Project Summary

United States

Environmental Protection

Agency

Municipal Solid Waste (MSW)

Combustor Ash Demonstration

Program “The Boathouse”

Frank J. Roethel and Vincent T. Breslin

National Risk Management

Research Laboratory

Cincinnati, OH 45268

Research and Development

This report presents the results of a

research program designed to examine the engineering and environmental

acceptability of using municipal solid

waste (MSW) combustor ash as an aggregate substitute in the manufacture

of construction quality cement blocks.

Approximately 350 tons of MSW combustor ash was combined with Portland cement to form standard hollow

masonry blocks using conventional

block making technology. The resultant stabilized combustor ash (SCA)

blocks were used to construct a boathouse on the campus of the University

at Stony Brook.

Periodically, over a 30-mo period, air

samples collected within the boathouse

were examined and compared to ambient air samples for the presence and

concentrations of suspended particulates, particulate and vapor phase

PCDD/PCDF, volatile and semi-volatile

organic compounds and volatile mercury. Analyses of the air samples indicate no statistical difference between

the air quality within the boathouse and

ambient air samples. Rainwater

samples following contact with the

boathouse walls were collected and

analyzed for the presence of trace elements. Results show that the SCA

blocks retain contaminants of environmental concern within their cementitious matrix. Soil samples were

collected prior to and following the construction of the boathouse and the results sμggest that block debris

generated during the boathouse construction was responsible for elevated

concentrations of trace elements in surface soils. Engineering tests show that

the SCA blocks maintain their structural integrity and possess compressive strengths similar to standard

concrete blocks.

This Project Summary was developed

by EPA’s National Risk Management

Research Laboratory, Cincinnati, OH,

to announce key findings of the research project that is fully documented

in a separate report of the same title

(see Project Report ordering information at back).

Introduction

Since 1985, scientists at the Waste Management Institute (WMI) of the Marine Sciences Research Center at the University

at Stony Brook have been assessing the

feasibility of using stabilized MSW combustor ash in a variety of marine and

terrestrial applications. To date, two artificial reefs have been constructed on the

sea floor of Long Island Sound using

blocks of stabilized combustor ash. Over

the past six years, results showed there

was no release to the environment of either organic or inorganic constituents of

environmental concern from the stabilized

combustion residue blocks placed in Conscience Bay.

A second series of studies were initiated at Stony Brook to assess the potential use of MSW combustor ash as an

aggregate substitute in the manufacture

of construction quality cement blocks. Using combined ash from several resource

recovery facilities, scientists manufactured

standard construction quality cement

EPA/600/SR-95/129 August 1995
2

blocks that meet or exceed ASTM performance standards.

The third series of studies began in

1990 with the construction of the boathouse. This phase of the investigation furthered the structural testing of the ash

blocks and extended the scope of the

environmental and health impact assessment in a terrestrial setting. Research was

conducted to measure changes in ash

block chemistry, surrounding soil chemistry, rain water chemistry, air quality within

the boathouse, and to evaluate long-term

structural performance of the stabilized

combined and bottom ash blocks.

Results of this study lead to the manufacture of 14,000 stabilized ash blocks,

using both bottom and combined ash from

the Westchester County waste to energy

(WTE) facility, located in Peekskill, NY.

Block fabrication employed conventional

block making machines currently used by

the industry.

This investigation was initiated following the completion of construction activities. The primary objectives of this study

were to determine if:

1)air quality within the boathouse was

adversely impacted due to the

presence of the SCA blocks, and was

substantially different from outdoor

ambient air samples;

2)metals of environmental concern leach

from the SCA blocks following a

rainfall event;

3)concentrations of trace metals

associated with the soils surrounding

the boathouse become elevated

following the construction; and,

4)weathering effects adversely impact

the structural integrity of the SCA

blocks.

Boathouse Construction

Approximately 100 tons of combined ash

and 250 tons of bottom ash were collected from the Westchester County Resource Recovery Facility, Peekskill, NY in

spring 1990. The collected ash was processed at an aggregate processing facility

on Long Island to remove ferrous metals

and achieve the necessary particle size

distribution for block fabrication. Following

processing, the ash was transported to

Barrasso & Sons, Islip Terrace, NY, a

local cement block manufacturer, where

approximately 4,000 combined SCA blocks

and 10,000 bottom SCA blocks were produced.

The boathouse measures 27 m in

length, 18 m in width and 7 m in height.

The western and northern exterior walls

were constructed using bottom SCA blocks

while the eastern and southern exterior

walls are composed of combined SCA

blocks. The interior of the structure is divided into five separate rooms. All interior

walls are constructed using bottom SCA

blocks. The boathouse is supported by

conventional concrete footings and pad.

