Exhibit 7 – Potable Well Search Results
For the

TABLE OF CONTENTS
Final Re~ort
Conceptual Development of a Pozzolanic Cap
for the
Closure of Basin D at the Hutsonville Power Station
PHOTO Hutsonville Power Station Basins A and D
1. TABLE 2
FIGURE 2
Unconfined Compressive Strength Development
for Selected Mixes
1. PLACEMENT OF THE DRAINAGE LAYER
2. AND TOP SOIL FOR COVER SYSTEM
3. POZZOLANIC CAP MATERlAL
4. FINISHED LANDFILL
Attachment 1
Natural Resource T.echnotogy, I nc.
TRANSMITTAL
Attachment 3
GeoSystems
Inc.
Attachment 4
Appendix A -2
Analytical Laboratory Reports
from
Dalare Laboratories
Philadelphia Pa.
1. Rut sonvill e
2. Ar s'e'ni c
  1. Silver

SOURCE

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ENERGY

GENERATING

375A04

TECHNOLOGY

HUTSONVILLE

ILLINOIS

FIGURE

DRAWN

BYRLH

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Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

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Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

AMEREN SERVICES

GROIIIND WATER MODEL EVALUATION OF

IMPOUINDMIENT CLOSURE OPTIONS

AMERENCIPS HIUTSONVIILLE POWER

STATION

CRAWFORD

COUNTY

ILLINOIS

PROJECT NO 1375

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

GROUNDWATER

MODEL EVALUATION OF IMPOUNDMENT

CLOSURE

OPTIONS

AMERENCIPS

HUTSONVILLE POWER STATION

JANUARY

2000

INTRODUCTION

Background

AmerenCIPS

operates

the

Hutsonville Power Station in Crawford

County

Illinois

The Power

Station is located on the west bank of the Wabash River between the Towns of Hutsonville and

