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Land Ban Exemption Granted to Armco Steel Co.
(now known as AK Steeel Co.)
Federal Register, Volume: 55 , Issue: 100 , Page: 21236 (55 FR 21236) ,
Wednesday, May 23, 1990
(FRL 3781 6)
Proposing the Granting of an Exemption to Armco Steel Company, L.P., for the Continued Injection of Hazardous Waste Subject to the Land Disposal Restrictions of the Hazardous and Solid Waste Amendments of 1984
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of Intent to Grant an Exemption to the Armco Steel Company, L.P. of Middletown, Ohio for the Continued Injection of Waste Pickle Liquor.
SUMMARY: The United States Environmental Protection Agency (USEPA or Agency) today is proposing to grant an exemption from the ban on disposal of hazardous wastes through injection wells to the Armco Steel Company, L.P. (Armco), of Middletown, Ohio. Armco may continue to inject Resource Conservation and Recovery Act (RCRA) regulated hazardous waste Code K062 (Waste Pickle Liquor) into two disposal wells, WDW No. 1 and WDW No. 2, after the prohibition date of August 8, 1990, if the exemption is granted. Armco submitted a petition to the EPA under 40 CFR part 148, which allows any person to petition the Administrator to determine whether its continued injection of certain hazardous wastes is harmful to human health or the environment. After a comprehensive review, the EPA has determined that there is a reasonable degree of certainty that Armco's injected waste will not migrate out of the injection zone over the next 10,000 years.
DATES: The USEPA is requesting public comments on today's proposed decision. Comments will be accepted until July 2, 1990. Comments postmarked after the close of the comment period will be stamped "Late". A public meeting and a public hearing will be scheduled for this proposed action and notice will be given in a local paper and to all people on a mailing list developed by the USEPA and the Ohio EPA. If you wish to be notified of the dates and locations of the public meeting and hearing, please contact the person listed below.
ADDRESSES: Submit written comments, by mail, to: United States Environmental Protection Agency Region V, Underground Injection Control Section (5WD TUB 9), 230 South Dearborn Street, Chicago, Illinois 60604, Attn: Edward P. Watters, Cheif.
FOR FURTHER INFORMATION CONTACT: Allen Melcer, Lead Petition Reviewer, UIC Section, Water Division, 5WD TUB 9, 230 S. Dearborn, Chicago, Illinois 60604, Office Telephone Number: (312) 886 1498.
SUPPLEMENTARY INFORMATION:
I. Background
A. Authority
The Hazardous and Solid Waste Amendments of 1984 (HSWA), enacted on November 8, 1984, impose substantial new responsibilities on those who handle hazardous waste. The amendments prohibit the continued land disposal of untreated hazardous waste beyond specified dates, unless the Administrator determines that the prohibition is not required in order to protect human health and the environment for as long as the waste remains hazardous (sections 3004(d)(1), (e)(1), (f)(2), and (g)(5) of RCRA). The statute specifically defined land disposal to include any placement of hazardous waste in an injection well (section 3004(k) of RCRA). After the effective date of prohibition, hazardous waste can be injected only under two circumstances: (1) When the waste has been treated in accordance with the requirements of 40 CFR part 268 pursuant to section 3004(m) of RCRA, (the EPA has adopted the same treatment standards for injected wastes in 40 CFR part 148, subpart B); or
(2) When the owner/operator has demonstrated that there will be no migration of hazardous constituents from the injection zone for as long as the waste remains hazardous. Applicants seeking an exemption from the ban must demonstrate either:
(a) That the waste undergoes a chemical transformation so as to no longer pose a
threat to human health and the environment; or
(b) That fluid flow is such that injected fluids would not migrate vertically upward
out of the injection zone or to a point of discharge in a period of 10,000 years
(40 CFR 148.20(a)).
The USEPA promulgated final regulations on July 26, 1988, (53 FR 28118) which govern the submission of petitions for exemption from the injection prohibition (40 CFR part 148). A time frame of 10,000 years was specified for the demonstration, not because migration after that time is of no concern, but because a demonstration which can meet a 10,000 year time frame will likely provide containment for a substantially longer time period, and also allow time for geochemical transformations which would render the waste nonhazardous or immobile. The Agency's standard thus does not imply that leakage will occur at some time after 10,000 years; rather, it is a showing that leakage will not occur within that time frame.
