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� <br />�:i��:%:'� � � <br />- -s �:.,�.�:�i <br />TECHNICAL MEMORANDUM <br />TO: <br />FROM: <br />CC: <br />RF,: <br />DATE: <br />� <br />Kent Peterson, Bituminous Roadways <br />Jared Anderson & Ed Noefs, Wenck Associates, 1nc. <br />Greg Korstad, Larkin & Hoffman <br />Additiona] Odor/Hydrogen Sulfide Ambient Air Quality Analysis <br />October 20, 2� 10 <br />Wenck Assoelates, Inc. <br />1800 Pioneer Creek Ctr. <br />P.O. 8ax 249 <br />Meple Plein, MN 55359-0249 <br />(763)479�4200 <br />Fax(763)479-4242 <br />E-mail: wendcmp�wenckcom <br />This memorandtim summarizes the results from additional hydrogen sulfide air dispersion <br />modeting for Bituminous Roadways' proposed asphalt plant/asphalt cement storage facility, to <br />be located in Roseville, Minnesota. Hot mix asphalt production and asphalt cement storage and <br />handling can result in odors. Odors can be traced primarily to hydragen sulfide in asphalt <br />cement. Hydrogen sulfide can be present due to sulfur in crude oil. To address the potential for <br />hydrogen sulfide impacts from the proposed operation, an odor impac� analysis f�r the proposed <br />project was conducted. Prior modeling analyses have included emission sources from the hot <br />mix asphalt plant, the asphalt cement storage facility and the asphai[ tanl:er railcar heating. On <br />October 15, 2010 you requested that Wenck Associates, Inc. (Wenck) surnmarize the predicted <br />1-hour hydrogen sulfide (HZS) concentrations from the proposed hot mix asphalt (HMA) plant <br />alone in comparison with the H2S concentrations from the proposed asphah cement storage <br />facility as well as the asphalt tanker railcar heating. Similar to all other modeling analyses <br />completed for the proposed HMA plant and asphalt cement storage faeility, Wenck used <br />AERMOD to complete the modeling analysis. <br />The maximum predicted H2S conce.ntrations at the property boundaries fi•om these proposed <br />gruups of emission sources are listed in Table 1. Also listed in Table 1 are the odor thresholds <br />relied upon in the Environmental Assessment Worksheet that the predicted impacts are compared <br />against. The results in Table I assume that ar.tivated car6on would be used to control the HZS <br />emissioos while the raitcars are being heated. <br />Table 1. 1-Hour Hydrogen Sulfide Predicted Concentrations <br />Impact HMA Tank Railcar All Sources with <br />Plant Farm Heating Railcars Controlled� <br />�u1�m3) (N�n►3) (F��m3) �PP�m� <br />Nlodeled Concentrntion 4.4 <br />Odor Nuisdnce Threshold <br />Minnesota State Standard <br />Odor Detection Threshold <br />6.9 � 1.9 I 72 <br />56 <br />42 <br />ll <br />EAW Modeling <br />All Sources with <br />Raitcars Uncontrolled' <br />(PP�m') <br />I 8.8 <br />'Tbe concemretions lis�ed for ihe HMA Plant, Tank Ferm and Railcar Heating oper:rtions are not additive becsuse �heir individ�nl maximom <br />impai�, cnrur under di(ferent Lhoiir cvems ond locaiions in �he modcl compared to ihe ma:imum e�ent for all units opero�ing simultancously. <br />�i <br />— <br />N�Tatin�caMu:3�BUamincut R�11 7qM Rosenllt CU�aJeling�memc�N'1s•memo IU2ulU0a <br />�i <br />