Loading...
HomeMy WebLinkAboutNC0001422_LV Sutton 9-29-2016_20160929�� DUKE f'C EAERGY. September 29, 2416 I�Ir. �. gay cimmerman_ P.G. Director, Division of Water Resources North Carolina Department of Environmental Quality i'oii Flail service Center Raleigh, NC 27699-1611 RE: Response Lo DEQ letter uated Hugusi ly, �D.L6 L.V. Sutton Energy Complex Comments on Geochemical Modelins (Corrective Action Plan Part 1, ANpendix D, and Corrective HRion Plan PaR c_ Kppendix C) Dear Iglr. cimmerman: ouRe Energy, along witR our con,eltants, and Department of Environmental Quality i;DEQ) staff discussed the above -referenced letter during a conference call on �eptemDer ��, �O.t6. � Re list of participants on this conference call is included in Attachment 1 to this letter. Below is Duke Energy's understanding from tRis conference call. Steve Lancer, DEQ Central Office, oNened the discussion by paraphrasing the four genera[ comments provided in tRe aRove-referenced letter. In summary, DEQ requested o n=oised Site Conceptual Model using the geochemical model information to describe the distribution of constituents with predictions on how conditions may chanee with future remedial actions. Morella Sanchez -King, DEQ Wilmington Regional Office, reiterated specific comment �� from tRe aRove- referenc�d letter re�ardins specific information for Sutton describing the unique conditions on the north side of the sys� asR Qasin �ivoRR ,cones; tRe central raR or tPfe site tTransition N-5 Zones; and southeast of the 1971 ash basin {South Zone]. Dr. FaILa stated tRai LRe TIOW LranspoR mecnarnsms slioald uho Be ��nsidered. The anomalies observed at Sutton may not have purely geochemical explanations. � here may be other source contributions or e..planations. For Example, boron is assumed to be larsely unaffected by geochemistry; thus, changes along a transect are more IiRely due to LranspoR anti geologic conditions. Dr. Powell stated that the existine global �eochemical model way developed as a guide to determine if LRe retardation factors will Re signincantly cRansed morn those used in the groundwater transport model, understanding that pH and redox are the primary parameters that may change Lhe mobility of constituents. It is not t�Lhnically possible to construct a completely coupled transport/geochemical model oecause dear gradients are generally not oBsersed, there is extreme variability in the data, and groundwater chemistry at the Sutton site is not at equilibrium (geochemica� modes are Gasea on an assumption of eMuilibrium). Therefore, the global model provides a predictive estimation tool; for examp�e_ if oxygen is introduced to tRe system as a result of a remediati;,n ;tip the model predicts how the K� (mobility of constituents) could change (increase or decrease). � Re next step for tRe geocnemical ICI. for CiR1R1e� tea.-� [eC[c� September ty, �Oib model would be to rnoia�l �peciflc sites, narrow down the Kd values, and answer specific water chemis�ry related quesrions. Dr. Falra aescrioea iRai iRe iran,port modelins conducted to date used conservative Ka values for each consci�uen� (such as zero for boron} co reflex actual size observed conditions or tRe lowest .alae measured br the University of North Carolina -Charlotte (UNCC} labora�ory. Dr. Powell Hared rhac is is unlikely additional geocRemical mo�eling woal� predict lower Kd values than those currently used in the flow and transport model. .ed Campbell, Ksnevil�e Regions, orrice, tRen n=gaested additional clariryon the planned approach. Dr. Powell described PHREEQC as one dimensional. Dr. Powell further describeC rRar rRe nex� step of rRe geocRemical n+oaeling would be to run in batch mode alone transects for comparison �o ac�ual site condirions wichour incorporaring i�ow. bill DeuucR, DEQ contractor, Hated this approach uses a single Ko without PHREEQC flow capabilities and does nor provide undersranding of rRe capacities or venous RyiaroxiCes and other adsorbents. PHREEQC will show dissolving process and their effect. Dr. Powell indicated rhe capaciry comments in rReobove-reverence iener .mere ve�,r helpful. Dr. Powell stated that titrations could be run to evalua�e the stability ar exrreme high and low