United States Environmental Protection Agency National Risk Management Research Laboratory Cincinnati, OH 45268 Research and Development EPA/600/SR-95/129 August 1995 vvEPA Project Summary Municipal Solid Waste (MSW) Combustor Ash Demonstration Program "The Boathouse" Frank J. Roethel and Vincent T. Breslin This report presents the results of a research program designed to exam- ine the engineering and environmental acceptability of using municipal solid waste (MSW) combustor ash as an ag- gregate substitute in the manufacture of construction quality cement blocks. Approximately 350 tons of MSW com- bustor ash was combined with Port- land cement to form standard hollow masonry blocks using conventional block making technology. The result- ant stabilized combustor ash (SCA) blocks were used to construct a boat- house 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 ambi- ent air samples for the presence and concentrations of suspended particu- lates, particulate and vapor phase PCDD/PCDF, volatile and semi-volatile organic compounds and volatile mer- cury. Analyses of the air samples indi- cate 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 ele- ments. Results show that the SCA blocks retain contaminants of environ- mental concern within their cemen- titious matrix. Soil samples were collected prior to and following the con- struction of the boathouse and the re- sults suggest that block debris generated during the boathouse con- struction was responsible for elevated concentrations of trace elements in sur- face soils. Engineering tests show that the SCA blocks maintain their struc- tural integrity and possess compres- sive 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 re- search project that is fully documented in a separate report of the same title (see Project Report ordering informa- tion at back). Introduction Since 1985, scientists at the Waste Man- agement Institute (WMI) of the Marine Sci- ences Research Center at the University at Stony Brook have been assessing the feasibility of using stabilized MSW com- bustor ash in a variety of marine and terrestrial applications. To date, two artifi- cial 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 ei- ther organic or inorganic constituents of environmental concern from the stabilized combustion residue blocks placed in Con- science Bay. A second series of studies were initi- ated at Stony Brook to assess the poten- tial use of MSW combustor ash as an aggregate substitute in the manufacture of construction quality cement blocks. Us- ing combined ash from several resource recovery facilities, scientists manufactured standard construction quality cement ------- blocks that meet or exceed ASTM perfor- mance standards. The third series of studies began in 1990 with the construction of the boat- house. This phase of the investigation fur- thered the structural testing of the ash blocks and extended the scope of the environmental and health impact assess- ment in a terrestrial setting. Research was conducted to measure changes in ash block chemistry, surrounding soil chemis- try, 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 manu- facture 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 follow- ing the completion of construction activi- ties. 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 col- lected from the Westchester County Re- source Recovery Facility, Peekskill, NY in spring 1990. The collected ash was pro- cessed 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 pro- duced. 