Underground injection disposal

Some liquid wastes undergo disposal by injection into the deep subsurface. Underground injection disposal is not allowed for liquid hazardous wastes and sludges that contain 500 mg l-1 or more of arsenic (40 CFR 148.12). The underground injection of many K and other listed arsenic wastes is also not permitted (40 CFR 148.14-148.15). 

Larkin, R.G. and Clark, J.E., Modeling density changes in hazardous disposal well plumes, in Underground Injection Science and Technology, Tsang, C.F. and Apps, J.A., Eds., Elsevier, New York, 2007. 

According to the Toxics Release Inventory, in 1996, the estimated releases of lead of 15,147,385 pounds (6,870,738 kg) to land from 1,454 large processing facilities accounted for about 89.4% of total environmental releases (TRI96 1998). An additional 794 pounds (360 kg), constituting less than 0.005% of the total environmental releases, were released via underground injection (TRI96 1998). Also, some of the estimated 370,905,354 pounds (168,239,838 kg) of lead transferred off-site may be ultimately disposed of on land. It should be noted that TRI-reported releases to land include, but are not limited to, releases to soil. Table 5-1 lists amounts released from these facilities. The TRI data should be used with caution, however, since only certain types of facilities are required to report. This is not an exhaustive list. 

Because acrylonitrile is listed as a hazardous substance, disposal of waste acrylonitrile is controlled by number of federal regulations (see Chapter 7). Rotary kiln, fluidized bed and liquid injection incineration are acceptable methods of acrylonitrile disposal (HSDB 1988). Underground injection is another disposal method. The most recent quantitative information on amount of acrylonitrile disposed in waste sites is for 1987. Emissions were 0.9 metric tons in surface water, 152 metric tons disposed through Publicly Owned Treatment Works (POTW), 92 metric tons disposed of on land 1,912 metric tons by underground injection (TR11988). Because acrylonitrile is relatively volatile and is also readily soluble in water, release to the environment from waste sites is of concern. 

Hexachloroethane and waste containing hexachloroethane are classified as hazardous wastes by EPA. Generators of waste containing this contaminant must conform to EPA regulations for treatment, storage, and disposal (see Chapter 7). Rotary kiln or fluidized bed incineration methods are acceptable disposal methods for these wastes. Underground injection may also be used (HSDB 1995). 

According to the TRI, approximately 92,755 pounds of hexachloroethane were transferred to landfills and/or treatment/disposal facilities by industrial manufacturers or processors in 1993 (see Section 5.2) (TRI93 1995). No hexachloroethane was discharged to publicly owned treatment works (POTW), but 1,081 pounds were disposed of by underground injection. These data do not include disposal of hexachloroethane-containing wastes by the militaiy. 

No data were located regarding historic disposal trends or the amounts of 1,4-dichlorobenzene disposed of by different means. According to the most recent Toxics Release Inventory (TRI96 1998), a total of 762,085 pounds of 1,4-dichlorobenzene were released to the environment. Of this total, 521,143 pounds of 1,4-dichlorobenzene wastes were transferred off-site (presumably for incineration), 79 pounds were sent to publicly owned treatment works (POTWs), 2,000 pounds were released via underground injection,... 

Today, trends in waste disposal have changed markedly, as shown in the table on page 165. The single most common method of disposal is deepwell or underground injection, in which wastes are buried in abandoned mines, caves, or other underground structures, where, the assumption is, they will remain for very long periods. 

No releases (0 pounds) of DeBDE occurred via underground injection (TRI99 2002). Releases to the environment from facilities that produce, process, or use DeBDE are summarized in Table 6-1. The data from the TRI should be used with caution since only certain types of facilities are required to report (EPA 1995c). This is not a comprehensive list. Solid waste from commercial production of OBDE is typically disposed in landfills (EPA 1994). 

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. 

Releases of aniline in industrialized countries is considerable. According to the US Toxic Release Inventory, during 1998, eighty-two factories in the US released 1,449,754 lbs. of aniline, 217,223 to the atmosphere, 19,549 to surface waters, 1,161,911 by underground injection, 252 to land and 50,819 to disposal sites. While aniline waste is nowadays subjected to recovery, management, energy recovery and waste treatment, this was not so in the past, when anilines caused environmental injuries. The toxic impact of many dyes, e.g. in waste streams and releases to surface waters, arises from the fact that they are degraded, cleaved or reduced to aromatic amines. 

Carbon sequestration involves three steps—capture, transport, and disposal. The current estimated cost of capture and compression of CO2 to pipeline pressure (110 bar) is approximately US 30-50 per ton of CO2. Transport of CO2 adds US 1-3 per ton per 100 km. Disposal costs vary, but in some cases, they are quite low, e.g., US 4 per ton of CO2 for some forms of underground injection. 

Costs of solids disposal by road spreading and underground injection have been reported (124) to be 40/m3 and 36/m3, respectively. A recent survey conducted by the authors indicated that current (1994) cost of solids treatment to remove oil and water is about 50/m3. Total disposal cost of the cleaned solids by landfill or land farming typically varies between 110/m3 and 125/m3, although costs as high as 180/ m3 have been quoted. 

Underground Injection. A cost-effective and environmentally safe method of solids disposal involves the injection of a slurry of solids... 

Of the 1,362 pounds of MBOCA released to the atmosphere in 1991 from TRI facilities, no releases of MBOCA to land or through underground injection were reported. An additional 5,228 pounds were reported to have been transferred to off-site waste treatment, storage, and disposal facilities (TRI91 1993). The TRI data should be used with caution since only certain types of facilities are required to report. 

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