York

Section

Township

Range 11W

The coal-fired

power

plant

has been in

operation

since the

1940s

There

are

currently

two units

operating

at the

plant completed

1953

unit

and 1954

unit

with

combined

generating capacity

of 164 MW

Fly

ash from

the

operating

units is collected

electrostatic

precipitator

and sluiced

lined ash

impoundment

Bottom ash is sluiced to

separate pond

and

eventually recycled

Sluice water

from both the bottom ash

pond

and lined

fly

ash

impoundment

is routed

through

unlined ash

impoundment

before

discharge

to the Wabash River via an NPDES

permitted

outfall The lined

ash

impoundment

was

constructed in

1986

and has

an area

of about 12

acres

Most of this

area

ponded

The unlined

impoundment

was

constructed

1968

and has

an area

of about

17 acres

Only

the southern

portion

of the unlined

impoundment

ponded

the northern

portion

dry

In addition to the

impoundments

there is

ash

laydown

area

between the

impoundments

that

covers an area of about

acres The ash

laydown

area is

dry

Groundwater

quality

has been monitored at this

facility

since 1984 Concentrations

boron

sulfate

and several other

parameters

exceed Illinois Class

groundwater

standards at some

monitoring

wells

Boron

and sulfate are indicator

parameters

for

coal

ash

leachate in

groundwater

hydrogeologic

assessment

report

for this

facility

was

prepared

August

1999

Science

Technology Management

and Natural Resource

Technology NRT 1999

That

MODEL REPORT

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Resource

Technology

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

HUTSONVILLE

GROUNDWATER

MODEL EVALUATION

report

describes

hydrogeologic

conditions and

sources

for elevated concentrations

boron

sulfate

and other constituents in

groundwater

Monitoring

wells and

boring

locations used in the

hydrogeologic

assessment

well

site

layout

are

shown in

Figure

The

purpose

of this work

was

to model

groundwater

flow and

transport

at the site to

predict

the

effect of different closure scenarios for the unlined

impoundment

groundwater quality

Four

closure scenarios

were

modeled

Dewatering

with

cap

Dewatering

with

native soil

cap

Dewatering

with

compacted

clay

cap

constructed

specified

Illinois

Title

Part 811.3 14

Dewatering

with

synthetic

barrier

cap

Summaries from the

hydrogeologic

assessment

are

presented

below

and

modeling procedures

assumptions

and results

are

described

in the

following

sections

Summary

Hydrogeologic

Assessment

The

upland portion

of the site is underlain

thin

layer

sandy

sediments

which

are

underlain

sandstone

bedrock

The lowland

portion

of the

site

the Wabash River

valley

underlain

alluvium that coarsens

downward

Regional

groundwater

flow

through

these

materials is

predominantly

northeast toward the Wabash

River

although

localized

irregularities

occur

due

the unlined

impoundment

and

past pipe

leaks

between the

impoundments

Groundwater

samples

from

some

sample

locations had

concentrations

boron

manganese

sulfate TDS iron

and nickel

higher

than Class

groundwater

standards

High

iron and nickel

concentrations

were

found in locations where coal

was

present

however

there

was no

evidence

that

iron and nickel from the coal

pile

and coal

spill

areas is

migrating beyond

those areas

Manganese

ubiquitous

local

groundwater exceeding

the Class

standard in

background

and

downgradient groundwater

Boron

and sulfate2

are

migrating

east toward the Wabash River The

Passive

dewatering

via

gravity drainage

is assumed for all scenarios

Because TDS

indicator

parameter

rather

than

specific

constituent in

groundwater

it does not

migrate

but it

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HUTSONVILLE

GROUND WA TER MODEL EVALUATION

primary

sources

of boron

were

identified

the unlined

impoundment

and the ash

laydown

area

between the

impoundments

while the unlined

impoundment

ash

laydown area

and coal

pile

were

all identified

as sources

of sulfate

MODEL INVESTIGATION GENERAL APPROACH

Boron

transport

was

modeled because it has

high

concentration

in all

source areas

and is mobile

groundwater

The model

was

first calibrated

produce

head and

concentration

distribution

representative

of conditions while the unlined

impoundment

was

in service

The

calibrated

model was then used as

starting point

predict changes

in boron concentrations

caused

removing

the

impoundment

from service

Three model codes

were

used to simulate

groundwater

flow and contaminant

transport

post-

closure

leachate

percolation

was

modeled

using

the

Hydrologic

Evaluation

of Landfill

Performance

HELP model

groundwater

flow was modeled in three dimensions

using

MODFLOW

and

contaminant

transport

was

modeled in three dimensions

using

MT3DMS

The HELP model

provided

leachate

percolation

rates for

input

MODFLOW

and MODFLOW

calculated the flow field that MT3DMS used in the contaminant

transport

calculations

Help

Simulation of Closure Alternatives

Help

Model

Description

The

Hydrologic

Evaluation

of Landfill Performance

HELP

code

was

developed by

the U.S

Environmental Protection

Agency

and is used

extensively

waste

facility

assessments HELP

predicts

one-dimensional vertical

percolation

from

landfill or soil column

based

precipitation

evapotranspiration

runoff

and the

geometry

and

hydrogeologic

properties

layered

soil and waste

profile

For this

investigation

the

most-recent

version of HELP

Version 3.07

Schroeder

1994

was selected to estimate

percolation i.e

water

flux

from the

impoundment

for four closure

tends to be elevated where sulfate is elevated

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HUTSONVILLE

GROUNDWATER MODEL EVALUATION

scenarios

The

hydrologic

data

required by

and entered into HELP

are

listed in Table

and

described in the

following paragraphs

Help

Model

Set-up

Four

closure scenarios

were

modeled

Cap

assumes

the

impoundments

were

allowed to dewater and the ash

uncapped

with

poor

vegetative

cover

This scenario

assumes

that

measures are

taken

facilitate surface

water

runoff

Native Soil

Cap

one-layer

cap

comprised

of three feet of

native soils with

fair

grass

cover

Compacted Clay

Cap

three-layer

cap

comprised from

top

bottom

of three feet of

native soil with fair

grass cover

three feet of

low-permeability compacted clay

and

one

foot

gravel

subbase

Synthetic

Cap two-layer cap comprised

from

top

bottom

one

foot of native soil

with fair

grass cover

and

30-mil HDPE

synthetic

barrier material

Each closure scenario

was

simulated

for

two

impoundment

cases

One

impoundment

case

represented

the southern

portion

of the unlined

impoundment

that

currently ponded

and the

other

represented

the northern

portion

of the unlined

impoundment

that is

dry

For

all

scenarios

the

ash

was

assumed

uncapped

with

runoff

during

the

first

year

2001

while the

impoundment

dewatered and the closure alternative

was enacted

Scenario-specific changes

were

simulated

beginning

the second

year 2002

and

through

the

end of the simulation

2010

10-year

simulation

2001 through 2010

was

sufficient

for the

system

reach

equilibrium

after

enactment

of the closure scenario

Input

Data

Climatic

input

variables were

synthetically generated by

the model

using

modified default values

for

Evansville Indiana

and

latitude of 39.13

for the Hutsonville Power Station Rainfall

frequency

and

temperature

patterns

for

than 100 cities

are

programmed

into HELP

Evansville was selected as the closest

city

to Hutsonville

The model used Evansvilles

precipitation

and

temperature

patterns

with

average

monthly precipitation

data recorded

the

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HUTSONVILLE

GROUND WA TER MODEL EVALUATiON

two

closest

monitoring

stations

with

long-term

records3

generate

daily precipitation

and

temperature

data

Physical input

data were based on the

configuration

of the

impoundment

and

combination of

measured

and assumed soil

properties

The ash

was

subdivided

into three 60-inch

thick

sublayers

This

subdivision resulted in

rapid percolation responses

to surface

changes

such

dewatering

than

two

90-inch

layers

yet

provided

the

same

results

six

30-inch

thick

layers

The 15-foot combined

thickness of the ash

layers represented

the estimated thickness

of ash

above the water table after

dewatering

Hydrogeologic

properties

for the ash and

cap

soils

were

selected from the HELP database For

simulation of the

ponded portion

of the

impoundment

initial moisture

content

of the

uncapped

ash was set

equal

to its

porosity

expected

under saturated conditions

Dewatering

of the

saturated ash

was

then modeled for

one

year

Then the four closure scenarios

were

simulated

with initial moisture

content

of the ash

layers equal

the moisture

content

calculated

HELP

the end of the first

dewatering

year

Initial moisture

content

the

cap

materials used in the

closure scenarios

was set

equal

their field

capacity

Initial moisture

conditions for the

dry

part

of the

impoundment

were

simulated

similarly

the

ponded impoundment

except

that values for

the first

year

were set

the model based

average

climatic

conditions

The HELP

modeling

assumed that sluicewater

discharge

to the

impoundment for

the wet

impoundment scenario

ceased

immediately

before

the simulation

began

the

cap

was

instantaneously

placed

at the end of the first

year

the

cap

materials and ash had uniform texture

and

hydraulic properties

there

was no

lateral

groundwater

flow into

out of the

impoundment

and all

leakage

groundwater

was

vertical Other

assumptions

inherent

the model are listed

in Schroeder et al

1994

Precipitation

recorded at the Hutsonville

power

station and

average temperature

data recorded

Palestine

Illinois

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HUTSONVILLE

GROUND WA TER MODEL EVALUATION

Help

Model

Execution

Two

types

of HELP simulations

were

performed

sensitivity

analysis

and

prediction

analysis

The

sensitivity

analysis

was

performed

identify

critical factors

affecting performance

of the

proposed

closure scenarios

The

prediŁtion analysis

was

conducted

estimate

percolation

rates

for each closure

scenario

which

were later

input

the

groundwater

flow

model

Help

Model Results

Sensitivity analysis

results

are

presented

in Table

The model

was

sensitive to

vegetation

assumptions

which

affect

calculation

evapotranspiration

and

runoff

and the

hydraulic

properties

of the

cap

materials

The most sensitive

parameters

were ash

permeability

the

vegetation

assumption

used in the runoff

calculation

and

placement quality

of the

synthetic

cap

material

which

changed

total

predicted

flux

to -42

percent

-36

percent

and 104

percent

respectively

The

large change

for

placement quality

occurred when

defect

density

for

poor

placement

was assumed

All

other

parameters

changed

flux

less than 20

percent

The

model was not

sensitive

within

tested

ranges

to the thickness and

presence

gravel

subbase

and to soil runoff

parameters

other than

vegetation

This

analysis

indicates

that the model is sensitive to selected

input parameters

The

parameters

used for the

prediction

runs

represent conservatively

reasonable estimates

and

assumptions

current and future conditions at the unlined ash

impoundment

Prediction

analysis

Model results for the

wet

portion

of the

impoundment

show

percent

decrease in

monthly

percolation

flux

the end of the first

year

due to

impoundment

dewatering Figure 2a

Differences

between

the closure

scenarios

were

negligible compared

to the decrease in flux due

dewatering Figure 2b however

the scenarios with

clay

synthetic

cap

performed slightly

better than the scenarios with no

cap

native soil

cap Figure 2c

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HUTSONVILLE

GROUNDWATER MODEL EVALUATiON

Model results for the

dry portion

of the

impoundment

show

initial decrease

Figure 3a

which

expected

since these scenarios did not

assume

saturated ash

surface

ponding

Annual

leachate

percolation

flux after the first

year

is similar to that

predicted

for the wet

portion

of the

impoundment

Figures

The

significance

of the

predicted

differences in leachate

percolation

flux

groundwater quality

near the Hutsonville unlined ash

impoundment

was tested

by inputting

these values into

groundwater

flow and

transport

model

which is described below

Groundwater Flow/Contaminant

Transport

Modeling

Flow and

Transport

Model

Descriptions

MODFLOW

uses

finite difference

approximation

to solve

three-dimensional

head

distribution in

transient

multi-layer heterogeneous anisotropic variable-gradient

variable-

thickness

confined

or unconfined flow

systemgiven

user-supplied inputs

hydraulic

conductivity

aquifer/layer

thickness

recharge

wells

and

boundary

conditions

The

program

also calculates water balance at

wells

rivers

and drains

MODFLOW was

developed by

the United States

Geological

Survey

McDonald

and

Harbaugh

1988

has been

extensively

tested for

accuracy

van

der

Heijde

and

Elnawawy 1993

and is the

most

widely

used code for

groundwater

model

applications Rumbaugh

and

Ruskauff 1993

Major assumptions

of the

code are

groundwater

flow is

governed by

Darcys

law

the

formation behaves as

continuous

porous

medium

flow is not affected

chemical

temperature

density gradients

and

hydraulic properties

are

constant

within

grid

cell

Other

assumptions

concerning

the

finite difference

equation

can be

found in McDonald and

Harbaugh

1988

MT3DMS

Zheng

and

Wang 1998

is the latest version of MT3D

It calculates concentration

distribution for

single

dissolved

solute as

function of time and

space

Concentration

distributed

over

three-dimensional

non-uniform

transient flow field Solute

mass

may

input

at discrete

points

wells

drains

river

nodes

constant head

cells

areally

distributed

evenly

unevenly

over the land surface

recharge

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HUTSONVILLE

GROUND WA TER MODEL EVALUATION

MT3DMS accounts

for

advection

dispersion

diffusion

first-order

decay

and

sorption Sorption

can

calculated

using

linear Freundlich or

Langmuir

isotherms First-order

decay

terms

may

be differentiated for the

adsorbed

and

dissolved

phases

The

program

uses

finite difference

solution

third-order

total-variation-diminishing

TVD

solution or one

of three Method of Characteristics

MOC

solutions

The finite difference

solution can be

prone

to numerical

dispersion

for

low-dispersivity

transport

scenarios

and the

MOC solutions sometimes fail to

conserve

mass

The TVD solution is not

subject

to numerical

dispersion

and

conserves

mass well

but is

computationally

intensive

For this

modeling

the TVD

solution was

attempted first however

results outside the

area

interest

were

anomalous

e.g

in the

thousands and

negative

thousands

Therefore

the finite

difference solution

was used

resulting

in similar concentrations

the TVD solution within the

area

of interest and concentrations

near zero

outside the

area

of interest

Zheng

and

Wang 1998

indicated that the effects

of numerical

dispersion

are

minimal when

grid

Peclet4

numbers are

smaller than 4.0

Since

Peclet number of 3.3

was maintained for this

analysis5

the finite

difference solution is

acceptable

MT3D has been tested and

verified

and is

widely

used

van

der

Heijde

and

Elnawawy

1993

Major assumptions are

changes

in the concentration

field do

not

affect

the flow

field

changes

in the concentration

one

solute do not affect the concentration

of another

solute

chemical and

hydraulic properties

are constant within

grid cell

and

sorption

instantaneous and

fully reversible

and

decay

is not reversible

Flow and

Transport Conceptual

Model

Hydrostratigraphy

developed

from

boring logs

collected

during plant

construction

1954

original monitoring

well installation

1984

and the

hydrogeologic

assessment

1999

indicate

that the

upland

area near the

impoundment

consists of sand and

gravel

varying thickness

Peclet number

Grid

spacing

divided

by longitudinal dispersivity

5Pe

100303.3

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HUTSONVILLE

GROUND WA TER MODEL EVALUATION

typically

feet

underlain

to more

than 30 feet of sandstone

The

upper

sand

appears

grade

fine-grained

silty clay

toward the northern

portion

of the

plant

site

thick

shale unit

underlies the sandstone

at an

approximate

elevation

of about 415 to 420 feet

The

Wabash River

valley

contains

relatively fine-grained

alluvium

from land surface to an elevation

of about 410 to 415

feet

underlain

sand and

gravel

elevation of about 350 feet

The

primary

direction of

groundwater

flow is

east discharging

into the Wabash River and its

tributariesa

regional groundwater

sink

There

are

three

sources

water natural

recharge

within the model

domain

percolation

water from the

impoundment

and

groundwater

flow from

the west

Flow and

Transport

Model

Set-up

Modeling

was

conducted in

multiple steps

First

the flow model

was

calibrated

to current

conditions

e.g

active

use

of the

impoundment

represented

heads measured

November 1998 This

measurement

event was

selected because all

new wells installed for the

hydrogeologic

assessment

were

measured

at that

time

and because river elevation and

groundwater

elevation

head

values

older wells

were near

long-term

median

values Next the

transport

model

was

run

and model

predicted

concentrations

were

calibrated

observed boron

concentration

values

These calibration

runs were

conducted

assuming steady

state flow

Multiple

iterations

of flow and

transport

model calibration

were

conducted

to achieve

acceptable

match to observed data

Sensitivity analyses

were

then conducted to test the effect of

selected

parameters

model results

Once the model

was

calibrated

and tested for

sensitivity prediction

modeling

was

performed

Monthly

leachate

percolation

rates

predicted by

HELP

were

used

simulate

dewatering

during

the

first

year

then annual

percolation

rates were

used

simulate

the effects of the four closure

scenarios for 19

yearstotal

simulation time

was

years

The MODFLOW model allowed

use

of both HELP

cases

ponded

and not

ponded

at the

same

time

Decreasing percolation

rates

were simulated

using

time-dependent

specified

flux

recharge

boundary

Leachate

concentrations

percolation recharge

water

were

held constant

in this

analysis

Four

prediction

scenarios

were

modeled

one

for each closure scenario

modeled with HELP

MODEL REPORT

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Resource

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HUTSONVILLE

GROUND

WA TER MODEL EVALUATION

Grid and

Boundaries

four

layer

60 node

grid

was established

with variable

grid spacing ranging

from 100 feet

to 500 feet in

length parallel

to the

primary

flow

direction and 100 feet to 500 feet

perpendicular

the

primary

flow

direction

Figure

The

largest

node

spacings

were near

the

upgradient

and

lateral model

boundaries

and the finest node

spacings

were

along

the

river and

near

the

impoundment

Flow and

transport

boundaries

Figure

Appendix

were

the

same

for all scenarios

The

upgradient

edge

of the model was

constant head

Dirichiet boundary

The lower and lateral

boundaries

were

no-flow

Neumann

boundaries

The

downgradient

boundaries

were

either

MODFLOW river

Mixed

boundaries

layers 2-4

or no

flow

layer

The

upper

boundary

was

time-dependent specified

flux

Neumann boundary

with

specified

flux rates

equal

to the

recharge

rate or

the

rate

percolation

from the

impoundment

Two

types

transport

boundaries

were

used

Specified

mass

flux

Cauchy condition

boundaries

were

used

to simulate downward

percolation

of solute

mass

areas

where the

source

was

above the

water table

and

constant

concentration

Dirichlet condition

boundaries were used

areas

where the

source

i.e

coal

ash

was

below the water table

The former

boundary

condition

assigns

specified

concentration

recharge

water

entering

the

cell

and in

this

application

the

resulting

concentration

in the cell is

function of the relative

rate and

concentration

of water

percolating

from the ash

compared

to the rate and concentration

groundwater

flow The latter

boundary type assigns

the

specified

concentration

to all water

passing

through

the cell

Flow Model

Input

Values and

Sensitivity

Flow model

input

values

are

listed in Table

and described below

Aquifer Top/Bottom

Groundwater in the

upper

sand

aquifer

unconfined

therefore the

top

the

aquifer

was the water table and the elevation of the

top

model

layer was

set at 460

feet

value

higher

than the water table

elevation

of 427 to 450 feet The

top

layers

2-4

was

the base

of the

overlying layer

MODEL REPORT

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Resource

Technology

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

HUTSONVILLE

GROUNDWATER MODEL EVALUATION

The base of the

upper

sand unit was determined

contouring

bedrock elevation and

importing

the contour data into MODFLOW The

corresponding

base elevations for

layer

were

between

424 and 450

feet

The base of the second

layer corresponded

to the base of the

sandstone

418 feet The base of the third

layer corresponded

to the

top

of the

valley

fill sand

unit

412 feet

The base of the bottom

layer 350 feet corresponded

to the base of the unlithified fill in the

Wabash

River

valley

Layer

one

of the model included

zone

with

hydraulic conductivity

representing

coal

ash

This

zone was

also used

source

area representing

saturated

ash

during prediction modeling

The

base elevation of this

zone was

based

contouring

as was

the rest of model

layer

Base

elevations

were contoured

from 424

444 feet

Hydraulic Conductivity

Hydraulic

conductivity

values

Appendix

were initially

derived

from field measured

values

then

adjusted during

calibration

The

largest

variation from initial

field values

was

for the

alluvium

where the modeled value of 30 ftld

compared

single

field

measured value of 0.7 ftld at

MW-7

was

necessary

for flow

calibration

and

across

the northern

portion

layer

where

value

0.1 ft/d

compared

to values of

ftld at MW-9 and

MW-

resulted in best head match

Vertical

anisotropy

ratios were set at

2.0

everywhere

except

the

alluvium

where

ratio of 10

was

the lowest

possible

without

affecting

calibration

The

larger

Kx/Kz ratio

represented expected

stratification within the alluvium

The shale bedrock

underlying

the sandstone

was not

discretely

modeled

Rather

cells

representing

shale

all in

layers

and

were

set

with

no-flow

boundary

conditions

This

setting

inherently

assumed that

groundwater

flow in the shale

was