Due to the impracticality of removing

SCA blocks directly from the boathouse

walls for experimentation, test walls were

fabricated using both bottom and combined SCA blocks remaining following construction. Three walls were constructed

one using the bottom ash blocks, a second using the combined ash blocks and a

third using conventional cement blocks that

were purchased from a local masonry supplier. Each wall was composed of 64

blocks, stacked 8 blocks high and 8 blocks

across and was located adjacent to the

boathouse.

Results and Discussion

Air Quality Determinations

Air samples were collected every 4 mo

over a 2-yr period and analyzed for total

suspended particulates, particulate and

vapor phase PCDD/PCDF, volatile mercury and volatile and semi-volatile organic

compounds. All air quality analyses, including PCDD/PCDF determinations, were

conducted by the New York State Department of Health (DOH) in their laboratories

in Albany, NY.

Total Suspended Particulates

(TSP)

Boathouse TSP concentrations ranged

from 4.8 μg/M3

 to 24 μg/M3, with the exception of a spike of 168 μg/M3 in September 1992. The outdoor control site also

experienced a spike in particulate concentration, of 120 μg/M3, during September 1992, but otherwise maintained a

concentration range from 8.4 μg/M3 to 64

μg/M3 (Table 1). On average, suspended

particulate levels measured at the outdoor

control site were higher than inside the

boathouse. A two-way ANOVA comparing the TSP data collected inside the boathouse to the outdoor control site yielded

no statistical differences between these

two data sets. The average TSP loads,

both inside the boathouse and at the outdoor control site were well below the OSHA

criteria of 5 mg/M3

PCDD and PCDF

Concentrations

Tables 2 and 3 present the particulate

and vapor phase concentrations of PCDDs

and PCDFs measured from Hi-volume air

sampling experiments conducted both inside the boathouse and at an outdoor

control site. For five of the six sampling

events, total PCDD/PCDF concentrations

within the boathouse environment ranged

between 0.19 pg/M3 to 3.62 pg/M3. The

September 1992 sampling event resulted

in a total PCDD/PCDF concentration of

17.86 pg/M3. At the control site, for five of

the six sampling events, total PCDD/PCDF

concentrations ranged between 0.70 pg/

M3 to 4.00 pg/M3. The May 1992 sampling

event resulted in a total PCDD/PCDF concentration of 22.5 pg/M3

.

The results of a two-way analysis of

variance comparing total individual PCDDs

and PCDFs inside the boathouse to the

outdoor control site with respect to time

revealed that no statistically significant difference existed for any of the isomers.

Volatile Mercury

Volatile mercury was detected during

one of the six sampling events for both

inside the boathouse and outdoor control

site. The concentration of mercury measured inside the boathouse during May

1992 was 58 ng/M3

, while the outdoor

control site during January 1992 was measured at 87 ng/M3. Detection limits varied

from 21-73 ng/M3

 according to the volume

of air sampled and sensitivity of the analytical procedures employed.

No significant difference was measured

for mercury concentrations measured inside the boathouse and the outdoor control site. All mercury concentrations were

well below the NIOSH toxicity limit of

50,000 ng/M3.

Volatile Organic Compounds

Two analytical techniques were employed in evaluating the presence and concentration of volatile organic compounds

(VOCs). The USEPA canister method was

used to measure 13 VOCs and the

Porapak-N method was used to measure

44 VOCs. Porapak-N is a cavity rich polymer on which VOC’s are easily trapped if

an air flow is directed over the material.

Between these two methods, the presence and concentration of 46 VOCs was

determined.

 Of the 46 VOCs analyzed, 11 were

detected inside the boathouse and 12 were

detected at the outdoor control site. Except for methylene chloride, every compound detected inside the boathouse was

also observed at the outdoor control site.

The compounds detected both inside the

boathouse and outdoor control site included chloroform, chloromethane,

tetrachloroethene, ethylbenzene, m/p-xylene, o-xylene, carbon tetrachloride, benzene, 1,1,1-trichloroethane, and toluene.

Hexane was detected only at the outdoor

control site. Table 4 lists all the detected

VOC concentrations for both the canister

and Porapak-N sampling methods.
3

Table 1. Total Suspended Particulate Concentrations

Concentration (μg/M3)

Sampling Events Inside Boathouse Outside Boathouse

Jan-92 8.9 44

May-92 24 61

Sept-02 168 120

Jan-93 4.8 64

May-93 11 NA*

Sept-93 6.8 8.4

*May 93 control sample was not available due to analytical problems.

