Subsurface Waste Disposal Research Articles

TOUGHREACT—A simulation program for non-isothermal multiphase reactive geochemical transport in variably saturated geologic media: Applications to geothermal injectivity and CO 2 geological sequestration

TOUGHREACT is a numerical simulation program for chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media. The program was written in Fortran 77 and developed by introducing reactive geochemistry into the multiphase fluid and heat flow simulator TOUGH2. A variety of subsurface thermo-physical–chemical processes are considered under a wide range of conditions of pressure, temperature, water saturation, ionic strength, and pH and Eh. Interactions between mineral assemblages and fluids can occur under local equilibrium or kinetic rates. The gas phase can be chemically active. Precipitation and dissolution reactions can change formation porosity and permeability. The program can be applied to many geologic systems and environmental problems, including geothermal systems, diagenetic, and weathering processes, subsurface waste disposal, acid mine drainage remediation, contaminant transport, and groundwater quality. Here we present two examples to illustrate applicability of the program. The first example deals with injectivity effects of mineral scaling in a fractured geothermal reservoir. A major concern in the development of hot dry rock and hot fractured rock reservoirs is achieving and maintaining adequate injectivity, while avoiding the development of preferential short-circuiting flow paths. Rock–fluid interactions and associated mineral dissolution and precipitation effects could have a major impact on the long-term performance of these reservoirs. We used recent European studies as a starting point to explore chemically induced effects of fluid circulation in the geothermal systems. We examine ways in which the chemical composition of reinjected waters can be modified to improve reservoir performance by maintaining or even enhancing injectivity. The second TOUGHREACT application example is related to CO 2 geologic sequestration in a saline aquifer. We performed numerical simulations for a commonly encountered Gulf Coast sediment under CO 2 injection conditions in order to analyze the impact of CO 2 immobilization through carbonate precipitation. Using the data presented in this paper, the CO 2 mineral-trapping capability after 10,000 years can reach 60 kg/m 3 of sandstone by secondary carbonate mineral precipitation such as siderite, ankerite, and dawsonite. Most of the simulated mineral alteration pattern is consistent with the field observations of natural CO 2 reservoirs.

Origin and movement of groundwater and major ions in a thick deposit of Champlain Sea clay near Montréal

At a site near Montréal, piezometers and core samples were used to assess the origin, age, and rate of groundwater movement in a 28 m thick deposit of Champlain Sea clay. 3H occurs only within the upper 3–4 m, which indicates that groundwater below this surficial weathered zone originated prior to 1952. Concentrations of 18O, Na+, and Cl− in water from the deepest piezometer suggest that the deep clay was deposited in a mixture of about 33% seawater and 67% freshwater. Profiles of several major ions show a gradual increase in concentration with depth. Mathematical simulations of vertical migration of Ca2+, Mg2+, K+, Na+, and Cl− provide close matches to the field profiles when only upward diffusion of these ions into the surficial freshwater zone is included in the model with a diffusion time of approximately 10 000 a. When the downward advection rate of 0.13 cm ∙ a−1 obtained from field measurements of hydraulic gradient and hydraulic conductivity is included in the model, the simulated major-ion profiles deviate markedly from the field profiles. This suggests that the hydraulic gradient in the clay is less than the threshold gradient necessary to cause Darcian flow. This study suggests that, in areas where clayey Champlain Sea deposits are thick, opportunities exist for locating waste disposal facilities that would have no significant potential for causing contamination of groundwater resources beneath the clay. Key words: groundwater, permeability, diffusion, environmental isotopes, threshold gradient, geochemistry, subsurface waste disposal.