negligible

Model

sensitivity

hydraulic conductivity ranged

from

negligible

high

The model

was

most

sensitive to the

layer

sand unit and the

layer

sandstone

and

was

generally

not

sensitive

vertical

hydraulic conductivity

Storage

No field data

were

available

defining

these

terms so

representative

values for similar

materials

were

obtained from Smith and Wheatcraft

1993

The

storage

term had no

effect

MODEL REPORT

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Resource

Technology

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HUTSONVJLLE

GROUNDWATER

MODEL EVALUATION

model calibration because it

was

calibrated at

steady state

however it did

slightly

effect the rate

at which

groundwater

elevation

decreased

percolation

rates

decreased

representing

dewatering

of the

pond

This effect

groundwater

elevation had

corresponding

slight

effect

predicted

concentrations

the

impoundment dewatered

but

effect

long

term

concentrations

Therefore

the model is insensitive to this

parameter

Rechare

Recharge

rates for the unlined

impoundment

i.e

percolation

were

based

HELP

results For

simplicity

HELP results

were

averaged

for

periods

where there

was

little

change

predicted percolation

rate

Figure

Recharge

rates for the rest of the model domain

were

set

during

calibration

Recharge

zones are

illustrated in

Appendix

River Parameters

The Wabash River and tributaries

were

represented by head-dependent

flux

nodes that

required inputs

for

river

stage

width

bed

thickness

and

bed

hydraulic conductivity

The latter three

parameters

are

used to calculate

conductance term for the

boundary

node This

conductance term

was

determined

adjusting hydraulic conductivity during

model

calibration

while

bed thickness

was

set at

i.e

bed

hydraulic conductivity represented

conductance

normalized for river width and bed

thickness

River

stage

for the Wabash River

was set near

mean

stage

the

approximate

elevation in November

1998

and

adjusted

slightly during

calibration

River

stage

for the tributaries

was

determined from USGS

topographic

maps

Sensitivity analysis

showed that the model

was

highly

sensitive

the

presence

of the rivers and

tributaries

but not

very

sensitive

to the conductance term used

Transport

Model

lnput

Values and

Sensitivity

Transport

model

input

values are listed in Table

and described below

Initial Concentration

Initial concentration

for the calibration

run was

set at

zero

Initial

concentration

for the

prediction

runs was the final calibration concentration

Source Concentration

Two

primary

sources were

simulated

For calibration

runs

which

simulated

current

conditions

the

primary

source was

percolating

water

from the

unlined

impoundment

After the

impoundment

dewaters

the dominant

source

expected

to be

leaching

of ash in the unlined

impoundment

that remains below the water table

Therefore

second

MODEL REPORT

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Resource

Technology

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HUTSONVILLE

GROUND WA TER MODEL EVALUATION

primary

source

term representing

the saturated

ash was

added for

prediction scenarios

beginning

two

years

after the

impoundment

is removed from service

This

assumes

that

mass

that time will be

primarily

from

leaching

of ash below the

water

table

rather than

percolation

from the

impoundments

Mass

for the saturated ash

source term was

function of

groundwater

velocity

the cells

representing

saturated

ash and the saturated

thickness of those cells

Concentrations

at several wells were sensitive

to the concentration

of the

percolation

source

term

Only

well MW-8 was sensitive to the concentration

of the saturated ash

source term

and

resulting

concentrations

at this well varied

greatly

with

changes

in saturated

source

concentration

Concentrations

MW-7

were not

significantly

influenced

the saturated ash

source term

during

the

period

simulated

Secondary

sources were the lined

impoundment

and

the coal

pile

Concentrations

for these two

sources were

set at 20 and

mg/L respectively

based

concentrations

in leachate

samples

obtained

during

the

hydrogeologic

investigation

Effective Porosity

Effective

porosity

values

were

based

ranges provided by

Mercer

and

Waddel

1993

Predicted concentrations

were

not sensitive

to this

term

was not

adjusted

during

calibration

Dispersivizy

One well

MW-3

was

highly

sensitive

dispersivity values

and the value of 30 ft

was selected

during

calibration based on

predicted

concentration

at that well

Transverse and

vertical

dispersion

were

estimated

according

to ratios

developed by

Geihar

et al

1985

Retardation Retardation is calculated

the model based

the distribution coefficient

The Kd value used for the

sandy

materials in this model

0.17 mLIg

was based on

testing

performed by

NRT for similar materials in another state The Kd value for the silt materials

0.85 mL/g

was assumed

factor

five

higher

than

for sand

While concentrations

at several

wells varied with

no concentrations

varied

more than 10

percent

this number

was

not

adjusted during

calibration

MODEL REPORT

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Resource

Technology

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HUTSONVILLE

GROUNDWATER MODEL EVALUATION

Flow and

Transport

Model

Assumptions

and Limitations

Several

simplifying assumptions

were made while

developing

this model

The

impoundment

dewaters for

one

year

For closure scenarios with

caps

the

cap

placed

the

impoundment

at the end of the

first

year

Leachate

is assumed to

instantaneously

reach

groundwater e.g migrate through

the

unsaturated

zone

River

stage

and natural

recharge

are

assumed constant over

time

Leachate

concentrations

are assumed to remain constant over time

The model is limited

the data used for

calibration

which

adequately

define the

local

groundwater

flow

system

and the

sources

and extent of the

plume

These data

are

from

points

near the Hutsonville ash

impoundments

Groundwater

flow data

were

representative

of data

collected

during

the

980s and

1990s

while concentration

data

are

mostly representative

of data

collected

during

the

late

990s

Therefore

model

predictions

transport

distant from the

impoundment

will

not

reliable

predictions

transport

near

the

impoundment

and the

reliability

of model

predictions

decreases with

increasing

time

Flow and

Transport

Model Results

Calibration

The model was first calibrated to observed

groundwater

head data collected in November

1998

and then

observed concentration

data

mostly

collected from

November 1998

through May

1998

exception

the concentration

date

range

was

made for

wells

MW-2 and

MW-3

Boron concentrations

at these wells were affected

by leaking pipe

that

was

not simulated in the

model because the volume of the

pipe

leak

was unknown

the leak

was

temporary

i.e transient

and the calibration was

performed

for

steady

state conditions

Therefore

these wells were

calibrated to the concentration

range

recorded

prior

to the

pipe

leak

Head calibration results

were

generally good

with modeled heads

generally

within 1-foot

target

heads

Figure

6a and

Figure 7a particularly

between

and

downgradient

of the

impoundments

The

areas

largest discrepancy

were near

MW-6

MW-9

and MW-I

The

MODEL REPORT

Natural

Resource

Technology

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

HUTSONVILLE

GROUNDWATER MODEL EVALUATiON

discrepancy

at MW-9 is

acceptable given

its distance from the

impoundments

and

the

sparse

geologic

data in that

area

The

discrepancies

at MW-6 and MW-i

are

likely

due to the close

proximity

of these wells

the unlined

impoundment

where heads

change

rapidly

over

short

distance

Given this

observation

and

considering

that concentration

match

for

these

two wells

was

acceptable

the head

discrepancy

is also considered

acceptable

Concentration

calibration was within the

range

of observed concentrations

at most

monitoring

wells

Figure

6b and

Figure 7b

The model calculated

elevated boron concentrations

at wells

with observed boron concentrations

greater

than Class

standards

and

generally

did

not show

elevated boron concentrations

for wells with low boron concentrations

The

two notable

exceptions

for wells MW-7D and MW-

12 were

both

cases

where the model calculated

higher

concentrations

than observed

The low observed concentration

at MW-7D could not be

replicated

without

using

unrealistically

low

hydraulic conductivities

and would have

probably

required

several additional model

layers

to simulate The

high

concentration

at MW- 12 is

likely

due to model discretization Concentration

match

may

have

improved

with

finer

grid spacing

however

this result

was conservatively

high

and such

grid spacing

was

considered

unwarranted

Slightly

low concentrations

were

predicted

for MW-6 and MW- 13

The

concentration

discrepancy

at MW-6

was

likely

due to model

discretization

similar

MW-i2

The

discrepancy

MW-13

where observed boron concentration

higher

than

any

other

monitoring

well on

site

likely

related to the

pipe

leak that was not simulated

Prediction

Modeling

was

performed

predict

effects

impoundment

dewatering

and closure

groundwater quality

Closure effects

were

simulated

by decreasing

the

MODFLOW

recharge

rate in the area beneath the unlined

impoundment

and ash

laydown

area The

recharge

rate for

the wet and

dry portions

of the unlined

impoundment

was

decreased

illustrated in

Figures

and

addition

was assumed

that the

ash

laydown

area would be treated

similarly

to the

dry

portion

of the unlined

impoundment.6

Directory

Active site

calibration

Hut5

No-cap

scenario

Hut5a

Native soil scenario

I-Iut5b

Clay

cap

scenario

Hut5f

Synthetic

cap

scenario

Hut5e

Steady

state

sensitivity

analyses

Hut5tnn

where nnOl 02

Transient

sensitivity

analyses

Hut5aSn

where

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Exhibit 6. Statewide aquifer maps showing no major bedrock aquifers within 300 feet of ground surface at Hutsonville and total

dissolved solids concentration greater than 10,000 mg/L in aquifers deeper than 500 feet below ground surface.

CH2\2470678.1

Hutsonville

Power

Station

Hutsonville

Power

Station

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Exhibit 7 – Potable Well Search Results

Map and related well records from: http://meltwater.isgs.uiuc.edu/website/ilwater/viewer.htm

On June 16, 2005, NRT conducted a search for potable well records within a ½ -mile radius of

Pond D using the Illinois State Geological Survey’s (ISGS) online interactive map of well

records at the website above. Hutsonville Power Station Plant wells #1 and #2 are numbered 90

and 88 on the map above. Wells 60, 61, and 64 are owned by Margaret Dement and are used for

irrigation (64 does not appear to be correctly located on the map). Well number 66 is also used

for irrigation and is owned by Duane Wampler. Well 73, a City of Hutsonville water supply

well, is approximately one mile south of Pond D.

The following landowners were identified within approximately ½ mile of Pond D: J.P, Allison

(three residences), J.Grimes, Slaughter, M. Kelly, M. Dement. Records for potable wells

servicing these landowners could not be located through the ISGS. Representatives from the

Hutsonville Power Station field inspected these residences; no well heads were observed at the

three residences to the south (Slaughter, Kelly, Dement). There are wells servicing the

residences to the west (Allison, Grimes). These wells are upgradient of both the plant and

upgradient monitoring wells MW-10 and 10D.

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Exhibit

Mixing

Calculation

Showing

Effectof

Boron

Wabash

River

Quality

Low

Flow

7-day

10-year

low

flow

Hutsonville

Station

1234

3.OE09

L/day

Boron

ratewhile

Pond

was

service

lb/day

1.1E07

mg/day

Boron

rate

after

Pond

dewatered

and

capped

lb/day

2.3E06

mg/day

Boron

concentration

increase

Wabash

River

low

flow

due

from

Pond

When

Pond

Dwas

servioe

0.0038

mg/L

After

Pond

dewatered

and

oapped

0.0008

mg/L

Median

boron

oonoentration

Wabash

River

City

Hutsonville

0.0550

mg/L

Typioal

boron

laboratory

deteotion

limit

0.0038

mg/L

Conclusion

The

oaloulated

boron

oonoentrationinorease

the

Wabash

River

low

flow

due

groundwater

while

Pond

was

servioe

was

order

inoreasefrom

loadingpredioted

ooour

after

dewatering

and

oapping

Pond

well

below

thedeteotion

limits

boron

analytioal

methods

These

oaloul

Wabash

River

Pond

Dare

negligible

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Source

ISWSCR

441

1988

Source

Exhibit

Fig

Source

Exhibit

Fig

L1/Q710

L2/Q710

Source

Exhibit

Source

USEPA

SW-846

Method6010c

---

nitudelower

than

median

observed

concentrations

The

calculatedconcentration

tions

indicate

that

the

effectsof

boron

groundwater

discharge

the

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Natural

MEMORANDUM

Resource

Technology

Inc

Michael

Bollinger

Ameren Services

FROM

Bruce Hensel

DATE

August 19

1999

STORET

Data

Wabash River

near

Hutsonville

Wabash

River water

quality

data from the

STORET

database

were not

included

the

hydrogeologic

assessment

for the Hutsonville ash

impoundments

because the closest downstream

station with relevant

parameters

is in

Hutsonville

about two river miles

downstream

and

because there

are no

upstream

data with relevant data for

comparison

However

thought you

might

be interested in these data as an overview of

general

water

quality

in the Wabash

River

therefore

they

are

summarized in this

separate

memorandum

The STORET data contained records from Station

3341920

Wabash River

at Hutsonville

for

boron

manganese

iron

and nickel

Only

one other

nearby

station contained boron

data

and

records for that

station

which was

just

downriver of the station

used

had no

records after 1980

There

was

also

one station

that

based

latitude

may

have been

the

plant however boron

iron

manganese

and nickel

were

not monitored at that station

although

sulfate

was

Two

agencies reported duplicate samples

to the database for the station that

used so

queried

it to

only report

records for the

agency

with the most records The results

are

provided

in Table

The results in Table

show

that maximum Wabash River

concentrations

the

City

Hutsonville

are

similar

the 95th

percentile

concentrations

background groundwater quality

presented

in Table

of the

hydrogeologic

assessment

and median concentrations

are lower than

or similar to the medians

displayed

Figures

10 13 14

and 15 of the

hydrogeologic

assessment

also included

plot

of boron concentration

in the Wabash River at Hutsonville

versus time

and

the

resulting graph

appears

indicate annual

peaks occurring

the end of almost

every year

Whether these

peaks

are due to river

stage

or some other cause are unknown

Overall

Wabash

River water

quality

appears

good

this

station

relative

background

groundwater

concentrations

observed

at the

plant

however

it is difficult to determine

possible

plant

impacts

Wabash River water

quality

because there

are no

upstream

data for

comparison

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Table

Wabash River Water

Quality

Statistics from STORET Database

Statistics

Sulfate

Boron

Iron

Manganese

Nickel

Count

113

118

117

Max

mg/L

0.204

0.100

0.049

0.025

Median

mg/L

0.055

0.050

0.015

Average

mg/L

0.071

0.051

0.012

0.013

mg/L

0.005

0.010

0.005

STORET Station Information

AGENCY

STATION

LAT

LONG

LOCATION NAME

21 ILAMB

3341920

390637

873918

WABASH RIVER AT HUTSONVILLE IL

Period of Record

Station

10/8/69

throuqh

12/15/98

Data Distribution of Selected

Parameters based

iron

count

Years

Number of Records

Records/yr

1969-1979

1980

1981 -1985

1986-1989

1990-1998

Boron

250

200

-J

ISO

100

Jan-

Jan

Natural Resource

Technology

Inc

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Conceptual Developmettt

Of a Pozzoianic Cap

For the

Closure of

Basin D

at

the

HutsonviUe Power Stadion

VFL

Technology Corp.

16

Hagerty Boulevard

West Chester, Pennsylvania

19382

(610) 918-1100

PHONE

(610)

918-7222

FAX

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

~~6ral

Resource ~eibqology

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Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

TABLE OF CONTENTS

BACKGROUND

OVERALL PROGRAM CONCLUSIONS

TREATABILITY STUDY

4.1

RAW MATERIALS CHARACTERIZAION

4.2

REAGENTS

MIX DESIGN PREPARATION

4.4

MIX DESIGN PERFORMANCE TESTING

EXRAPOLATION TO FULL-SCALE OPERATIONS

APPENDIX

VFL

Technology Corporahohon

March 26,2003

Hutsonville Power Station

C-170342 

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Final Re~ort

Conceptual Development of

a Pozzolanic Cap

for the

Closure

of Basin D at the Hutsonville Power Station

1.0 Background

Basin D at the Hutsonville Power Station is an inactive ash disposal area that needs a

cap for final closure (Photo

1). Natural Resources Technology

(NRT),

Pewaukee,

Wisconsin, contracted the services of

VFL

Technology Corp.

(VFL)

to determine the

feasibility of developing a concept for the creation, manufacture, and placement of a

pozzolanic cap for Basin

D at the Hutsonville Station.

The purpose of this report is to present a

final 

summary

of the information, findings

and test results that have

been generated for the conceptual development of the

pozzolanic cap for the closure of Basin

D at the Hutsonville Power Station in

Hutsonville Lllinois.

The Program Goals of this study were to:

a

Attempt to develop a pozzolanic cap material that would achieve a

permeability of 1 x 1 ~'~crn/sec,

and have an unconfined compressive strength

of approximately

1 50 psi.

If the 1

1 ~-~cm/sec

goal is unrealistic or unachievable with

these materials, estimate the most realistic performance

of these materials

under field conditions.

Produce a cost-effective pozzolanic cap material that

can be easily handled

and placed

with common earth moving equipment.

Attempt to

minimize the amount of regarding needed to prepare Basin D for

the cap, while maximize the

use of Basin A

fly

ash as a stable fill material

and

as a construction material for the development of the pozzolanic cap.

To accomplish these goals,

VFL and

NRT

developed a scope of work for the project.

VFL

employed the help of GeoSystems Consultants Ind. to assist with the

geotechnical

engineering portion of the program. The scope of work basically

included:

A field assessment of the site

(VFL

and GeoSystems);

VFL

Technology Corporation

Hutsodle Power Station

C-1703-02

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

PHOTO

Hutsonville Power Station Basins A and D

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

A review of existing geotechnical data of the site to detennine if additional

information is needed to finalize the cap design and construction

(GeoSystems).

Collect samples of the Basin materials

(VFL). 

Conduct a treatability study to determine if a powlanic cap can be developed

to meet the current design guidelines for closure cap construction and develop

an operational approach to construct the cap (VFL).

Conceptual development of the basic cap design, appearance and estimated

volumes of material to be used

in the cap construction (GeoSystems).

March 5 and 6,2002, representatives of VFL Technology Corp. and GeoSystems

Consultants Ind. visited the HutsonviIle site. Samples

fiom the two basins were

collected, and existing geotechnical

data 

was reviewed. The Hutsonville ash samples

were tested at VFLYs Corporate lab

in West Chester Pa. using a variety of locally

available stabilization reagents.

2.0 Overall Program Conclusions

The preliminary geotechnical evaluation indicates that the construction of a

pozzolanic cap is definitely feasible; however, some additional, more refined

analyses

are needed to finalize the engineering and design of the cap system.

The results of the Treatability Study program show that it is feasible to

construct a structurally stable, environmentally acceptable Pozzolanic Cap

and

use this cap in the final closure of Basin D at the Huntsville Power Station.

Althou

1 x 10-

P

cm/sec,

the permeability

the results of

results

several

mixes

not meet

are

the

in the

original

mid to

goal

low

10-'cm/sec

range.

By using Basin

A ash

asa

construction material for the pozzolanic cap,

ap~oxirnately 160,000 yds3 of ash can be utilized, which significantly

extends the life

of Basin A.

All of the mixes that were considered potential candidates for cap

construction easily met the unconfined compressive

strength goal of 150 psi.

3.0 Geotecbnical Investigation

As indicated above, the geotechnical data review, conceptual design, material

volume estimates, preliminary settlement and slope stability analyses were conducted

by GeoSystems. The report of their findings and analyses

has been included in

Appendix 1 of this report.

VFL Technology Corporation

March 26,2003

Hutsonville power station

C-1703-02

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

In summary, GeoSystems believes the construction of a pozzolanic cap is feasible

and will be

an effective system; however, some additional information is needed to

complete the

final 

engineering and design of the cap system.

overview of the conclusions of the GeoSystems report indicate:

. . . .

A parametric analysis varying cap permeability from1 x 1 ~-~cm/sec

10-~cm/sec

yielded "effectiveness" ranging

hm

78% to 97%.

. . . . . ..

.....

As the slope of the

final

cover increases fiom 1% to 5%, the volume of

regarding reduces fiom

1 10,000~ds~

to 75,000 yds3

. . . . . .

; . ...

With a 5% slope, the volume of ash fill material needed from

Basin 

A is

estimated to be 160,000 yds3

. . . . . . . . . . . .

. . ...

The volume of the pozzolanic cap (3 feet thick) is estimated to be 100,000

yds3 and varies little as the slope varies hm 1% to 5%.

. . . . . . . . ..

A graphical presentation of a conceptual, representative cross section of

Basin 

showing the cap design, regarding requirements, needed fly ash fill material fiom

Basin

A, etc.

was

developed by GeoSystems (part of GeoSystems report

see

Appendix 1) and has

been included here as Figure 1 for reference purposes.

4.0

Treatability Study

A few 'Terformance Goals" were established for the

final

pozzolanic cap material.

The intent was to see if the stabilized materials could meet the existing cap design

specifications,

and if

not, 

determine how well they performed against these existing

specifications. The "Performance Goals" for this project

were

to:

Develop a permeability of 1

l~-~cm/sec,

or determine how close the

stabilized materials can realistically come to these specifications.

Develop approximately

1 50 psi unconfined compressive strength.

Attempt to develop a cost-effective

mix

design that can be easily implemented

an constructed in the field.

Develop a cap system that

was

environmentally acceptable (minimizes

leaching).

