Smallmvolume hazardous-waste Masood Ghasserni Sandra Quinlivan Michael Powers T R W Environmental Engineering Division Redondo Beach, CaliJ 92078 Most inventories of hazardouswaste generation and management carried out in the U S . in recent years have been concerned primarily with large-volume generators in the manufacturing industries (Standard Industrial Classifications [SICs] 20-39). While small generators are responsible for only a small portion of the hazardous wastes produced in this country, the number of small generators far exceeds that of large generators. Moreover, because of the ubiquitous small generators and the nature of difficulties in regulating them, smallgenerator wastes can have considerable environmental impact.
Regulatory background Section 3002 of the Resource Conservation and Recovery Act of 1976 (RCRA) requires the EPA administrator to promulgate regulations governing the generators of hazardous wastes. These regulations, first proposed by EPA on Dec. 18, 1978 (40 CFR Part 250, p 58946), contain a provision for conditional exemption of “small” generators, defined as those producing and disposing of less than 100 kg/month of hazardous wastes. The proposed “cutoff” level was based on very limited survey data indicating that, at least for the manufacturing industries, an exemption cutoff of 100 kg/month should allow for the control of 99.6-99.9% of potentially hazardous waste generated, while at the same time excluding approximately 60% of the generators. Acknowledging the difficulty of balancing the need to protect human health and the environment with the need to hold the administrative and economic burdens of waste management within reasonable and practical limits, the preamble to 786
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Here are estimates of the number, geographic d ist ri b u t ion, major contributing industries, as well as an analysis of the technical impacts of a conditional exempt ion regulation f o r such generators
the proposed regulations suggests alternative regulatory approaches and solicited comments and ideas on these approaches, The profiles presented here were developed in connection with a major study for the EPA Office of Solid Waste, and aim at providing a more comprehensive data base for addressing the issue of sniall generators.
An SIC-by-SIC approach An industry- by-indus t ry (SICby-SIC) assessment approach was used to develop composite national and EPA regional profiles for small-volume hazardous-waste generators. For analysis purposes, a waste-generation rate of 5000 kg/month was considered as a probable upper limit for defining small generators. A11 SICs listed in the “Standard Industrial Classification Manual” were examined individually, and those which could be readily identified as nongenerators of hazardous wastes (such as SIC 64, Insurance Agents, Brokers, and Service) were eliminated from further consideration. Farmers and retailers, except gasoline service stations, were eliminated also. This preliminary screening was followed by a more detailed evaluation which led to the elimination of additional SICS on the basis of being nonhazardouswaste generators, large generators, or generators of wastes covered under other regulations. The SICs determined to contain small generators were subjected to an in-depth evaluation culminating in the development of a waste-generation profile for each S I C or SIC group. Each profile consists of estimates, on a national or EPA regional basis, of the number of generators, and waste quantities in 13 waste-generation categories: less than 100 kg/month; 100-200 kg/month, 200-300 kg/ month, and so on up to 900-1000 kg/month; 1000-2000 kg/month; 2000-5000 kg/month; and greater than 5000 kg/month. The profiles for
0013-936X/80/0914-0786$01 .OO/O
@ 1980 American Chemical Society
individual SICS were aggregated to develop overall national or EPA regional profiles for small generators. Based on the Dec. 18, 1978 proposed guidelines and regulations, a waste is considered hazardous if it appears on the EPA’slist of hazardous wastes or if it meets certain ignitability, corrosivity, reactivity, or toxicity criteria. EPA will revise and update its list of hazardous wastes as new data become available on the characteristics of various wastes and the environmental significance of waste components. Nearly all of the wastes appearing on the EPA’s Dec. 18, 1978 hazardous-wastes list are from the manufacturing industries, many of which have been the subject of previous industry studies. Since a large number of industries reviewed in the present study were from the nonmanufacturing sector, considerable technical and engineering judgment had to be exercised in determining whether or not wastes which were not listed, or wastes for which ignitability, corrosivity, reactivity, and toxicity data were not available, should be considered hazardous. In the present study, a waste was considered potentially hazardous if it was judged to: possess characteristics similar to (or to contain components of) the listed wastes contain constituents which, based on published literature data for pure substances, would meet the hazardous waste criteria for toxicity, reactivity, corrosivity, and the like. Because waste oil (a listed hazardous waste) and waste-oil generators have certain unique features (for example, large number of generators, fuel value of waste, and the existence of a waste-oil-refining industry) which may warrant separate and special regulatory considerations, they were excluded from the present analysis.
