1 Greenridg e Lan e # 2 Lincoln , M A 0177 3 Octobe r 20 , 200 5 Departmen

to f Environmenta

l Protectio n Burea u o f Wast e Preventio

n On e Winte r Stree t8 t hFloo r Boston , M A 0210 8 Attn : Rober

tDonaldso

n Subject : Comment

s o n Propose d 31 0 CM R7.06(l)(c

) Opacit y Rul e Iappreciat e th e opportunit

y to provid

e comment

s o n th e propose d 31 0 CM R7.06(l)(c ) Opacit

y rule . Overal l th e rul e reflects areasonabl

e balanc e betwee n th e goa l o f optimizin g opacit y emissio n control an dth e nee d t o establis

h limit s tha

t ar e achievable . Th

e us e o f 6-minut e bloc k averagin g t o repor t opacit y emission

s i s als o supported

, a s i t provides a

n averagin g tim e tha t i s mor e consisten t wit h th e behavio r o f opacit y tha n th e specification s i n 31 0 CM

R7.06(l)(a) an

d (b) , avoidin g designatin

g unavoidabl

e instantaneou

s spike s a s exces s emissions . Th

e 6-minut e bloc k perio d i s also consisten

t wit h th e averagin g time use d i n federa

l opacit y monitorin

g rules Ther e are, however

, severa l mino r revisions t o th e rul e bein g requeste d i n a n effort t o simplif y implementatio

n requirement

s an d mak e the mmor e consisten

t standar d monitorin

g practices . Mor e generally , wit

h regar d to rul e implementation , i t

i s fel t tha t conformanc

e wit h thi s propose

d rul e shoul d no t involv e mor

e onerou s complianc

e requirement

s (i.e . mor e frequen t Metho d 9 testin g o r mor e elaborat e deviatio n tracking ) tha

n i s applicabl

e t o th e large r utility boiler

s subjec t t o 31 0 CM R7.06(l)(a) an

d (b) . Rul

e procedure

s shoul d b e kep t a s simpl e a s feasibl e to facilitat

e prope r implementation . Complianc e provisions i n severa

l recen t Ai r Plan s designe d t o implemen t th e substantiv

e conten t o f apreviousl

y propose d versio n o f thi s opacit y rul e wer e significantl

y mor e comple x tha n warrante d b y th e natur e o f th e opacit y emissio n issu e o r wer e neede d t o ensur e prope r conformanc

e wit h propose d opacit y limits . Mor e specific requeste

d revisions t

o th e propose d rul e ar e detaile d below . Sectio n 7.06(l)(c)(l)b . 1 . Requiremen

t tha t Tw o Excepte d Opacit y Incident s Occu r within th e Sam e Hour : I t i s requeste d tha t 7.06(l)(c) l .

b b e revise d t o eliminat e th e requiremen

t tha t th e tw o excepte

d elevate d opacit y incident s occu r withi n asingl

e hour . Th

e basi c inten t o f thi s exception , t

o allow an y boile r u p t o (2 ) tw o opacit y incident s > 27 % i n acalenda

r quarte r durin g specia l operatin g conditions , seem

s appropriate , a

s opacit y emission

s ar e ver y sensitiv e t o combustio n conditions , an

d eve n prope r operatin g practices ma

y no t b e sufficien

t t o avoi da n occasiona l excursio n unde r all circumstances . Unanticipate d change s i n th e combustio

n process , a s wel l a s startup s an

d shutdowns , ca

n produc e unavoidabl

e transien t conditions resultin g i n brie f period s o f elevate d opacit y n o matte r ho w wel l boile

r operatio n i s 1maintained . Also , th e nee d t o minimiz e 0 2 t o promot e NO x contro l make s operatin g shifts mor e susceptibl

e t o mino r air/fue l imbalance

s tha t ca n produc e opacit y spikes . Th e designatio

n o f tw o exception

s a s abas e cas e seem s reasonable

, sinc e asourc e whos e operatin g demand s mak e i t mor e susceptibl

e to opacit y excursion

s ma y elec t t o instal l a datalogge r an d tak e advantag

e o f th e additiona

l exception

s provide d i n 7.06(l)(c)(l)c , whic

h seem s appropriate . However , ther e doe s no t see mt o b e an y reaso n t o requir e tha t th e tw o elevate