VFL's treatability study can be broken down into four basic areas: Raw Materials

Characterization; Reagents;

Mix

Design Development

and Mix 

Design Performance

Testing. Each of these areas is discussed fUrther in the following sections of this

report.

WL Technology Coporation

March 26,2003

Hutsonville Power Station

C-1703-02

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

FLY ASH TO BE RELOCATED

TOPSOIL COVER

GRANULAR DRAINAGE LAYER

FLY ASH NEEDED FOR GRADING

//I-''/

POZZOUNIC CAP

REVISED

12-2642

REPRESENTATIVE CROSS SECTION

POND D

HUTSONVILLE POWER STATION

HUTSONVILL~,

ILLINOIS

GeoSystems

Consultants,

Inc.

FIGURE

APRIL 2002

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

4.1

Raw Materials Characterization

During the site visit, VFL collected six (6) samples of ponded ash from

different locations

Basin 

A, and two (2) samples of ash from different

locations in Basin

D. The six samples fiom Basin A and two samples from

Basin

D were individually tested for moisture content, pH, density and Loss

on Ignition

(LOI).

The

natural 

solids content of the ash excavated fkom Basin A ranged from

71 -4%

74.2%

solids

(40.0%

34.8%

moisture

dwb). The pH values for

Basin A ranged fkom 8.4 to 1

1 .O,

while the LOI's for Basin A ranged from

2.1% to 8.9%. All

ash

samples showed varying degrees of bleeding (draining

of fiee liquids from

the material).

As indicated previously, the intent is to use material fiom Basin

A to produce

the pozzolanic

cap for the closure of Basin D. In order to simulate fbll-scale

operations, the

"as

received" samples of ash fiom Basin A were allowed to

decantldrain. This was done to estimate the handling and solids content

characteristics of the

ash that will be used in the full-scale operations. The

data showed that

some of the ash samples decanteddrained nicely, while

others did not decantidrain

as

well. The decanted/ldrained solids content of

the Basin

A materials ranged fiom

73.9%

solids

(35.3%

23.5%

moisture

dwb), or a 1.4% to

8.8%

increase in solids content.

The

two samples of ash collected fiom Basin D showed a solids content range

of 72.9% to 82.6% solids (37.2% to 2 1.1

moisture

dwb). The sample

that showed the

high solids content was

taken 

fiom a stockpile of material

that

was sitting on the Basin

(age

unknown). The pH's for the two samples

collected from

Basin D were 8.8 and 8.2 respectively. The results of the

physical analysis of

the ash samples can be found on Table 1 of this report.

WL Technolorn Cornoration

March 26. 2003

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

TABLE

Physical Characterization of the Hutsonville Ash

In addition to the physical characterization of the

ash

samples listed above, an

elemental analysis and TCLP Ieachate analysis for the 8 RCRA metals was

run

on a composite sample of the Hutsonville ash. The composite sample

was

generated by combining equal portions of ash samples

A- 1

through A-6.

The results of the chemical analyses are listed below in Table 2. The actual

data reports from Dalare Labs in Philadelphia, Pa. have been included in

Appendix

A-2.

VFL

Technology Corpwotion

March 26,2003

Hutsonville Power Station.

C-1703-02

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

TABLE 2

Elemental and TCLP Analysis of the HutsonviPle Ash

Arsenic

Barium

Cadmium

Chromium

Lead

Mercury

Selenium

Silver

Notes: Total

Total Elemeirtal Concentration in mghg

Leachable

TCLP Leachable Metah in mg/l

< =

Lm than

VFL

has used numerous

reagents 

in the development of pozzolanic

construction materials. VFL reviewed these various reagents and

based on

previous full-scale experience

with similar projects, selected what it believes

to be the best performing, commercially available

(in large quantities), and

most cost-effective reagents for this project, fiom sources in the vicinity of

the job site. These

reagents 

include:

Portland Cement,

Class

C Fly Ash (self-setting

type) 

Fluidized Bed Residue Ash

Quicklime

FGD Scrubber Sludge (used to make the particle size of the

mix

design

finer, which improves permeability)

Native Soils

(used to make the particle size of the mix design finer, which

improves permeability).

VFL experienced a few minor delays in the treatability study portion of the

project. These delays are directly attributed to the delays in receiving some

of the samples

of reagents from the various vendors. One of the most

Hutsonville

VFL Technolom

Power

Corporation

Station

March 26,2003

C-1703-02

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

problematic was the FGD Scrubber Sludge, which was finally received on

date

06/06/02.

4.3

Mix Design Preparation

In order to simulate full-scale conditions, VFL combined the six (6)

decanted/drained samples of ash hm Basin A into one (1) composite ash

sample that was used to prepare all of the mixes. The solids content of this

composite sample was approximately

79% solids (26.6% moisture

dwb).

All

mix designs were prepared in a laboratory mixer and mixed to the

consistency expected to

be achieved using full-scale processing equipment.

All

mix designs were damp, granular, soil-like materials that could be easily

handled and placed

with common earth moving equipment. A11 of the mixes

were prepared on the "wet side of

optirniun

moisture" to assure that there was

enough moisture

in the mix for reagent hydration and proper compaction.

This "wet side of optimum moisture" consistency also minimizes the

potential for dusting

during full-scale operations. See Table

2 for the mix

designs developed this project.

Solids contents,

as well as wet and dry compacted densities were recorded for

all mixes. These values

will

be used as operating specifications during full-

scale production and placement operations.

All mixes were compacted into standard size compaction molds, labeled,

and

stored in sealed plastic bags to' insure proper curing and prevent moisture loss

during their curing cycle.

4.4

Mix

Design Performance Testing

Immediately after mix preparation, all of the mixes were evaluated for

consistency, handlability, and constructability. As mentioned above, all of

the

mixes

had a damp, granular, soil-like consistency.

All

mixes could be

easily handled, transported and placed

with common earth moving

equipment.

All of the mixes could support heavy equipment t~dlic

immediately after placement and compaction. This

means that multiple lifts

of stabilized material could be sequentially placed on top of each other

throughout

the day during full-scale operations.

As proposed, all of the mixes were tested for unconfined compressive

strength (UCS) in accordance

with ASTM C

39.

All compressive strength

cylinders were tested in duplicate and capped prior to UCS testing. The mix

designs and UCS test results can be found in Table

of this re~ort.

WL

Technology Corporation

Hutsonville Power Station

C-1703-02

March

26.2003

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Overall, the mixes generally performed as expected, with the exception of the

quicklime mixes. All mixes showed good solids contents as well

as

wet and

dry compacted densities. Based on the

mix

densities, costs, UCS results, etc,

the best performing mixes were selected for the next phase of permeability

testing. These mixes were:

Mix 1

10% cement

Mix

5% cement

Mix

5% fluidized bed residue

Mix

6.3% cement

15% native soils

Mix1

30% FGD Filtercake

10% cement

Mix 16

30% FGD Filtercake

10% quicklime

Triaxial permeability tests were

run

on the above listed mixes after 28 and 84

days of curing. The results of these tests are listed in Table #3 of this report.

During the 84

day

permeability testing, a problem was discovered in the test

results.

All

of the test specimens showed higher (more permeable) values

than 

the 28 day results. In some cases, it

was

over an order of magnitude.

This 

data trend is extremely unusual for pozzolanic reaction mechanisms,

which are known to improve

with time. It was concluded that the entire set

of cylinders must have been damaged during

transport

and handling.

Companion cylinders were tested again after

curing 84 days and these

permeability values fell

in the expected range.

The only

mix

that did not show the normal permeability improvement

characteristics was

Mix

#16.

All of the indicator parameters for this Mix

looked promising (consistency, compaction characteristics, densities, strength

development, etc.), yet the permeability data

did not follow the usual trends.

At this

point, it should be remembered that the mixes prepared in this

program

are

considered to beexcellent indicator mixes to examine the

feasibility of the program and provide data to determine the basis for a frnal

mix design. Further refinement of the

mix design can be assessed to improve

performance, permeability, and cost-effectiveness of the pozzolanic cap

material

as

necessary.

After reviewing all of the permeability data listed in Table #3, it appears that

the realistic performance range for

these 

types of pozzolanic materials is the

low 1 oacm/sec to the mid+low 10=]cm/sec range for materials to

produced under full-scale field conditions. The.typical 1

10-~crn/sec liner

spec means that the material must be in the 10-~cm/sec range so as not to

exceed the1 x 10-~cmlsec spec under field conditions. These types of values

are extremely difficult to meet with most materials under field conditions.

VFL

Technology

Corporation

Mamh 26,2003

Hutsonville

Power Station

C-

1703-02

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

TABLE

TREATABILITY STUDY SUMMARY SHEET

Mik

Mix Design,%

. .

. ,: .

~uinbef!. <FI~$~s&

:fllt&&~t$~

&.3&1'.~&

a$&&&+ 

(B .

and).;

.~eagents~

10.0

81.1

12.5

86.9

80.5 12.3 113.4 91.2 22

138

Solids

100

~--

Note:

Reagent added on

a dry weight basis

soil-fly ash blend.

'UCS strength data is average of

cylinders.

'FGD sludge added on a wet weight basis to ash.

Stockpile time for all mixes was

30 minutes.

Soil added on a wet weight basis.

Reagents added on

a dry weight basis

Second set of mrmeability nsulfs for mixes 14 and 16 am at 56day cures.

:::. :

$, ?.\-: .;

$[sUk9

11.9

11.7

10.9

11.4

12.3

12.5

:c&nfjnti

,Density.

&;,5*&~:~

..,:.(&h&f

10.0

5.0

li~~&&

UCS'

.Wet

Dry

,5uR:

.,;.

;<:

,.j;:.

.,.

,::.:;L.r 

'. ..

;I :

-_---

6.3

12.5

Permeability

(cmlsec)

K20

f;hnI;;

$?.&*<%,

15.0 .

30.0

---

FBRj

116.0

116.5

113.4

107.5

106.4

97.7

{Qdimw.

28,d.y

..j,>:Y*

... :.

184

277

291

94.5

93.5

93.3

89.8

87.5

82.4

+X$;i?.*.$

w&

10.0

20.0

-28 day

.: ..... ;:."'.... .1' '..

. ';:

. . . . . . ,

5.37~~'

5.03~"

1.75~~'

6.6

10.0

84 day

..).j.

. . ..I.

.:.

. . *. ..

7.64~~'

4.74~~~

5.84~~'

56 day

84 day

.. -

.: '..

231

125

124

276

583

;;;;,+: ;*..

..P.

: 7

~2.

x:..(%]:gt:

77.3

77.91

79.9

81.1

, .. .

,;.'..'

305

165

114

372

609

6.3

10.0

. 81.5

80.3

82.3

83.5

82,2

84.3

11.6

12.0

12.8

12.9

83.5

83.4

83.5

81.9

112.4

113.0 

114.2

112.4

11.7

11.9

12.4

12.6

86.9

91.2

114.2

117.4

110.7

113.1

123

168.

164

364

95.4

97.9

92.4

92.6

130

157

110

320

194

314

142

416

304

603

------.

191

380

4.32~~~

2.91 E"

1.99~~'

1.30~~~

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

FIGURE 2

Unconfined Compressive Strength Development

for Selected

Mixes

Days

Cured

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Based on all of the above data, the four (4) mixes best performing mixes in

the study were then tested for leachate characteristics using the

TCLP

leaching procedure. The results of the TCLP leaching tests are presented in

Table

of this report.

TABLE

TCLP Leachate analysis of the Treated Ash

Arsenic

Barium

Cadmium

Chromium

Lead

Mercury

Selenium

Silver

Notes:

Treated material curedfor 84 days

AII results expressed in

PPM. unless otherwise noted.

PPM

Parts per MiIIion

=Less than

As can be seen in Table #4, all of the mixes showed

ve_rv 

low leaching potential.

One interesting trend to observe is the fact that all of the stabilized mixes reduced the

leachable level

of arsenic,

barium 

and lead when compared to the original, untreated

ash.

This is a common trend seen in the leachate characteristics of pozzolanic

stabilization matrices.

Upon reviewing

all of the data generated in the study, the most promising reagents

and material blends to produce a pozzolanic cap under field conditions appear to

be:

Basin A fly ash and cement (Mix 1 and 2)

Basin

A fly ash, onsite soil and cement (Mix 9 and 10)

Basin

A fly ash, FGD Filtercake and cement (Mix 14)

VFL

techno log^

Corporation

March 26. 2003

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

FBR was not included in the final selection for several reasons. FBR has been used

in the past for various construction needs including permeability which is why we

have included it in

this treatability study. FBR is quite useful when handled properly

and used in the correct application. Recently, there have been reports on several

construction projects that some

FBR7s

are susceptible to expansion problems.

Situations where it should be avoided are employing it where slight expansion is not

acceptable.

FGD sludge is a good additive for most mix applications. However, FGD sludge

fiom each power plant can be very different (chemically

and physicdIy) based on the

coal source and type of boiler used. Another issue that VFL

has with

FGD

sludge, in

this specific application, is making sure that it is mixed thoroughly

with the other

ingredients.

FGD sludge is a very sticky material. It is difficult to accurately feed it

into a portable processing system because the

FGD sludge has a tendency to adhere

to the sides of feed hoppers that are

used on portable pugmill plants (known as

bridging). In most construction applications, where precise

mix

designs are not

required, this is not a problem.

The mixes containing cement tend to be the easiest to quality control in field

construction applications. Cement is

a manufactured product and varies very little.

Further optimization testing is recommended for the

final mix design prior to full-

scale operations. -VFL would recommend that a test pad be constructed with full-

scale equipment and sampled in substantial conformance

with 35 Illinois

Administrative Code

(IAC)

Part 8 16 to evaluate the proposed process equipment

train and optimized the final mix design.

5.0 Extrapolation to Full-scale Operations

The basic full-scale operational approach that VFL would use to construct the

pozzolanic cap for Basin D's closure would conform to the following schedule of

events:

Regrade Basin D to the lines

and

grades specified by the Engineer.

Excavate the

fly

ash fiom Basin A and allow it to drain to the proper moisture

content before using it

in the mix design. Run OnRun Off to and from the

area

will be controlled and water drained from the ash will be routed back

through the plants pond system.

Construct a processing

area in the vicinity of the two Basins. Erect the

processing plant, silos and any other ancillary processing equipment needed.

Construct haul roads to and from

the placement area.

Process the designated mix design.

Place and compact the stabilized cap mix as

soon 

as possible to the lines and

grades established by the Engineer for the final cap design.

VFL Technology Corporation

March 26.2003

Hutrionville Power ~Ltion

C-1703-02

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Cover the placed material with the cover soils to protect the pozzolanic cap

fiom severe weather events.

Place

the topsoil and vegetate

as

soon as possible.

To develop the necessary documentation for submittal to the State Regulatory

Agencies, the basic Quality Control program for the pozzolanic cap construction

would involve:

Quality Control conformation testing on the materials to

be used in the cover

system

and

their placement.