B. Facility Operation and Process
The Armco facility in Middletown, Ohio, is a fully integrated steel plant which produces flat rolled carbon steel for the automotive and appliance industries. The facility injects one liquid hazardous waste, waste pickle liquor, which is produced as a by product of steel pickling and galvanizing operations. This waste is injected into two on site Class I hazardous waste injection wells, WDW No. 1 and WDW No. 2, both injecting into the Mt. Simon Sandstone and the Middle Run Formation. WDW No. 1 was drilled and completed in 1967 and WDW No. 2 in 1968. The total volume of fluid injected is 156,500,000 gallons in WDW No. 1 and 131,700,000 gallons in WDW No. 2 as of September, 1989, for a combined yearly average of 14.8 million gallons.
C. Waste Minimization
Section 3002(b) of RCRA requires that generators of hazardous waste have "* * * a program in place to reduce the volume or quantity and toxicity of such waste to the degree determined by the generator to be economically practicable". Armco has implemented a waste minimization program which includes the installation of an automatic control system for acid feed and pickle bath temperature. This system minimizes the acid used as a raw material and thus minimizes the amount of waste generated by making continious acid feed adjustments as process conditions require. Armco sends waste pickle liquor to its plant in Ashland, Kentucky for acid regeneration. A total of 4,793,273 gallons of pickle liquor have been sent to the Ashland plant since January, 1989. Armco also uses the waste pickle liquor as an inorganic coagulant in the two wastewater treatment plants located within the plant boundaries. The acid regeneration and use as a commercial chemical substitute reduces the quantity of hazardous waste injection at Armco by 30 percent.
D. Submission
On February 9, 1989, Armco submitted a petition for exemption from the land disposal restrictions of hazardous waste injection under the HSWA Amendments to RCRA pursuant to the regulations set forth at 40 CFR part 148. This submission was reviewed for technical accuracy and revision documents are dated Feburuary 12, 1990, and April 30, 1990. Several supplemental submissions were made during this period and thereafter to resolve minor deficiencies. The total submission was reviewed by staff at the USEPA, the Ohio EPA, and, in part, by the Ohio State Geological Survey as well as a private consultant hired by the USEPA to assist; in its review.
II. Basis for Determination
The draft decision to approve Armco's petition for continued injection was reached after a careful consideration of the factors involved in an environmentaly protective injection operation. These factors include: The type of waste injected, well construction, well operation, proof of the mechanical integrity of both wells, properties of the injection and confining zones, including their ability to receive and confine the waste, a detailed search for any abandoned boreholes which may serve as a conduit for upward waste migration, and comprehensive modeling of the existing waste plume to predict pressure buildup and future movement of the plume, both vertically and laterally, for the next 10,000 years. In order to be conservative, the values used for input into the models were consistently chosen so as to over predict the pressure buildup and waste plume movement caused by the injection activity. The following sections describe each of these factors in more detail.
A. Waste Description and Analysis
The waste being injected is waste pickle liquor and is defined under 40 CFR part 261 as Waste Code K062. This waste is listed as a hazardous waste because it is corrosive (i.e., it has a pH less than or equal to 2.0) and because of its concentration of chromium (i.e., above a treatment standard of 0.32 milligrams per liter (mg/1)). The injected waste at Armco has an average pH of less than 0.2 and a chromium content ranging from 5 20 mg/1.
B. Well Construction and Operation
Armco injection well WDW No. 1 was constructed in 1967 with two strings of casing, both cemented to the surface (See Figure 1). Armco injection well WDW No. 2 was constructed in 1968 with three strings of casing, each cemented to the surface. Injection takes place through tubing set on packers at depths of 2842 feet and 2916 feet, respectively. Waste within each injection tubing is isolated from the casing by a flud filled annulus which is continously monitored, filled with corrison inhibitor, and maintained at pressures between 390 and 450 pounds per square inch gauge (psig) above the injection pressures, as measured at the surface. The monitoring system is designed to trigger alarms and warn an operator to shut off injection if the injection or annulus pressure exceeds the maximum permitted levels, or if the annulus pressure falls below the minimum permitted level in either well.