d incident s > 27 % provide

d unde r 7.06(l)(c)(l) b occu

r withi n th e sam e 6 0 minut e period . Limitin g th

e two eligible incident

s > 27 % t o lie withi n a6

0 minut e perio d seem s overl y restrictive , an

d somewha t arbitrary . Particularl y a t startup , th e combustio

n process i s variable , an

d transien t conditions ma

y occu r a t an y time . Oftentime s suc

h transient

s accompan

y th e placemen

t o f eac h burne r int o service ; an d th e sequencin

g o f individua l burne r lite-off s coul deasil y exten d ove r mor e tha n a n hour , particularl y a s effort s t o reduc e opacit y ma y includ e aslowe r rampin g u p durin g startup . Mor e generally , du

e t o th e largel y rando mnatur e o f suc h transients , i t

doe s no t see m appropriat e t o confin e th e two allowe

dgenera l exceptio n excursion

s t o asingl e 6 0 minut e period . 2 . Applicabilit

y o f Exceptions : i t

i s suggeste

d tha t languag e b e adde d t o 7.06(l)(c)(l) b clarifyin g tha

t th e two elevate

d inciden t exceptio n i s applicabl

e o n a n individua

l boile r basis . Th e curren t 7.06(l)(c)(l) b languag

e i s silen t o n thi s issue, an

d coul db e interprete

d t o indicat e tha t th e tw o exception

s ar e allowe dpe r facilit y no t pe r boiler, whic

h doe s no t see mconsisten

t wit h th e inten t o f thi s provision . Simila

r clarifyin g languag

e shoul d b e adde d to 7.06(l)(c)(l)c . Sectio n 7.06( 1 VcfflLk . Th e limite dtargete

d exception

s provide d i n 7.06(l)(c) l .c ar

e strongl y supported

, howeve r mino r refinement s an d clarification s ar

e requested

. 1 . Numbe

r o f Allowe dElevate

d Incidents : I t

i s requeste

d tha t 7.06(l)(c) l .c includ

e a n Alternativ e Minimu m(Floor ) numbe r o f allowe d elevate d incident s betwee n 27 % an d 60% , i n additio n t o th e basi c restrictio

n o f 0.1 % o f operatin g time . Th

e type s o f operatin g conditions requirin

g us e o f th e exception

s describe d i n paragrap

h 7.06(l)(c)l.c . (e.g . startup , shutdown, loa

d change , etc. ) occu

r mos t frequentl y fo r limite dus e boilers . Thi s i s on

e instanc e i n whic h mor e operatin g tim e doe s no t correspon d t o alarge r nee d fo r a n exceptio n A suggeste

d valu e fo r thi s Alternativ

e Floo r i s eleve n (11 ) elevate

d incident s pe r quarter , whic h correspond

s to abou t hal f o f th e theoretica

l maximu mnumbe r o f elevate d incident s tha t woul db e allowe dfo r auni t operatin g continuousl

y (i.e . ther e ar e approximatel

y 21,90 0 6-minut e period s i n aquarter

, an d 0.1 % o f 21,90 0 = 2 2 allowe delevate d 6-minut e period s fo r acontinuousl

y operatin g unit) . Wit h thi s refinement

, th e languag e i n 7.06(l)(c)l. c wouldb

e revise d t o specif y tha t th e numbe r o f elevate d incident s greate r tha n 27 % bu t les s tha n 60 % pe r calenda r quarte r durin g specia l conditions canno

t excee d one-tent h o f on e percen t (0.1% ) o f th e tota l 6-minut e bloc k averages , o

r 1 1 pe r quarter , whicheve r i s les s restrictive . 22 . Numeri c Dat aReductio n System: th

e requiremen

t fo r th e Numeri c Dat aReductio n Syste mt o hav e aprintou

t capabilit y shoul db e expande d t o allow outpu

t o f opacit y dat at o a n electroni c file. Id o no t believ e al l dat alogger s ca n b e directl y attache d t o aprinter . I n an

y case , i t ma y b e mor e convenien

t t o downloa ddat afromth e logge r to acompute

r fro mwhic

h printouts o f 6-minut e bloc k values ca n the n b e generated. I t i s requeste

d the n tha t th e first sentenc e o f 7.06(l)(c) l .c b

e revise dt o stat e "Fo r afacilit y equippe d wit h avisibl e emissio

n monito r wit h anumeri c dat areductio n syste mtha t ca n printou t o r outpu t to a n electroni c file individua

l bloc k average s etc. " (suggeste

d ne w tex t i s i n bold) . 3 . Criteri afo r

Approvin g Us e o f th e Exception

s i n thi s Provision : Th

e 7.06(l)(c)l,c . tex

t indicate s tha t th e DE P "may " approv

e th e exception

s specifie di n thi s provision . I t

i s requeste d tha t thi s languag

e b e clarifie dt

o indicat e tha t th e 7.06(l)(c)l. c exception

s wil l normall y b e approved, i f

consisten t wit h th e approve d Pla n o f Goo dOperatin g Practice s (POGOP) . 4 . Definitio n o f

