Geo

chem

ical

Cha

ract

eriz

atio

n of

C

oal C

ombu

stio

n R

esid

uals

in

Var

ying

Env

iron

men

tal C

ondi

tion

s

Laur

a S.

Ruh

l* , A

vner

Ven

gosh

^, G

ary

S.

Dw

yer^

, Hei

leen

Hsu

-Kim

+

*Uni

vers

ity

of A

rkan

sas

at L

ittl

e R

ock;

Dep

t. of

Ear

th S

cien

ces

^D

uke

Uni

vers

ity;

Dep

t. of

Ear

th a

nd O

cean

Sci

ence

s;

+D

uke

Uni

vers

ity;

Dep

t. C

ivil

and

Env

iron

men

tal E

ngin

eeri

ng

2015

Wo

rld

of

Co

al A

sh (

WO

CA

) C

on

fere

nce

in N

asvh

ille,

TN

- M

ay 5

-7, 2

015

htt

p:/

/ww

w.f

lyas

h.in

fo/

Geo

chem

ical

Cha

ract

eris

tics

Fiv

e h

un

dre

ds

pow

er p

lan

ts n

atio

nw

ide

gen

erat

e ap

pro

xim

atel

y 13

0 m

illi

on t

ons

of c

oal a

sh e

ach

yea

r

30%

of C

CR

s pr

oduc

ed a

re u

se in

the

Uni

ted

Stat

es, w

hile

70

% is

sto

red

in im

poun

dmen

ts (w

et a

nd d

ry).

Fate

of C

CR

s

Stor

age

and

Env

iron

men

tal I

ssue

s

Impo

rtan

ce o

f Spe

ciat

ion

Man

y fa

ctor

s th

at

cont

rol t

he

mob

iliza

tion

of

elem

ents

ass

ocia

ted

wit

h co

al c

ombu

stio

n pr

oduc

ts (p

H, s

olid

-liq

uid

rati

o, r

edox

co

ndit

ions

, and

re

peat

ed e

xpos

ures

).

•C

oal a

nd C

oal C

ombu

stio

n R

esid

ues

(CC

Rs)

as

wel

l as

the

CC

R tr

ansp

ort w

ater

(or

efflu

ent)

wer

e sa

mpl

ed fr

om s

ever

al fo

ssil

plan

ts w

ith

a di

scre

te s

ourc

e of

coa

l at t

he

tim

e of

sam

plin

g.

•Le

achi

ng e

xper

imen

ts w

ere

perf

orm

ed o

n th

e C

CR

s co

llect

ed s

imul

atin

g a

rang

e of

co

ndit

ions

.•

The

leac

hate

s w

ere

anal

yzed

for

chem

istr

y an

d is

otop

ic c

hara

cter

isti

cs.

Inve

stig

atio

n

Inve

stig

atio

nC

ondu

cted

sys

tem

atic

leac

hing

exp

erim

ents

un

der

a w

ide

spec

trum

of s

imul

ated

en

viro

nmen

tal c

ondi

tion

s:

1)a

wid

e ra

nge

of p

H c

ondi

tion

s (E

PA M

etho

d 13

13);

2)di

ffer

ent S

/L r

atio

(EPA

Met

hod

1316

);

3)M

ine

Wat

er L

each

ing

Proc

edur

e(M

WLP

);

Met

hods

•Tr

ace

met

als

on I

CPM

S•

Cat

ions

on D

CP-

OE

S•

Ani

ons

on I

C•

Alk

alin

ity

titr

atio

n•

Isot

opes

on

TIM

S

Aft

er e

xper

imen

ts: L

each

ate

sam

ples

wer

e an

alyz

ed fo

r m

ajor

, tra

ce e

lem

ents

, and

is

otop

es.

EPA

Met

hod

1313

-pH

Leac

hing

exp

erim

ents

w

ith

pH v

alue

s ra

ngin

g fr

om 2

to 1

3.

•Li

quid

to s

olid

rat

io o

f 10:

1.

•Th

e so

lven

ts u

sed

incl

ude

dilu

te s

olut

ions

of n

itri

c ac

id (H

NO

3) a

nd p

otas

sium

hy

drox

ide

(KO

H) i

n re

agen

t w

ater

.

•R

eact

ed fo

r 24

hou

rs.

•Fi

lter

ed a

nd p

rese

rved

.

0

1000

2000

3000

4000

5000

6000

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

Amount Released mg/kg

pH

Metho

d 13

13‐p

H Variance

Mg

Al Ca

0

100

200

300

400

500

600

700

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

Amount Released mg/kg

pH

Metho

d 13

13‐p

H Variance

Li B Fe (q

ual)

Mn

Sr

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

Amount Released mg/kg

pH

Metho

d 13

13‐p

H Variance

V Cr Cu As Se Mo

EPA

Met

hod

1316

Bat

ch L

iqui

d to

Sol

id r

atio

exp

erim

ents

•L/

S ra

tios

from

0.5

to 1

0•

CC

R m

ater

ial r

eact

ed w

ith

reag

ent

wat

er•

Rea

cted

for

24 h

ours

•Fi

lter

ed a

nd p

rese

rved

110100

1000

10000

100000

02

46

810

12

Boron Concnetration (ug/L) 

L/S Ra

tio

Boron Co

ncen

tration vs L/S

110100

1000

10000

100000

02

46

810

12

Boron Concnetration (ug/L) 