Table 2. PCDD/PCDF Concentrations (pg/M3) Measured Within the Boathouse

Inside Boathouse

Analyte Jan-92 May-92 Sep-92 Jan-93 May-93 Sep-93

2378 TCDD <0.04 <0.05 <0.013 <0.001 <0.003 0.007

12378 PCDD <0.04 <0.07 0.02 <0.001 <0.003 <0.006

123478 HxCDD <0.06 <0.12 <0.007 0.002 <0.005 0.01

123678 HxCDD <0.06 <0.11 0.026 <0.003 <0.005 <0.009

123789 HxCDD <0.05 <0.11 0.02 <0.005 <0.004 0.008

1234678 HpCDD 0.151 <0.17 0.17 0.015 0.064 0.076

12346789 OCDD 1.05 0.762 0.55 0.23 0.23 0.25

2378 TCDF <0.03 <0.04 1.1 0.007 0.014 0.02

12378 PCDF <0.03 <0.05 0.89 <0.003 0.007 0.006

23478 PCDF <0.04 <0.06 0.61 <0.004 <0.002 0.01

123478 HxCDF <0.03 <0.06 0.41 <0.007 0.003 0.011

123678 HxCDF <0.04 <0.06 0.19 <0.003 <0.003 0.008

234678 HxCDF <0.04 <0.08 0.025 <0.002 <0.003 0.009

123789 HxCDF <0.04 <0.07 0.007 <0.002 <0.003 0.008

1234678 HpCDF 0.077 <0.10 0.11 0.015 0.019 0.023

1234789 HpCDF <0.07 <0.17 0.026 <0.002 <0.009 0.011

12346789 OCDF 0.156 <0.19 0.094 0.016 <0.010 0.028

OTHER TCDD <0.04 <0.05 0.089 0.003 <0.003 0.007

OTHER PCDD <0.04 <0.07 0.023 <0.002 <0.003 <0.006

OTHER HxCDD 0.138 <0.11 0.054 <0.002 0.019 0.025

OTHER HpCDD 0.167 0.284 0.16 0.082 0.046 0.114

OTHER TCDF 0.121 0.328 6 0.01 0.071 0.079

OTHER PCDF 0.201 0.225 6.8 <0.002 0.03 0.02

OTHER HxCDF 0.16 0.182 10.68 0.011 <0.003 0.023

OTHER HpCDF 0.032 <0.10 0.044 0.003 <0.003 0.007

TOTAL 2.903 3.621 17.86 0.186 0.361 0.502

Eight of the twelve compounds detected

were greater inside the boathouse than

the outdoor control site. It is generally the

case that observed VOCs indoors are

greater than measured outdoors. More

importantly, 10 of the 11 compounds observed inside the boathouse were also

detected at the outdoor control site, indicating the major factors influencing VOC

content in the air were the same for both

sampling sites.

Rain Water Evaluations

Rain water sampling consisted of four

sample types; bottom ash blocks (BA),

combined ash blocks (CA), cement blocks,

and a blank. Two replicates of each of

these four sample types were collected

during each of the eight sampling events,

distributed over a 29-mo period. Immediately following sample collection, the pH

and volume of the rain water samples

were recorded prior to chemical analyses.

Chemical analyses consisted of measuring the concentration of calcium, cadmium,

copper, and lead in the rainwater samples.

Rain Water pH

The pH was measured to ascertain the

degree of influence the ash blocks may

have had on rain water chemistry. The pH

of the BA and CA rain samples decreased

from 10.21 to 6.7 and 10.3 to 6.2, respectively, while the cement rain samples decreased from 9.5 to 6.7 following 29-mo

of block exposure (Table 5). Althoμgh a

decrease in pH was measured over time,

the measured decrease in pH for the BA

and CA rain water samples was not uniform. During this period the blank rain

sample pH ranged from 4.9 to 6.9.

Rain Water Chemistry

Rain water chemistry was evaluated to

determine the extent of inorganic leaching

from the ash blocks. The rain water

samples were each analyzed for a representative sub-set of the elements measured in the ash blocks including calcium,

copper, cadmium, and lead (Table 6).

Results of a two-way ANOVA showed

that the calcium concentration in the cement block rain water samples was statistically greater than the BA, CA, and blank

rain water samples. Calcium content of

the BA and CA rain water samples was

not statistically different from the blank

rain water samples. Calcium in the cement rain samples ranged from 9.5 to

25.6 mg/L, whereas the BA, CA and blank

samples ranged from 0.3 to 1.9 mg/L,

with one outlyer of 12.9 mg/L.

The results of a two-way ANOVA

showed that no significant difference in

cadmium concentration existed between

the ash block and blank rain water

samples. Cadmium content of the CA block

rainwater ranged from <0.3 to 2.1 μg/L,

while the cement block rain water ranged

from <0.3 to 2.6 μg/L.

Copper in the cement and blank rain

water samples were measured at <0.03

mg/L for every sampling event. Copper

concentration in the BA rain water ranged

from 0.51 to 0.70 mg/L, while the CA rain

water ranged from <0.03 to 0.30 mg/L.

