IEnvironmental Protection Agency

Transcription

1 IEnvironmntal Protction Agncy 14 APR B0Q ORAL HEARlNa RECEIVED Dublin Wast to Enrgy Projct f OH Sub No. I I Rcd From: FiYiL, EPA Oral Haring Combind Brif of Evidnc - Watr Mr. Hans Jacob Vstd Dr. Dort Rasmussn Dublin Wast to Enrgy Ltd Brif of Evidnc April 2008

2 CONTENTS 1 INTRODUCTION 2 QUALIFICATIONS AND EXPERIENCE 3 THERMAL PLUME IMPACT 4 BIOCIDE IMPACT i

3 I 1 INTRODUCTION DHI was commissiond by DONG Enrgy (formrly Elsam) and latr Dublin Wast to Enrgy Limitd to invstigat th disprsion of cooling watr dischargd from th WtE facility into th Rivr Liffy and to valuat th impact on th cosystm of th rciving watrs of th possibl us of biocid additivs in 'th dischargd cooling watr. A 3D hydrodynamic modl that simulats th watr lvls, currnts, salinity and tmpratur of th lowr Rivr Liffy, Dublin Port and a part of Dublin Bay was stablishd. Th modl rproducd th xisting situation for diffrnt tidal and rivr run-off situations by comparison with masurmnts of watr lvls, tmpratur, salinity and currnts. Th modl was applid to assss th ffct of th discharg and intak of cooling watr for th WtE facility on th tmpratur conditions in th marin nvironmnt.. Th modl also simulatd th addition of biocid to th dischargd cooling watr, th disprsion of th biocids and th dcay in natur in ordr to assss th impact on th marin cosystm. Extnsiv vidnc on ths issus was prsntd by us in a joint prsntation at th An Bord Planala oral haring in April 2007, in which w laboratd upon Chaptr 12 of th EIS and addrssd th mattrs raisd in submissions by th public on ths topics. I prpard th vidnc on th hydrodynamic modlling. My collagu Dr Dort Rasmussn prpard th vidnc on th choic and potntial impact of biocid us in th cooling watr systm. In this joint prsntation w intnd to addrss th issus raisd in objctions to th EPA Proposd Dcision in rlation to th disprsion of cooling watr and th addition of biocids. A-I -1

4 2 QUALIFICATIONS AND EXPERIENCE Mr Hans Jacob Vstd I hold a Mastr of Scinc dgr in Civil Enginring from th Tchnical Univrsity of Dnmark, 1983 majoring in Hydraulics, Soil Mchanics and Structural Enginring. I am a mmbr of th Danish Socity of Profssional Enginrs and th Danish sction of th "Consil National ds IngCniurs t ds Scintifiqus d Franc" (CNISF). I hav bn activ in th fild of hydraulics and coastal nginring for 23 yars of which 21 yars hav bn with DHI. Sinc 1988 I hav bn involvd in th dvlopmnt of numrical simulation tools at DHI and was instrumntal in th arly dvlopmnt of th DHI modl for 3-dimnsional flow MIKE 3. I hav through my carr gaind xtnsiv xprinc in stuarin problms and th dvlopmnt and application of numrical hydrodynamic and transport modls. This involvs spcial knowldg of hydrodynamics, advction-disprsion, cooling watr and thrmal plums, cohsiv sdimnts and storm surg modlling. I hav also actd as rviwr for svral intrnational journals, th EU Commission, th Norwgian Scintific Council and th Dutch Scinc Foundation. I am a mmbr of PIANC Working Group 43 on minimisation of siltation problms in harbours. I am tchnically rsponsibl for cooling watr and thrmal plum studis at DHI. Prsntly I am Had of Projcts in th Coastal and Estuarin Dpartmnt at DHI. Rcnt cooling watr, thrmal plum, stuary and coastal flooding projct xprinc: 0 Rcirculation Study and Bathymtric Survy Works for 240MW Nt Coal-Fird Elctric Gnrating Plant, Quintro Bay, Chil ( ), Vnic Storm Surg Modl Systm ( ) 0 Hydraulic studis for location of cooling watr intak and outfall. Q-Chm 11. Msaid Port, Qatar (2006) 0 Ras Laffan Thrmal Plum Study (2005) 0 Dvlopmnt of storm surg modl basd on MIKE 21 FM, for th Irish coast (2004) 0 0 Hydraulic Studis for Zawiya Combind Powr Plant ( ) Simulation of salinity and tmpratur in th Vnic Lagoon. ( ) 0 Hydraulic Studis for Bnghazi Powr Plant ( ) 0 Loir Estuary, rstoration and dcision support ( ) 0 Thrmal Pollution and Environmntal Impact Odns Fjord, Dnmark ( ) A-2-2