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 di- vided 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 com- bined SCA blocks remaining following con- struction. Three walls were constructed one using the bottom ash blocks, a sec- ond using the combined ash blocks and a third using conventional cement blocks that were purchased from a local masonry sup- plier. 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 mer- cury and volatile and semi-volatile organic compounds. All air quality analyses, in- cluding PCDD/PCDF determinations, were conducted by the New York State Depart- ment of Health (DOH) in their laboratories in Albany, NY. Total Suspended Particulates (TSP) Boathouse TSP concentrations ranged from 4.8 |ig/M3 to 24 |ig/M3, with the ex- ception of a spike of 168 |ig/M3 in Sep- tember 1992. The outdoor control site also experienced a spike in particulate con- centration, of 120 |o,g/M3, during Septem- ber 1992, but otherwise maintained a concentration range from 8.4 |ig/M3 to 64 |ig/M3 (Table 1). On average, suspended particulate levels measured at the outdoor control site were higher than inside the boathouse. A two-way ANOVA compar- ing the TSP data collected inside the boat- house 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 out- door 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 in- side 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 con- centration 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 dif- ference 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 mea- sured inside the boathouse during May 1992 was 58 ng/M3, while the outdoor control site during January 1992 was mea- sured at 87 ng/M3. Detection limits varied from 21-73 ng/M3 according to the volume of air sampled and sensitivity of the ana- lytical procedures employed. No significant difference was measured for mercury concentrations measured in- side the boathouse and the outdoor con- trol site. All mercury concentrations were well below the NIOSH toxicity limit of 50,000 ng/M3. Volatile Organic Compounds Two analytical techniques were em- ployed in evaluating the presence and con- centration 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 poly- mer on which VOC's are easily trapped if an air flow is directed over the material. Between these two methods, the pres- ence 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. Ex- cept for methylene chloride, every com- pound detected inside the boathouse was also observed at the outdoor control site. The compounds detected both inside the boathouse and outdoor control site in- cluded chloroform, chloromethane, tetrachloroethene, ethylbenzene, m/p-xy- lene, o-xylene, carbon tetrachloride, ben- zene, 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. ------- Table 1. Total Suspended Particulate Concentrations Concentration (\ig/Nr) Sampling Events Jan-92 May-92 Sept-02 Jan-93 May-93 Sept-93 Inside Boathouse 8.9 24 168 4.8 11 6.8 Outside Boathouse 44 61 120 64 NA" 8.4 May 93 control sample was not available due to analytical problems. Table 2. PCDD/PCDFConcentrations (pg/M3) Measured Within the Boathouse Inside Boathouse Analyte 2378 TCDD 12378 PCDD 123478 HxCDD 123678 HxCDD 123789 HxCDD 1234678 HpCDD 12346789 OCDD 2378 TCDF 12378 PCDF 23478 PCDF 123478 HxCDF 123678 HxCDF 234678 HxCDF 123789 HxCDF 1234678 HpCDF 1234789 HpCDF 12346789 OCDF OTHER TCDD OTHER PCDD OTHER HxCDD OTHER HpCDD OTHER TCDF OTHER PCDF OTHER HxCDF OTHER HpCDF TOTAL