Process control testing of the mix design during production in substantial

conformance

with 35 IAC Part 81 6.

Quality

Control of the cap mix design during placement and compaction in

substantial conformance

with

QAIQC

procedures outlined in 35

IAC

Part

816.

Moisture monitoring on the excavated and drained Basin A

fly

ash. Control

and QC confirmation checks on the reagents and any other materials of

construction that

will

be used in the mix design

Plant calibration.

Insure that

Basin D has been regraded to the lines and grades specified.

Insure that the cover system

has been installed to the lines and grades

specified.

The cap construction activities listed in this section have been used by

VFL on

several other pozzolanic cap projects. To demonstrate

this, the foIlowing photos of a

pozzolanic cap system that VFL constructed on an industrial landfill in New Jersey

have been included for review.

VFL Technology Corporation

Hutsonville Power

Station 

C-1703-02

March 26,2003

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

PLACEMENT OF THE DRAINAGE LAYER

AND TOP SOIL FOR COVER SYSTEM

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

REGRADING LANDFILL

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

PROCESSING EQUIPMENT

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

PLACEMENT

ANID 

COMPACTION

THE

POZZOLANIC CAP MATERLAL

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

COMPACTED

AM)

GRADED

POZZOLANIC CAP MATERlAL

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

FINISHED LANDFILL

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

GeoSystems

Consultants,

Inc. 

Task 2:

Review

Readily

Available Geotechnical

Data

Mr. C.A. Robb of NRT submitted selected geotechnical data regarding the subsurface

conditions, site drawings,

and tables containing vo1umetric data for Basin

'73." 

list of

these documents is included as Attachment

These documents were reviewed to

ascertain subsurface conditions

in the vicinity

of Basin "D." 

Several inferred subsurface

cross section and the associated test boring logs were evaluated. These data were then

used to develop an "Idealized Cross Section" of the completed

Basin 

closure at the

location GeoS

ystems

believes, is the critical section with respect to slope stability.

Soil 

strength characteristics were estimated

based 

information 

presented in relevant test

boring logs. Where soil (strength) data

was

not available, GeoSystems

used engineering 

judgment to select reasonable strength values for subsurface

-and 

embankment soils and

impounded flyash.

GeoSystems also obtained and reviewed selected sections

of

the State

of

nfinois Title

35:

Environmental Protection, Subtitle B (Waste Disposal Part 816, Alternative Standards for

Coal Combustion Power Generating Facilities Waste Landfills), and Subtitle G (Waste

Disposal Part 8 11, Standards for New Solid Waste Landfills).

Task 

3: Engineering

Consultation Services

GeoSystems provided Engheeriig Comdting Services

regarding

the geotechnical issues

for the project. Specifically the following issues were addressed:

Field Investigation Prom

GeoSystems identified data

gaps

in the geotechnical information provided with respect to

performing the design evaIuatioa. These deficiencies include insufficient laboratory data

that characterizes physical and engineering properties of the impounded

flyash,

containment-dikes, the various soil strata underlyidg the site, and the stratigraphy in the

areas judged to be critical with respect to slope stability. It is

our opinion 

that at least 6

additional test borings are required to develop adequate cross sections

in

critical areas

and to obtain samples for physical and engineering property laboratory testing. These

data would be used to perform analyses regarding slope stability

and

settlement.

Alternate C~D

Effectiveness

Based on a review of the pertinent sections of the State of Illinois Title 35 Code, a

pozzolanic

barrier layer is

an

acceptable alternate cover

system

in

lieu of using

goemembrane cover system. To evaluate the effectiveness

of

the pozzolanic cover

system,

the

HELP computer model was used.

USEPA's computer model HELP (Hydrologic Evaluation of Landfill Performance) has

been used to perform a water balance to estimate the

quantity 

of fluid percolating through

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

GeoSystems Consultants, Inc.

the

final

cover system to the basin materials, estimate the amount of runoff, and head on

the cover system barrier layer.

HELP

uses a

water balance method to estimate the quantity of precipitation which will

theoretically penetrate the

basin

kal cover system'and percolate through the waste. Site-

specific climatological and design data can be input into the model

In

order to assess final

cover performance.

To determine the

quantity

of

rainfall penetrating the final cover, the model estimates

runoff, cover system drainage, and evapotranspiration. These calculations

are generally

based on assumptions made regarding the runoff coefficient, root

zone 

depth, quality of

plant cover, soil porosity, field 'capacity, and

initial water content.

All

rainwater

remaining after

runoff, 

cover system drainage,

and

evapotranspiration can either become

leachate or can be incorporated into the

waste.

The

HELP model is generally accepted as a useful tool in the evaluation of cap and liner

designs. To

simplify the

analysis 

of these designs, it makes several assumptions. These

include steady state flow and homogeneous isotropic layers. Steady state flow

may

achieved

in an unknown number of

years 

after the site has been closed and

final

cover

installed. The non-homogeneous nature of the

basin materials could result in rainwater

channeling through -voids, resulting

in

non-uniform flow. The effect

of

rainwater

absorption

by

the waste or

trapped

rainwater remaining from active operations can be

accounted for by setting the initial water content .of the waste.

These 

amptions make

the HELP model useful as a tool to

compare 

various design options.

The information needed to

run the

HELP 

model includes climatologic, design, soil, and

runoff data. To assist the user in operating the HELP model, the program can generate

synthetic climatologic data

for 20 years using internal databases with weather conditions

for

139

cities throughout

the

United States @vansville, IN was used for present

study, 

which is about 90

miles

fiom the site),

vegetation cover

types,

and

18 soil types. The

user 

may select default values fiom these databases that best represent the expected site-

specific conditions. Details of data input

a. modeling results (using the 20-year

synthetic weather generator) are presented

in Attachment 2.

HELP analyses were performed

using 

a 6-foot thick cap section

feet pozzolanic

cap, 3

feet cover soil: 0.5 to 1.5 feet drainage, 2.5 to 1.5 feet cover

soil).

Permeability of the

pozolanic

cap was varied fiom

1xl0-' 

lx

10"

cmfsec, and final cover slopes

varied

fiom 

1% to

5%.

Based on the results of the modeling, the proposed cover design for Hutsonville Flyash

Basin 

"D" fofthe flat cap area would result in a range of

8 to 97 percent effectiveness in

elhhating drainage

through

the cover system to the basin materials. These percentages

are based on the average total precipitation for one year and

the

"percolation fiom

base

cover"

values calculated using the

HELP 

model (see Table 1). The "percolation from

base

of cover" is assumed to be the amount of leachate, which is a conservative

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

GeoSystems Consultants, Inc.

required Slope Stability analyses for submission to the state.

Volume

Calculations

Volume calculations for

fly

ash utilization associated with the various slopes (1% to 5%)

for the hale closure configurations were performed. The results are presented in

Attachment

Based on the analyses performed, the -following conclusions

have

been

developed:

As the slope of

the final cover increases fiom 1% to 5% the volume of soil to be

regraded reduces fiom 1

10,000 

yd3

for 1 

to 75,000 yd3 for 5%.

the slope of the final cover increases from 1% to 5%, the volume of structural

fill 

increases fiom

0

yd3

for

1%

160,000 

yd3 for

5%.

The volume of protective soil cover (3 feet including vegetative support Iayer and

drainage layer) varies little with

the change in final 

cover grade from

1%

to 5%

(-100,000 

yd3).

The volurne of pozzolanic cap

feet thick) varies little with the change in final

cover grade from 1% to 5%

(-100,000 

yd3).

Utilization of flyash from

Basin 

"A"

increases with increasing slope from 1% to

5%.

Erosion Potential

Erosion control of

the cover system is important, because loss of the soil cover overlying

the barrier layer increases the

potential for damage by gnawinghurrowing animals, thus

decreasing the effectiveness of the banier. Erosion

may

wind- 

andlor water-induced.

The potential for erosion by these two environmental factors should be

evaluated

using 

the Universal

Soil. 

Loss Equation (USLE) and the Wind Erosion Equation (WEE).

Erosion calculations are highly dependent upon the type and condition of vegetation

anticipated

after closure. Erosion loss' due to wind

and

water can be calculated based on

the anticipated short and long term condition of the cover system. No calculations were

performed for this

phase of the design process.

Freeze-Thaw Effects

The maximum estimated frost penetration depth in Central Illinois is 30 inches

and

the

. -

average depth of

frost

penetration is about 10 inches.

conceptual cover system

design  

for the flat area could provide for

soil 

depth above the barrier.

final cover will not be

sensitive to freeze-thaw effects

when 

properly designed

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

GeoSystems

Consultants,

Inc. 

. .

Air Emission Control

Airborne migration of landfill materials \Kill be predominantly migration of dust particles

during 

closure subgrade preparation and initial placement of the general fill layer. As the

general

fill layer (variable thickness) installation proceeds, the potential for fugitive dust

containing landfilled materials would lessen and

then be virtually eliminated once. the

general

fill 

has been partially completed over the entire site.

CONCLUSIONS

Additional field investigation is necessary to better define the geotechnical properties of

the impounded flyash, containment dikes, and various soil skata underlying the site, as

well as better defining the stratigraphy for the critical sections identified.

A pozzolanic cap having a

minimum

thickness of

feet (0.91 meters) can be constructed.

A parametric

analysis 

varying cap permeability from

1x1

0.'

cds to

1x1

0"

cds yielded

"effectiveness":

ranging 

from 78 percent to 97 percent. The permeability of the cap

greatly influences its "effectiveness."

Post-closure settlement

has been estimated to be about 1 foot for the cases evaluated.

This is

a rough estimate based on interpretation of engineering properties fiom soil

descriptions presented

in the boring logs provided, and assumed properties' of .the

impounded flyash. Laboratory test data were available for use in-these .evaluations.

Based on review of results fiom the Preliminary Analyses, insufficient data

are

available

to perform .a comprehensive evaluation at this he.

supplemental field investigation

designed to obtain relevant soil property

data is needed to perfom the required. Slope

Stability analyses for submission to the state.

LIMITATIONS

The

ooncl'usions and recommendations presented in this report are based on the

assumptions that the subsurface conditions at the site

and

the assumed soil properties do

not deviate appreciably

from 

those disclosed by the test boring data p*ovided

and

that the

proposed design

is substantially in conformance with the project description.

GeoSystems

Consultants 

should be notified immediately should differing conditions be

encountered or

if significant

changes 

in design are contemplated, so that appropriate

revisions

can be made to the recommendations.

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

GeoSystems Consultants,

Inc.

We

sincerely appreciate the opportunity to submit this Progress Report for this

challenging project. If you have any questions, please do not hesitate to contact us.Very

truly

yours; 

GEOSYSTEMS CONSULTANTS,

MC.

U~alabria, PhD., P.E.

Princip

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Table 1: ,

~ozzolanic

Cap

Effectiveness

Case

30"

topsoil. 6" sand at 1x10~ cmls, 36 ponolanic cap on a 1% slope

Case

8:

30"

topsoil.

6" sand at 1x10-' cmls,

36

pozzclanic

cap

on a 5% slope

Case 2A:

18" topsoil, 18 sand

zit

1x1~~

crn/s,

36" ponofanic cap on a 1

slope

Case

28:

18" topsail, 18" sand at 1x10.' cmls, 36" ponolanic cap on a 5% skpe

% Effectiveness

Cases

Case 1A

Case 1 B

Case

Ponolanic Cap Permeability

(cmls)

1x1 0-7

95%

95%'

96%

9

7.Yo

o-~

1 x1

0-=. 

78%

79%

78%

79%

81%

86%

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Attachment 1

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Natural

Resource

T.echnotogy, I

nc.

TRANSMITTAL

To:

Vl?L

Technotogy Corporation

Date: March

11,2002 

16

Ragerty Boulevard

Project

No: 1375 

West

Chester, PA

19382

From:

Christopher

Robb

Re: Data Transfer Soil

brings, Topography,

tc.

Attn: Mr. Doug Martin

Ameren Services

Hutsonville Power

Station

For

Your

Files

As Requested x

For

Review

13

Approve and

Return

Copies:

Description

Boring

Logs

EW-1, MW-6, MW-7, MW-7D, MW-8,

GP-20

GP-23, MW-11,

MW-IIR,

SB-I01

tdSB-103,

W-14.

)

p(PARTIA1,

copy)

Fig=

No.

Oe&&c

Clr-s

3w)

Bedras=l;       

375-13tf) 

ve No. 

V-C)

Fiu

Nn

7!

375-R10),- 

Tahle-2 -

of uu

Cover

Titl~m

81 1

-ail

. .

Comments:

Doug,

Pleasefind enclosed copies

of

the above listed materials. The follotving,is

quick list of some

additional potentiaIIy

useful 

information:

r

GP-20,21,Z and

23

are

inside

of

the unlined ash impoundment (Pond D).

R

No soil borings were performed in

Pond 

D's berm.

For

Pond D 

fill: estimated approximately

15,500 

cy fill below water

surface. 

*.. ... -_.-- .-.-.----

-.-. . -

. -- -

-- -

23713

Paul Road,

Pewaukee, WI 

55072

Phone

262/523-9000 

r Fax

2621523-9001

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Attachment

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

POZZOLANIC

CAP PERFORMANCE

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Cap

Design

A-

CASE

1/41

30" TOPSOIL, 6" SAND

7

l+CASE

1B:

30" TOPSOIL, 6 SAND AT 1E-3,36 POUOLANlC CAP, 5% SLOPE

:+CASE

2A: 76" TOPSOIL; 18"'SAND AT 7E-2,36"

POZZOLANIC 

CAP;I% SLOPE

-&-CASE 28:

18"

TOPSOIL,

18"

--.-

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

VFL-15. OUT

0

tffffh**tf~)f*t*t*t*fdt**tC..****tCa~fff*f:***~~*+f*%%*+*******5*****************

~~f*t***~f**+*******c***cf*****************k********~************************* 

* *

HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE

drt

* *

HELP MODEL VERSION 3.07

(1

NOVEMBER 1997)

DEVELOPED BY EMRONMENTAL LABORATORY

USAE WATERWAYS EXPERIMENT STATION

. *+

dr*

FOR USEPA RISK REDUCTION ENGINEERING LABORATORY

+ ?:

PRECIPITATION DATA FILE:

M:\ENGINE- HELP-M-~\DATA~.D~

TEMPERATURE. DATA FILE

M:\ENGINE-I\HELP-M-~\DATA~.D~ 

SOLAR RADIATION DATA FILE:

M:\ENGINE- HELP-M-~\DATA~~.D~~

EVAPOTRANSPIRATION DATA: bl

\ENGINE-I\HELP-M-~\D,ATA~~.