con0irions ro assess Row mucR or a ceRo;n constituent could be sequestered under varying conditions. Bill Deutsch brought rhe discussion bacR ro rRe specinc areas at �ution ansa tRat o,-.on+alies should be explained by the Geochemical Site Conceptual Model to help with prediction of future condirions. � he model sRoule vaciliiate evaluaiio�,s .here the pH and arsenic concentrations are high, and where selenium is high and p� is low. Dr. Power inf7icatea tRe plan woal� be to look at these sNecific areas with lower extractable iron to test the global model understandings. Redox is srable. Exrraaable iron concentrations need io oe determined for the model to be Nredictive. It was also noted that errors in the original mutton text regarding conversion ov ER �o pe roe incorporation into the PHREEQC model were in the text only, the actual modeling was correLt. The measured i�fzP values were correcref7 vor tRe reference elei`tro�e anti tPiose values were appropriately converted to pe prior to incorporation into PHREEQC input files. � he conclusions are oases on correE[ mottel information. Bill Deutsch suggested conductins ferric hydroxide analysis in the anomalous areas and when dissolurion/IeacRing resrs are Done, Re recommenbeti analrzin� for other chemicals. Dr. Powell stated that conducting additional laboratory analyses coupled wirh rhe adairiona� geocrtemical moi�el�ng or new site data wilt not be possible by the November 1 Submittal deadline. However, Dr. Powell scared char Dune irnergy could use existing sol�R dna aqueous phase data to calculate irrsitu Ko values for sampling events where both sees of dare are available. Ted Campbell commenced char rhe current Corrective Hcrion Plans �CHPi pro�ia� predictive flow and transport models with a single Kp for each constituent and asked what would be done in rhe furore. Dr. Falta seared Rat �Re gra,-.sport models dont support certain constituents of interest �CQI} migra�ing from the ash basin in certain areas, even wirR a very low Rd, suggesting otRe� sod, ces. Dr. Falta also stated that the fate and transport models could be rerun if the geochemical modeling indicates it is possible ro Rave a lower Rd ;,aloe than what was previously modeled. However, boron was modeled with a Kd of zero ac Sutton. Mr. Jay zimmerman getter 5ei7tc Rlbc� Z9, ��26 Dr. Powell sugtiested that rather than coupling she flaw and geochemical model, she recommenaetl approach woulia De to maze the n�oselinti iterative i.e., if the seochemicai model sugtiests a lower Kp may occur Shan had been previously evaluated in �I1e CKP_ toes ��e rlow anis transport model coelLl be re,,eated with the lower Kd). Knowins specific areas of in�eres� for each site, as provided in she above- referencela letter ror sunon. woui� Qe lielpiul to focus future efforts. Bolin i oerfer, Duke Energy, asked if comments on the other six puke Energy Progress, LLC. {DEP) models would be forthcoming �o Relp locus the worn to specific transects of interest. Steve Laster indicated that DEQ comments are fo<<h-coming buy nog sure of exac� aiming. ,oho �oepier inRicaie� it woulia tse �ener��ial to have an extension for submittal of sites other than Sut�on �o capture she pending commen�s. ��eve [osier reques�ee tRat Dune Enerby p�o.ide a letter askinti for the extension and a plan for what will be provided. Ted Campbell sugges�e0 a follow-up action item woelia �� ror suture submittals to better ex,,lain the rationale and applicability of she global geochemical model as a quali;wive. preaiaive pool ane 11ow it can Qe used io evaleate possible chanties as a result of the anticipated remedial actions. Pro osed Path Forward for Sutton Geochemical Modelin 6asea on the aRove saiscussion, Dune Energy will update the Sutton tieochemical model in order �ha� i� be mare sire -specific as reques�ed by DEQ. µlong wits �I1a�, the rational anti applicability of the global model will be further described on a site specific basis �o support a beer unders�anding of sire specific conditions ane pateniia! ruiure cnanties to site conditions that may occur as a result of remedial action. Mare specifically for Su«on: - The geochemical model for Sutton will be run to examine �11e sianiliry