The BA rain sample collected in May

1992 had a lead concentration of 17.9 μg/

L. All remaining rain water samples were

below the instrumentation detection limit

of <2.5 μg/L. The single detected lead

value of 17.9 μg/L value surpassed the

USEPA drinking water limit for lead of 15
4

Table 3. PCDD/PCDF Concentrations (pg/M3) Measured

Outside Boathouse - Control Site

Analyte Jan-92 May-92 Sep-92 Jan-93 May-93 Sep-93

2378 TCDD <0.04 <0.09 <0.028 <0.016 <0.012 <0.014

12378 PCDD <0.05 <0.13 0.002 <0.003 <0.013 <0.018

123478 HxCDD <0.07 <0.23 <0.003 <0.011 <0.018 <0.027

123678 HxCDD <0.07 <0.22 0.006 0.029 <0.017 <0.025

123789 HxCDD <0.07 <0.21 <0.005 0.032 <0.015 <0.023

1234678 HpCDD 0.243 <0.36 0.067 0.29 0.094 0.16

12346789 OCDD 1.21 0.847 0.68 1.57 0.32 0.54

2378 TCDF <0.04 1.067 0.033 0.052 0.033 0.028

12378 PCDF 0.079 1.006 0.006 0.016 0.018 0.016

23478 PCDF 0.051 0.496 0.009 0.035 0.023 0.029

123478 HxCDF 0.077 0.267 0.013 0.05 <0.010 0.028

123678 HxCDF 0.049 <0.12 <0.008 0.018 <0.01 0.022

234678 HxCDF <0.05 <0.14 0.009 0.022 <0.012 0.027

123789 HxCDF <0.05 <0.14 0.001 0.007 <0.011 <0.015

1234678 HpCDF 0.139 <0.19 0.045 0.11 0.027 0.14

1234789 HpCDF <0.09 <0.32 0.009 0.011 <0.028 0.026

12346789 OCDF 0.172 <0.38 0.096 0.12 <0.046 0.11

OTHER TCDD <0.04 <0.090 0.055 0.032 <0.012 <0.014

OTHER PCDD <0.05 <0.130 0.027 0.011 <0.013 <0.018

OTHER HxCDD 0.205 <0.220 0.046 0.059 0.049 0.15

OTHER HpCDD 0.249 <0.460 0.063 0.3 0.086 0.21

OTHER TCDF 0.162 7.914 0.197 0.058 0.055 0.152

OTHER PCDF 0.458 6.392 0.077 0.089 0.069 0.115

OTHER HxCDF 0.246 0.885 0.046 0.053 0.026 0.103

OTHER HpCDF 0.044 <0.190 0.009 0.079 <0.003 0.034

TOTAL 4.004 22.49 0.764 1.383 0.70 1.394

Table 5. Mean pH and Volume of Rain Water Samples Analyzed

Treatment pH/Volume Jan May Sep Jan Sep Mar May

(mL) 92 92 92 93 93 94 94

Bottom Ash pH 10.2 9.9 8.3 9.1 8.5 6.7 6.7

Volume 70 NA 460 2100 60 520 430

Combined Ash pH 10.3 9.3 9.0 8.4 9.1 8.3 6.2

Volume 150 NA 410 1600 230 865 1120

Cement pH 9.5 8.1 7.6 8.1 8.6 7.0 6.7

Volume 130 NA 300 1700 100 860 790

Blank pH 5.3 6.2 5.5 4.9 6.9 5.5 5.8

Volume 250 NA 720 1300 460 860 1130

Table 4. Range of VOC Concentrations

Analyte Detection Inside Outdoor Method

μg/M3 Method Boathouse Control Site Blank

Hexane Canister <dl 29.9 <dl

Chloroform Porapak-N 4.5 1.0 0.01

Chloromethane Canister 1.5 1.4 - 1.7 <dl

Methylene Chloride Canister 2.8 <dl <dl

Tetrachloroethene Porapak-N 1.5 1.0 0.01

Ethylbenzene Canister 5.4 - 5.5 4.7 <dl

M/P-Xylene Canister 6.3 - 13.5 3.3 <dl

O-Xylene Canister 5.5 - 17.4 4.8 <dl

Carbon Tetrachloride Porapak-N 0.5 - 0.7 0.5 - 0.7 <dl

Benzene Can/P-N 2.5 - 9.2 2.0 - 4.7 <dl

1,1,1-Trichloroethane Porapak-N 1.1 - 24.0 1.0 - 2.7 0.01 - 0.2

Toluene Can/P-N 3.0 - 47 2.8 - 68.0 0.01 - 0.7

μg/L. Since every sample measured <2.5

μg/L, the value of 17.9 μg/L was attributed

to sample contamination or an analytical

error.

Soil Chemistry

The elemental content of soil surrounding the boathouse was examined to quantify any potential contribution of heavy

metals from the boathouse blocks. Prior

to the construction of the boathouse, soils

samples were collected on three separate

occasions. In addition, eight sampling

events were conducted over a 30-mo period following construction. Soil samples

were collected at four depths and analyzed for a representative sub-set of the

metals measured in the ash blocks. The

soil metal analyses consisted of calcium,

cadmium, copper, lead, and zinc. The data

from the two bottom ash wall soil sites

(BASS) were combined to form one data

set as were the two combined ash wall

soil site (CASS) data. Only one control

soil site (CSS) was used. The range of

concentrations observed is presented in

Table 7.