The average injection rate at Armco has varied from a low of 0 gallons per minute (gpm) to a high of 41.2 gpm for WDW No. 1, and from 0 gpm to 49.5 gpm in WDW No. 2. The average monthly flow rates are 26.3 gpm and 12.3 gpm. The historical maximum surface injection pressure is 55 psig with an average of 25 psig. The maximum permitted injection pressures of 638 and 640 psig are below the maximum value necessary to initiate or propagate fractures in the injection zone.
C. Mechanical Integrity Test Information
To assure that the waste does not leak prior to reaching the injection zone, mechanical integrity tests (MITs) of each well are required. Section 148.20(a)(2)(iv) requires that satisfactory MITs be performed within one year prior to petition submission and also allows for requiring an MIT within one year of USEPAs petition decision. Armco's injection wells were tested in November of 1987. The test consisted of a radioactive tracer (RAT) survey and an annulus pressure test. Annulus pressure tests were also run in 1988 and, most recently, in December, 1989. RAT surveys were run on April 26, 1990.
Results of these tests demonstrated that the wells have mechanical integrity and confirmed the positive results recorded on continous monitoring equipment. From both a constructive and operation standpoint, the Armco injection wells ensure, with a reasonable degree of certainty, transmission of the injected fluid to the injection zone without leakage.
D. Site Description
As part of the "no migration" demonstration under part 148, subpart C, any Class I hazardous waste injection well petitioner must identify the strata within the injection zone which will confine fluid movement above the injection interval and the strata which act as a confining zone. The injection zone is divided into two parts, the injection interval and the containment interval. The injection interval is the interval in which waste is directly emplaced. The containment interval is the interval which will contain the waste for at least 10,000 years. The confining zone is one or more formations capable of preventing fluid movement above the injection zone. This section describes the properties of each interval with emphasis on those characteristics which make it a good receiving or confining zone.
1. Regional Geology
The Armco facility is located in Butler County, near Middletown, Ohio. It is situated on the southern edge of the Ohio Indiana Platform, and is underlain by a sedimentary rock sequence approximately 3296 feet thick consisting of carbonates, sandstones, siltstones and shales. These units dip to the southwest at about 15 feet per mile.
As shown in Figure 1, the lowermost underground source of drinking water (USDW), defined as water with less than 10,000 mg/l total dissolved solids, is the Cincinnatian Group, the base of which is located at a depth of approximately 522 feet, as measured in WDW No. 1. The top of the injection zone is the top of the Eau Claire Formation at a depth of 2423 feet. There is thus about 1901 feet of separation between the top of the injection zone and the base of the lowermost USDW.
The Armco facility is located in an area of moderate seismic risk.
Earthquakes that may cause damage in the future are most likely to be centered in seismically active areas to the south and southwest, namely, the New Madrid and Wabash Valley fault zones located in Arkansas, Tennessee, Kentucky, Missouri, southern Indiana and southern Illinois. Approximately 8 earthquakes have been recorded within a 40 mile radius of the Armco facility.
No earthquake has ever been recorded which has had an epicenter within Armco's area of review. All recorded earthquakes within a 40 mile radius have been of low intensity, ranging from below scale to IV on the Modified Mercalli Scale.
Damage to disposal well systems or alteration of the hydrologic properties of the injection or confining zones would not be expected to occur from intensity IV earthquakes. For example, damage to underground pipes would be expected to occur only for intensity levels of IX or greater. Seismic activity induced by injection a ctivity is also highly unlikely due to the lack of evidence of faults at the site.
2. Injection Zone Description
The injection zone must have sufficient permeablility, porosity, thickness and areal extent to prevent migration of hazardous fluids out of this zone.
The injection zone at Armco is 873 feet thick and consists of the upper Middle Run Formation, the Mt. Simon Sandstone, and the Eau Claire Formation at a depth of 2423 to 3296 feet below surface (Figure 1). These formations are continuous and extend over much of the midwestern United States. At the Armco site, the injection zone formations are laterally extensive and undisturbed by faults or significant fractures, as documented by a suite of openhole logs and geologic literature.
