vvEPA United States Environmental Protection Agency Solid Waste and Emergency Response (OS-305) EPA/530-SW-90-029B March 1990 Characterization of Municipal Waste Combustion Ash, Ash Extracts, and Leachates Executive Summary ------- Printed on paper that contains at least 50 percent recycled fiber. ------- EXECUTIVE SUMMARY This report has been prepared for the United States Environmental Protection Agency (EPA) and the Coalition on Resource Recovery and the Environment (CORRE). EPA and CORRE have cosponsored this study, conducted by NUS Corporation, to enhance the data base on the characteristics of Municipal Waste Combustion (MWC) ashes, laboratory extracts of MWC ashes, and leachates from MWC ash disposal facilities. The Coalition on Resource Recovery and the Environment (CORRE) was established to provide credible information about resource recovery and associated environmental issues to the public and to public officials. In providing information, CORRE takes no position as to the appropriateness of one technology compared to others. CORRE recognizes that successful waste management is an integrated utilization of many technologies which taken as a whole, are best selected by an informed public and informed public officials. Incineration of municipal solid waste (MSW) has become an important waste disposal alternative because it provides an effective means of reducing the volume of MSW as well as an important source of energy recovery. .Currently, 10 percent of MSW is incinerated. Based on the number of municipal waste combustion (MWC) facilities being planned across the country, this percentage is expected to increase to roughly 16-25 percent by the year 2000. As incineration has grown in popularity, so has concern over the management of increasing volumes of ash. Ashes from MWC facilities have, on occasion, exhibited a hazardous waste characteristic as determined by the EP Toxicity Test. The debate regarding the regulatory status of ash and the representativeness and validity of the EP test continues. Congress is considering several legislative initiatives that would give EPA clear authority to develop special management standards for ash under Subtitle D of RCRA. To conduct this study, NUS collected combined bottom and fly ash samples from five mass-burn MWC facilities and leachate samples from the companion ash disposal facilities. R339911 ES-1 ------- The facilities sampled were selected by CORRE to meet the following criteria: The facilities were to be state-of-the-art facilities equipped with a variety of pollution control equipment. The facilities were to be located in different regions of the United States. The companion ash disposal facilities were to be equipped with leachate collection systems or some means of collecting leachate samples. The identities of the facilities are being held in confidence. The ash and leachate samples collected were analyzed for the Appendix IX semivolatile compounds, polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs), metals for which Federal primary and secondary drinking water standards exist, and several miscellaneous conventional compounds. In addition, the ash samples were analyzed for major components in the form of oxides. The ash samples were also subjected to six laboratory extraction procedures and the extracts were then analyzed for the same compounds as the ash samples. The following six extraction procedures were used during this study: Acid Number 1 (EP-TOX),. Acid Number 2 (TCLP Fluid No. 1). Acid Number 3 (TCLP Fluid No. 2). Deionized Water (Method SW-924), also known as the Monofill Waste Extraction Procedure (MWEP). CQ2 satu rated deionized water. Simulated acid rain. These extraction procedures have been used separately by a variety of researchers on MWC ashes but never have all six