5 Dr Dort Rasmussn I hold a Ph.D and a Mastr of Chmical Enginring from th Tchnical Univrsity of Dnmark, 1983, with ky qualifications in: Risk Analyss and Hazard Assssmnts; Computr Modlling of th Fat of Pollutants in th Environmnt; Modlling of th physical-chmical proprtis of pur chmicals and mixturs; and databas dvlopmnt. I hav mor than 18 yars of xprinc in projct managmnt, rsarch and consultancy assignmnts for privat companis and nvironmntal authoritis. Rcnt nvironmntal risk assssmnt and fat modlling of chmicals in coastal aras: 0 Assssmnt of pollutants dischargd into th Caspian Sa from an offshor nrgy production platform (2006) Assssmnt of th consquncs of dpositing harbour sludg from R0m0 Harbour in th Waddn S (2005) 0 Modlling th concntrations of chmicals in th Lillbalt (Dnmark) ara from multipl dischargs from wast watr tratmnt plants - using ECO lab (2004) 0 Risk assssmnt of lachat from a land-fill with harbour sludg Port of Esbjrg, Dnmark (2004) Assssmnt of th consquncs of dpositing harbour sludg in a confind land fill at Waddn Sa (2004) Environmntal hazard and risk assssmnt of PAHs in producd watr from oil rigs. Clint: Danish Environmntal Protction Agncy (2002) 0 Assssmnt of th fat of Orimulsion 400 in th watr column and th tainting in fish in Th North Sa. (2001) 0 Assssmnt of nvironmntal risks associatd with nlargmnt of Copnhagn Harbour by rclamation infill of pollutd soil (2000) A-2-3 DHI Watr 8 Environmnt

6 3 THERMAL PLUME IMPACT 3.1 Thrmal Plum Modlling Th stimatd impact of th thrmal plums was dtrmind through th application of th thrmal plum modl known as MIKE 3. MIKE 3 is a hydrodynamic and thrmodynamic modl dvlopd by DHI that has bn applid to mor than 30 cooling watr studis alon at DHI sinc Th modl is part of th DHI MIKE softwar systm and is usd undr mor than 150 licncs (s Th DHI MIKE softwar is considrd an industry standard that has bn scintifically documntd and approvd in pr rviwd articls.! It is rcognisd by organisations such as Fdral Emrgncy Managmnt Agncy (FEMA) in th US. 3.2 Application to Rivr Liffy A MIKE 3 modl was st up and calibratd for th particular conditions of th Rivr Liffy, Dublin Harbour and Dublin Bay. Th modl simulats th watr lvls, currnts, salinity and tmpratur distribution dpnding on th tidal lvations in Dublin Bay, frshwatr run-off from th Rivr Liffy, Rivr Tolka and th Doddr, mtrological conditions (wind, air prssur, hat xchang with atmosphr) as wll as discharg of hat from Poolbg, Synrgn and North Wall and th watr from Ringsnd Wast Watr Tratmnt Plant. Th modl was calibratd by comparison with fild data and information including tidal lvations, currnt masurmnts, salinity and tmpratur masurmnts. Th following information and data wr spcifically collctd and applid for th st-up and calibration of th modl: Tmpratur masurmnts at outfall in Jun 2004 (prpard for Elsam Enginring by Svnd Ol Hansn ApS, Rvision 1 March 2005). Bathymtric survy of Rivr Liffy nar outfall in March 2006 (prpard by DHI). Masurmnts of tmpratur, salinity, watr lvls and currnt masurmnts in Rivr Liffy in May 2006 (prpard by RPS). Rivr run-off data for Rivr Liffy, Rivr Tolka and Doddr (Sourc - th Irish Environmntal Protction Agncy). Currnt and Tids Study Dublin Bay (Sourc - Irish Hydrodata Limitd, Rathmacullig Wst, Ballygarvan, Co. Cork Dcmbr 1989). A-3-4