L/S Ra

tio

Boron Co

ncen

tration vs L/S

BR efflue

ntKstE

fflue

n t

Spilled

 Kingston 

Porewater

JS Efflue

nt

110100

1000

10000

100000

02

46

810

12

Strontium Concentration (ug/L)

L/S Ra

tio

Strontium Con

centratio

n vs

L/S

110100

1000

10000

100000

02

46

810

12

Strontium Concentration (ug/L)

L/S Ra

tio

Strontium Con

centratio

n vs

L/S

110100

02

46

810

12

Arsenic Concentration (ug/L)

L/S ratio

Arsenic Co

ncen

tration vs

L/S

Spilled

 Kingston 

Porewater

= 1200ug

/L

JS Efflue

nt

KstE

fflue

nt

BR Efflue

nt

0.1110100

1000

10000

02

46

810

12

Selenium Concnetration (ug/L)

L/S Ra

tio

Selenium

 Con

centratio

n vs L/S

Spilled

 Kingston 

Porewater

JS Efflue

ntKstE

fflue

ntBR

 Efflue

nt

Min

e W

aste

Lea

chin

g Pr

oced

ure

(MW

LP)

Sim

ulat

ion

of a

sh in

an

acid

m

ine

envi

ronm

ent:

•D

ilute

sulfu

ric

acid

•20

L/S

rat

io•

Rea

cted

for

18 h

ours

02468101214

12

34

pH

MWLP Step

MWLP Steps

Control (no

 CCR

 just

solutio

n)Kingston

 CCR

Bull Ru

n

Spilled

 Kingston

John

 Sevier

01

23

Natural pH

Step

 0

020406080100

120

Amount Released (mg/kg)

AMD W

ash Step

Mine Wastin

g Leaching

 Procedu

re

Li B Fe Mn

Zn Sr

Step

 1

Step

 3Step

 2

Bor

on a

nd S

tron

tium

as

CC

R

leac

hate

indi

cato

rs

(‰)

Was

tew

ater

Seaw

ater

+3

9‰

Coa

l

Mar

ine

Car

bona

tes

0.70

6-0.

71

Seaw

ater

Con

tinen

tal W

eath

erin

g

B a

nd S

rIs

otop

ic R

atio

s

Isot

opic

Rat

ios

from

Eff

luen

t

FGD

Isot

opic

Rat

ios

from

Eff

luen

t

Isot

opic

Rat

ios

and

pH

Che

mic

al V

aria

tion

s w

ithi

n a

Faci

lity

Sum

mar

y

•Th

e lo

wes

t L/S

rat

io r

elea

sed

the

high

est

conc

entr

atio

ns (i

n m

ost c

ases

).•

Som

e L/

S ra

tios

wer

e si

mila

r to

fiel

d po

rew

ater

and

efflu

ent c

once

ntra

tion

s.

•pH

val

ues

are

very

impo

rtan

t in

dete

rmin

ing

rele

ase

of e

lem

ents

of c

once

rn.

•B

uffe

ring

cap

acit

y of

the

ash

dim

inis

hes

wit

h in

crea

sed

acid

exp

osur

es.

Sum

mar

y C

onti

nued

•D

eple

ted

Bor

on is

otop

ic r

atio

s ca

n be

use

d in

sur

face

wat

ers/

leac

hate

s as

a tr

acer

.•

Stro

ntiu

m is

otop

ic r

atio

s ca

n be

use

d in

so

me

inst

ance

s de

pend

ing

on th

e su

rrou

ndin

g hy

drog

eolo

gy.

•St

ront

ium

isot

opic

rat

io c

hang

es w

ith

pH/i

ncre

ased

leac

hing

. •

Bor

on r

etai

ns th

e de

plet

ed s

igna

ture

. •

Diff

eren

ces

in c

once

ntra

tion

wit

hin

a pl

ant

and

slig

ht v

aria

nces

in is

otop

ic r

atio

.

Bro

ader

Con

side

rati

ons

•C

CR

s ar

e ve

ry h

eter

ogen

eous

and

hav

e a

wid

e ra

nge

of c

ompo

siti

ons

base

d on

coa

l sou

rce,

pl

ant c

onfig

urat

ion,

and

trea

tmen

t pro

cess

es.

•E

nvir

onm

enta

l con

diti

ons

such

as

pH

chan

ges,

red

ox s

tate

s, a

nd b

uffe

ring

cap

acit

y ar

e im

port

ant i

n le

acha

bilit

y.

•Le

achi

ng e

xper

imen

ts c

an b

e a

good

indi

cato

r to

und

erst

and

how

the

CC

Rs

will

rea

ct w

ith

the

envi

ronm

ent a

nd p

oten

tial

app

licat

ions

of

CC

R u

sage

.

Ack

now

led

gem

ents

Than

k yo

u to

Jim

How

erfo

r hi

s as

sist

ance

.

This

pro

ject

was

fund

ed b

y th

e N

atio

nal

S

cien

ce F

oun

dat

ion

and

an

OR

AU

Gra

nt.

Fu

rth

er r

ead

ing:

R

uhl,

et a

l. E

nvir

on. S

ci. T

echn

ol. 2

010,

44,

927

2-92

78

Ruh

l, et

al.

Env

iron

. Sci

. Tec

hnol

. 201

2,46

, 122

26-1

2233

R

uhl,

et a

l. E

nvir

on. S

ci. T

echn

ol. 2

014,

48, 1

4790

–14

798