The injection interval, or the interval into which waste is directly emplaced, is the lower Eau Claire Formation, the Mt. Simon Sandstone, and the upper Middle Run Formation, located at a depth of 2900 to 3296 feet below ground surface, with a thickness of 396 feet. Analysis of well logs and cores from the Armco site shows that the rock unit through this interval is a poorly sorted, fine grained to coarse grained sandstone with minor siltstone and dolomite. Both the permeability and porosity of the injection interval are suitable for waste injection. Core analyses show that the injection interval has a permeability of approximately 55 millidarcies (md), and an average porosity of about 13.5 percent. The injection interval contains 8 times the volume of dolomite necessary to neutralize all of the waste pickle liquor to be injected.
The upper injection zone, or "containment interval", is the upper 477 feet of the Eau Claire Formation, consisting of interbedded dolomitic sandstones, siltsones, and shales. The containment interval contains approximately 50 feet of shaly sandstone at the base and contains shale beds with sandstone interbeds towards the top. The total shale thickness of the containment interval is 255 feet. The lowermost portion of the containment interval, is a 50 foot thick white to dark gray, fine to medium grained, subrounded sandstone with interbedded shale and sand at the base. The sand portions exhibit moderate lateral permeability and porosity, so that it acts as a "bleed off" zone to dissipate vertical pressures and divert waste movement laterally. The shale rich parts of the containment interval have a porosity of 13.5 percent and permeability of 10 5 md, as measured from cores, which will substantially inhibit the movement of waste through these zones.
3. Confining Zone Description
The confining zone must be (1) laterally continuous, (2) free of transecting, transmissive faults and fractures over an area sufficient to prevent fluid movement and (3) of sufficient thickness and possessing lithologic and stress characteristics that inhibit the vertical propagation of fractures. The confining zone for the Armco injection operation is the Knox Dolomite, which is laterally extensive and free of transmissive faults and fractures throughout the area of review. At Armco, it is located at a depth below ground surface between 1172 and 2423 feet and has a thickness of 1251 feet, as measured in WDW No. 1 (Figure 1). It is separated from the lowermost USDW by 650 feet of permeable and less permeable strata.
The Knox Dolomite is composed of white to brown, fine to coarse grained cyrstalline dolomite containing pyrite and chert, with 90 feet of shale at the base. Geophysical logs show low porosity ranging from 0 to 4 percent at this site. The Knox Dolomite would serve as another major hydraulic barrier to vertical movement of injected waste, if it escaped the injection zone. The presence of a few thin beds with porosities up to 9 percent that would act as pressure bleed off zones enhances the Knox Dolomite's adequacy as a confining unit. Based on a review of all available information, the Agency has concluded that the Knox Dolomite is an adequate confining zone for Armco's injection operation.
In addition to the confining zone, the Wells Creek Formation, Black River Limestone, and Trenton Limestone, located between the top of the confining zone and the base of the lowermost USDW, provide additional assurance that contaminants will not reach drinking water sources. The Wells Creek Formation, a light gray, medium grained sandstone, is permeable and serves as a buffer unit above the confining zone. The Black River and Trenton are limestones with some interbedded sandstone and shale, that provide additional containment properties above the confining zone.
4. Area of Review
The Area of Review (AOR) is the area within which the petitioner must identify all wells which penetrate the confining zone and demonstrate that they have been properly completed or plugged. The AOR for Class I hazardous waste injection wells is a 2 mile radius around the well bore, unless a larger area is required based on the calculated cone of influence. The cone of influence for Armco was calculated using the criteria of 99 percent pressure dissipation. The maximum pressure rise is calculated to be 278 psig at the WDW No. 2 wellbore. One percent of this value is approximately 2.8 psig. Area of Review calculations conducted with 2.8 psig as a "critical pressure rise" yield a maximum radius to the cone of influence of 2,313 feet. This is well within the 2 mile (10,560 feet) designated Area of Review. Thus, the area of review has been designated to be 2 miles. Armco has performed a well search within a 2 mile radius of the injection well, and found that there are no wells that penetrate the confining zone within this area. Therefore, no corrective action under 40 CFR part 146 is needed at this facility for the area of review at this time.