Jan-92 <0.04 <0.04 <0.06 <0.06 <0.05 0.151 1.05 <0.03 <0.03 <0.04 <0.03 <0.04 <0.04 <0.04 0.077 <0.07 0.156 <0.04 <0.04 0.138 0.167 0.121 0.201 0.16 0.032 2.903 May-92 <0.05 <0.07 <0.12 <0.11 <0.11 <0.17 0.762 <0.04 <0.05 <0.06 <0.06 <0.06 <0.08 <0.07 <0.10 <0.17 <0.19 <0.05 <0.07 <0.11 0.284 0.328 0.225 0.182 <0.10 3.621 Sep-92 <0.013 0.02 <0.007 0.026 0.02 0.17 0.55 1.1 0.89 0.61 0.41 0.19 0.025 0.007 0.11 0.026 0.094 0.089 0.023 0.054 0.16 6 6.8 10.68 0.044 17.86 Jan-93 <0.001 <0.001 0.002 <0.003 <0.005 0.015 0.23 0.007 <0.003 <0.004 <0.007 <0.003 <0.002 <0.002 0.015 <0.002 0.016 0.003 <0.002 <0.002 0.082 0.01 <0.002 0.011 0.003 0.186 May-93 <0.003 <0.003 <0.005 <0.005 <0.004 0.064 0.23 0.014 0.007 <0.002 0.003 <0.003 <0.003 <0.003 0.019 <0.009 <0.010 <0.003 <0.003 0.019 0.046 0.071 0.03 <0.003 <0.003 0.361 Sep-93 0.007 <0.006 0.01 <0.009 0.008 0.076 0.25 0.02 0.006 0.01 0.011 0.008 0.009 0.008 0.023 0.011 0.028 0.007 <0.006 0.025 0.114 0.079 0.02 0.023 0.007 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 ob- served inside the boathouse were also detected at the outdoor control site, indi- cating 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. Immedi- ately following sample collection, the pH and volume of the rain water samples were recorded prior to chemical analyses. Chemical analyses consisted of measur- ing 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, respec- tively, while the cement rain samples de- creased from 9.5 to 6.7 following 29-mo of block exposure (Table 5). Although a decrease in pH was measured over time, the measured decrease in pH for the BA and CA rain water samples was not uni- form. 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 repre- sentative sub-set of the elements mea- sured 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 ce- ment block rain water samples was statis- tically 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 ce- ment 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 |ig/L, while the cement block rain water ranged from <0.3 to 2.6 jag/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 |ig/ L. All remaining rain water samples were below the instrumentation detection limit of <2.5 |ig/L. The single detected lead value of 17.9 |ig/L value surpassed the USEPA drinking water limit for lead of 15 ------- Table 3. PCDD/PCDF Concentrations (pg/M3) Measured Outside Boathouse - Control Site Analyte 2378 TCDD 12378 PCDD 123478 HxCDD 123678 HxCDD 123789 HxCDD 1234678 HpCDD 12346789 OCDD 2378 TCDF 12378 PCDF 23478 PCDF 123478 HxCDF 123678 HxCDF 234678 HxCDF 123789 HxCDF 1234678 HpCDF 1234789 HpCDF 12346789 OCDF OTHER TCDD OTHER PCDD OTHER HxCDD OTHER HpCDD OTHER TCDF OTHER PCDF OTHER HxCDF OTHER HpCDF TOTAL Jan-92 <0.04 <0.05 <0.07 <0.07 <0.07 0.243 1.21 <0.04 0.079 0.051 0.077 0.049 <0.05 <0.05 0.139 <0.09 0.172 <0.04 <0.05 0.205 0.249 0.162 0.458 0.246 0.044 4.004 May-92 <0.09 <0.13 <0.23 <0.22 <0.21 <0.36 0.847 1.067 1.006 0.496 0.267 <0.12 <0.14 <0.14 <0.19 <0.32 <0.38 <0.090 <0.130 <0.220 <0.460 7.914 6.392 0.885 <0.190 22.49 Sep-92 <0.028 0.002 <0.003 0.006 <0.005 0.067 0.68 0.033 0.006 0.009 0.013 <0.008 0.009 0.001 0.045 0.009 0.096 0.055 0.027 0.046 0.063 0.197 0.077 0.046 0.009 0.764 Jan-93 <0.016 <0.003 <0.011 0.029 0.032 0.29 1.57 0.052 0.016 0.035 0.05 0.018 0.022 0.007 0.11 0.011 0.12 0.032 0.011 0.059 0.3 0.058 0.089 0.053 0.079 1.383 May-93 <0.012 <0.013 <0.018 <0.017 <0.015 0.094 0.32 0.033 0.018 0.023 <0.010 <0.01 <0.012 <0.011 0.027 <0.028 <0.046 <0.012 <0.013 0.049 0.086 0.055 0.069 0.026 <0.003 0.70 Sep-93 <0.014 <0.018 <0.027 <0.025 <0.023 0.16 0.54 0.028 0.016 0.029 0.028 0.022 0.027 <0.015 0.14 0.026 0.11 <0.014 <0.018 0.15 0.21 0.152 0.115 0.103 0.034 1.394 Table 4. Range of VOC Concentrations Analyte ug/M3 Hexane Chloroform Chloromethane Methylene Chloride Tetrachloroethene Ethylbenzene M/P-Xylene O-Xylene Carbon Tetrachloride Benzene 1, 1, 1 -Trichloroethane Toluene Detection Method Canister Porapak-N Canister Canister Porapak-N Canister Canister Canister Porapak-N Can/P-N Porapak-N Can/P-N Inside Boathouse ------- Table 6. Metal Concentrations in Rain Water Samples Analyte Cd (g/L) Cu (mg/L) Treatment Bottom ash Combined Ash Cement Blank Bottom ash Combined Ash Cement Blank Concentration Jan 92 May 92 Sep92 Jan 93 Sep93 Dec 93 Mar 94 <0.3 <0.3 <0.3 <0.3 0.6 (0.2) 0.3 (0.02) <0.03 <0.03 5.1(5.1) 2.1 (0.6) <0.3 <0.3 0.7(0.6 0.1 (0.02) <0.03 <0.03 <0.3 <0.3 2.6 (3.3) <0.3 0.54 (0.69 0.04 (0.02) <0.03 <0.03 1.4 (1.4) 1.7(0.7) <0.3 1.2 (1.3) 0.51 (0.7) <0.03 <0.03 <0.03 <0.3 <0.3 <0.3 0.3 (0.2) 0.55(0.7) 0.05(0.01) <0.03 <0.03 2.1 (1.9) <0.3 <0.3 <0.3 <0.03 <0.03 <0.03 <0.03 <0.3 <0.3 <0.3 <0.3 <0.03 <0.03 <0.03 <0.03 May 94 Ca (mg/L) Bottom ash Combined Ash Cement Blank 2.5(0.1) 3.0(0.7) 11.2 (4.7) 1.9 (1.6) 1.8 (0.4) 4.1(1.1) 10.6 (2.6) 0.3(0.1) 4.7(0.4) 6.0 (1.9) 22.2 (4.4) 12.9 (17.2) 2.6(0.7) 3.7(0.1) 25.6 (3.9) 0.4 (0.0) 2.2 (1.0) 4.1 (0.7) 15.4 (6.3) 1.7(0.6) 6.7(0.8) 5.1(1.4) 9.5 (0.8) 1.4 (0.2) 7.6 (0.6) 9.2 (2.8) 21.7(1.4) 0.5(0.0) 10.2 (2.9) 24.9 (2.5) 10.2 (0.9) 0.6 (0.8) <0.3 <0.3 <0.3 <0.3 <0.03 <0.03 <0.03 <0.03 Pb (g/L) Bottom ash Combined Ash Cement Blank <2.5 <2.5 <2.5 <2.5 17.9 (23.5) <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <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 (fig/g) Measured in Soil Samples Analyte Treatment Soil Depth Pre-Boathouse Post-Boathouse Ca Bottom Ash 2 8 14 20 Combined Ash 2 8 14 20 Control 2 8 14 20 Not Determined Not Determined Not Determined Not Determined Not Determined Not Determined Not Determined Not Determined Not Determined Not Determined Not Determined Not Determined 2660 (1650) - 46300 (31300) 610 (40) - 1880 (2120) 210 (50) - 720 (440) 160 (15) - 600 (180) 300 (260) - 14600 (1160) 250 (180) - 1550 (280) 170(190)- 1600(1180) 150 (100) - 810 (160) 250 (20) - 380 (50) 105 (15) -410 (60) 100 (60) - 270 (50) 50 (20) - 220 (90) Cd Bottom Ash Combined Ash Control Cu Bottom Ash Combined Ash Control 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) 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) 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) 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) 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) 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) (continued) 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 dif- ferential resulted from a dilution effect caused by the addition of Portland ce- ment and sand to the ash during block fabrication. The BA and CA blocks con- tained 55% and 64% ash respectively. The concentration of inorganic constitu- ents 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 contri- bution from the sand and cement com- prising 45% and 36% of the BA and CA blocks respectively. The metal concentra- tions measured in the control cement blocks (Table 10) were used to roughly estimate the contribution of the ash ce- ment fractions of the BA and CA blocks. The measured concentrations in the BA blocks for