Calcium concentrations in soil collected

from the 2 cm BASS increased, while

samples from the 2, 8, 14, and 20 cm

CASS decreased with time. The calcium

content in the BASS, CASS, and CSS

decreased statistically with respect to

depth. At all measured depths, BASS and

CASS concentrations were statistically

greater than those measured at the CSS.

Calcium is a major component in the

Portland cement used to fabricate the ash

blocks, foundation and pad of the boathouse and the highly soluble nature of

this constituent would explain the concentration variations between the treatment

and control sites.

All post-placement soil data were statistically greater in cadmium than the pretreatment data sets.

Ash Block Chemistry

Metals are subdivided into one of three

categories based on their concentrations.

Major metals include those inorganic constituents with concentrations above 1000

μg/g. Minor metals are composed of components which ranged in concentration

from 100 μg/g to 1000 μg/g, and trace

metals include all constituents below 100

μg/g.

The constituents measured in the bottom and combined ash used in block fabrication are presented in Table 8. The

major elements include iron, aluminum,

zinc, lead, copper, and the salts; calcium,

sodium, magnesium, and potassium. The

minor metals consisted of barium, chromium, manganese and nickel. Arsenic and
5

Table 6. Metal Concentrations in Rain Water Samples

Concentration

Analyte Treatment Jan 92 May 92 Sep 92 Jan 93 Sep 93 Dec 93 Mar 94 May 94

Ca (mg/L) Bottom ash 2.5 (0.1) 1.8 (0.4) 4.7 (0.4) 2.6 (0.7) 2.2 (1.0) 6.7 (0.8) 7.6 (0.6) 10.2 (2.9)

Combined Ash 3.0 (0.7) 4.1 (1.1) 6.0 (1.9) 3.7 (0.1) 4.1 (0.7) 5.1 (1.4) 9.2 (2.8) 24.9 (2.5)

Cement 11.2 (4.7) 10.6 (2.6) 22.2 (4.4) 25.6 (3.9) 15.4 (6.3) 9.5 (0.8) 21.7 (1.4) 10.2 (0.9)

Blank 1.9 (1.6) 0.3 (0.1) 12.9 (17.2) 0.4 (0.0) 1.7 (0.6) 1.4 (0.2) 0.5 (0.0) 0.6 (0.8)

Cd (g/L) Bottom ash <0.3 5.1 (5.1) <0.3 1.4 (1.4) <0.3 2.1 (1.9) <0.3 <0.3

Combined Ash <0.3 2.1 (0.6) <0.3 1.7 (0.7) <0.3 <0.3 <0.3 <0.3

Cement <0.3 <0.3 2.6 (3.3) <0.3 <0.3 <0.3 <0.3 <0.3

Blank <0.3 <0.3 <0.3 1.2 (1.3) 0.3 (0.2) <0.3 <0.3 <0.3

Cu (mg/L) Bottom ash 0.6 (0.2) 0.7 (0.6 0.54 (0.69 0.51 (0.7) 0.55 (0.7) <0.03 <0.03 <0.03

Combined Ash 0.3 (0.02) 0.1 (0.02) 0.04 (0.02) <0.03 0.05 (0.01) <0.03 <0.03 <0.03

Cement <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03

Blank <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03

Pb (g/L) Bottom ash <2.5 17.9 (23.5) <2.5 <2.5 <2.5 <2.5 <2.5 <2.5

Combined Ash <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5

Cement <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5

Blank <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5

Table 7. Mean and Standard Deviation Range of Metal Concentrations (μg/g) Measured in Soil Samples

Analyte Treatment Soil Depth Pre-Boathouse Post-Boathouse

Ca Bottom Ash 2 Not Determined 2660 (1650) - 46300 (31300)

8 Not Determined 610 (40) - 1880 (2120)

14 Not Determined 210 (50) - 720 (440)

20 Not Determined 160 (15) - 600 (180)

Combined Ash 2 Not Determined 300 (260) - 14600 (1160)

8 Not Determined 250 (180) - 1550 (280)

14 Not Determined 170 (190) - 1600 (1180)

20 Not Determined 150 (100) - 810 (160)

Control 2 Not Determined 250 (20) - 380 (50)

8 Not Determined 105 (15) - 410 (60)

14 Not Determined 100 (60) - 270 (50)

20 Not Determined 50 (20) - 220 (90)

Cd Bottom Ash 2 <0.01 - 0.03 (0.01) 0.19 (.03) - 0.90 (0.27)

8 Not Determined 0.11 (.03) - 0.99 (.021)

14 Not Determined 0.05 (.03) - 2.33 (2.58)

20 <0.01 - 0.03 (0.01) .045 (.01) - 1.17 (0.75)