procedures been used on the same MWC ashes. This study was designed to compare the analytical results of the extracts from all six procedures with each other and with leachate collected from the ash disposal facilities used by the MWC facilities. R339911 ES-2 ------- All sampling, laboratory preparation, and laboratory analysis followed stringent EPA quality assurance/quality control (QA/QC) procedures. The work was performed in accordance with the Work Plan (Appendix A) prepared by NUS for this project and with a QA/QC Plan prepared by NUS and approved by EPA. A detailed listing of the positive results is presented in a data base which is included in this Report as Appendix B (Ash), Appendix C (Leachate), and Appendix D (Ash Extracts). The results in the data base are presented as reported by the laboratories, complete with the laboratory's qualifications. Summaries of the results are presented in Sections 2.0 through 7.0. These summaries include the laboratory's qualifiers and also qualifiers placed on the data as a result of data validation. When the laboratories did not report a positive value for a compound (i.e., the compound was not present above laboratory detection limits), the compound was reported as not detected (ND) in the tables in the text. The laboratory detection limits are the method detection limits for each specific method, unless interferences were encountered during the analysis. When interferences occurred, the laboratory adjusted the method detection jimits by an appropriate dilution factor. The analytical methods used in this study were selected so that.the method detection limits were well below present levels of human, environmental, or regulatory concerns. The EPA publication "Interim Procedures for Estimating Risk Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-Dioxins and Dibenzofurans (CDDs and CDFs)" was used to evaluate the dioxin data. These procedures use Toxicity Equivalency Factors (TEFs) to express the concentrations of the different isomers and homologs as an equivalent amount of 2,3,7,8-Tetrachloro Dibenzo-p-Dioxin (2,3,7,8-TCDD). The Toxicity Equivalents, as calculated by using the TEFs, are then. totaled and compared to the Centers for Disease Control (CDC) recommended upper level of 2,3,7,8-TCDD Toxicity Equivalency of 1 part per billion in residential soil (Kimbrough, 1984). The major features of the five MWC facilities are provided in Table ES-1, and the major features of the MWC Ash Disposal Facilities are provided in Table ES-2, Pertinent information regarding the operating conditions of the MWC facilities, as well as information about the air pollution control equipment used by the facilities, is also provided in Table ES-1. R339911 ES-3 ------- 30 to U) TABLE ES-1 MAJOR FEATURES OF MWC FAQLITIES Operational Features Facility Type Startup Date Capacity Combustion Temperature Temperature of air entering the boiler Volume of air entering boiler C«i»i«-*-ja f\f act* quench water Air pollution control equipment Approximate waste composition ZA Energy recovery, continuous feed, reverse- reciprocating grate. May 1986 275 tons/day/boiler 2 boilers 1,800-2.000°F at stoker Under fire: 250°F Over fire: ambient Under fire: 70,000-90,000 Ib/hour Over fire: 41,000 Ib/hour Clr\s\r rtr^ine mln t*i^+t*r Lime slurry is injected into flue gas after economizer, fabric filter baghouses. Residential: 40% Commercial/ Light Industrial: 60% ZB Energy recovery, continuous feed, reciprocating grate. Early 1987 75 - 100 tons/day/boiler 2 boilers 1,800°F Under fire: ambient Over fire: ambient Under fire: 1 0,890 cuft/min Over fire: 5,900 cu ft/min /VhAt tit A +A»*4A.