7 0 Opn boundary conditions of tidal variation from a largr modl of th ntir Irish Sa (supplid by RPS). 0 Irish Coast Pilot. Offshor and coastal watrs round Irland including routs to th Irish Sa from Atlantic Ocan Landfalls (Thirtnth Edition, Th Hydrographr of th Navy, 1994). 0 Impact of th Rivr Liffy discharg in nutrint and chlorophyll concntrations in th Liffy stuary and Dublin Bay (Irish Sa). T.G. O Higgins and G.G. Wilson. Estuarin Coastal and Shlf Scinc 64 (2005) pp Th application of a such a hydrodynamic numrical simulation modl of watr flow and hat xchang is a rcognisd and rcommndd standard mthod of assssing th impact on th marin nvironmnt of thrmal plums from discharg of cooling watr (s for xampl pags 30, 277, 282 and 287 in th Rfrnc Documnt on th Application of Bst Availabl Tchniqus to Industrial Cooling Systms Dcmbr 2001 (BREF-documnt), Rf. /lo. 3.3 Cumulativ Impact In ordr to calculat th cumulativ impact of thrmal plums, th modlling took into account all dischargs of wast hat to th Rivr Liffy from th Poolbg pninsula, s Figur 3.1. Figur 3. I Location of all intaks and outfalls includd in th modlling A-3-5

8 Th cumulativ impact was dtrmind on th basis of all xisting powr plants oprating at fdl licnsd valus. Th valus adoptd in th simulations ar givn in th tabls blow. Tabl 1 idntifis th thr powr plants with thrmal discharg to th Rivr Liffy and Tabl 2 idntifis th WtE oprating charactristics, / Tabl 1 - Thrmal Dischargs to Rivr Liffy * maximum pump capacity 3.4 WtE Facility Oprations Th outfall tmpratur of th WtE cooling watr is qual to th tmpratur of th watr at th point of intak plus th tmpratur incras in th condnsr that is rquird to cool th stam turbin gnrator. This is shown schmatically in Figur 3.2. Th outfall tmpratur will thrfor vary in lin with variations in th tmpratur of th Rivr Liffy. Th connction btwn th intak and outfall tmpratur is important for calculating th cumulativ impact of all th thrmal dischargs in th Rivr Liffy. Th tmpratur ris of cooling watr for th WtE facility rlativ to th intak tmpratur will b 9 dgrs C for 98% of hourly valus ovr a yar (oprating at maximum limits). Rivr Liffy T - c Dublin WTE '- Inlt Tmpratur 1 =T I I I I Figur 3.2 Th outfall tmpratur of th cooling watr from th WtE is qual to th intak watr tmpratur plus th incras in tmpratur ovr th condnsr. Th maximum watr tmpratur dischargd to th Rivr Liffy will b 9 C abov th inlt tmpratur. A-3-6 DHI Watr 8 Environmnt