Combined Ash 2 <0.01 - 0.24 (0.02) 0.14 (.07) - 1.54 (0.8)

8 Not Determined 0.12 (0.04) - 1.47 (0.85)

14 Not Determined 0.095 (.05) - 0.95 (0.5)

20 <0.03 (0.01) - 0.05 (0.04) 0.23 (0.2) - 0.98 (0.8)

Control 2 <0.01 - 0.08 (0.01) 0.09 (0.02) - 0.67 (1.0)

8 Not Determined 0.11 (0.1) - 0.67 (0.5)

14 Not Determined 0.06 (0.03) - 0.91 (1.0)

20 <0.01 - 0.11 (0.03) 0.044 (0.009) - 0.78 (0.36)

Cu Bottom Ash 2 6.5 (0.3) - 17.4 (0.1) 10.4 (4.0) - 100 (140)

8 Not Determined 4.8 (0.9) - 49.1 (55)

14 Not Determined 4.3 (.05) - 25.5 (5.2)

20 5.8 (0.2) - 6.8 (0.3) 4.7 (0.4) - 27.5 (20)

Combined Ash 2 5.8 ).6) - 7.1 (1.2) 8.8 (6.3) - 100 (74)

8 Not Determined 6.2 (3.0) - 46.1 (19)

14 Not Determined 4.5 (6.2) - 50.3 (46)

20 3.5 (0.2) - 6.8 (0.3) 5.1 (5.6) - 26.0 (3.6)

Control 2 6.5 (0.9) - 7.3 (0.6) 5.8 (1.7) - 14.9 (3.4)

8 Not Determined 6.3 (1.0) - 16.6 (6.8)

14 Not Determined 4.8 (1.0) - 12.5 (0.50

20 4.2 (0.1) - 4.3 (0.3) 3.3 (1.0) - 19.9 (21)

cadmium were present in trace amounts,

whereas silver and selenium were never

detected.

Chemical Composition of Ash

Blocks

The metal content of the bottom and

combined ash samples (Table 8) were

generally greater than the BA and CA

blocks (Table 9). This concentration differential resulted from a dilution effect

caused by the addition of Portland cement and sand to the ash during block

fabrication. The BA and CA blocks contained 55% and 64% ash respectively.

The concentration of inorganic constituents measured in the ash blocks should

have equaled either 55% or 64% of the

inorganic material measured in the ash

sand samples, plus any additional contribution from the sand and cement comprising 45% and 36% of the BA and CA

blocks respectively. The metal concentrations measured in the control cement

blocks (Table 10) were used to roμghly

estimate the contribution of the ash cement fractions of the BA and CA blocks.

The measured concentrations in the BA

blocks for arsenic, magnesium, manganese, sodium, and zinc, and in the CA

blocks for arsenic, calcium, iron, and nickel

did not agree with the calculated concentrations. The remaining nine metal concentrations in the BA and CA blocks were

within expected concentrations.

The differential between the expected

and actual ash block metal concentrations

is an artifact of the non-homogeneity of

the block mixes. The machinery which fed (continued)
6

measured from November 1991 to May

1993 (Table 8).

Of the seventeen metals measured, only

arsenic and copper appeared to decrease

with time in both the BA and CA blocks.

Ranges are discussed in the full report.

Block Compressive Strengths

Engineering studies conducted over a

period of 30 mo show that the ash blocks

have maintained their structural integrity

possessing compressive strengths equal

to conventional cement blocks. The compressive strengths of all BA, CA and control blocks are outlined in the full report.

Conclusions

Both bottom and combined MSW combustor ash, when combined with Portland

cement, can be successfully stabilized into

conventional construction quality cement

blocks. The construction of a boathouse

on the campus of the State University of

New York demonstrated the potential for

this utilization strategy. Engineering studies conducted over a period of 30 mo

show that the ash blocks have maintained

their structural integrity possessing compressive strengths equal to conventional

cement blocks.

Air quality investigations demonstrate

that within the boathouse the concentrations of suspended particulates, PCDD/

PCDF, volatile organic compounds and

volatile mercury are statistically similar to

ambient air.

The pH and Ca content of rain water

increased following contact with the stabilized ash blocks. Trace amounts of copper were measured following rain water

contact with bottom ash blocks, but these

concentrations were below public drinking

water standards.

Enrichment in the inorganic content of

surface soils was observed when compared to control site soils. Given the limited leaching of elements from the ash

blocks surface soil elemental enrichment

is attributed to ash block debris resulting

from the construction of the boathouse.