- vnj-J U.A;IA^ blowdowns, septic system discharge, floor drains. Dry lime is injected into flue gas after economizer, fabric filter baghouses. Fly ash has phosphoric acid added to it and is agglomerated before being mixed with bottom ash. Residential: 80% Commercial/ Light Industrial: 20% Facilities ZC Energy recovery, continuous feed, reverse- reciprocating grate. January 1987 400 tons/day/boiler 3 boilers 1,750-1.800°F Under fire: 380°F Over fire: ambient Under fire: 34,000 ft3/min Over fire: 11,000ft3/min T^.^;-..,., «.«{!. .,»+ *,^_ neighboring sewage treatment plant. Electrostatic precipitators. Residential: 60% Commercial/ Light Industrial: 40% ZD Energy recovery, continuous feed, reciprocating grate. 1975 750 tons/day/boiler 2 boilers 1 500-1 700UF flue gas as it enters superheater Under fire: ambient Over fire: ambient Under fire: 48,000 ft3/m in Over fire: 32,000 ft3/min /- I' J U -1 blowdowns. Electrostatic precipitators Residential: 90% Commercial/ Light Industrial: 10% ZE Energy recovery, continuous feed, reciprocating grate. September 1987 75^ tons/day/boiler 2 boilers 1,800°F at the grate Under fire: ambient Over fire: ambient ../ . t . vvasiewdier irom piani processes. Lime slurry is injected into flue gas after economizer, electrostatic precipitators. Fly ash has water added to it and is agglomerated before being mixed with bottom ash. Residential: 65% Commercial/ Light Industrial: 35% I/I ------- TABLE ES-1 MAJOR FEATURES OF MWC FACILITIES PAGE TWO Operational Features Amount of electricity generated Amount of electricity used internally by facility Material removed from incoming refuse Material removed from ash Facilities ZA 13.1 megawatts/hour 1.7 megawatts/hour Large appliances, other unacceptable material diverted to demolition landfill. Ferrous metal removed from ash at the MWC facility. ZB 4.5 megawatts/hour 0.63 megawatts/hour Large appliances, material that will not pass through the boilers. None. ZC 29 megawatts/hour 2.5 megawatts/hour Large appliances, material that will not pass through the boilers. Ferrous metal removed from ash at the MWC facility. ZD 35 megawatts/hour 2.5 to 3.5 megawatts/hour Large appliances, material that wilt not pass through the boilers. Ferrous metal removed from ash at the MWC facility. ZE 45 megawatts/hour 7 megawatts/hour Large appliances, material that will not pass through the boilers. Items greater than 10 inches in diameter, m v> ------- U> ID TABLE ES-2 MAJOR FEATURES OF MWC ASH DISPOSAL FACILITIES Operational Features Facility Type Startup Date Disposal Capacity Amount of Ash Disposed Materials other than Ash disposed of Leachate Collection System Ash ZA Monofill - single clay liner 1986 83.400 cubic yards 150 tons/day . None Perforated PVC pipe in a coarse aggregate envelope Final cover -soil and HOPE Only as bulldozer spreads ash in ash fill. Facilities ZB Monofill - double liner (HOPE and compacted till soil) October 1988 90,000-100,000 tons 60 tons/day None Slotted HOPE Daily cover - sand. Non working face covered by plastic to limit leachate generation Bulldozer spreads and compacts ash in 8- 1 2 inch ifts. ZC Codisposed facility - bottom-clay liner synthetic sidewall liners Landfill -1984 Ash Disposal- 1985 Total capacity 9 million tons 400,000 tons/year. 40% ash (2/3 of ash from ZC MWC facility). Non-burnable materials from 2 MWC facilities. Overflow from 2nd MWC facility. Main header - PVC collection trenches - gravel with fabric filter Daily -native soil and shredded tires. ntermediate - native soils. inal - native soils. Track mounted compactor. ZD Monofill - unlined. Ash is placed over trash deposited before 1975 1975 Remaining capacity - 990,000 tons (6 years) 450 tons/day None None - leachate samples were'collected from well points installed in the ash Daily cover -soil. Intermediate -soil compacted to 10-fi Dermeability. :inal- clay or HOPE. Only as bulldozer spreads ash in ash fill. ZE Monofill - double liner (HOPE and clay) 1987 Pe ..utted for 20 