arsenic, magnesium, manga- nese, sodium, and zinc, and in the CA blocks for arsenic, calcium, iron, and nickel did not agree with the calculated concen- trations. The remaining nine metal con- centrations 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 ------- Table 7, Continued Analyte Treatment Soil Depth Pre-Boathouse Post-Boathouse Pb Bottom Ash 2 8 14 20 Combined Ash 2 8 14 20 Control 2 8 14 20 Zn Bottom Ash 2 8 14 20 Combined Ash 2 8 14 20 Control 2 8 14 20 6.7(0.5)- 13.0(6.2) Not Determined Not Determined 7.9(0.2)- 11.0(2.7) 7.0 (1.0) - 7.5 (0.9) Not Determined Not Determined 6.0 (0.3) - 9.9 0.2) 21.0 (1.6) - 40.0 (3.3) Not Determined Not Determined 6.4 (0.2) -2 1.0 (1.3) 17.0 (0.40) - 19.0 (0.9) Not Determined Not Determined 17.0 (0.4) - 18.0 (4.3) 13.0 (1.6) - 55.0 (14.6) Not Determined Not Determined 15.0 (0.5) - 19.0 (0.4) 20.0 (1.4) - 23.0 (1.0) Not Determined Not Determined 14.0(0.4)- 16.0(1.1) 17.2 (11. 6) -40.6 (37.6) 5.6 (1.5) -52.3 (40.7) 6.2 (1.5) - 15.0 (9.5) 6.2(1.1)- 14.2(5.2) 13.4 (4.3) - 41.3 (17.4) 7.6 (0.5) - 19.6 (17.5) 3.6 (2.0) -26.2 (17.9) 4.5(0.3)- 16.8(12.9) 9.4 (8.4) -23.7 (1.1) 12.1 (4.0) - 20.9 (5.9) 5.6(1.9)- 11.7(2.2) 4.6 (4.4) - 6.8 (3.4) 53.0 (23) - 170 (21) 15.7 (24) -46.6 (12) 8.5 (2.1) - 48.6 (37) 16.5 (2.8) - 74.9 (80) 23.0 (7.2) - 140 (85) 17.8 (2.0) - 75.3 (20) 14.0(5.7) -51.0(11) 17.0 (0.2) -41.1 (11) 17.1 (12) -28.7 (2.8) 14.2 (9.3) - 31.2 (2.5) 13.5 (16) -29.4 (8.7) 10.8 (1.4) - 20.9 (2.5) TableS, Mean and Std. Dev. Concentration of Metals Measured in MSW Combustor Ash Analyte ([ig/g) Bottom Ash Combined Ash Fe Ca Al Na Mg K Zn Pb Cu Ba Cr Mn Ni As Cd Ag Se 89100 (15400) 64700 (7250) 51700(3200) 47800 (1850) 10500 (400) 7500 (60) 6080 (220) 3260 (750) 2200 (340) 730 (65) 250 (10) 130 (10) 130 (20) 20.4 (3.2) 26.5 (3. 1) <5 <19 80200 (1900) 72000 (3340) 5200 (3700) 37500 (750) 11800(310) 11100(400) 5370 (120) 4070 (120) 1600 (330) 870 (45) 220 (40) 930 (30) 140 (20) <25 59.4 (10) <5 <25 the constituents (sand, ash, cement, and water) during block fabrication lacked the precision required to make each block chemically identical. Concrete block manu- facturing does not require identical chemi- cal composition. The boathouse blocks were manufactured in twelve separate batches, which added to the chemical de- viance between blocks. Variability in the block mixes was further demonstrated by large standard deviations and concentra- tion differences between samples encoun- tered in block chemistry. Trends Observed for the Block Metal Concentrations In the BA blocks, calcium, chromium, sodium, and aluminum displayed concen- tration ranges that consistently overlapped each other for every sampling event. In the CA blocks, lead, iron, magne- sium, calcium, cadmium, chromium, po- tassium, sodium, manganese, barium, zinc, and aluminum displayed overlapping con- centration ranges for each sampling event. Nickel concentrations in the CA blocks during November 1993 were greater than 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 com- pressive strengths of all BA, CA and con- trol blocks are outlined in the full report. Conclusions Both bottom and combined MSW com- bustor 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 stud- ies conducted over a period of 30 mo show that the ash blocks have maintained their structural integrity possessing com- pressive strengths equal to conventional cement blocks. Air quality investigations demonstrate that within the boathouse the concentra- tions 