on an operating schedule of 8,233 hours/year (either engine or flare). Emissions of the pollutant with the highest emission rate, CO, will be about 35 tons/year. This facility will not be a major source of criteria pollutant emissions. HAZARDOUS AIR POLLUTANTS 17. A major source is a facility that has the potential to emit 10 tons/yr or more of any single HAP or 25 tons/yr or more of combined HAPs. The two HAPs emitted at the highest level are shown below. All others will be emitted in much lower quantities. This source is not a major source of hazardous air pollutants. Hazardous Air Pollutant Potential to Emit (tons/year) Benzene Toluene Other Total ADDITIONAL REQUIREMENTS NSPS / NESHAP APPLICABILITY CFR Part 60, Subpart JJJJ, is applicable to each engine (generator set) to be installed because they were manufactured in 2010.

7 Page 7 of CFR Part 63, Subpart ZZZZ is applicable to each engine to be installed because they were manufactured in Subpart ZZZZ requires subject engines at area sources to meet the requirements in the NSPS (40 CFR 60, Subpart JJJJ). The NESHAP does not add any additional requirements. 20. Specific applicable requirements of the NESHAP and the NSPS are not included in the permit because DEQ rescinded its adoption of these federal rules. It was determined that they are best implemented by US EPA at the manufacturers level. RACT APPLICABILITY 21. The RACT rules are not applicable to this source because it is not in the Portland AQMA, Medford AQMA, or Salem SKATS. TACT APPLICABILITY 22. Biogas from the digester tanks is combusted in the engine generator. The engine generator set is subject to NSPS and NESHAP requirements and is therefore not subject to TACT. In addition, the flare is a back-up control device for digester tank biogas combustion. SOURCE TESTING PROPOSED TESTING 23. Emission factors for the generator were engineering estimates from the manufacturer. The permittee will be required to conduct a source test to verify that these emission factors are correct. The test must be conducted within 180 days of the facility start-up. 24. Emission factors for the flare will not be tested. Flares are commonly used to combust excess biogas at waste water treatment facilities. Emission factors for the flare, except SO 2, were taken from reliable published data. The SO 2 emission factors are engineering estimates, based on H 2 S in the biogas prior to combustion. PUBLIC NOTICE 25. Pursuant to OAR (5)(a), issuance of Simple Air Contaminant Discharge Permits require public notice in accordance with OAR (3)(b), which requires that the Department provide notice of the proposed permit action and a minimum of 30 days for interested persons to submit written comments. The public notice was mailed on April 20, 2011 and the comment period will end on May 20, 2011, 5 p.m. ka:gg