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Mr. Frank DeMaris October 18, 2010 Page 5 of 7 for the Geer Road Landfill (Stanislaus County)required an air assist fan and 0.1 lb/MMBtu for PM-10. There are also approximately nine BACT determinations in the CARB database for flares. This includes, but is not limited to, a flare installed in the SDCAPCD jurisdiction in 2002 and two installed in the SCAQMD jurisdiction in 2001. There were three PM/PM-10 determinations ranging from 0.008 lb/MMBtu(based on natural gas AP-42, which has two times the BTU content of LFG)to 0.1 lb/MMBtu. The EPA database established BACT limits ranging from 0.022 lb/MMBtu to 0.10 lb/MMBtu for PM-10. ADDITIONAL REVISIONS/INFORMATION REQUESTED SJVAPCD noted during our recent meeting that individual emission limits for SOx must be included for individual combustion devices, in this case the engines and flare. Ameresco requests the flare and engines emissions limit for SOx to be 74.46 lbs/day and 3.10 lb/hr, each. This is based on the worst- case scenario of the total possible combined emissions of the flare and the engines being emitted from one device. Ameresco recommends using a worst-case scenario as a result of our siloxane pretreatment system's reaction to hydrogen sulfide in the raw LFG. The siloxane pretreatment system's media bed has an affinity with hydrogen sulfide, which will cause hydrogen sulfide to collect on the media bed. However, its affinity toward hydrogen sulfide is less than its affinity to siloxane compounds and other VOCs. As a result, as the media bed operationally approaches its regeneration cycle and its media bed becomes saturated, hydrogen sulfide may be released from the media bed. We also request a site-wide emissions limit of 17.0 tpy for the flare and engines to remain below the emission offset limit of 17.4 tpy (34,750 lb/yr). Please note that the maximum SOx emissions from the equipment on a facility-wide basis at 150 ppmv sulfur(assuming the maximum flow of LFG to the engines and flare)are 13.59 tpy. This is well below the proposed facility-wide cap. Ameresco would like to work with the SJVAPCD to develop a reasonable testing program for SOx emissions for the waste gas flare. This would likely include annual stack testing of the flare for SOx as well as periodic sulfur content testing of the raw gas to the plant as a whole. In order to avoid emission offsets for VOCs, Ameresco requests to cap the emissions of VOCs to 9.99 tpy. As noted in the Response to Notice of Incomplete Application dated October 2010,the total VOC emissions for the engines and flare are 21,293 lb/yr or 10.65 tpy. This is 1,293.71 lb/yr or 0.65 tpy (6.5%)over the offset threshold of 20,000 lb/yr or 10 tpy. The LFGTE facility could operate in any configuration as long as the emissions remained at 19,999 lb/yr or 9.99 tpy or less. Note that these emission estimates are based on 100%uptime and 100%load for both the engines and the flare. During the course of a year, both the engines and flare will be down for maintenance. In addition,the flare is not expected to operate 24 hours per day, 365 days per year because it operates in a cyclical, batch-type operation or 24 hours in every 48-hour period. Finally,LFG engines usually have on-line times of approximately 95%. Therefore,Ameresco believes the total VOC emissions will remain under the cap. Compliance would be determined with throughput and source test data and calculated on a 12-month rolling average basis. In order to avoid emission offsets for CO or modeling to demonstrate compliance with ambient standards(to avoid modeling),Ameresco requests to cap the emissions of CO to 99.99 tpy. The total CO emissions for the engines and flare are 219,300 lb/yr or 109.65 tpy. This is 19,300 lb/yr or 9.65 tpy(9.65%)over the offset threshold of 200,000 lb/yr or 100 tpy. The LFGTE facility could operate in