Significance of Regulatory Constraints on the operation of Packerless Waste Injection Wells

Summary U.S. federal regulations for groundwater protection require all hazardous-waste disposal wells to be constructed so that casing leaks can be reliably monitored. Wells constructed with static-fluid seals instead of packers are incapable of meeting this requirement and are therefore not in compliance with the regulations. Introduction Though fluids (liquids) have been injected into the subsurface to recover minerals and to dispose of oilfield brine in the U.S. for many years, deep-well disposal has been an approved means of industrial waste management for only a few decades. This method now accounts for the subsurface disposal of increasingly large volumes of industrial liquid waste. If not property controlled, the injected waste could threaten the safety of our drinking water supplies. In the past, subsurface waste disposal was generally regulated by state programs, which varied widely in technical detail. The need for uniform standards for groundwater protection has been obvious for some time. In recognition of this need, the U.S. Congress enacted the Safe Drinking Water Act in 1974 and the Hazardous and Solid Waste Amendments (HSWA) in 1984. The Underground Injection Control (UIC) regulations, which are a part of the HSWA, set minimum standards for the siting, construction, and operation of injection wells in the U.S. The U.S. Environmental Protection Agency (EPA) administers this program directly or through the states to meet the Congressional mandate. UIC regulations require all injection wells to be constructed with tubing set in packers. This feature allows the well operator to use the tubing/casing annulus for monitoring well casing leaks that could endanger the safety of adjacent underground sources of drinking water (USDW's). As of 1984, only 80% of all hazardous-waste disposal (Class I) wells in the U.S. were completed with packers. The regulations permit the operation of packerless wells only if the operator can demonstrate that the mechanical integrity of these wells can be reliably monitored at a level comparable with that of the well with packer. The most common type of the packerless well currently approved by the EPA features a "static-fluid seal" in the annulus-i.e., annulus filled with a mineral oil, in place of the packer, which totally isolates the annulus from the injected waste. This paper examines the extent that the packerless well with the static- fluid seal is comparable with a conventional well with packer in providing reliable protection to groundwater. Considerations of theory and available operating-well data from the Great Lakes region facilities suggest that packerless wells do not meet applicable requirements and therefore do not comply with UIC regulations.

4448690 Subsurface waste disposal system: Sam W Maphis assigned to Genstar Waste Transfer Inc

4448690 Subsurface waste disposal system: Sam W Maphis assigned to Genstar Waste Transfer Inc

Reversible ion-exchange fixation of cesium-137 leading to mobilization from reservoir sediments

The radioactive fission product, 137Cs, has been observed to mobilize from bottom sediments of two South Carolina reservoirs during summer thermal stratification and hypolimnetic anoxia. Mobilization is attributed to ion-exchange displacement of 137Cs from sediments by cations such as NH + 4, Fe +2 and Mn +2 released under anaerobic conditions. Three types of 137Cs binding sites to sediment clay minerals are identified: 1) surface and planar sites from which 137Cs is generally exchangeable by all cations studied (Na +, NH + 4, H +, Cs +, Ca +2, Mg +2, Fe +2, and Mn +2); 2) wedge sites where 137Cs exchange is sterically limited to cations of similar size and charge (NH + 4, Cs +, K +, and perhaps H 3O +); 3) interlayer sites from which 137Cs is not readily exchanged. More than 15 years after final 137Cs inputs, the reservoir sediments we studied showed the following percentage distribution of sites: 2 to 9% surface sites, 6 to 13% wedge sites, and 78 to 85% interlayer sites. In contrast, lake and stream sediments near Oak Ridge, Tennessee receiving 137Cs inputs more than 20 years earlier had greater than 99% of their 137Cs associated with non-exchangeable interlayer sites. The difference is attributed to the paucity in the South Carolina sediments of weathered micaceous clay minerals with their abundant interlayer sites. Such interlayer deficient clays are dominant in the Atlantic and Gulf coastal plains of the United States and elsewhere. This suggests that 137Cs will be physically and chemically more mobile in such areas as well as more biologically available. Mobility will be enhanced in regimes where cation inputs favoring 137Cs exchange occur. Subsurface waste disposal sites where anaerobic conditions develop with NH + 4 production and Fe +2 and Mn +2 release might be such a regime.