9 ~ 3.5 I WtE Thrmal Discharg. J Th impact of thrmal discharg from th WtE facility is assssd in two stps. Firstly, th baslin situation is simulatd with all th xisting powr plants in opration (Synrgn, Poolbg and North Wall). Scondly, th WtE facility is includd and th simulation is rpatd. Th two simulatd tmpratur rsults ar thn subtractd and th xcss tmpratur arising from th inclusion of th WtE facility is 'dtrmind. In this mannr th cumulativ ffcts of all powr plants ar includd in th assssmnt as wll as thir possibl intraction, i.. th possibility that th intak tmpraturs may b highr than in a rivr whr no hatd dischargs tak plac and rcirculation of intak and outfall watr may occur has bn takn into account in th modlling. Figur 3.3 shows th simulatd rising tid surfac layr thrmal plums from North Wall, Synrgn, WtE and Poolbg powr plant. Th intraction btwn th Poolbg powr plant and th WtE / Synrgn plums is obsrvd. Th Liffy Estuary is not salmonid frshwatr for th purposs of th Europan Communitis (Quality of Salmonid Watrs) Rgulations 1988 (th "Salmonid Rgulations"), howvr th impacts of th WtE thrmal plum wr masurd against th standards st out in th Rgulations at th rqust of th Dpartmnt of Communications, Marin and Natural Rsourcs. Th tmpratur rquisits for th purposs of th Salmonid Rgulations ar as follows: "Tmpratur masurd downstram of a point of thrmal discharg (at th dg of th mixing zon as dtrmind by th local authority) must not- a) Excd th unaffctd tmpratur by mor than 1.5" C; b) Excd (i) 21.5" C ; or (ii) 10" C, during th priodfrom 1 Novmbr to 30 April whr spcis which nd cold watr for rproduction ar prsnt. A thrmal discharg must not caus suddn variations in tmpratur. (Tmpratur limits to b conformd with for 98% of th tim). '' No mixing zon has bn dfind for th Liffy Estuary as it is not dsignatd salmonid watr. Figur 3.4 shows that th combind ara of impact of thrmal plums from th Dublin WtE and Synrgn is stimatd to b approximatly 25% of th cross sction of th Rivr Liffy for th 1.5' C rquirmnt, 25 % of th cross sction for th 21.5" C rquirmnt, and 33% for th 10" C rquirmnt. Th facility will b opratd on a stady basis all yar around. Thus suddn variations in tmpratur conditions du to th opration of th plant will not occur. A-3-7

10 ,. 'i Figur 3.3 Th absolut surfac tmpratur at rising tid. Th thrmal plum from Poolbg rachs th WtWSynrgn thrmal plum. Figur 3.4 Cross sction of th Liffy at th WtWSynrgn outfall. Th blu colour indicats th ara whr th tmpratur is lss than xcss tmpratur 1.5 C, C in summr and 10' C in wintr, for 98% of th tim. A-3-8

11 3.6 Impact on Synrgn Th proposd location of th WtE cooling watr intak is at th outlt of th xisting opn channl that convys cooling watr from th Synrgn powr plant as wll as from th plannd WtE facility. Th potntial impact of th WtE cooling watr intak location on absolut cooling watr discharg has bn takn into considration. Th simulations basd on th MIKE3 modl indicat th possibl incras in tmpratur of th intak watr for th Synrgn facility as a rsult of cooling watr dischargd from th WtE facility. Th xcss tmpratur is calculatd as th diffrnc btwn th absolut tmpraturs in th Synrgn intak with and without th WtE in opration. Th simulation without th WtE (th baslin situation) includs Synrgn, Poolbg and North Wall in opration. Th Synrgn intak is locatd at -3.57m OD Poolbg. This corrsponds to -6.3m blow Man Sa Lvl (MSL). Th watr dpth at th outfall is approximatly 10 mtrs and th intak is thus approximatly.3.7m abov sabd. Th modl applis 5 layrs ovr th vrtical. Th thicknss of th layrs varis with th tid and th intak is in btwn layr 3 and 4. Th point of th intak is accordingly put in layr 3, i.. at mid-dpth in ordr not undrstimat th impact on Synrgn. Th location of th thrmal plum dpnds on th tid. Figur 4.1 shows th inland movmnt of th thrmal plum at rising tid at th surfac as wll at mid-dpth. A-3-1 DHI Watr 8, Environmnt

12 Figur 3.5 Simulation of absolut tmpraturs of thrmal plum at rising tid for surfac and mid-dpth. Oprafion at full licnsd valus, includs WtE facility, summr situation. Dpnding on th watr movmnts in th Rivr Liffy th WtE facility inducs an xcss or additional tmpratur incras at th Synrgn intak that varis with th tid as shown in Figur 4.2 and 4.3 for th wintr and summr situation, rspctivly. Th incras in-xcss tmpratur occurs at rising tid whn th thrmal plum movs inland. This ffct is most pronouncd at spring tid and lss at nap tid. For th wintr situation th maximum incras in xcss tmpratur is 0.50 " C and th avrag incras is 0.15" C. For th summr situation th maximum incras in xcss tmpratur is 0.76" C whil th avrag incras is 0.20" C. A-3-2