Dl1

SOIL AND DESIGN DATA FILE:

M:\ENGINE-~\HELP-MU~\DATA~O.D~O 

OUTPUT DATA FILE:

M:\ENGINE- HELP-M-~\vF~~s.oL~~.

TIME:

16:55. 

DATE

3/27/2002

TITLE:

V~~/meren

servi

ces-~utsonvi 

Power

station

NOTE:

INITIAL

MOISTURE CONTENT OF THE LAYERS AND SNOW WATER WERE

COMPUTED AS NEARLY STEADY-STATE VALUES BY THE PROGRAM,

LAYER

--------

1

TYPE 1 

VERTICAL PERCOLATION LAYER

MATERIAL TEXTURE NUMBER

THICKNESS        

- -

.18.00 

INCHES

POROSIlY

0.4630 VOLIVot

FIELD CAPACrrY

0.23.20 

VOL/VOL

WILTING

POINT       

0.1160 VOL/VOL

INITIAL SOIL WATER CONTENT

0.2404 VOL/VOL

EFFECTIVE SAT. HYD.

COND. 

0.369999994000~-03 CM/SEC 

LAYER

--------

2

TYPE

2

LATERAL DRAINAGE LAY+

Page I 

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

VFL-is .OUT

MATERIAL 

TWURE NUMBER

THICKNESS         

18.00 INCHES 

POROSrrY

0.4570 VOL/vOC

FIELD

CAPACITY      

0.13 10 VOL/VOL

WILTXNG POINT

t

O.OS8O 

VOL/VOL

INITIAL SOIL WATER CONTENT

0.1477 VOL/VOL

EFFECrIVE SAT.

HYD. 

COND.

O.10OOOOOO5000E-02 

CM/SEC

'SLOPE          

- -

1.00 

PERCENT

DRAINAGE LENGTH

375.0

FEET 

LAYER

--------

NPE 3

BARRIER SOIL 

LINER

MATERIAL TEXTURE NUMBER

0

THICKNESS

- -

36.00

INCHES

POROSS7-Y

0.5410 VOL/VOL

FIELO CAPACITY

0.1870 VOL/VOL

WILTING POINT

0.0470 VOL/VOL

INITIAL SOIL

WATER CONTENT

0.5410 VOL/VOL

EFFECTIVE 

SAT.

HYD. 

COND.

0.999999975000E-05 CM/SEC

GENERAL

DESIGN 

AND EVAPORATIVE ZONE DATA

,..

----------------------------------------

NOTE: SCS 

RUNOFF CURVE NUMBER WAS COMPUTED FROM DEFAULT

SOIL DATA BASE USING SOIL TEXTURE

8 WITH A

FAIR STAND OF GRASS, A SURFACE SLOPE OF

I.%

AND A

SLOPE

LENGTH OF 375.

FEET. 

SCS RUNOFF CURVE NUMBER

FRACTION 

OF AREA ALLOWING RUNOFF

AREA PROJEtTED ON HORIZONTAL PLANE

EVAPORATIVE ZONE DEPTH

INITIAL WATER IN EVAPORATIVE ZONE

UPPER 

Lfm OF

EVAPORATIVE 

STORAGE

LOWER LIMIT 

OF EVAPORATIVE

STORAGE 

XN3XtAL 

SNOW WATER

INITIAL 

WATER IN LAYER MATERIALS

TOTAL

INITIAL

WATER

TOTAL SUBSURFACE INFLOW

78.50

1Oo.O  

PERCENT

1.000

ACRES

21.0

INCHES 

5.014

INCHES

9.705 

INCHES 

2.262. INCHES 

0.000 INCHES 

26,462

INCHES

26.462

INCHES

0

.OO

NCHES/YEAR

EVAPOTRANSPIRATXON

-----------------------------------

AND

WEATHER DATA

NOTE:

EVAPOTRQNSPIRATION DATA WAS .OBTAINED

FROM 

EVAN

SVL

L L E

INDIANA

STATION

LATINDE

38.03 DEGREES

MAXIMUM LEAF AREA

INDEX       

0.00

START OF GROWING SEASON (3ULIAN DATE)

END OF

GROWING SEASON 

(JULIAN

DATE)

300

EVAPORATIVE 

ZONE

DEPTH

21.0 

INCHES

Page

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Attachment 3

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

FLY ASH TO BE RELOCATED

FLY ASH

NEEDED 

FOR GRADING

7

/--

TOPSOIL COVER

I--

GRANULAR

DRAINAGE LAYER

REPRESENTATIVE CROSS SECTION

POND D

UUTSONVILLE

POWER 

STATION

GeoSystems

HUTSONVILLE,

Consultants,

ILLINOIS

1

Inc.

FIGURE 1

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Attachment

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Ameren Services

Hutsonville Power Station

Basin 

"D" Closure

EARTHWORK QUANTITIES

VOLUMES

GRADING

Basin "D Flyash to be relocated

Calculated

fill from Basin

"A"

Material needed to fill basins

Total

borrow 

material from BasinWA"

CAP

Total Cap,

36" Pouolanic Cap

18" Drainage Layer

18" Topsoil

TOTAL FLYASH BORROW REQUIRED

107,561

(57,828)

15,500

(42,328)

201',047

100,524

50,262

58,195

SLOPE

85,751

42,338

15,500

57,838

200,745

100,373

50,186

158,211

71,811

142,531

15,500

158,031

200,960

100,480

50,240

258,511

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Earthwork

Quantities

for

Closure

Flnal Cap Grade

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Appendix A -2

Analytical Laboratory Reports

from

Dalare Laboratories

Philadelphia

Pa.

VFL Technology Corporation

Morch

26.2003 

Hutsonville Power Station

C-1703-02

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Dalare Associates lnc.

7 S. 24th Street

Philadelphia,

PA,

03

Te~ephone'215-567-1953/Facsirnil~2~~-~~67-~~~8

- - .

ANALYTICAL AND

ENVl

RONM ENTAL

TESTING

April 25,

2002

,El

WL Technology 

Attn 

. :

Rocus' Peters 

41

West

16 Kagerty

Chestgr,

Blvd.

PA 19382

. -

Dear Mr. Peters:

We have examined the sample submitted

and

would

report

our

findings 

follows

Date Received:

4/2/02 

Analytical 

Report

3 28

Total Metals:

Arsenic 

Barium 

Cadmiurn

- -

Chromium 

Lead

, +.

Selenium

Silver

TCLP Leachate

Hutsonville Power

Flv Ash (3/28/02) 

Arsenic 

Barium

Chromium 

Mercury 

Selenium

Silver

mg/~g

milligrams 

per

Kilogram 

mg/~.

milligrams per Liter 

<-.: ,

Less

than 

C..

I.:.'....

...

-p&k,~&

Paul 

A tt,~,,

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Date 

Received: 9/27/02

Dalare Associates

Inc. 

21 7 S. 24th Street

.Philadelphia, PA. 191 03

Telephone 215

567

1953

Facsimile 215

567

1168

ANALMICAL AND

ENVIRONMENTAL TESTING

October 2, 2002

VEL

Technology 

Attn.: Rocus 

Peters

16 Bagerty

Blvd. 

West Chester, PA 19382

Dear Mr. Peters:

We have examined the samples submitted. and would report our findings as 

follows 

Analytical.

Report 

910

Rut sonvill 

TCLP 

Leachate

Arsenic 

Barium

Cadmium 

Chromium 

Lead

Mercury

Selenium

Silver 

0!010

.PPM 

0.28

PPM

(0.01

PFM. 

0.06

PPM

(0.02

PPM

0.001 PPM

0.019 PPM

0.01

PPM

PPM

PPM

parts per Million

Less than

The

TCLP Leachate

was

analyzed in accordance with the method described in

the

Federal ~e~iqter,

Volume 55, No.

61,

3/29/90,

pages 11863-75. 

Very

truly

yours,

DALARE

ASSOCIATES, INC. 

PAW: j c.

Paul

A. Weber

.. .

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Dalare

Associates Inc.

21 7

S.

24th Street

Philadelphia, PA.

1910; 

Telephone

5

567

1953

Facsimile 2 15

567

1 168

ANALMICAL AND ENVIRONMENTAL

TESTING

VFL

Technology 

Attn.:

Rocus 

Peters

16 Eagerty Blvd.

West 

Chester. PA 19382

October

2002

Dear Mr. Peters:

We have examined

the samples submitted 

and

would 

report

our

findings

as

follows 

Date Received: 9/18/02

Analytical

Report 

/,,

908

TCLP ~eachate:

Ar s'e'ni c

Barium

Cadmium 

Chromium

Lead

Mercury

Selenium 

Silver

0.010 PPM

0.14

PPM.

0.01

PPM

0.05

PPM

0.02

PPM

0.001

PPM

(0.010 PPM

0.01

PPM

(0.010

PPM

0.11

PPM

(0.01

PPM

0 .Ol

PPM

<0.02

PPM

0.001 PPM

0 .OlO PPM 

0.01

PPM

Parts per

Million 

a

Less than

The

TCLP Leachate

was

analyzed 

in.accordance

with 

the

method described in 

the

FederalRegister,

Volvlie

55. 80.61, 

3/29/90.

pages 11863-75. 

PAW:

jc-

a.

. .

Very

truly

yours. 