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 stabi- lized ash blocks. Trace amounts of cop- per 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 com- pared to control site soils. Given the lim- ited 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 compo- sition of the ash blocks reveal a non- homogeneous mix of reactants (ash, sand, Portland cement). The machinery used in the manufacture of the ash blocks lacks the precision to consistently blend the re- actants 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 suggest that each batch was suffi- ciently different in its chemistry to render non-conclusive any evaluation of block ------- Table 9. Mean and Standard Deviation of Inorganic Concentrations (gig) Measured in Stabilized Ash Blocks Pre-Treatment Post-Treatment Analyte Block Type Nov91 May 92 Nov92 May 93 Nov93 Major Metals Ca Fe Al Na Mg K Zn Pb BA CA BA CA BA CA BA CA BA CA BA CA BA CA BA CA 79300 60100 81100 38200 30900 38600 16000 35000 8600 8200 7500 7700 5300 3200 2800 2300 (6200) (7300) (7300) (1900) (2200) (7200) (2500) (17300) (680) (340) (690) (190) (860) (240) (380) (290) 70500 71900 31700 23800 24500 29400 13600 12400 5100 8000 5100 7500 1400 3200 1800 2100 (2100) (1600) (3600) (7700) (830) (660) (380) (750) (170) (290) (340) (340) (140) (140) (510) (320) 73400 74800 33700 23200 24100 29300 12400 11800 5600 8400 4900 7700 1200 3200 1500 2100 (4300) (3700) (1400) (8400) (1300) (1000) (220) (650) (270) (290) (310) (320) (300) (270) (430) (250) 68700 61200 37400 26500 27000 30000 15900 10000 4900 11400 5500 8600 1700 3600 1600 2100 (7000) (11900) (220) (9100) (1000) (1000) (4000) (2100) (1500) (3100) (890) (2100) (150) (320) (360) (370) 66800 69800 39300 41100 NA NA NA NA 7300 11700 5600 7200 3000 5800 1400 2400 (9900) (8600) (7400) (8100) (730) (1400) (320) (420) (350) (1200) (240) (350) Minor Metals Cu Mn Ba Cr Ni Cd As Ag Se BA CA BA CA BA CA BA CA BA CA BA CA BA CA BA CA BA CA 830 1200 760 550 630 430 70.2 77.9 100 45.0 27.1 33.3 21.0 24.3 <0.1 <2.2 <0.2 <2.2 (250) (400) (60) (60) (70) (30) (10.8) (3.8) (10.0) (3.9) (6.1) (1.6) (4.7) (4.2) 720 720 530 520 250 350 70.8 86.0 30.0 55.0 10.3 33.5 19.8 47.7 <2.2 <2.2 <2.2 <2.2 (260) (80) (30) (20) (20) (20) Trace (15.1) (15.1) (4.9) (11.0) (1.1) (1.4) (11.1) (13.6) 650 810 550 530 280 370 Metals 75.1 80.6 34.0 45.0 11.5 35.2 <4.1 12.2 <2.2 <2.2 <2.2 <2.2 (170) (100) (40) (20) (40) (40) (6.4) (3.4) (5.0) (7.0) (1.8) (2.4) (0.7) 690 740 570 550 420 600 86.8 110 26.0 40.0 8.9 32.9 <4.1 5.5 <2.2 <2.2 <2.2 <2.2 (120) (150) (30) (50) (50) (70) (24.5) (35.3) (4.2) (2.9) (1.3) (1.1) (1.4) 510 500 500 550 380 520 77.2 74.7 120 35.2 11.9 35.2 4.9 8.9 <2.2 <2.2 <2.2 <2.2 (180) (160) (100) (70) (140) (120) (7.0) (6.8) (15.4) (10.1) (2.1) (10.1) (2.6) (3.1) Table 10, Mean and Std. Dev. Concentration of Metals Measured in Control Blocks Analyte Concentration(g/g) Ag Al As Ba Ca Cd Cr Cu Fe K Mg Mn Na Ni Pb Se Zn <1.1 32300(11100) <5 190 (50) 23000 (6900) <10 7.8 (1.3) 24 (12) 14500 (810) 5800 (1900) 1100(380) 170 (10) 28900 (3200) 8.6(2.1) <0.25 <2.2 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 fulfilment of Cooperative Agreement No. CR818172-01-0, by the Research Foun- dation of the State University of New York under the sponsorship of the U.S. Envi- ronmental Protection Agency. ------- 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) CombustorAsh 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 BULK RATE POSTAGE & FEES PAID EPA PERMIT No. G-35 EPA/600/SR-95/129 ------- |