Some legal and administrative aspects of underground waste disposal in Australia and the United States of America

There are increasing social pressures for a better environment and these are giving rise to an increasing body of case and statutory law related to waste disposal, pollution and health. Some of the inadequacies of past and present legislation and administration are described. The legal and environmental framework for the most common subsurface waste disposal methods is discussed. Some problem areas are highlighted. Of particular hindrance to satisfactory waste disposal and environmental protection is the fragmentary nature of the legislation and administration in Australia. The importance for legislation and administration of seeing waste disposal and its environmental interaction as a continuous process is emphasised. The various types of legal controls, both governmental and private, are described for Australia and to a lesser extent the U.S.A. Legal principles associated with private controls are highlighted and subsurface property right differences between U.S.A. and Australia are noted. Some trends in statutory and civil law are indicated for both countries and several amendments to Australian legislation are suggested.

Using models to simulate the movement of contaminants through groundwater flow systems

Prediction of the movement of contaminants in groundwater systems through the use of models has been given increased emphasis in recent years because of the growing trend toward subsurface disposal of wastes. Prediction is especially critical when nuclear wastes are involved. Contaminant transport models which include the effects of dispersion have been applied to several field situations. However, factors that limit the routine use of these models include the difficulty of determining the field coefficient of dispersion and numerical difficulties encountered when solving the dispersion equation. Regional size models which neglect the effects of dispersion have had limited success because of the scarcity and poor quality of field data. Another difficulty in the development of contaminant transport models is the current lack of knowledge regarding the quantification of chemical reaction terms. This review examines the formulation of contaminant transport models, application to field problems, difficulties involved in obtaining input data, and current status of modeling efforts.

Potential for Subsurface Disposal of Industrial Wastes in Oklahoma: ABSTRACT

The main goal in selection of a subsurface disposal site is that the waste be emplaced in such a manner that it is isolated from freshwater supplies and the biosphere during its hazardous life. This can be accomplished only through detailed investigation of the lithology, porosity, permeability, thickness, lateral extent, depth, fluid content, and compatibility of a potential reservoir. Additional data for the area around a potential disposal site are also needed concerning the structure, geologic framework, confining rocks, hydrology, mineral resources, and the presence of boreholes or other excavations. Rock types that are most desirable for subsurface waste disposal in Oklahoma are porous and permeable sedimentary rocks, such as sandstone, limestone, and dolomite, although fractured shale or mined caverns in shale and salt may also be suitable. Thick sequences of sedimentary rock make up most geologic provinces in the state, and it appears that most areas are underlain by reservoir rocks that locally can safely contain industrial wastes. Major sandstone reservoirs that are locally capable of accepting liquid wastes include the Simpson Group, Springer Formation, Pennsylvanian sandstones, granite wash, and Permian sandstones; major carbonate reservoirs include the Arbuckle Group, Hunton Group, Mississippian limestones, Brown dolomite, and Permian dolomites. Where used for waste disposal, these reservoirs typically have porosities ranging from 5 to 20% and permeabilities ranging from 20 to 2,000 md. At present, 17 wells are being used in Oklahoma to inject acids, caustics, solvents, process waters, salt water, paints, urea, detergents, metal-bearing solutions, and cement slurries into reservoirs 385 to 7,350 ft (116 to 2,205 m) below the surface. Most facilities inject at average rates of 40,000 to 400,000 gal/day and with injection pressures that range from 380 to 450 psi (2,618 to 3,100 kPa). End_of_Article - Last_Page 475------------

Effect of Subsurface Waste-Disposal Practice on Groundwater Resources in Hawaiian Islands: ABSTRACT