Measurements of the chemical composition of the ash blocks reveal a nonhomogeneous mix of reactants (ash, sand,

Portland cement). The machinery used in

the manufacture of the ash blocks lacks

the precision to consistently blend the reactants in identical fashion. Numerous

batches, each potentially having a slightly

different ratio of ingredients, were required

in fabricating the nearly 14,000 blocks used

in the construction of the boathouse. The

data sμggest that each batch was sufficiently different in its chemistry to render

non-conclusive any evaluation of block

Table 7. Continued

Analyte Treatment Soil Depth Pre-Boathouse Post-Boathouse

Pb Bottom Ash 2 6.7 (0.5) - 13.0 (6.2) 17.2 (11.6) - 40.6 (37.6)

8 Not Determined 5.6 (1.5) - 52.3 (40.7)

14 Not Determined 6.2 (1.5) - 15.0 (9.5)

20 7.9 (0.2) - 11.0 (2.7) 6.2 (1.1) - 14.2 (5.2)

Combined Ash 2 7.0 (1.0) - 7.5 (0.9) 13.4 (4.3) - 41.3 (17.4)

8 Not Determined 7.6 (0.5) - 19.6 (17.5)

14 Not Determined 3.6 (2.0) - 26.2 (17.9)

20 6.0 (0.3) - 9.9 0.2) 4.5 (0.3) - 16.8 (12.9)

Control 2 21.0 (1.6) - 40.0 (3.3) 9.4 (8.4) - 23.7 (1.1)

8 Not Determined 12.1 (4.0) - 20.9 (5.9)

14 Not Determined 5.6 (1.9) - 11.7 (2.2)

20 6.4 (0.2) - 21.0 (1.3) 4.6 (4.4) - 6.8 (3.4)

Zn Bottom Ash 2 17.0 (0.40) - 19.0 (0.9) 53.0 (23) - 170 (21)

8 Not Determined 15.7 (24) - 46.6 (12)

14 Not Determined 8.5 (2.1) - 48.6 (37)

20 17.0 (0.4) - 18.0 (4.3) 16.5 (2.8) - 74.9 (80)

Combined Ash 2 13.0 (1.6) - 55.0 (14.6) 23.0 (7.2) - 140 (85)

8 Not Determined 17.8 (2.0) - 75.3 (20)

14 Not Determined 14.0 (5.7) - 51.0 (11)

20 15.0 (0.5) - 19.0 (0.4) 17.0 (0.2) - 41.1 (11)

Control 2 20.0 (1.4) - 23.0 (1.0) 17.1 (12) - 28.7 (2.8)

8 Not Determined 14.2 (9.3) - 31.2 (2.5)

14 Not Determined 13.5 (16) - 29.4 (8.7)

20 14.0 (0.4) - 16.0 (1.1) 10.8 (1.4) - 20.9 (2.5)

the constituents (sand, ash, cement, and

water) during block fabrication lacked the

precision required to make each block

chemically identical. Concrete block manufacturing does not require identical chemical composition. The boathouse blocks

were manufactured in twelve separate

batches, which added to the chemical deviance between blocks. Variability in the

block mixes was further demonstrated by

large standard deviations and concentration differences between samples encountered in block chemistry.

Trends Observed for the Block

Metal Concentrations

In the BA blocks, calcium, chromium,

sodium, and aluminum displayed concentration ranges that consistently overlapped

each other for every sampling event.

In the CA blocks, lead, iron, magnesium, calcium, cadmium, chromium, potassium, sodium, manganese, barium, zinc,

and aluminum displayed overlapping concentration ranges for each sampling event.

Nickel concentrations in the CA blocks

during November 1993 were greater than

Table 8. Mean and Std. Dev. Concentration of Metals Measured in MSW Combustor Ash

Analyte (μg/g) Bottom Ash Combined Ash

Fe 89100 (15400) 80200 (1900)

Ca 64700 (7250) 72000 (3340)

Al 51700 (3200) 5200 (3700)

Na 47800 (1850) 37500 (750)

Mg 10500 (400) 11800 (310)

K 7500 (60) 11100 (400)

Zn 6080 (220) 5370 (120)

Pb 3260 (750) 4070 (120)

Cu 2200 (340) 1600 (330)

Ba 730 (65) 870 (45)

Cr 250 (10) 220 (40)

Mn 130 (10) 930 (30)

Ni 130 (20) 140 (20)

As 20.4 (3.2) <25

Cd 26.5 (3.1) 59.4 (10)

Ag <5 <5

Se <19 <25
7

Table 9. Mean and Standard Deviation of Inorganic Concentrations (g/g) Measured in Stabilized Ash Blocks

Pre-Treatment Post-Treatment

Analyte Block Type Nov 91 May 92 Nov 92 May 93 Nov 93

Major Metals

Ca BA 79300 (6200) 70500 (2100) 73400 (4300) 68700 (7000) 66800 (9900)

CA 60100 (7300) 71900 (1600) 74800 (3700) 61200 (11900) 69800 (8600)

Fe BA 81100 (7300) 31700 (3600) 33700 (1400) 37400 (220) 39300 (7400)