years, approximately 3.8 million tons 525 tons/day None Slotted HOPE Daily cover -soil. Intermediate -soil compacted to 10'6 Jermeability. Final -clay of HOPE Vibrating roller. i m t/> a\ ------- The major findings of the ash sampling and analyses.during this study are described in the following paragraphs. Of the five ash samples (one from each facility) analyzed for the Appendix IX semivolatile compounds, four samples contained bis(2-ethylhexyl)phthalate, three contained di-n-butyl phthalate, and one contained di-n-octyl phthalate. Two PAHs, phenanthrene and fluoranthene, were detected in only one of the five ash samples. These semi-volatile compounds were detected in the parts per billion (ppb) range. The results for the five ash samples (one from each facility) analyzed for PCDDs/PCDFs are presented in Table ES-3. This table also includes the calculated Toxicity Equivalents (TE) for each homolog of PCDD/PCDF. These TEs were calculated using EPA's methodology (EPA, March 1987). The data in this table indicate that PCDDs/PCDFs were found at extremely low levels in each ash sample. The Total TE for each ash sample was below the Centers for Disease Control (CDC) recommended 2,3,7,8-TCDD Toxicity Equivalency limit of 1 part per billion in residential soil (Kimbrough, 1984). All 25 of the ash samples (five daily composites from each facility) were analyzed for the metals on the primary and secondary drinking water standards lists as well as for the oxides of five major ash components. Although, the results from these analyses indicate that the ash is heterogeneous, this heterogenicity appears to have been reduced by the care taken when compositing the ash samples during this study. Comparison of the results of this study with results reported in the literature (EPA, October 1987) indicates that the variability of results for each compound appears to have been reduced in this study. Metals showing the widest range of concentrations among samples collected at each facility included barium (ZB); cadmium (ZB); chromium (ZD, ZE); copper (ZA, ZB, ZC); lead (ZD); manganese (ZA, ZC); mercury (ZE); zinc (ZB, ZD, ZE); and silicon dioxide (ZA). Metals showing the widest variation of concentrations between the facilities included barium (results for Facility ZC are lower than the results for the other facilities); iron (results for each facility vary from all of the other facilities); lead (results for Facility ZD are higher than the results for the other facilities); mercury (results for Facilities ZC and ZD are lower than the results for the other facilities); R339911 ES-7 ------- 30 U> U) TABLE ES-3 ASH DIOXIN RESULTS Compound 2,3,7,8-TCDD Other TCDD 2,3,7,8-TCDF Other TCDF 1,2,3.7,'8-PeCDD Other PeCDD 1.2,3,7,8-PeCDF 2.3.4.7,8-PeCDF Other PeCDF 1,2,3,4,7,8-HXCDD 1,2,3,6,7.8-HxCDD 1,2,3,7,8.9-HXCDD Other HXCDD 1,2,3,4,7.8-HXCDF 1. 2,3,6, 7.8-HxCDF 1,2,3,7,8,9-HXCDF 2,3A3.7,8-HXCDF Other HXCDF 1,2,3,4,6,7,8-HpCDD Other HpCOD 1, 2,3,4,6, 7,8-HpCDF 123478 9-HpCDF Other HpCDF OCDD OCDF TOTAL TEs Toxicity Equivalency Factor (TEF)0> 1 0.01 0.1 0.001 0.5 0.005 01 0.1 0.001 0.04 0.04 0.04 0.0004 0.01 0.01 0.01 0.01 0.0001 0.001 0.00001 0.001 0 001 0.00001 0 . 0 Samples (pg/g or ppt) ZA-AH-003 Value 10 206 263 1,688 33 317 61 46 484 12 17 28 154 74 131 36 5 281 159 140 139 g 51 313 66 Toxicity Equivalents 10 2.06 26.3 .1.69 16.5 1.59 6.1 4.6 0.484 0.48 0.68 1.12 0.062 0.74 1.31 0.36 0.05 0.0281 0.159 0.0014 0.139 0 008 0.00051 0 0 74.5 ZB-AH-001 Value 24 351 617 3,721 118 759 194 162 1,527 40 34 79 342 336 524 127 54 939 319 288 539 4R 197 544 243 Toxicity Equivalents 24 3.51 61.7 3.72 59 3.80 19.4 16.2 1.53 1.6 1.36 3.16 0.137 3.36 5.24 1.27 0.54 0.0939 0.319 0.00288 0.539 OfldR 000197 0 0 211 ZC-AH-003 Value 16 281 236' 1,208 71 1,051 64 56 607 66 90 120 925 218 279 193 70 635 1,849 1,511 653 R3 254 6,906 563 Toxicity Equivalents 16 2.81 23.6 1.21 35.5 5.26 6.4 5.6 0.607 2.64 3.6 4.8 0.37 2.18 2.79 1.93 0.70 0.0635 1.85 0.0151 0.653 A nft3 0 00254 0 0 119 ZD-AH-003 Value 35 541 626 2,633 NO 1,910 151 171 1,736 86 148 194 853 654 660 479 124 1,686 1.555 1,384 1,842 384 4,519 893 -- - - Toxicity Equivalents 35 5.41 62.6 2.63 0 9.55 15.1 17.1 1.74 3.44 5.92 7.76 0.34 6.54 6.60 4.79 1.24 0.169 1.56 0.0138 1 84 . 