E. Model Demonstration of No Migration
The demonstration of no migration of hazardous constituents from the injection zone at Armco involves the use of a family of predictive mathematical models known as Injection Forecast. This family of models is used to predict the buildup of pressure and the transport of waste from the injection well. The Injection Forecast model has been validated by comparing its results against results generated by numerical models. The successful use of the Injection Forecast model for sites similar to Armco provides confidence that the model is validated and is appropriate for use at this site.
1. Model Development and Calibration
The Armco Steel model was developed by incorporating hydrogeological data of the site and surrounding vicinity into a conceptual model. These values were derived from well logs, cores, published literature, and well tests. The site was evaluated using a single layer analytical model. A calibration exercise was used to refine estimates of hydrogeologic parameter values for the injection interval. For this analysis, it was assumed that the injection interval was laterally infinite. A calibration exercise reproduced the pressure responses recorded during an interference test run October 22 27, 1989, indicating that the parameter values, taken as a group, adequately represent the injection interval. The parameter values for the injection interval included a permeability of 55 md, a porosity of 13.5 percent and a skin factor of 0.12. Armco's estimates for these parameters are realistic. Reasonably conservative values were chosen for all other parameters used to model injection induced pressure and waste transport; details of this are discussed below.
Two simulation time periods were considered in the demonstration: An historical and 20 year future operational period and a 10,000 year post-operational period. The waste plume was modeled in two ways: The pressure buildup and plume movement was calculated both laterally within the injection interval and vertically into the overlying upper Eau Claire Formation. The pressure buildup analysis assumed injection into the lower Eau Claire Formation and the upper Mt. Simon Sandstone. The bottom of the injection zone was assumed to be impermeable to fluid flow. Armco's assumptions for the pressure analysis are realistic.
2. Pressure Buildup Analysis
For the historic period up to September 30, 1989, the actual injection volumes of 156,500,000 gallons for WDW No. 1 and 131,700,000 gallons for WDW No. 2 were input into the model. For the future operational period, October 1, 1989, to September 30, 2007, the model used a rate of 90 gpm combined for both wells. A waste specific gravity of 1.18, a brine viscosity of 0.71 centipoise (cp), and a vertical permeability for the base of the containment interval in the Eau Claire Formation of 10 1 md, were used to predict vertical pressure buildup in the injection zone. The injection rate used in the model conservatively exceeds actual conditions. The historical combined average injection rate is approximately 19.3 gpm, but the future rate is modeled at 90 gpm. The modeled injected volume, based on overestimation of the injection rates, amounts to approximately 3 times the historic volume in the two decades after 1987. The vertical permeability for the shales within the Eau Claire Formation was estimated using geophysical logs and core data to be 1 x 10 5 md. The model used a vertical permeability value of 1 x 10 1 md to provide additional conservatism in the pressure buildup and vertical migration analyses. Thus, the model will over predict pressure buildup. Modeling predicted that at the end of the 20 year future operational period, the maximum pressure buildup at the WDW No. 1 wellbore will be not more than 224 psi, and at WDW No. 2 not more than 278 psi. The modeled pressure buildup is greatest near the injection wells and declines to less than 2.8 psig, where 99 percent of the pressure buildup caused by injection activities has dissipated, at a distance of less than 0.5 miles. If injection is maintained at or less than the present rate, as expected, then this distance, and the maximum pressure buildup, will be much smaller.
3. Short Term Vertical Migration
The predicted pressure buildup at the end of the operational period was used as a basis for modeling the vertical migration of waste. Sensitivity analyses were conducted by estimating the ranges of values possible for each parameter and then selecting conservative values. Vertical transport at Armco is most sensitive to injection rate and the vertical permeability of the shales within the Eau Claire Formation. Based on an injection rate of 90 gpm and a permeability of 1.0 x 10 1 md, waste movement due to pressure driven flow during the operational period is estimated at less than 115 feet. More realistic parameter values result in a shorter distance. The 115 foot estimate is reasonably conservative and over predicts waste transport because (1) it is based on an injection rate of 90 gpm into one well, whereas the actual combined average injection rate is 19.3 gpm, (2) the vertical permeability of the containment interval was modeled as 1 x10 1 md, whereas core data show the actual vertical permeability to be approximately 10 5 md, (3) the site was modeled to inject continuously into a single well, whereas actual injection occurs into two wells so that the maximum injection pressure buildup will be less than calculated, and (4) the containment interval was modeled with a porosity of 6 percent, whereas core data show the actual porosity to be approximately 13.5 percent.