0ALAR.E

ASSOCIATES

INC

3s

Paul 

A. Weber

a8Q&

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Exhibit 12

RULES

and

REGULATIONS

ENVIRONMENTAL

PROTECTION

AGENCY

40 CFR Part 261

530Z93009

FRL46898

Final

Regulatory

Determination

on Four

LargeVolume

Wastes From the Combustion

of Coal

Electric

Utility

Power

Plants

Monday August

1993

42466

AGENCY

Environmental

Protection

Agency

ACTION Final

regulatory

determination

SUMMARY

Todays

action

presents

the

Agencys

final

regulatory

determination

required

Section

3001b

of the Resource

Conservation

and

Recovery

Act

RCRA on

four

largevolume

fossilfuel combustion

FFC

waste

streamsfly

ash

bottom

ash

boiler

slag

and flue

gas

emission control wastestudied in the

Agencys

February

1988 Report

Congress

Wastes from the Combustion of Coal

Electric

Utility

Power Plants

RTC

EPA has concluded that

regulation

under

Subtitle

of RCRA is

inappropriate

for the four waste streams that were studied

because of the limited risks

posed by

them and the existence of

generally

adequate

State and Federal

regulatory

programs

The

Agency

also believes that the

potential

for

damage

from these

wastes

most

often determined

site or

regionspecific

factors and that the current State

approach

regulation

is thus

appropriate

Therefore

the

Agency

will continue

exempt

these wastes from

regulation

hazardous

wastes

under

RCRA

Subtitle

However

EPA

believes that

industry

and the

States

should continue

to review the

appropriate

management

of these wastes

EPA

will consider these wastes

during

the

Agencys

ongoing

assessment

of industrial

nonhazardous wastes under RCRA Subtitle

EPA

plans

to make

final

regulatory

determination

the

remaining

FFC waste

streams

beyond

the four listed above

subject

Section 3001b

RCRA

April

1998

EFFECTIVE

DATE

September

1993

FOR FURTHER

INFORMATION

CONTACT

For further information on the

regulatory

determination

contact the

RCRA/Superfund

hotline at

800

4249346

or 703

412

9810

or Patti

Whiting

703 3088421

SUPPLEMENTARY

INFORMATION

Table of Contents

Background

2008

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Orig

US Gov Works

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

Statutory Authority

History

of the Combustion Waste Exclusion

Overview

of the

Report

Congress

Scope

of the

Report

Study

Factors

Preliminary Findings

LargeVolume

Wastes

LowVolume Wastes

Waste

Utilization

Public Comment Process

Supplemental

Analysis

and Notice of Data

Availability

Scope

of the

Regulatory

Determination

AsGenerated

LargeVolume

Wastes

AsManaged LargeVolume

Wastes

III

Factors Considered in

Making

the

Regulatory

Determination

Regulatory

Determination for Four

LargeVolume

CoalFired

Utility

Wastes

Regulatory Flexibility

Act

Regulatory

Determination Docket

Appendix AAnalysis

of and

Responses

Public

Comments

on the

Report

Congress

Appendix

BAnalysis

of and

Responses

to Public Comments on the Notice of Data

Availability

Background

Statutory Authority

Todays

notice is issued under the

authority

of Section

2001b

RCRA

which

requires

that

after

completion

of the

Report

Congress

mandated

Section

2008 Thomson Reuters/West

No Claim to

Orig

US Gov Works

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

8002

RCRA

the Administrator must determine

whether Subtitle

regulation

fossil fuel combustion wastes is warranted

Regulatory

Determination for Four

LargeVolume

CoalFired

Utility

Wastes

The

following

discussion

presents

EPAs conclusions

regarding

the

regulatory

status of

largevolume

coalfired

utility

wastes under RCRA

The determination

to whether

regulation

of such wastes under Subtitle

is warranted

is based

upon

the

February

1988

Report

Congress

comments

on the

Report

Congress including

comments received

at the

public hearing

held in Denver on

April 26 1988

the

information collected

for the

February

12 1988 Notice

and comments received

the Notice

Based

all of the available

information

EPA has concluded that

regulation

the four

largevolume

fossilfuel combustion

wastes

as hazardous

waste

under

RCRA

Subtitle

is unwarranted

Below are the

Agencys

responses

to each

step

of the

decision

methodology

Step

Does the

management

of this waste

pose

human

health/environmental

problems Might

current

practices

cause

problems

in the future The

Agency

has

determined that the answer to this

question

yes

Substep

Has the

waste

currently managed

caused

documented

human health

impacts or

environmental

damage

Response

The

Agency

has

determined

that the waste has caused

documented

impacts

but at

very

limited number of sites

accordance

with the

methodology

described

above

EPA

first addressed whether

the

management

of this waste

currently

poses

human health/environmental

problems

and whether current

practices

could

cause problems

in the future

In its

examination

potential/actual

cases in which

danger

to human health or the

environment

could be attributed to the

management

of fossilfuel combustion

wastes

the RTC included information from several studies that documented

occasional

exceedences

primary

and

secondary drinking

water

standards

groundwater

underlying

fossilfuel waste

management

sites

supplement

the RTC

data

EPA

conducted

State file reviews in States selected for their

geographical

representation

and

large

coalfired

electricity generation capacity

Overall

both

efforts indicate that the extent of actual

damage

cases/environmental

harm

associated

with

large

volume FFC waste

management

appears

limited

42473 EPA used the test of

proof developed

support

the

Report

Congress

Mineral

Processing

Wastes to evaluate

the

potential

damage

cases

As described

Chapter

of that

report

the

test

proof requires

that

case

satisfy

least

one of three conditions scientific

investigation

concluding

that

damages occurred

administrative

ruling concluding

that

damages occurred or

court decision

out

ofcourt settlement

concluding

that

damages

occurred

For the six

damage

cases

described

below

scientific

investigation

was the measure of

proof satisfied

since

the

data most

supported

application

of this measure

2008 Thomson Reuters/West

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Orig

US Gov Works

Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

applying

the

test

EPA first considered

whether actual documentation

exists

that

shows that human health or environmental

harm occurred

e.g

contaminated

groundwater

water

supply well

observed

impacts

on wildlife

Only

limited

number of

largevolume

FFC waste

management

sites

actually

meet this criterion and

can

be considered

proven

damage

cases

These cases include the two sites

identified

in the

RTC as

well

four additional sites identified

during

recent

data collection

efforts

EPA notes that of these six

cases only

one case can

clearly

be attributed to

fly

ash

management

alone

The

remaining

five cases are

associated

with the

comanagement

of the

largevolume

wastes with other wastes

Because

comanagement

large

and lowvolume

wastes

is the

predominant

waste

management practice

limited information exists on

independently managed large

volume wastes

The RTC described

site that involved

dike failure that caused

accidental

release from

fly

ash

disposal lagoon

river This

case

resulted in

substantial

damage

to river

organisms

The other case described

in the RTC

involved

comanagement

In this

case

release occurred from

fly

ash and

petroleum

coke waste

disposal

site that resulted in the contamination

drinking

water

wells with selenium and vanadium

This site is ranked on the

CERCLA

Superfund

National

Priority

List

Site

EPAs more recent data collection efforts resulted in the identification

of four

additional

sites that

are

considered

proven

cases

damage

see

the

Supplemental

Analysis

of Potential Risks to Human Health and the Environment

from

LargeVolume

Coal Corcbustion

Waste

found in Docket no

F93FFCAFFFFF

Each case involves co

management

of wastes at

older

unlined waste

management

units These incidents

involved

groundwater

contamination and/or

vegetative

damages

due

to releases from

waste

management

units

summary

there is minimal documentation

impacts

drinking

water sources in

the

vicinity

of coalfired utilities In

addition

it is

important

to note that

the

damage

case sites were chosen for

study

because

of known releases and

cannot

necessarily

extrapolated

to the

general

universe

Also

most releases have been

from unlined units at older sites that in

many

States

are

now subject

stringent design

and

operating

criteria

Furthermore

actual

cases

of harm to

human health or the environment

may

be limited to

few

sites

often with other

contributing factors including

additional

pollutant

sources attributed to the co

management

with other

FFC

and

nonFFC wastes

The review of such cases of co

management

will be reserved

for the

remaining

waste

study

FN7 The

percentage

of units

required

to meet more

stringent design

and

operating

criteria will increase as older units reach

capacity assuming

typical

lifetime

fo 15

years

and

new

units

come

online

and are

subject

to these

stringent

requirements

The FFC waste

damage

case/environmental

data collected

to date

indicate

therefore

that

although

the extent

appears

limited damage

to the environment

has

occurred

Although

the releases

are

often confined

to the

vicinity

of the units

and have not reached

environmental/human

receptors

the

potential

for

exposure

necessitates

further

analysis

Substep

which examines

the

potential

risks

posed by

these

wastes

2008 Thomson Reuters/West

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Substep

Does EPAs

analysis

indicate that

the waste could

pose significant

risk

human health or the environment

any

sites that

generate

coal combustion

wastes

under either current

management practices

plausible mismanagement

scenarios

Responses

Groundwater contamination

and surface water contamination

through

groundwater

recharge

are

possible

under some

plausible

conditions

unlined units

Available

information on the environmental conditions

of the sites indicates

ecological

and natural resource

damages

are of

most

concern

because

potential

for

human

exposure

is limited

The RTC contains considerable

information on the four

largevolume

coal combustion

wastes

fly ash

bottom

ash slag

and flue

gas

desulfurization

FGD sludge

Information

includes waste characteristics

and

management

practices

environmental

factors

affecting

human

exposure potential

disposal sites

and evidence of

ecological

damage

at coal corcbustion sites

addition

EPA collected

supplemental

information from various EPA offices and other Federal

agencies

State

agencies

and the electric

utility industry

waste

characterization management

and

potential impacts

This

supplemental

information included

groundwater

monitoring

data for 43 coal combustion waste sites collected

from State

regulatory

agencies

and from EPA site visit

reports

All data used in this

supplemental

analysis

are available

for

public inspection

in the docket No F93FFCAFFFFF

bibliography

of the sources used in the risk

analysis

is found in

Appendix

of the

Supplemental

Analysis

of Potential Risks to Human Health and the Environment

from

LargeVolume

Coal Combustion

Waste

also found in Docket no F93FFCAFFFFF

The first

step

of the

methodology

was to evaluate

constituents

of concern

identified by

waste

characterization

data using

risk screen

analysis

process

which

applies

conservative

and

simplified methodology

the constituents

and

pathways

to determine

they

are

concern

The risk

screen

compared

waste characterization

data with

screeninglevel

criteria The

screening

criteria

were developed

identify wastes constituents

and

pathways

requiring

further

analysis

that

wastes

captured

the screen

may

not be of

concern Criteria for 23 constituents

primarily metals

were

developed

for

groundwater

surface

water ingestion

and inhalation

exposure

pathways

using

methodology

similar to that used in the mineral

processing

regulatory

determination

In the cases where the

Agency regulatory

levels

had

changed

since

the mineral

processing

RTC

the

screening

criteria were also

updated

Groundwater

exposure

criteria

were developed using

the

MCLs set

the

Agency

protect drinking

water

primary

MCL had been established

for

particular

parameter

then

healthbased level

HBL

was calculated

using

Agency

cancer

slope

factors or noncancer reference doses

RfDs

from IRIS

In instances where

the calculated

HBL

was less than

corresponding

MCL both values were considered

the

screening

FN8 U.S Environmental

Protection

Agency

Integrated

Risk Information

System

IRIS

November 1992

update

Screening

criteria based on

primary

MCLs were derived

by multiplying

the MCL

2008 Thomson Reuters/West

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Orig

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Electronic Filing - Received, Clerks' Office, August 11, 2008--Exhibits 1,2,5-10, & 12