0.00384 0 0 189 ZE-AH-003 Value 10 120 176 1,136 35 248 52 43 448 11 11 22 "104 95 134 45 20 280 122 0 155 ID 44 294 59 - -- -- Toxicity Equivalents 10 1.2 17.6 1.14 17.5 1.24 5.2 4.3 0.448 0.44 0.44 0.88 0.042 0.95 1.34 0.45 0.20 0.028 0.122 0 , 0.155 0.016 0.00044 0 0 ' 63.7 do O) Toxicity Equivalency factors are EPA's current recommended Factors, (EPA, March 1987). ND Not detected below 221 pg/g. ------- sodium (results for Facilities ZD and ZE are lower than the results for the other facilities); calcium oxide (the results for Facilities ZA and ZB are higher than the results for the other facilities); and silicon dioxide (the results for Facility ZC are higher than the results for the other facilities). Some additional findings of the ash sampling and analyses are as follows: « The ashes are alkaline with the pH ranging from 10.36 to 11.85. The ashes are rich in chlorides and sulfates. The total soJuble solids in the ashes varied from 6,440 to 65,800 ppm. The ashes contained unburnt total organic carbon (TOC) ranging from 4,060 ppm (0.4 percent) to 53,200 ppm (5.32 percent). The major findings of the leachate sampling and analysis during this study are summarized in the following paragraphs. Only four Appendix IX semivolatile compounds were found in the ieachates from the ash disposal facilities. Benzoic acid was found in both leachate samples collected at one of the five ash disposal facilities. Phenol, 3-methylphenol, and 4-methylphenol were found in some of the leachate samples from one of the other facilities. All of these compounds were detected at very low levels (2-73 ppb). PCDDs/PCDFs were only found in the leachate from one facility. The homologs found are the more highly chlorinated homologs. The data obtained during this study appears to indicate that PCDDs/PCDFs do not readily leach out of the ash in the ash disposal facilities. The low levels found in the Ieachates of the one facility probably originated from the solids found within the leachate samples because these samples were not filtered nor centrifuged prior to analysis. None of the leachate samples exceeded the EP Toxicity Maximum Allowable Limits established for the eight metals in Section 261.24 of 40 CFR 261. In addition, the data from this study indicate that although the Ieachates are not used for drinking purposes, they are close to being acceptable for drinking water use, as far as the metals are concerned. R339911 ES-9 ------- Some other findings of the leachate sampling and analyses are as follows: Sulfate values ranged from 14.4 mg/L to 5,080 mg/L, while Total Dissolved Solids (TDS) ranged from 924 mg/L to 41,000 mg/L. The field pH values ranged from 5.2 to 7.4. Ammonia (4.18-77.4 mg/L) and nitrate (0.01-0.45 mg/L) were present in almost all leachate samples. Total Organic Carbon values ranged from 10.6 to 420 ppm. The major findings from the analysis of the ash extracts during this study are summarized as follows: Of the five composite samples of the deionized water (SW-924) extracts analyzed for the Appendix IX semivolatile compounds (one from each facility), only one sample contained low levels of benzoic acid (0.130 ppm). None of the extracts contained PCDDs/PCDFs. These data confirm the findings of the actual field leachate samples that PCDDs/PCDFs are not readily leached from the ash. The data obtained during the metals analyses of the