Deep-well injected wastes sources

Sources, Amounts, and Composition of Deep-Well-Injected Wastes. 785... 

The sources, amounts, and composition of injected hazardous wastes are a matter of record, because the Resource Conservation and Recovery Act (RCRA)5,14 requires hazardous waste to be manifested (i.e., a record noting the generator of the waste, its composition or characteristics, and its volume must follow the waste load from its source to its ultimate disposal site). The sources and amounts of injected hazardous waste can be determined, therefore, based on these records. Table 20.2 shows the estimated volume of deep-well-injected wastes by industrial category.3 More than 11 billion gallons of hazardous waste were injected in 1983. Organic chemicals (51%) and petroleum-refining and petrochemical products (25%) accounted for three-quarters of the volume of injected wastes that... 

The sources, amounts, and composition of existing deep-well-injected hazardous wastes... 

Source U.S. EPA, Assessing the Geochemical Fate of Deep-Well-Injected Hazardous Waste A Reference Guide, EPA/625/ 6-89/025a, U.S. EPA, Cincinnati, OH, June 1990. 

Water with a salinity of less than 10,000 mg/L is considered to be a potential underground source of drinking water. By regulatory definition, deep-well injection of hazardous waste can occur only in very saline waters or brines. Actual salinities of waters in currently used deep-well injection zones vary greatly.70 Normally, the term brine is used to refer to the natural waters in deep-well injection zones. As noted above, however, this term is not technically correct if TDS levels are less than 35,000 mg/L. 

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) ... 

There are no known natural sources of hexachlorobutadiene which contribute to environmental levels. The main source of hexachlorobutadiene in the United States is its production as a by-product of chlorinated hydrocarbon synthesis. An estimated 100,000 pounds of this by-product are released to the environment each year. The majority of hexachlorobutadiene-containing waste is disposed of by incineration, with lesser amounts disposed by deep well injection and landfill. 

For petroleum waste management a deep-well injection disposal process has long been used. This method transfers liquid wastes underground and away from fresh wastewater sources. It is also used to dispose of saltwater in oil fields. 

Deep-well injection is used to transfer liquid wastes far beneath the ground. The injection wells must be placed as far away as possible from drinking water sources. The type of waste to be injected will affect the depth of the wells. 

As described in an earlier problem, deep-well injection is an ultimate disposal method that transfers liquid wastes far underground and away ifom freshwater sources. Like landfarming, this disposal process has been used for many years by the petroleum industry. It is also used to dispose of saltwater in oil fields. When the method first came into use, the injected brine would often eventually contaminate groundwater and freshwater sands because the site was poorly chosen. The process has since been improved, and laws such as the Safe Drinking Water Act of 1974 ensure that sites for potential wells are better surveyed. 

Deep-Well Injection Today, EPA regulations generally ban deep-well injection. In deep-well injection, pumps move liquid wastes through pipes deep into the earth into porous rock formations or natural underground domes. Normally, the well depth is below any useful imderground water sources. If there are suitable sites, deep-well injection can avoid transportation costs and processing costs. 

Other point sources of groundwater pollution include both deep injection wells and shallower dry wells used to inject chemical wastes (including radioactive waste) directly into the subsurface environment. While it is customary to make waste injections into deep aquifers that are salty or otherwise unusable for potable water, it is not unusual for injection wells to leak, or to force the flow of water from one layer of aquifer into another, resulting in contamination of an otherwise usable source of groundwater. 

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