Sources of information The primary information sources used for the SIC-by-SIC assessment, Volume 14, Number 7, July 1980 787
and for developing waste-generation profiles, included hazardous-waste surveys conducted by various states, data files of EPA and its contractors. trade associations, samples of individual establishments in each SIC, and 1976 Census Bureau data on the number and geographic distribution of establishments in each SIC. All 50 states and 10 EPA regional offices were contacted for data on hazardous-waste generators. Evaluation of the state data led to the selection of 20 states whose information constitutes the “state data base” for this study. These 20 states are Alaska, Arizona, California, Connecticut, Georgia, Iowa, Kansas, Kentucky, Maine, Massachusetts, Minnesota, Mississippi, Missouri, New Hampshire, New Mexico, New York, Oklahoma, Rhode Island, Texas, and Washington. The state data base, which was computerized and subsequently used for developing many waste-generation profiles (primarily for the manufacturing SICS), covers 2553 establishments in 366 two-, three-, and four-digit SICs. Seventy-four trade associations provided information on hazardouswaste generation and management practices of their member firms, and assisted in obtaining such information from individual establishments. Of the very large number of establishments contacted, 342 provided data or general information on the nature of their operation, waste quantities produced, and disposal methods employed. Estimates Several options were investigated for estimating the number of generators in various waste-generation-rate categories and associated waste quantities for an SIC. Exceptions were made for very limited cases in which “per employee” or “per unit production capacity” waste-generation data were used to estimate waste quantities (because of the lack of other data). Otherwise, the waste-generation profile for an S I C was estimated by projecting the observed distribution of waste-generation rates for the plants in the state data base-or for plants .whose data were obtained from other sources-to the nation as a whole or to an EPA region. The following procedure was used for extending the data to the nation or EPA region: The monthly waste-generation rates for establishments in the sample were rank-ordered, and cumulative percentages of the number of plants generating waste quantities less than indicated rates .were calculated. These data were plotted on normal788 Environmental Science a Technology
probability and lognormal-probability papers to obtain the line of best fit. The distribution indicated by the line of best fit was then applied to the census data on the total number of establishments in the nation (or region) for an SIC. Allowances were made for the estimated fractions of plants which, based upon the survey results for Iowa, Massachusetts, and NewYork, were considered “zero” generators and ‘‘large’’ generators. The total waste associated with establishments in a waste-generationrate category was calculated by multiplying the number of establishments in the category by the “midpoint” waste-generation rate for that category. A computer program was developed and used to carry out the distribution analysis based on samples and the profile calculations. The computer-calculated overall national profiles were adjusted downward to allow for the estimated number of generators which recycle wastes and the estimated waste quantities recycled. The percentage of small generators employing waste recycling and the percentage of waste they recycled were estimated, based on the aggregated state data and information collected from other sources. Profiles of small generators The generators producing 5000 kg/month or less of hazardous wastes are estimated to number close to 722 000 and to generate 1.4 million metric tons of wastes annually. These generators account for 94.7% of all
generators and 2.3% of the total waste produced. Figure I is a graphical presentation of the estimated number of generators and waste quantities associated with various waste-generation categories. Even though there is a larger percentage of small generators, their contributions to the total quantity of hazardous waste produced in the nation are very low. Thus, while generators producing 100 kg/month or less of hazardous waste account for 74% of the total number of generators, the waste produced by these generators amounts to less than 0.3% of the total waste produced nationally. Waste-generation profiles indicate that an estimated 17% of all generators are in the manufacturing SICs and that they account for approximately 96%of the total waste. Establishments in the nonmanufacturing industries account for 83% of all generators and 4% of the total waste. Small generators in the manufacturing industries account for 13% of all small generators and 47% of waste produced by small generators (compared to 87% and 53%, respectively, for small generators in the nonmanufacturing industries). The average waste-generation rates for small generators in the manufacturing and nonmanufacturing sectors are 576 kg/month and 98 kg/month, respectively. The major contributing SICs in the nonmanufacturing sector are S I C 17 (Construction-Special Trade), SIC 55 (Automobile Dealers and Gasoline Service Stations), S I C 72 (Personal Services), and S I C 75 (Automotive
Repair Services). These SICs collectively account for 79% of the small generators and 78% of the waste in the nonmanufacturing sector. The major contributing SICs in the manufacturing segment are S I C 27 (Printing and Publishing), SIC 34 (Fabricated Metal Products), and S I C 35 (Machinery, Except Electrical), which together account for 58% of the small generators and 47% of the waste in the manufacturing sector. Figure 2 presents the distribution of small generators and associated waste quantities among the 10 EPA regions. As indicated by the data, EPA Regions 2,4,5, and 9 have the greatest number of small generators and produce the largest quantities of waste.