ash extracts indicate that, in general, the extracts from the EP Toxicity, the TCLP1, and the TCLP2 extraction procedures have higher metals content than the extracts from the deionized water (SW-924), the CO2, and the Simulated Acid Rain (SAR) extraction procedures. The EP Toxicity Maximum Allowable Limits for lead and cadmium were frequently exceeded by the extracts from the EP Toxicity, TCLP 1, and TCLP 2 extraction procedures. One of the extracts from the EP Toxicity extraction procedure also exceeded the EP Toxicity Maximum Allowable Limit for mercury. None of the extracts from the deionized water (SW-924), the CO2, and the Simulated Acid Rain (SAR) extraction procedures exceeded the EP Toxicity Maximum Allowable Limits. In addition, the majority of the extracts from these three extraction procedures also met the Primary and Secondary Drinking Water Standards for metals R339911 ES-10 ------- Table ES-4 compares the range of concentrations of the metals analyses of the ash extracts with the range of concentrations for leach-ate as reported in the literature (EPA, October 1987). and the range of concentrations for the leachates as determined in this study. For the facilities sampled during this study, the data in Table ES-4 indicate that the extracts from the deionized water (SW-924), the CC>2, and the SAR extraction procedures simulated the concentrations for lead and cadmium in the field leachates better than the extracts from the other three extraction procedures. R339911 ES-11 ------- 30 UJ TABLE ES-4 COMPARISON OF ASH EXTRACT METAL ANALYSES RESULTS WITH LEACHATE METAL ANALYSES RESULTS Parameter Arsenic Barium Cadmium Chromium Copper Iron Lead Manganese Mercury Selenium Silver Sodium Zinc EPTOX Extracts 23-455 25-1,200 ND-86 24-5,170 ND-82,000 ND- 19,700 250-8,540 ND-203 ND ND 33,600- 225,000 67-95,600 TCLP1 Extracts ND 161-1,850 ND-1,150 ND-8.0 5-858 ND-7,220 ND-1 0,500 ND-5,170 ND-3.8 ND ND 1.380,000- 1,640,000 9.7-79,500 Samples (ng/L) TCLP2 Extracts ND-60 12-809 ND-1, 560 ND-799 5.4-1,400 ND-1 62,000 ND-26,400 3.8-7,370 ND-4.6 ND ND 38,700- 228,000 26-164,000 CO2 Extracts ND-53 126-530 ND-354 ND-9.8 8.8-620 ND-304 ND-504 ND-2,390 ND-1 55 ND ND-1 6 24,800- 168,000 5-127,000 DIH2O Extracts ND-45 139-3,050 ND-7.6 ND-1 6 12-534 ND-115 ND-3,410 ND-20 ND-0.96 ND ND 24,100- 209,000 5.4-1,340 SAR Extracts ND 129-3,960 ND-6.0 ND-10 8.5-610 ND-97 ND-3,940 ND-6.4 ND-1.1 ND-23 ND 24,200- 201,000 12-1,290 Leachate (Literature)O) 5-218 1,000 ND-44 6-1,530 22-24,000 168- 121,000 12-2,920 103-4,570 1-8 2.5-37 70 200,000- 4,000,000 ND-3,300 Leachate (CORRE) ND-400 ND-9,220 ND-4 ND-32 ND-1 2 108-10,500 ND-54 310-18,500 ND ND-340 ND 188,000- 3,800,000 5.2-370 m NJ ------- s UJ 10 TABLE ES-4 COMPARISON OF ASH EXTRACT METAL ANALYSES RESULTS WITH LEACHATE METAL ANALYSES RESULTS PAGE TWO Parameter Aluminum Oxide* Calcium Oxide* Magnesium Oxide* Potassium Monoxide* Silicon Dioxide* Samples (pg/L) EPTOX Extracts ND-1 50.000 592,000- 4,810.000 27,300- 130;000 10,100- 189,000 5,090-98,700 TCLP1 Extracts ND-62,800 666,000- 2,750,000 55-375,000 14,600- 210,000 379-51,700 TCLP2 Extracts ND-1 52,000 692,000- 3,640,000 623-137,000 15,100- 1,110,00 820-143,000 COj Extracts ND-90,700 398,000- 1,920,000 207-59,300 12,300- 155,000 418-71,800 DIH2O Extracts ND-203,000 . 141,000- 1,740,000 21-379 13,100- 189,000 402-3,990 SAR Extracts ND-1 18,000 142,000- 1,800,000 12-430 14,500- 181,000 364-3,770 Leachate (Literature)C) NR 21,000 NR 21,500 NR Leachate (CORRE) ND-920 64,600- 8,390,000 14,800- 367,000 79,700- 1,620,000 470-15,300 m i/> ND Not Detected. . NR Not Reported in the literature. <» EPA, October 1987. * The ash extracts were analyzed as ions for these compounds and reported as oxides. The leachates were analyzed and are reported as ions for these compounds. ------- ------- |