factor of 10 to simulate scenarios where

only

limited dilution of waste leachate

occurs

prior

exposure

HBLs were derived from

IRIS9

drinking

42474 water or oral

cancer

slope

factors CSFs

representing

iio5

lifetime

cancer

risk

or RfDs

Calculation

of the HBLs relied on the

following

conservative

assumptions

the

maximally

exposed

individual

drinking

liters of water

per

day

365

days

per

year

for

lifetime duration of 70

years

The 70year

exposure

duration

was

chosen to maintain

comparability

with the

MCLs

this

approach

is consistent

with

that taken in the mineral

processing

regulatory determination

These

assumptions

yield

the

following general equations

HBLCSF

mg/l

110

70 kg/ CSF mg/kg/d

l/d 70

HBRfD

mg/l

RfD mg/kg/day

70 kg/2 1/day

As with the MCLbased

criteria

the HBLs

were

multiplied by

factor of 10 to

simulate

scenario where

only

limited dilution of

waste

leachate

occurs

prior

exposure

Groundwater

exposure

criteria were

compared

with waste EP

Toxicity

and

TCLP

analysis

results for each of the four waste steams

FN9 Ibid

The surface water

exposure

criteria

were

selected to

represent potential

harm to

aquatic organisms exposed

surface

water

releases of

wastes

waste

leachate

The criteria were derived

by multiplying

the freshwater chronic Ambient Water

Quality

Criteria

AWQC

for nonhuman effects

factor of 100 to simulate

scenario

where

only

limited dilution occurs

Surface

water

exposure

criteria were

compared

with waste EP

Toxicity

and TCLP

analysis

results for the four waste

streams

The

ingestion

screening

criteria were derived from IRIS oral RfDs and oral

CSFs

assuming

incidental

ingestion

of solid waste materials

Exposure assumptions

are

ingestion

rate of 200

mg/day

from

ages

and 100

mg/day

from

ages

to 31

resulting

average

of 0.114

soil/day an

adult

receptor weight

of 70

and

exposure

of 350

days/year

for 30

years

For CSFderived

values

lifetime

averaging

years

was assumed

These

assumptions

were then used to calculate

the

concentration

constituent

waste that would result in an

exposure

equivalent

to the RfD

the concentration

corresponding

lifetime

cancer

risk

1x105

The

equations

for RfD and CSFbased criteria are shown below

CriterionRfD

mg/g

RfD

mg/kg/d

365

d/y

350

d/y

0.114

soil/d

CriterionCSF

mg/g

105/CSF

mg/kg/d 70 kg 365 d/y 70

350 d/y 30

0.114

soil/d

No dilution factor

was

employed

deriving

the criteria for solid

samples

The

exposure

pathway

assumes

exposure

particulate

whole waste material

Ingestion

exposure

criteria were

compared

with waste total constituent

analysis

results for

the four waste steams

2008 Thomson Reuters/West

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The

exposure

assumptions

used in

deriving

inhalation

exposure

criteria include 50

MUg/m3

airborne dust

concentration

adult inhalation volume of 20 m3/d 70

body

weight

exposure frequency

of 350

days per year exposure

duration of 30

years

and

for CSFderived

values

year

lifespan

averaging

time and

1x105

risk of cancer

Note that 50

MUg/m3x20

m3/d results in

soil

exposure

rate of

mg/d

The

equations

used to derive the criteria from both inhalation RfDs and

inhalation CSFs

are

shown below

CriteriaRfD

mg/g

RfD

mg/kg/d

365

d/y

350

d/y

0.001

soil/d

CriteriaCSF

mg/g

lxlY5/CSF mg/kg/d 70 kg 365 d/y 70

350

d/y 30

0.001

soil/d

Again

dilution factor

was

employed

deriving

the criteria for solid

samples

The

exposure pathway

assumes

exposure

particulate

whole

waste

material

Inhalation

exposure

criteria were

compared

with waste total constituent

analysis

results for the four waste steams

FN1O 50

MUg/m3

is the National Arcbient

Air

Quality

Standard for annual

exposure

particulates

The

screening

criteria described

above were then

compared

EP TCLP

and total

constituent

data from the RTC and

subsequent

data

collection

efforts

For all

waste constituents

that exceeded

screeninglevel

criterion at

than 10

percent

of the sites

sampled

or exceeded the criteria

more than

factor of

further

analysis

was conducted

summary

screening

criteria

exceedences

reported by

waste

type

and

exposure

pathway can

be found in

Appendix

of the

Supplemental

Analysis

of Potential Risks

to Human

Health and the Environment

from

LargeVolume

Coal Combustion Waste

The results of the risk

screening

suggest

that of the

largevolume wastes fly

ash

and

FGD

sludge

are

of most

concern

The risk

screen

also identified

groundwater

surface

water

and inhalation

exposure pathways

needing

further

analysis

The

constituents

needing

further

analysis

included

arsenic cadmium chromium lead

mercury

nickel Ph selenium

and silver

The

Agency

then evaluated

the

release

transport

and

exposure

potential

of those

constituents wastes

and

pathways

for which the risk

screen

indicated that further

analysis

was

necessary

When

available monitoring

data were used to determine

the

potential

for human and environmental

exposure

In other

cases

information on the

physical

setting

of coal combustion waste sites and

the waste

management

practices

was used

evaluate

exposure

potential

the case of the inhalation

pathway

the

potential

for human health risk was evaluated

using

atmospheric

fate and

transport

model For the inhalation

pathway

the

potential

for human

health

risk

when evaluated

using

atmospheric

fate and

transport model

was

found to be

negligible

For more information on the air

pathway analysis please

consult the

Supplemental

Analysis

of Potential Risks to Human Health and the

Environment

from

LargeVolume

Coal Combustion Waste

Further

analyses

of the

groundwater

and surface water

pathway

are summarized below

2008 Thomson Reuters/West

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Groundwater

monitoring

data were used in both the

groundwater

and surface water

exposure

pathway

analyses

summary

table of the

groundwater

monitoring

sites is

Appendix

of the

Supplemental

Analysis

of Potential Risks

to Human

Health and

the Environment

from

LargeVolume

Coal Combustion Waste found in the docket

When

interpreting

the

groundwater

monitoring data

the

Agency

took several factors into

account

First

many

of the sites

may

have

comanaged

their coal combustion

wastes with

other

wastes

such as boiler

cleaning

solution or

pyrites

The

extent to

which

these

other wastes

may

have contributed

groundwater

contamination

could not be

conclusively

determined

because it was difficult to assess in

many

cases whether

comanagement

had occurred and without this

information

it was

not

possible

separate

the effects of the

largevolume

wastes from the other wastes

However

least two site

operators

asserted

that

they

believed

that

comanaged wastes

and

not the

largevolume wastes

were

the

cause

groundwater

contamination

The

Agency

took the

presence

comanaged

wastes into account when

evaluating

the

risk

from the

largevolume

coal combustion wastes

Second some

of the sites have other

possible

sources

of contamination

nearby

the extent that

they

can

determined

these

sources

are

noted in the

summary

table referenced

above

Finally

in the case of some contaminants

e.g iron

naturally occurring

levels

may

quite high

Again

to the extent that

naturally

occurring

constituents

can be 42475 determined

to be

adding

downgradient

concentrations

this is noted in the

summary

table

With these considerations

mind

the

Agency

determined

that available

data from

coal

combustion

waste landfills and surface

impoundments

demonstrated

the existence

potential

for human

exposure

groundwater

contamination

because coal

combustion

waste

constituents

identified in the risk screen as

needing

further

study

were found to be

leaching

onsite

in excess of the

primary

MCLs

Subsequent

analyses

of coal combustion waste sites

suggest however

that

potential

for actual

human

exposure

very

limited

For

example

nine sites of the

fortynine

sites with

groundwater

monitoring

data

had contaminants

above the MCL that

appeared

to stem from coal combustion

units

Another

ten sites had

upgradient

concentrations

equal

downgradient

concentrations

other

possible

sources

groundwater

contamination or in

two

cases

lack of

upgradient information preventing any

conclusions

about the

effects of the coal combustion units on

groundwater

contamination

Constituents

with

exceedences

include

arsenic barium cadmium chromium fluoride lead

mercury nickel

and selenium

Of the nine

sites

none were

completely lined

although

one site had

claylined disposal

unit with an underdrain

emptying

into

series of unlined

ponds

All nine sites have older

pre1975

units

four

consisting

of surface

impoundments

four

consisting

landfills

and

one

with both

types

of units

Fly

ash was the

principal

waste

disposed

of in all units

Four

sites of the nine also are known to have

accepted

comanaged

wastes

pyrites

boiler

cleaning wastes

demineralizer

regenerant

oil

ash

etc

and the others

may

have as well

Potential for human

exposure

groundwater

contaminants

from coal combustion

wastes

is limited because of the location of most coal combustion sites

Based on

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random

study

found in the RTC of one hundred

sites only

percent

of the

sites have

any

population

within

kilometer

and

only

percent

of the sites have

public drinking

water

systems

within

kilometers

Although

infiltration and

transportation

of contaminants

groundwater

varies with site or

regional

specific

factors

such

depth

groundwater

hydraulic conductivity

soil

type

and net

recharge

exposure

to coal combustion

waste

groundwater

contaminants

kilometers

from the

source

of contamination

is not

expected

occur

Of the

public

drinking

water

systems

within

kilometers

of coal combustion

waste

sites

just

under half

47 percent

are

expected

to treat the

groundwater

for hardness

i.e these

systems

have

groundwater

with over 240

ppm

CaCO3 which would tend

remove cocontaminant

metals as well

Coal combustion units also tend to be near surface water bodies The same RTC

study

revealed that 58

percent

of the sites

are

within 500 meters of

surface

water

body

The volume

and flow rate of surface water would tend to dilute and

divert the contaminant

plume

addition groundwater

contamination

appears

to be attributable

past

management

practices

As the

Agencys

groundwater

monitoring

data outlines

above

all of the nine sites with

clear indication of

groundwater

contamination

are

older

pre1975

unlined units

In contrast

of the 13 lined

sites only

one had

exceedences

of an

MCL

and that site had

equal

concentrations

upgradient

and

downgradient

Finally some

of the

groundwater

contamination

may

be attributable

management

with other

wastes

such as

pyrites

boiler

cleaning waste

and

demineralizer

regenerant

Because of the

prevalence

comanagement

several

public

comments

the RTC

reported

that the

predominant

industry practice

is to

codispose

of lowvolume

wastes

in ash or flue

gas

emission control

waste

ponds

the

largevolume

waste

may

not be the sole contributor

to the

groundwater

contamination

Two of the nine sites

report

that

comanagement

is the cause of the

contamination

conclusion

hazardous constituents

in coal combustion

waste

particularly

fly

ash and flue

gas

emission control

waste

have the

potential

leach into

groundwater

under

certain conditions Contaminants

of concern include

arsenic

cadmium chromium lead

mercury

and selenium

Available

data

suggest

however

that contamination

stems

from

older

unlined units

representing

past practices

and

that the units are not

typically

located near

populations

and

drinking

water

systems

addition

the sites within

kilometers of

public drinking

water

systems

about half have

groundwater

with over 240

ppm

CaCo3

and are therefore

expected

to treat the water for

hardness

thus

removing

cocontaminant

metals as

well

Furthermore

at least

some

of the

groundwater

contamination is attributable

other wastes

managed

with the

largevolume

coal combustion

wastes

Thus

potential

for human

exposure

solely

from the

largevolume

coal combustion

waste

from current

management practices

is limited

An examination

of the surface water

pathway

reveals

that although

direct

discharge

of untreated coal combustion waste to surface water is not

likely

because

of Clean Water Act

controls

few of the coal combustion

waste constituents

have

the

potential

in some

instances

to affect

nearby vegetation

and

aquatic organisms

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by migration

through

shallow

groundwater

nearby

surface waters This was

observed at one site where

migration

of boron to

nearby

wetland

was determined

the

State

be the cause of

vegetative

damage

many cases

natural attenuation

processes

are

expected

to dilute the contaminants

below levels of concern

For

example

if contaminants

reach surface

waters

the volume of surface water and its

high

flow

rate could dilute the contaminants

For those sites whose

nearby

water

bodies

may

have

low flow rate

e.g

lakes

swamps

or marshes however

coal

combustion waste

may

cause local environmental

damages

as was observed at the

above site

Even

when contaminated

groundwater

does not affect human health and the

environment

may

be considered

have caused

impacts

that limit future use of

that

groundwater

particular

available

data

suggest

that the

groundwater

number of coal combustion waste sites is contaminated

above

secondary

MCLs

SMCLs

such

secondary parameters

as iron

manganese

sulfate

and total dissolved

solids although

these

effects

may

be localized

through

dilution and attenuation

The SMCLs are

guidelines

generally

set to be

protective

of such aesthetic

considerations

taste odor potential

to stain

laundry

and human cosmetic

effects such as tooth and skin

staining

In addition to

being disposed

of in landfills and surface

impoundments

coal

combustion ash is often

beneficially

used both onsite and offsite

EPA continues

encourage

the beneficial

use

of coal combustion wastes

Because most offsite

applications

tend to immobilize the coal combustion

waste

e.g fly

ash used to

make

concrete

adverse

impacts

appear

to be

unlikely However

fly

ash is

applied directly

agricultural soil

there is

some concern

with metals

uptake by

food

crops

and cattle feed

addition

boron in the coal ash is

readily

mobilized and has

phytotoxic

effect on

plants Although

coal ash is not

frequently

used in

agriculture

any

42476

agricultural

use of coal combustion

waste should

carefully

evaluated

FN11 Characterization

of Coal Creek Station

Fly

Ash for Utilization

Potential

Energy

and Environmental

Research

Center February

1993 see Docket No F93FFCA

Substep

Does the waste exhibit

any

of the characteristics

of hazardous waste

Response

The

Agency

has

determined

that these wastes exhibit the characteristics

of hazardous

waste

infrequently

from

percent

of the

samples depending

waste

type

The RTC concludes

that

although

coal combustion

waste

may

leach contaminants

arsenic cadmium chromium lead

and

mercury

above

toxicity

characteristic

regulatory

levels

such exceedences

are

infrequent

and the

average

concentrations

of constituents

are below

characteristically

toxic

levels

full

bibliography

the sources of EP and TCLP data and

summary

of the results are

given

Appendices

and

of the

Supplemental

Analysis

of Potential Risks to Human Health

and the Environment

from

LargeVolume

Coal Combustion Waste

The results of

Step

of the

analysis

indicate that

the wastes

rarely

exhibit

any

characteristics

of hazardous waste and the waste

pose very

limited risk to human

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health or the environment

under certain

scenarios

such as unlined units sited over

shallow

groundwater

with

nearby drinking

water wells

Furthermore

since most

releases have occurred

unlined older

sites

EPA

recognized

that

review of

current waste

management practices

and

regulatory

control

governing

these

practices

was

appropriate

as outlined in

Step

of the

methodology

which assesses the need

for

more stringent regulation

Step

stringent regulation necessary

desirable The

Agency

has

determined that the answer is no

EPA

regulation

not

necessary

or desirable

evaluating

the

need for more

stringent

controls

to address the

potential

risks

associated

with the

management

of these

wastes

EPA first evaluated

the

adequacy

current

industry

waste

management practices

limiting

contaminant

release and

associated

risk

The

Agency

then viewed the

adequacy

of current State and Federal

regulatory

controls

addressing

these

wastes

For the

purposes

of this

analysis

EPA

supplemented

the data

supplied

in the RTC with site

visits

1992 EPA

study

under which the

Agency

obtained

and reviewed

State

regulations applicable

to FFC

waste

management

the

Department

Energys

1991

report

entitled Coal Combustion

Waste

Disposal Update

of State

Regulations

and Cost

Data dialogue

with

industry

and State

representatives

the Electric Power Research Institutes

Facility Design

and Installation Manual

1991

State file

searches

and literature reviews

Substep

Are

current

practices

adequate

to limit contaminant

release and

associated

risk

Response

The

Agency

has

determined

that

industry

practices

are moving

toward

increased

use

of control

measures

liners

covers

etc

and

groundwater

monitoring

The

Agencys

data on current

practices

indicate that

industry

moving

toward an

increased

use of control measures

e.g liners covers

and

groundwater

monitoring

For

example

the RTC noted that before

1975

less than 20

percent

units surface

impoundments

and

landfills in the United States for which data were

available

had installed some form of liner

More recent data

EEls

Power

Statistics

Database 1989

suggest

that 13 to 29

percent

of surface

impoundments

for which data are available have some form of liner and that 41

percent

landfills have some form of liner

As the

damage

case and

groundwater

monitoring

information

suggests

most of the releases have occurred at

older

unlined units

EPA

has observed

during

site visits that newer units are

generally

lined

Furthermore

most newer

utility

waste

management

facilities have

groundwater

monitoring

systems

and

many

also have leachate

collection

systems

Despite

the

positive

trends in

management

of FFC

wastes

some

of these units

may

be sited with

inadequate

controls

Therefore

in addition to

viewing industry management

practices

EPA collected

and evaluated

information on the extent of current State

and Federal

regulation

of coalfired

utility

waste

management

Substep

Are

current Federal and State

regulatory

controls

adequate

to address

the

management

of the waste

Response

Effluent limitations in the Clean Water Act

regulations

for steam

electric

power

plants

under 40 CFR

part

423

require

discharge

from new

fly

ash

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ponds

State

programs

are

generally

adequate

and

are

improving

with most States

now

requiring permits

and minimum

design

and

operating

criteria that would address

likely

risks

Additionally

Federal authorities exist

address

sitespecific

problems posing

threats to human health and the environment

under RCRA Section

7003

and CERCLA

Sections

104 and 106

The RTC included information on coalfired electric

utility

waste

regulation

all 50 States

updating

this

information

EPA conducted

review of States that

were selected

according

the

high

levels of ash

generated

in those

States

This

approach

resulted in

study

universe

of 17 States that

generate approximately

percent

of all coal ash in the United States

The data show that States have

generally

implemented

stringent regulations

for FFC waste since 1983

when

the State

regulation

review

was

conducted

for the

RTC

Under

developing

State industrial solid waste

management

programs

coal

fired utilities are more

frequently being required

to meet waste

testing standards

and waste

management

units often must

comply

with

design

and

operating requirements

e.g

liners and

groundwater monitoring

standards

Of the 17 States for which EPA

updated

the RTC

data

regulate

coalfired

utility

wastes

solid

wastes explicitly exempting

them from hazardous waste

regulation

16 States

require

offsite FFC waste

management

units to have

some

type

operating permit

with

design

and

operating

criteria

varying by State

12 have

mandatory

liner

requirements

while three States

provide

for

discretionary

authority

impose

liner

requirements on

sitespecific basis

impose

mandatory groundwater

monitoring

requirements

on FFC waste

disposal sites

and 16

impose

final cover

requirements

addition

some States have been

working

reduce the threat of

groundwater

and surface water

contamination

by discouraging

the

use of

wet

management

ponds

disposal practice

through permitting

requirements

and location

restrictions

On the Federal

level

National Pollutant

Discharge

Elimination

System permits

under the Clean Water Act

regulate

all direct

discharges

surface

water

Effluent limitations under 40

CFR

part

423

govern

steam

electric

power

generating point

sources and

require

no zero

discharge

surface waters from

new source fly

ash

transport

waters

CFR

422.15g

FN12 Of the

remaining

three

States

two States establish

requirements

based on

waste characteristics

and

one

exempts

these wastes

from their solid and hazardous

waste

management program

Considering industrys

trend toward more

protective

waste

management practices

the fact that State

regulatory

programs

are generally

adequate

and because Federal

authorities

exist that

can

address these

wastes

EPA has concluded that current

management practices

and

regulatory

controls

are

adequate

for

managing

the four

largevolume

FFC wastes

42477

Substep

Would Subtitle

effectively

address the

problems

associated

with the waste without

imposing significant

unnecessary

controls

Response

The

Agency

has

determined

that it is

unlikely

that Subtitle

would

effectively

address the

problems

associated

with the four

largevolume

fossilfuel

combustion wastes without

imposing

unnecessary

controls

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After

reviewing industry practices

and current State and Federal

regulation

EPA

reviewed the alternative

scenario of

regulating

the four

largevolume

FFC wastes

under

Subtitle

First

it was

recognized

that coal combustion

wastes

rarely

exceed the RCRA characteristics

for hazardous

waste

and

therefore

that most coal

combustion wastes would not be

subject

to Subtitle

controls unless

they

were

listed as hazardous wastes

Furthermore

it was noted that even if these wastes

were

listed

as hazardous

and

therefore

regulated

under Subtitle

such

approach

would be

inappropriate

for these

wastes

Subtitle

system

would

require

coal combustion units to obtain

Subtitle

permit which

would

unnecessarily

duplicate

existing

State

requirements

and would establish

series

waste

unit

design

and

operating requirements

for these

wastes

which would

generally

be in excess of

requirements

protect

human health and the environment

For

example

if such wastes

were placed

in the Subtitle

universe

all ash

disposal

units would be

required

to meet

specific

liner and

monitoring

requirements

Since FFC sites

vary

widely

in terms of

topographical geological

climatological

and

hydrological

characteristics

e.g depth

groundwater

annual

rainfall

distance to

drinking

water

sources

soil

type

and the wastes

potential

leach into the

groundwater

and travel

exposure points

is linked

such

factors

it is more

appropriate

for individual States to have the

flexibility

necessary

to tailor

specific

controls to

the site

or region specific

risks

posed by

these

wastes

EPA also reviewed the comments received

response

to the 1988 RIC and the

Notice

Comments received

on the RIC showed unanimous

support

for EPAs initial

recommendation that

largevolume

combustion wastes do not warrant

regulation

under

RCRA Subtitle

Specifically

the commenters

felt that current Subtitle

criteria together

with

existing

State

regulations

have

proved adequate

protect

human health and the environment

Furthermore

of the

respondents

to the Notice

who addressed the recommendation

that

largevolume

combustion

wastes do not warrant

regulation

under Subtitle

all

agreed

that the

supplemental

data

support

this

recommendation

For these

reasons

EPA concludes that Subtitle

inappropriate

to address the

problems

associated

with these wastes and that the site

or region specific

State

approach

appropriate

for

addressing

the limited human health and environmental

risks involved with the

disposal

of FFC wastes

The

Agency

encourages

States to

continue

develop

and

implement sitespecific approaches

these

wastes

EPA

believes that

industry

and the States should continue

to review the

appropriate

management

of these wastes

EPA will also consider these wastes

during

the

Agencys

ongoing

assessment

of industrial nonhazardous wastes under RCRA Subtitle

Should the characteristics

of the waste streams

change

result of

implementation

any

provisions

of the Clean Air Act as amended

1990

the

Agency

may

choose to reexamine the

exemption

Step

What would be the

operational

and economic

consequences

decision to

regulate

special

waste

under

Subtitle

Although

the

analysis

never

reached

this

point

EPAs

preliminary

examination

potential

costs under Subtitle

indicates that annual costs of full Subtitle

controls

would

range

between

$100 and $500 million

per year

This assumes that

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these wastes would be listed as hazardous in RCRA

part 261 subpart

However

these wastes were not

listed

the wastes would often not be

subject

to Subtitle

since

they

rarely

test

characteristically

hazardous

pursuant

part 261 subpart

Subtitle

controls include

groundwater monitoring liners

leachate

collection

closure/covers

dust

control

financial

assurance

location

restrictions

and

corrective

action

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