Disposal practices Table 1 shows the percentage distribution of small generators reporting various waste-disposal methods, and the quantity of waste handled by each method. According to the data, 51% of the small generators utilize landfill disposal to handle 46% of the total waste produced. Respondents to the state surveys who indicated waste disposal by landfilling, referred to the disposal site/method by a variety of names, including “sanitary” landfills, “industrial” landfills, “county dumps,” “state-approved” landfills, and “municipal” landfills. Except in states such as California and Texas, where landfill classification systems exist and landfills specifically designated for hazardous wastes are used by the respondents, it is believed that the majority of landfills referred to in the state surveys are sanitary landfills which may or may not meet the sanitary design requirements proposed under R C R A Section 4004. As shown in Table 1, recycling is the second most prevalent disposal method. The percentage of generators reporting other disposal methods and the percentage of waste handled by such methods are 26% and 33%, respectively. The percentage of small generators using on-site disposal and the percentage of waste handled at on-site facilities are 22% and 23% each. Assuming that the state data are representative of disposal practices for small generators in the manufacturing SICs, and that small generators in the nonmanufacturing SICs largely use landfills for waste disposal (based on data from sample plots), estimates were made of the number of small generators in the US.using the various disposal methods and of the quantity of waste handled by each method. These estimates, shown in Figure 1 along with the total number
TABLE 1
Percent distributionof small waste gener tities in the state data base by disposal Disposal m a t M
Landfilt Incineration Lagoon Deep-well injection Landspreading Others Recycle Total, %
2.9 1.5 2.6 0.1 5.8 6.6 2.6 P2.1
48.4
2.6 0.3 2.2 1 .a 2.8 20‘4 77.9
of waste generators, indicate that on an aggregated level, 96% of the estimated 722 000 small generators which dispose of waste by methods other than recycling use landfills, and 79% of the estimated 1.4 million metric tons of wastes produced each year by small generators are disposed in landfills.
Utility of profiles The profiles developed have been used to analyze potential technical impacts which may be associated with two of the several options available for regulating small-volume hazardouswaste generators. The two options considered are: quantity option-Generators that accumulate for disposal or produce hazardous waste in quantities not exceeding a set amount are exempt from rigorous regulations (for instance, the manifest requirements of R C R A Section 3002 and the waste-management requirements of R C R A Section 3004). phasing option-This is the same as the quantity option, except that the cutoff is initially set at a high level, but reduced in subsequent years to accommodate limited administrative resources in the first years of the regulatory program. Impacts Figure 3 presents plots of the percentages of generators and associated waste quantities which would be excluded from a conditional exemptiontype regulation system as a function of waste quantity exemption cutoff. Since the greatest number of small generators produce very little waste. a cutoff level of 100 kg/month would exclude
74% of all generators and 0.23% of all waste. As the cutoff level is raised, the increase in the percentage of generators excluded becomes less dramatic, while the percentage of waste excluded increases significantly. Thus, a 1000 kg/month cutoff would entail exclusion of 9 1% of all generators and 1.O% of all waste. Since the great majority of small generators are in nonmanufacturing industries, the impact of lower exemption cutoffs would be much greater on these industries than on manufacturing industries. Examples of industries with all establishments in the less-than-100 kg/month wastegeneration-rate category are Horticultural Specialties (SIC 018), and Construction-Special Trade Contractors (SICs 171 1, 1742, etc.). At each waste-exemption cutoff, nonexempt generators would be required to dispose of hazardous waste in facilities meeting R C R A Subtitle C requirements; those exempted would dispose of wastes in facilities meeting R C R A Subtitle D requirements. Based on published estimates of the capacities of existing commercial hazardous-waste-management facilities, it appears that severe capacity deficits exist in EPA Regions 8 (which currently has no commercial facilities), 6 , 4 , and 1, even if the exemption cutoff is set as high as 5000 kg/month. On the other hand, hazardous-wastemanagement facilities in EPA Regions 5, 7, 9, and 10 have more than adequate capacities to handle hazardous wastes from all generators within their respective boundaries, regardless of the cutoff level. The diversion of wastes from small Volume 14, Number 7, July 1980
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-1GURE 3
Impact of waste exemption cutoff on hazardous waste generators
Hazardous waste exemption cutoff,kgimonth
generators to Subtitle D facilities would have an insignificant impact on site-capacity requirements for such facilities. At certain Subtitle D facilities, disposing of hazardous waste with a larger volume of nonhazardous waste may provide a sufficiently high “dilution” of the hazardous waste to minimize potential adverse disposal impacts.