"One-Hour" : I t

i s requeste

d tha t th e al l reference

s t o "one-hour " i n 7.06(l)(c ) 1 . c b e revise dto specif

y "on e bloc k hour" . In thi s context

, bloc k hou r mean s cloc k hour. Th e evaluatio n an daggregatio

n o f dat ao n abloc k hou r basi s i s consisten

t wit h th e standar d configuratio

n o f mos t "numeri c dat areduction " devices , suc

h a s CEMS , Als o mos

t emissio n standard s specif y complianc

e o n abloc k hou r basis . I t i s recognize

d that, i n theory , aggregatio n o f dat ao n abloc k hou r basi s represent

s aslightl y les s conservativ

e complianc

e approac h tha n aggregatio

n ove r 6 0 minute s beginnin g a t th e firs t elevate d incident, bu

t i n practic e th e numbe r o f occasion s o n whic h thre e incident s wouldoccu

r withi n a6 0 minut e perio dbu t no t i n th e sam e bloc k hou r wouldb e minimal . Th

e benefi t o f avoidin g th e nee d fo r customizin

g th e configuration o f

amonitorin

g system , wit h it s accompanyin

g opportunit

y fo r imprope r implementation , i s fel t

t o b e mor e importan

t tha n th e sligh t increas e i n conservativenes s gaine

d b y performin

g 6 0 minut e aggregation

s o n arollin g basis . 5 . Interfac

e o f 7.06(l)(c)l. b an

d7.06(l)(c)l. c Exceptions : I t i s suggeste

d tha t languag e b e adde d to 7.06(l)(c)l. c t o clarif

y ma t th e exception

s provide di n 7.06(l)(c)l. b an

d 7.06(l)(c)l. c ar

e no t mutuall y exclusive . A sourc

e tha t choose s to instal l avisible emissio

n monito r wit h numeri c reductio n syste man dus e th e opacit y exception

s describe d 7.06(l)(c)l.c , shoul

dstil l b e eligible t o us e th e exception

s provide dunde r 7.06(l)(c)l.b . 6 . Applicabilit

y o f Exceptions : i t

i s suggeste

d tha t languag e b e adde d t o 7.06(l)(c)(l) c clarifyin g tha

t th e allowe dexception

s ar e applicabl e t o eac h individua

l boile r a t afacility - se e relate d Commen

t 2 fo r 7.06(l)(c)l. b Sectio n 7.06(l)(cU. d 1 . Complianc

e Method : Th

e languag e i n paragrap

h 7.06(l)(c ) 1 .d . shoul

db e clarifie dt

o indicat e tha t complianc

e wit h 7.06(l)(c ) opacit

y limit s ma

y b e demonstrate

d eithe r throug h Method9 testin g o r b y us e o f acertifie dopacit

y monitor , howeve r asourc e i s no t require dt o us e thei r visibl e emissio n monito r a s adirec t complianc

e monito r unless suc

h arequiremen

t i s containe d i n a n existin g 7.0 2 Ai r Pla n approval .

3Eve n th e larg e utilit y boiler s i n Massachusetts , whic

h ar e subjec t t o th e provisions o f

Section s 7.06(l) aan

db , an d whic h ar e equippe d wit h PS- 1 certifie dopacit

y monitor s mandate d b y th e federa l Aci dRai n Progra m(4 0 CF R75) , ar e no t require d t o us e thes e opacit y monitor s fo r direc t compliance, unless suc

h arequiremen

t i s containe

d i n a31 0 CM

R7.0 2 Pla n Approval . I n contrast , th e industria l boiler s tha t woul dqualif y fo r applicabilit

y unde r Sectio n 7.06(l)(c ) ar e typicall y equippe d wit h non-PS- 1 smok

e sensors , whic

h ar e require d unde r 31 0 CM R 7.04(2) . I t would , therefore , b

e inequitabl

e an d inappropriat

e t o designat e th e opacit y measuremen

t device s o n boiler s choosin g t o confor mt o th e Sectio n 7.06(l)(c ) provisions a

