Migration of wastes

Sufficient thickness and area to prevent upward migration of wastes... 

Interactions between corrosive wastes and casing and packing can threaten the integrity of a well if proper materials have not been used in construction. Of equal concern is the potential for failure of the confining zone due to physical or chemical effects. For example, dissolution of an overlying carbonate confining layer may allow upward migration of wastes. This process was observed when hot acidic wastes were injected in a Florida well. 

Deep well injection, done by pumping liquid wastes into a permeable stratum sandwiched between impermeable strata, at depths of one to three miles, was ruled out because of probable migration of wastes through the permeable stratum to distant acquirers. The method is used, however, with some non-radioactive wastes. 

Thermal and concentration dense convection has a visible effect on vertical migration of waste components. The thermal effect is more significant for the activity field, while the density effect is more significant for the TDS concentration field. 

The landfill must have a double liner system that can prevent any migration of wastes out of the landfill to the adjacent soil, groundwater, or surface water. The liner system must include a leachate collection and removal system between the two liners. 

The licensee must have plans for taking corrective measures if the environmental monitoring program detects migration of waste which would indicate that the performance objectives may not be met. 

The Natural Reactor. Some two biUion years ago, uranium had a much higher (ca 3%) fraction of U than that of modem times (0.7%). There is a difference in half-hves of the two principal uranium isotopes, U having a half-life of 7.08 x 10 yr and U 4.43 x 10 yr. A natural reactor existed, long before the dinosaurs were extinct and before humans appeared on the earth, in the African state of Gabon, near Oklo. Conditions were favorable for a neutron chain reaction involving only uranium and water. Evidence that this process continued intermittently over thousands of years is provided by concentration measurements of fission products and plutonium isotopes. Usehil information about retention or migration of radioactive wastes can be gleaned from studies of this natural reactor and its products (12). 

Early in the Corrective Action process, a decision may be made concerning whether or not containment is necessary to protect human health and the environment (HHE). If the release or threatened release presents danger to HHE, immediate action must be taken to halt migration. Under these circumstances, actions termed "Interim Measures" may be required, and excavation or containment measures may be directed by the regulatory agency. However, the Owner/Operator will be responsible for their implementation. In the event that containment is not required as an interim measure, containment may still be needed as part of the overall Corrective Action to halt the pollution migration if wastes or contaminants are to be left on-site. 

No-migration variances No-migration variances differ from capacity variances in that they apply to the disposal unit instead of to the waste, and allow wastes to be disposed of in the unit without meeting the treatment standards. To obtain a no-migration variance for a disposal unit, a facility must petition U.S. EPA and demonstrate that there will be no migration of hazardous constituents from the unit (i.e., the waste will not leak or escape from the unit) for as long as the wastes remain hazardous. 

Kaufman, M.I. and McKenzie, D.J., Upward migration of deep-well waste injection fluids in Floridan aquifer, South Florida, J. Res. U. S. Geol. Surv., 3, 261-271, 1975. 

Alternative final cover systems, such as the innovative evapotranspiration (ET) cover systems, are increasingly being considered for use at waste disposal sites, including municipal solid waste (MSW) and hazardous waste landfills when equivalent performance to conventional final cover systems can be demonstrated. Unlike conventional cover system designs that use materials with low hydraulic permeability (barrier layers) to minimize the downward migration of water from the cover to the waste (percolation), ET cover systems use water balance components to minimize percolation. These cover systems rely on the properties of soil to store water until it is either transpired through vegetation or evaporated from the soil surface. 

Land disposal sites result in soil contamination through leachate migration. The composition of the substances produced depends principally on the type of wastes present and the decomposition in the landfill (aerobic or anaerobic). The adjacent soil can be contaminated by direct horizontal leaching of surface runoff vertical leaching and transfer of gases from decomposition by diffusion and convection. The disposal of... 

Sorption can significantly diminish the mobility of certain dissolved components in solution, especially those present in minor amounts. Sorption, for example, may retard the spread of radionuclides near a radioactive waste repository or the migration of contaminants away from a polluting landfill (see Chapters 21 and 32). In acid mine drainages, ferric oxide sorbs heavy metals from surface water, helping limit their downstream movement (see Chapter 31). A geochemical model useful in investigating such cases must provide an accurate assessment of the effects of surface reactions. 

ISO 105-X10 Textiles - Tests for colour fastness - Part XIO Assessment of migration of textile colours into polyvinyl chloride coatings ISO 264 1976 Unplasticized polyvinyl chloride (PVC) fittings with plain sockets for pipes under pressure - Laying lengths - Metric series ISO 265-1 1988 Pipes and fittings of plastics materials - Fittings for domestic and industrial waste pipes - Basic dimensions Metric series - Part 1 Unplasticized poly(vinyl chloride) (PVC-U)... 

Due to the capacity of deep wells to store injected waste for a long period of time, if the correct measures are taken in design, construction and operation, deep well injection can provide an effective and environmentally safe method of concentrate management. The major environmental concern for deep well injection is the potential for contamination of nearby aquifers, which may be used as a source of drinking water. Six pathways have been defined that describe the potential migration of concentrate that can cause contamination of aquifers (Shammas et al. 2009 United States Environmental Protection Agency 2002) ... 

Deep geological disposal is the most favored solution for the permanent disposal of nuclear wastes with long half-lives. Although the locations of the burial places are selected with outmost care to avoid migration of the wastes in nature over a very long period of time, no barrier can be safe forever, so, numerous studies are in progress to determine the main factors that could cause leaks of radioactive nuclides. Soluble compounds in ground water are likely to play a major role in the release of actinides. 

In this study a series of surface water and deep soil samples were analyzed to detect ai migration or runoff of waste pesticides from typical Chemical Control Centers. Entomological evaluation of soil biota and monitoring of dermal exposure to pesticides of mlxer-appllcators took place throughout the 1980 season. No adverse effects as a result of the Chemical Control Centers were detected. 

Additional design, operating, and monitoring requirements may be necessary for facilities managing dioxin wastes in order to reduce the possibility of migration of these wastes to groundwater, surface water, or air so as to protect human health and the environment. 

Cement-based stabiUzation/solidification (S/S) is a technology for the in situ or ex situ treatment of hazardous wastes and hazardous waste sites. It is a process that uses cement and other additives or processes to physically and/or chemically immobilize the hazardous constituents of contaminated soils, sludges, sediments, or liquid wastes. The objective is to prevent the migration of contaminants in the environment by forming a solid mass. 

The Ecolotree buffer uses phytoremediation, or plant processes, for environmental remediation purposes. Ecolotree buffers can be used to reduce the migration of subsurface water and surface runoff, while also acting as an in situ remediation technique for both organic and heavy-metal contaminants, including benzene, toluene, ethylbenzene, and xylene (BTEX) chlorinated solvents ammunition wastes and excess nutrients in soil or water. The technology is commercially available and has been used at landfill and waste treatment sites. 

ISOTRON s ELECTROSORB C technology applies an electric field to induce migration of ionic contaminants from within porous concrete. This process provides an in situ alternative to concrete decontamination, thereby eliminating physical or mechanical damage of the concrete and allowing reuse of the structure or facility. The process generates minimal secondary waste and no airborne particulates common to conventional scabbUng or physical abrasion techniques. 

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