CA 38200 (1900) 23800 (7700) 23200 (8400) 26500 (9100) 41100 (8100)

Al BA 30900 (2200) 24500 (830) 24100 (1300) 27000 (1000) NA

CA 38600 (7200) 29400 (660) 29300 (1000) 30000 (1000) NA

Na BA 16000 (2500) 13600 (380) 12400 (220) 15900 (4000) NA

CA 35000 (17300) 12400 (750) 11800 (650) 10000 (2100) NA

Mg BA 8600 (680) 5100 (170) 5600 (270) 4900 (1500) 7300 (730)

CA 8200 (340) 8000 (290) 8400 (290) 11400 (3100) 11700 (1400)

K BA 7500 (690) 5100 (340) 4900 (310) 5500 (890) 5600 (320)

CA 7700 (190) 7500 (340) 7700 (320) 8600 (2100) 7200 (420)

Zn BA 5300 (860) 1400 (140) 1200 (300) 1700 (150) 3000 (350)

CA 3200 (240) 3200 (140) 3200 (270) 3600 (320) 5800 (1200)

Pb BA 2800 (380) 1800 (510) 1500 (430) 1600 (360) 1400 (240)

CA 2300 (290) 2100 (320) 2100 (250) 2100 (370) 2400 (350)

Minor Metals

Cu BA 830 (250) 720 (260) 650 (170) 690 (120) 510 (180)

CA 1200 (400) 720 (80) 810 (100) 740 (150) 500 (160)

Mn BA 760 (60) 530 (30) 550 (40) 570 (30) 500 (100)

CA 550 (60) 520 (20) 530 (20) 550 (50) 550 (70)

Ba BA 630 (70) 250 (20) 280 (40) 420 (50) 380 (140)

CA 430 (30) 350 (20) 370 (40) 600 (70) 520 (120)

Trace Metals

Cr BA 70.2 (10.8) 70.8 (15.1) 75.1 (6.4) 86.8 (24.5) 77.2 (7.0)

CA 77.9 (3.8) 86.0 (15.1) 80.6 (3.4) 110 (35.3) 74.7 (6.8)

Ni BA 100 (10.0) 30.0 (4.9) 34.0 (5.0) 26.0 (4.2) 120 (15.4)

CA 45.0 (3.9) 55.0 (11.0) 45.0 (7.0) 40.0 (2.9) 35.2 (10.1)

Cd BA 27.1 (6.1) 10.3 (1.1) 11.5 (1.8) 8.9 (1.3) 11.9 (2.1)

CA 33.3 (1.6) 33.5 (1.4) 35.2 (2.4) 32.9 (1.1) 35.2 (10.1)

As BA 21.0 (4.7) 19.8 (11.1) <4.1 <4.1 4.9 (2.6)

CA 24.3 (4.2) 47.7 (13.6) 12.2 (0.7) 5.5 (1.4) 8.9 (3.1)

Ag BA <0.1 <2.2 <2.2 <2.2 <2.2

CA <2.2 <2.2 <2.2 <2.2 <2.2

Se BA <0.2 <2.2 <2.2 <2.2 <2.2

CA <2.2 <2.2 <2.2 <2.2 <2.2

Table 10. Mean and Std. Dev. Concentration of

Metals Measured in Control Blocks

Analyte Concentration(g/g)

Ag <1.1

Al 32300 (11100)

As <5

Ba 190 (50)

Ca 23000 (6900)

Cd <10

Cr 7.8 (1.3)

Cu 24 (12)

Fe 14500 (810)

K 5800 (1900)

Mg 1100 (380)

Mn 170 (10)

Na 28900 (3200)

Ni 8.6 (2.1)

Pb <0.25

Se <2.2

Zn 56 (13)

chemistry alterations that may occur as a

result of weathering.

To date, no adverse environmental or

structural impacts have been observed in

the boathouse due to the use of MSW

combustor ash as an aggregate substitute

in the cement blocks.

The full report was submitted in

fullfilment of Cooperative Agreement No.

CR818172-01-0, by the Research Foundation of the State University of New York

under the sponsorship of the U.S. Environmental Protection Agency.
8

Frank J. Roethel and Vincent T. Breslin are with the Waste Management

Institute, a division of the Marine Sciences Research Center, State University

of New York, Stony Brook, NY 11794.

Diana R. Kirk is the EPA Project Officer (see below).

The complete report, entitled "Municipal Solid Waste (MSW) Combustor Ash

Demonstration Program “The Boathouse” (Order No. PB95-260279; Cost:

$19.50, subject to change) will be available only from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: 703-487-4650

The EPA Project Officer can be contacted at:

National Risk Management Research Laboratory

U.S. Environmental Protection Agency

Cincinnati, OH 45268

United States

Environmental Protection Agency

National Risk Management Research Laboratory (G-72)

Cincinnati, OH 45268

Official Business

Penalty for Private Use

$300

EPA/600/SR-95/129

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35