of iron ons aluminen� phases across the geochemical candi�ions of ►he sire (DEu ueneral Comment � � � rrom the above -referenced lett�rj. More specific �o General Commen� �_ solid phase Cul concentrations will b� used in the PHREEQC model where available. The sys�ems when bash she solid phase ons aMeeous phase COI concentrations are available are the ideal sys�ems �o model using PFIREEQC ansa to ia�termine if the distribution can be predicted. However, due Lo sire condi ions (such as oearocx flow zones, not applicable to Suttonl the solid phase data may not be available �hroughou� all Transect areas. • vvhen peRarming simula�ions esing site-specific groundwater ion concentrations, simulations using she Fe{II)/Fe{IIIA aara will �e consented to buffer the redox conditions (DEQ General Commen� as from she above -references lenerl anti compare that to simulations using the site measured Eh values. During she call bill Deu�scR suggesie� spat auRe Ene�sy couple the reaction to Fe{Ilj/Fe{OHj3{sj. Duke Energy apprecia�ed chis feeoGacR ansa will aRempt anis rattier than using aqueous Fe{Illj values. - DEQ General Commen� 3 from she above -references letter requested ailiaiiional discussion on fil�ra�ion �es�ing. � his will be incorporate0 as part or the site-specific models, targeting the analysis �o specific COIs where colloid �ranspoR cou10 Have an impact. - The site densities of iron and aluminum will be modified in the new sire-specirc models. The information wi11 then be used as a comparison �o she global model. - A fully integrated geochemical specia�ion/reaRive �ranspoR moQel will not Ge conducted. Rather changes in Ko values across she �ranseRs will be compared ro Elie Rd values reWuired in the flow and transport models �o approxima�e re�arda�ion of she 3 Mr. Jay Simmerman letter 5�ptem6�r Z9, 2D16 COIs. Note complete agreemen� is essen�ially impossible for many of she %uls which have a sienificant naturally occurring component because of the uncertainty in she lo�at;o�, of a source term" for example, sources of iron and manganese are ubi4uitous, in addition to wfiai may fie derived from the ash basinsl. i die sites ,pe�ir,c model transects will focus onsite specific COIs except where the global model dna file wafer quality r�;elts i�aicate that Kdvalues will not change significantly (up or down) fay cRanging site conditions. Recall tRai �f'i� r�toraation factor, R, is the bes� measure of cons�i�uent mobility an0 tPiat Rd is included in tf3e calculation. � Ae rale and �ranspoR model uses she re�arda�ion factor co model consti�uenz migration. For �ut�on_ the site specific geocnemical moiacl inTor,,,ocion ..ill be provided by November 1, 2016 as reques�ed. For she remaining six DEr facilities, tRe up�ate� geocnemical rnoa�lins .ill be comYleted in a fashion similar �o �ha� for Su«on. puke Energy requests dna extension f3eyona Idovemner 1 for tRese six facilities and as specific DEQ commence have nog been received. nuke Energy will update the geochemical model for these six facili�ies wi�hin 90 days of receip� of specific Df*u commen�s and requested flow transects. nuke Energy appreciates tfie Open ai,ca�;;on regarding the DEP beochemical models. if you have any ques�ions or need any clarification regarding tf�e inrormation pro�itl��, please contact Ed Sullivan at ed.sullivanC�duke-enersv.corn or at ysD-�»-s,ly at your convenience. RespeRTully suf3mitt�o, Rarry R. �iaeris SVP — Environmenr.al. P9eal�h � safety cc/a«: Mr. Bill ICliller—ADR Ms. Kathy Webb — SynTerra ICIr. Ryan Czop —17uRe Enemy Ms. Kim vviu—Duke Energy Mr. Ed Sullivan —Duke Energy IOIr. �oRn i oepfer —Duke Energy 4 Rt�tacRntent 1 DEq/Duke Energy Conference Call September 15, 2016 Ati�..Dunacyio Phone Sieve Lamer— DEQ Cenral office Eric �miih —DEQ C�ncrai Office Ted Campbell —DEQ Asheville Regional Office 'aeon Regie, — DEQ wil,�.in5ton Regional Office Morella Sanchez -King --DEQ Wilmington Regional Office bill Deutsch — DEQ Cvntru�o� john ioepier—Dune Enema Kathy Webb—SynTerra Corporation Perry vvaiGrep - syn i erra Lorpo�arion Erin Black - Synierra Corporacion Dr. Ran Faha - syn � erra Corporation Or. Brian Powell -SynTerra Corporacion Codd vvilson—P9DR inc. Bill Miller—HDR, Inc.