4. Long Term Vertical Migration
During the post operational period, molecular diffusion is the primary transport mechanism for the vertical migration of waste. Geologic literature a nd data from field experiments were used to determine a reasonably conservative ratio for the tortuosity of the containment interval to the tortuosity of the injection interval of 1.41 and a coefficient of molecular diffusion of 2 x 10 11 square meters per second. As an additional measure of conservatism, the model used more than twice the maximum concentration of the most mobile hazardous constituent, chromium (61.2 ppm). Based on these values the maximum vertical transport of the waste front during a 10,000 year post operational period is 135 feet.
Therefore, the total vertical migration at the Armco site will be less than 250 feet above the injection interval. The waste plume boundary is defiend as the point beyond which the chromium concentration is below 0.05 mg/1. Waste will be contained within the 130 foot thick sandy shale portion of the Eau Claire Formation during the operational period and within the shaly upper portion of the Eau Claire Formation during the 10,000 year post operational period.
5. Short Term Lateral Migration
Lateral transport of waste is modeled using analytical methods to determine the velocity of the waste plume and then multiplied by a time increment to get the transport distance. The waste plume is assumed to migrate laterally within an 87 foot thick interval having a porosity of 13.5 percent. The effective thickness was determined from a Temperature Survey and porosity was determined from core and log analyses of the Armco well. The estimate is realistic for porosity and conservative for effective thickness. Model results indicate that the waste will migrate laterally approximately 1,970 feet from the well during the 20 year operational period. Hydrodynamic dispersion, based on literature values of dispersivity of 20 feet, will increase this distance to 2,900 feet.
6. Long Term Lateral Migration
During the 10,000 year post oerational period, the waste plume will migrate due to the natural flow of groundwater in the Mt. Simon Sandstone and due to hydrodynamic dispersion. A groundwater flow velocity in the Mt. Simon Sandstone of 0.5 feet per year, based on published literature estimates, would result in an additional drift of the waste plume of 5,000 feet in 10,000 years. Hydrodynamic dispersion will result in, at most, an additional migration of 1,300 feet in 10,000 years, based on a dispersivity of 20 feet. Beyond this waste plume boundary, all hazardous constituents will be below health based limits and the waste will also not have hazardous characteristics, such as corrosivity. Therefore, using reasonably conservative values, the maximum predicted lateral migration of waste at the Armco site is 9,200 feet, or about 1.7 miles, in 10,000 years.
Therefore, Armco has demonstrated, to a reasonable degree of certainty, that hazadous constituents will not migrate vertically more than 250 feet nor laterally more than 9,200 feet, in a 10,000 year period. Hazardous constituents will not migrate vertically out of the injection zone nor laterally to a point of discharge, within this time period.
F. Quality Asssurance and Quality Control
Armco and its consultants have demonstrated that adequate quality assurance and quality control plans were followed in preparing the petition. Armco has followed appropriate protocol for locating records for penetrations in the Area of Review, for collection and analyses of geologic and hydrogeologic data, for waste characterization, and for all tasks associated with the modeling demonstration.
III. Conditions of Petition Approval
General conditions relating to this proposed exemption may be found in 40 CFR parts 140.23 and 148.24. Also, as a condition of granting this proposed exemption from the ban on injection of waste pickle liquor (KO62), the EPA requires that the following conditions be met by Armco:
(1) The combined monthly aveage injection rate for both wells must not exceed 90 gallons per minute;
(2) Injection shall occur only into the lower Eau Claire Formation, the Mt. Simon Sandstone, and the upper Middle Run Formation in the interval from 2900 feet to 3296 feet; and
(3) The petitioner shall be in full compliance with all requirements set forth in the Underground Injection Control permits issued by Ohio EPA.
The above conditions are being incorporated into the existing UIC permits for the wells by permit modification.
Dated: May, 15, 1990.
Richard Zdanowicz, Acting Director, Water Division, Region V. U.S. Environmental Protection Agency.
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