13 1 ' - Synrgn Intak Tmpratur Excss [dg C] - Tidal lvation [m] ~ 2.0, 50 I I I I I I 1 I I I I I I I I I I 0o:oo 0o:oo 0o:oo 0o:oo 0o:oo 0o:oo 0o:oo Figur 3.6 Excss tmpratur in Synrgn intak. Full licnsd thrmal dischargs. Wintr situation. Synrgn Intak Tmpratur Excss rniddpth [dg C] - Tidal lvation [m] 0o:oo 0o:oo 0o:oo 0o:oo 0o:oo 0o:oo 0o:oo Figur 3.7 Excss tmpratur in Synrgn intak. Full licnsd thrmal dischargs. Summr situation. Th ffct of lvatd tmpratur in th WtE intak was takn into considration in th assssmnt of both xcss and absolut tmpraturs for th purposs of th Salmonid Rgulation (s abov and brif prpard for th An Bord Planala haring Rf Th lvatd tmpratur of th WtE intak is shown in Figur 4.4. Th figur shows that thr is an incras in xcss tmpratur up to about 1.0' C as wll as significant suddn rductions of about 1 to 1.5" C. This is xplaind by th rdistribution of th flow around th outfall. Th incras in surfac outflow is compnsatd by an incrasd flow of coldr bottom watr that rducs th intak tmpratur. A-3-3

14 WtE Intak Tmprartur Excss middpth [dg C] - Tidal lvation [m] 5.0 i o 0o:oo 0o:oo 0o:oo 0o:oo 0o:oo 0o:oo 0o:oo Figur 3.8 Elvatd tmpratur in WtE intak. Full licnsd thrmal dischargs. Summr situation. A-3-4

15 4 BIOCIDE IMPACT 4.1 Th potntial impact of biocid us on watr quality has bn addrssd using intrnationally accptd mthodologis and a consrvativ approach. Th consrvativ risk assssmnt showd that vn whn using a continuous high dosag of 1 mg/l, an nvironmntal impact outsid th outfall of th facility is not xpctd, thus an impact on th watr quality is not xpctd. It should b notd that Schdul B.2 (Emissions to Watr) of th EPA Proposd Dcision stipulats a Hypochlorit/Chlorin mission limit valu of 0.2mg/l (24hr avrag), 0.5mg/l (maximum instantanous) which furthr highlights th consrvativ approach of th compltd risk assssmnt. Basd on rcordd mission amounts of chlorin and watr, it can b calculatd that in 2005 Synrgn opratd with an avrag mission concntration of 0.1 mg/l chlorin in its dischargd cooling watr.' Th dosing of th biocid should b kpt at a minimum. A sufficint biocidal tratmnt is monitord by masuring th total rsidual chlorin (TRC) in th dischargd cooling watr at th outlt. Th total rsidual chlorin should b kpt at a crtain minimum lvl. Th ffct of cumulativ biocidal dischargs has bn considrd. Th risk assssmnt and modlling of th us of biocid took into account th cumulativ ffcts of contributions from othr plants in th ara using th sam biocid. Th background concntration of th dgradation products of hypochlorit/chlorin du to usag at Synrgn powr plant, Poolbg powr plant and North Wall gnrating station was stimatd 'and was found to b at last on ordr of magnitud lowr than th concntration lvl at which no ffcts on th spcis in th watr ar xpctd. Rfrnc Rf. /1/ Europan Commission. Intgratd Pollution Prvntion and Control (IPPC). Rfrnc Documnt on th Application of Bst Availabl Tchniqus to Industrial Cooling Systms (BREF) Dcmbr Rf. /2/ ABP haring 1 Dublin Bay Powr Plant. EPA Annual Environmntal Rport. IPCL no Rporting priod: 1 January to 31 Dcmbr A-4-1

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