Geologic and hydrologic framework (K. J. Takasaki): Groundwater in Hawaii is present as basal water, as dike-impounded water, and as perched water. Basal water, the fresher part of it forming a lens-shaped body floating on saline groundwater, is in dike-free volcanic rocks and in sedimentary rocks. Dike-impounded water is confined to volcanic rocks in eruptive zones. Perched water is present in all rocks and at all altitudes. Most recharge to groundwater is in the wet interior mountains. Therefore, the main areas of recharge are upgradient from developed areas where most wastes are disposed of in the subsurface. This natural deterrent, by position of the recharge area, so far has kept much of the groundwater in its pristine quality state. Deterioration of the groundwater will increase as land developments encroach toward the recharge areas-the degree will depend greatly on the waste-disposal practices. Most natural discharge of groundwater is along the shore, downgradient from disposal wells. The contamination of the beaches rather than of the water supply is the main concern regarding subsurface disposal of wastes in the low areas under present conditions. Hydraulic, geochemical, and monitoring aspects of liquid-waste injection under Ghyben-Herzberg equilibrium End_Page 1453------------------------------ conditions (F. L. Peterson).-The success of injection operations depends primarily on injection capacity and fate of the injected waste. To evaluate these factors properly an understanding must be obtained of local hydrogeologic conditions, hydrodynamics of injection under Ghyben-Herzberg lens conditions, and possible chemical and biologic effects. Hawaiian hydrogeology is understood fairly well, and where adequate information is not available, it usually is possible to collect these data by careful field investigation. Considerable information is available from other parts of the world on the hydrodynamics of waste-water injection. However, much of this information is not directly applicable to injection in the Hawaiian environment. Particularly troublesome are the complications caus d by the extreme heterogeneity of Hawaiian receiving formations and Ghyben-Herzberg lens effects. Likewise, because chemical and biologic reactions depend on the nature of the injected waste, the receiving waters, and the receiving formations, many of the data collected elsewhere are not applicable in Hawaii. End_of_Article - Last_Page 1454------------

International Symposium on Underground Waste Management and Artificial Recharge

New Orleans, Louisiana, will be the site for an International Symposium on Underground Waste Management and Artificial Recharge to be held September 26–30, 1973. Sponsored by the American Association of Petroleum Geologists, the U.S. Geological Survey, and the International Association of Hydrological Sciences, the symposium will include papers on the theory and practice of subsurface waste disposal and the artificial recharge of aquifers. Hydrogeological, geochemical, environmental and regulatory aspects related to these subjects will be considered for acceptance on the program. Interesting field trips are planned in New Orleans and the surrounding area.