Safety considerations Regulations requiring small hazardous-waste generators to segregate hazardous waste from nonhazardous refuse and to dispose of them in Subtitle C facilities would entail transporting the hazardous waste in more “concentrated” form over longer distances. This would increase the probability of transportation accidents involving hazardous wastes, as well as the severity of the impacts associated with such accidents. It is estimated that lowering the exemption cutoff from 5000 kg/month to 100 kg/month would increase the probable number of hazardous-waste-related transportation accidents by 120 accidents per year, and the quantity of waste involved in such accidents by 474 metric ‘ tons/y. A decrease in self-hauling and an increase in demand for commercial waste haulers would be expected. As long as the containers are properly labeled, the diversion of hazardous waste from small generators to RCRA Subtitle D facilities should not present special safety hazards to operators of these facilities, provided that the operators are trained to identify incompatible wastes and to properly handle 790
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flammable and explosive wastes. In fact, with the implementation of RCRA, the net quantity of hazardous wastes entering Subtitle D facilities should decrease, since hazardous wastes from large generators would be diverted to Subtitle C facilities. The acceptance of hazardous waste from small generators in Subtitle D facilities is not expected to be a major issue in public opposition to siting such facilities. However, the public will have to be convinced of the adequacy of the proposed design and controls, and the capabilities of the operating agency.
Phasing regulations The phasing option for regulating small generators initially places the exemption cutoff a t a high level, but reduces the cutoff in steps in subsequent years. This option will allow time for regulatory and enforcement agencies to build up the necessary manpower and administrative machinery for regulating all small generators. The phasing option may also provide the commercial hazardous-waste transportation and disposal industries with additional time to expand their capacities to meet the added demand caused by implementation of the new regulations. Under the phasing option, small generators may also be given additional time to develop resource recovery or implement in-plant changes to reduce hazardous-waste production. The phasing option is essentially an extension of the “quantity option” and, except for some “phasing” of the im-
pacts, the impacts and considerations discussed in connection with the quantity option would apply.
Acknowledgments This feature is excerpted from a twovolume report entitled “Technical Environmental Impacts of Various Approaches for Regulating Small Volume Hazardous Waste Generators Pursuant to the Resource Conservation and Recovery Act of 1976,” Dec. I O , 1979, prepared by TRW Environmental Engineering Division for the Office of Solid Waste, U.S. EPA, under Contract No. 68-03-2560 (Work Directives Nos. T5012, T5014, and T5015) and Contract No. 68-02-2613 (Work Assignment No. 27). Gratitude is expressed to the EPA Project Officer, Robert Holloway, and to other EPA technical and management staff, especially Steve Lingle, Jan Auerbach, and Hugh Holman, for their advice and guidance during the program. Additional key project staff at TRW included K. Crawford, J. Davis, 9. Edmondson, M. Engen, H. Fisher, S. Paige, P. Painter, G. Richard, K. Scheyer, R. Scofield, A. Takata, C. Yu, and K. Yu.
Masood Ghasserni is senior project engineer at T R W Enuironmental Engineering Diuision and directs proprams in hazardous-wasre managemen? and toxic-substances control. He has an undergraduate degree in ciuil enginefring and M.S. and Ph.D. degrees in environmental engineering, all f r o m the Oniuersity of Washington.
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