s complianc e monitors . The

y shoul d b e designate

d a s indicato r monitors , wit

h deviation

s from th e Sectio n 7.06(l)(c ) limit s bein

g reportabl

e unde r th e Operatin g Permi t (Titl e V ) Program

, bu t thes e deviation

s woul dno t automaticall

y b e considere

d exces s emissions . I t shoul d b e note d tha t opacit y monitor s subjec t t o PS- 1 certification mus

t b e locate d i n accordanc e wit h specific siting criteria , ar

e subjec t t o stringen t desig n criteria , a

s well a s initial certification testing , non e o f whic h i s require

d fo r asmok e senso r unde r 31 0 CM R 7.04(2) . Also , PS- 1 opacit

y monitor s ar e typicall y calibrate d daily , an d ma y hav e qualit y assuranc e audit s conducte d o n aquarterl

y basis , non

e o f whic h i s typicall

y don e fo r asmok e sensor . Thus , neithe

r th e accurac y o f th e smok e sensors , no

r th e regulator

y provisions i n 31 0 CM

R 7.06(1 ) justifie s arequiremen t t o us e opacit y monitor s a s direc t complianc

e monitor s unde r Sectio n 7.06(l)(c) . Sectio n 7.06( 1 Vc)2.d 1 . Duratio

n an d Frequenc

y o f Specia l Conditio n Events : Th

e languag e i n paragrap

h 7.06(l)(c)2. d shoul

d b e revise d t o clarif y tha t th e descriptio

n o f th e "duration " an

d "frequency " o f

startup , shutdown, soo

t blow , an d othe r specia l event s presente d i n th e Pla n o f Goo d Operatin g Practice s i s aqualitativ e characterization , no t aquantitativ

e analysis . Sinc e mos t o f th e "specia l conditions " associate

d wit h elevate d opacit y incident s ar e th e resul t o f transien t combustio

n conditions whos

e duratio n canno t b e full y controlle

d an d whos e frequency i s likel y t

o depen d o n facilit y process demand

s an d othe r unpredictabl

e circumstances , i t

i s no t feasibl e t o quantitativel

y specif y th e duratio n o r frequency o f

thes e events . Fo

r example , th e frequenc y o f loa d shift s an d eve n o f startups , in a

n industria l facility , wil l var

y dependin

g o n process demands . Th

e duratio n o f loa d rampin g wil l b e affecte d b y th e severit y o f swings i n loa

d demand . Fue l switchin g frequency ma

y b e a function o f

change s i n fue l cost

s and/o r fue l availability . An

dcertai n opacit y generatin

g event s suc h a s burne r trip s ar e totally unpredictable . Eve n soo t blowin g schedule s ma y b e adjuste d base d o n th e duratio n boile r operatio n and/o r an y upwar d trend s i n opacit y emissions . However , i t i s als o recognize

d tha t th e operationa

l role s o f boiler s withi n afacilit

y ma y differ (i.e . unit s ma y b e bas e loaded , shoulde r units , peakin

g units , etc.) , an

d expecte d frequencies an d duration s o f th e specia l conditions producin

g elevate d opacit y excursion

s ca n b e differentiated t

o som e exten t base d o n thes e operationa

l roles . Therefor

e i t seem s appropriat

e fo r th e POGO P t o provid e agenera l descriptiv

e characterizatio

n o f th e expecte d frequency an d duratio n o f thes e specia l conditions consisten

t wit h th e norma l operationa

l rol e o f a boiler, bu t suc h description

s shoul d no t b e require d t o includ e quantitativ

e specifications .

4Sectio

n 7.06m(c)2. f 1 . Specificatio

n o f Emissio n Limit s fo r

Specia l Conditions : Thi s provisio n (7.06(l)(c)2.f

) shoul d b e deleted . Th e opacit y excursion

s excepte d unde r 7.06(l)(c ) ar

e produce d b y transient , off-design combustio n conditions tha

t ar e no t wel l behaved

, stabl e o r repeatable . A

s aresult, pas

t emissio n trend s displaye d durin g thes e specia l conditio n event s ar e onl y a n approximat