Subsurface Disposal of Waste in Kansas: ABSTRACT

The use of wells for the subsurface disposal of wastes has been practiced in Kansas since 1935. All the early waste-disposal wells were used to dispose of oil-field brine. Permits for the first industrial waste-disposal wells other than oil-field wells were issued in 1952. Two state agencies have jurisdiction over the subsurface disposal of oil-field wastes in Kansas. Before using a well for the subsurface disposal of oil-field or gas-field brines, the operator must submit plans and specifications for each disposal well to the Kansas State Corporation Commission. These must be approved by both the State Corporation Commission and the Kansas State Department of Health. The Corporation Commission, through its Oil and Gas Conservation Division, determines that the use of the proposed well will not result in loss or waste of gas or petroleum resources. The Department of Health, through its Oil Field and Subsurface Disposal unit, Division of Environmental Health, determines that use of the proposed well will not result in pollution to the water resources of he state. Before using a well for the subsurface disposal of industrial wastes other than oil-field or gas-field wastes, an application must be filed with, and a permit issued by, the Kansas State Department of Health. The maximum wellhead pressure that may be used to inject wastes into both classes of wells must be approved by the Department of Health. Periodic field checks of the amount of pressure used are made by field personnel of the Department of Health. The Oil Field and Subsurface Disposal unit is staffed by a supervisory geologist in Topeka and by 8 area geologists, each of whom is responsible for a specific section of the state. At present, there are 3,200 approved oil-field and gas-field saltwater disposal wells in use receiving a total of about 4,000,000 bbl of salt water per day. Not included are 2,600 saltwater repressuring systems in the state, which are made up of from one to several hundred injection wells. The depths of the oil- and gas-field disposal wells range from less than 500 to about 6,000 ft. Thirty-eight zones ranging from Upper Permian to Precambrian are being used. About 60% of the wells inject wastes into limestones or dolomitic rocks, 25% into sandstone, 5% into sandy or gypsiferous shale, 5% into salt or anhydrite zones, and 5% into conglomerate or granite wash. Injection pressures being used range from gravity at the wellhead to 0.5 psi/ft of depth to the injection zone. There are 31 industrial waste-disposal wells (other than oil- or gas-field wells) at 21 plants in the state including 10 LPG underground storage projects, 2 salt companies, 3 petroleum refineries, 4 natural gas compressor stations, 2 chemical manufacturing plants, and 2 fertilizer plants. Most industrial waste being disposed of in the subsurface consists of salt brine and is disposed of in Arbuckle rocks at depths ranging from about 3,000 to 6,000 ft. All wells are constructed to preclude any hazard to fresh water. The Department of Health's present policy concerning industrial wastes is that only those wastes that cannot be treated and disposed of by other practical methods will be considered for disposal in the subsurface. Use of the most permeable injection zone available at each s te is required regardless of depth in order to eliminate the need for wellhead injection pressure. Experience with both industrial and oil-field disposal wells shows that most operational problems are caused by (1) selecting an injection zone with inadequate permeability, (2) no preliminary waste treatment or inadequate waste treatment, or (3) failure to provide an effective maintenance program. End_of_Article - Last_Page 1599------------

Underground Waste Disposal at New Johnsonville, Tennessee: ABSTRACT

Deep-well disposal of acidic wastes has been employed successfully at the E. I. du Pont Pigments Plant, New Johnsonville, Tennessee, since 1967. In 1965, as part of a program to reduce surface discharge of waste fluids, together with other methods for waste disposal, an investigation of the feasibility of subsurface waste disposal was conducted. Basic data were developed and from this a proposal was made to the state for drilling a deep disposal well. A public hearing, attended by local, state, and federal representatives, was held and all inquiries answered. Under state permit, a 6,700-ft geologic test well was drilled. Receptive zones were found in the middle and lower Knox-Copper Ridge Dolomites (Cambrian). Laboratory studies conducted with rock cores showed that the w ste fluids are compatible with the formation rocks and their contained waters. Appropriate state agencies approved completion designs and the well was completed in 1966. Acidic wastes were injected into the well at design rates and pressures from 1967 through 1971, at which time the well was retired from service. Two additional waste wells have been drilled and are operating successfully. A fourth well is scheduled to be drilled in the near future. In addition to downhole monitoring systems on each well, the plant monitors many freshwater wells in the surrounding area, as well as 1 deep well on the plant property, for evidence of waste-fluid migration. To date, no vertical migration of waste has been observed. A second deep monitor well is to be drilled in conjunction with the upcoming fourth waste well. At New Johnsonville it has been shown that a properly installed waste-disposal well system can successfully remove undesirable waste fluids from the biosphere. End_of_Article - Last_Page 1605------------

AAPG‐USGS Underground Waste Symposium

The U. S. Geological Survey and the American Association of Petroleum Geologists will cosponsor a Symposium on Underground Waste Management and Environmental Implications December 6–9, 1971, at the Astroworld Hotel, Houston, Texas. It will include three days of technical sessions and one full day of field trips to chemical plants in the Houston area to observe surface pretreatment and deep‐well waste disposal procedures.The purpose of the symposium is to assess the current state of knowledge about subsurface waste disposal, to identify problems and areas of uncertainty requiring further investigation, and to anticipate realistic regulatory procedures. Among the principal topics to be discussed in the technical sessions will be hydrogeology, surface pre treatment of fluids, mechanics of injection wells, environmental considerations, and legal aspects.