e predicto r o f futur e emission

s behavior . Uncertainties inheren t i n suc h non-routin

e transien t event s make s historica l dat aaless tha

n reliabl e basi s fro mwhic

h t o extrapolat

e specific opacit y emissio n maxima. Sligh

t change s i n th e combustio

n process o

r operatin g circumstances , o

r eve n th e norma l gradua l wea r o f hardwar e components , migh

t affec t conditions sufficiently t o amplif y transien t opacit y spikes , an

d resul t i n ne w maximum. Fo r thes e reasons , i t

doe s no t see mappropriat

e t o requir e tha t specific opacit

y limit s b e identifiedfro mth

e historica l dat ase t use d t o develo p th e Pla n o f Goo d Operatin g Practice s (POGOP) . Tha

t dat ase t shoul d b e adequat e t o justif y th e designatio

n o f th e types specia

l conditions givin g rise to opacit y excursions , a

s require d i n 7.06(l)(c)2.e , bu

t i s unlikel y to b e adequat e t o appropriatel

y assig n specific emissio

n limit s fo r

eac h specia l condition . Th e uppe r limi t o f 60 % specifie d 7.06( 1 )(c)l.c , then , shoul d b e applicabl e t o excursion

s fo r an y specia l conditio n designate

d an d justifie di n th

e POGOP . N o requiremen

t t o identif y alternativ e emissio n limit s shoul

d b e include d i n thi s 7.06(l)(c ) rule . Conformanc

e wit h th e POGO P shoul d ensur e tha t source s d o no t us e th e exception

s unde r 7.06(l)(c)l. c a

s abasi s fo r relaxin g existin g opacit y controls . Th

e POGO P wil l contai

n operatin g procedure

s designe d t o maintai n prope r contro l o f opacit y emissions . To reinforce thi s idea , th e Opacit y Ai r Plan s approval s coul d includ e languag e makin g i t explicit tha t th e 7.06(l)(c)l. c exceptio

n shoul d no t b e construe d a s a n emissio n standard

, bu t rathe r th e sourc e ha s th e obligation t

o mak e al l reasonabl

e effort s t o mee t th e 7.06(l)(c ) opacit

y standar d o f 15%/27% a

t al l times to th

e exten t feasible . Sectio n 7.06(l)(c>

4 1 . Deviations : I t

i s requeste

d tha t asentenc e b e adde d a t th e en d o f thi s Sectio

n indicatin

g tha t "opacit y excursion

s > 27 % tha

t qualif y a s allowe d exception

s unde r 31 0 CM R7.06(l)(c)l. b an d 7.06(l)(c)l. c shal

l no t b e considere

d deviation

s unde r th e Operatin g Permit" . Overal l 31 0 CM R7.06(l)(c ) Pla n Approval Comment

s 1 . Statu s o f Previous Opacit

y Pla n Approvals : Opacit

y Ai r Pla n approval s wer e issue d t o severa l Massachusett

s source s implementin

g provisions o f

apreviousl

y propose d versio n o f 7.06(l)(c) . Sinc

e th e propose d regulatio n tha t wa s th e basi s fo r thes e existin g opacit y Ai r Plan s ha s bee n supercede

d b y th e curren t 7.06(l)(c ) proposal , i t

seem s appropriat

e tha t thos e Opacit y Ai r Plan s b e automaticall

y terminate

d immediatel

y onc e th e 7.06(l)(c ) rule ha

s bee n finalized, unles s asourc

e shoul d reques t tha t thei r existin g Ai r Pla n approva l remai n effective . A comple

x arra y o f implementin

g provisions wer

e include d i n thes e existin g Opacit y Ai r Plan s approval s tha t ma y n o longe r b e appropriat

e o r applicable , an

d therefor e i t woul dsee mpreferabl

e to formulat

e ane w Ai r Plan s permi t t o operationaliz

e th e final 7.06(l)(c ) rule , rathe

r tha n attemptin

g t o modif y th e existin g Ai r Plans . 5I t

i s als o requeste d tha t asource , whos e Pla n o f Goo d Operatin g Practice s (POGOP ) wa s previousl y approve d b y MADEP , b

e allowe d t o immediatel

y compl y wit h th e provisions o f th e 7.06(l)(c ) rule onc

e i t i s promulgate

d final , i n lie

u o f remainin g subjec t t o an y existin g Opacit y Ai r Plans . Suc

h a n approac h woul dpermi t a n expedite d conversio

n t o th e ne w rul e fo r source s tha t hav e alread y implemente

d approve d opacit y contro l an d monitorin

g practices . Than k yo u fo r you r consideratio

n o f thes e comments . Sincerely : 

# A Bo b Machave

r

6