Hazardous waste ground water

Aeration basins can be constmcted as concrete or steel tanks or earthen impoundments, although tanks are more common in the United States now because of ground water problems with leakage from impoundments and stringent regulation of impoundments for the treatment of hazardous waste. 

The general purpose of ultimate disposal of hazardous wastes is to prevent the contamination of susceptible environments. Surface water runoff, ground water leaching, atmospheric volatilization, and biological accumulation are processes that should be avoided during the active life of the hazardous waste. As a rule, the more persistent a hazardous waste is (i.e., the greater its resistance to breakdown), the greater the need to isolate it from the environment. If the substance cannot be neutralized by chemical treatment or incineration and still maintains its hazardous qualities, the only alternative is usually to immobilize and bury it in a secure chemical burial site. 

Methyl parathion has been released to the environment mainly as a result of its use as an insecticide on crops. It is applied to agricultural crops by aerial or ground spraying equipment. Methyl parathion has been detected in surface waters and sediments, rainwater, aquatic organisms, and food. There are no known natural sources of the compound. Methyl parathion has been identified in at least 16 of the 1,585 hazardous waste sites on the NPL (HazDat 2001). 

EPA. 1997c. Standards for owners and operators of hazardous waste treatment, storage, and disposal facilities. Ground-water monitoring list. U.S. Environmental Protection Agency. Code of Federal Regulations. 40 CER 264, Appendix IX. 

Irrigation return flows. When farmers irrigate agricultural land, water not absorbed into the ground can flow into reservoirs for reuse. This return flow often picks up pesticide or fertilizer constituents, potentially rendering it hazardous. Because this water may be reused on the fields, it is excluded from the definition of solid waste. 

Pivetz, B. E., Ground Water Issue. Phytoremediation of Contaminated Soil and Ground Water at Hazardous Waste Sites, EPA/540/S-01/500, Superfund Technology Support Center for Ground Water, OK, 2001. 

Standards for Owners and Operators of Hazardous Waste Treatment, Storage, and Disposal Facilities Appendix IX -Ground-water Monitoring List 0.1-10 pg/L (Practical Quantitation Limits for 2 Methods) 40 CFR 264 EPA 1980b... 

A Individuals residing near hazardous waste site Hazardous waste site Volatile chlorinated solvents Ground water used for drinking, bathing, cooking Ingestion, inhalation, dermal contact... 

Ram NM, Exner P, Bell R, et al. 1985. Feasibility of treating contaminated ground water at a hazardous waste site. In Proceedings of the NWWA/API conference on petroleum hydrocarbons and organic chemicals in ground water --prevention, detection and restoration, 513-534. 

A question of some importance, of course, is the method of disposal of these hazardous wastes. At one time, the two most popular methods of disposal were landfill and impoundment in surface bodies of water especially built to hold such wastes. Both of these methods pose serious problems, however, as hazardous wastes can sometimes evaporate into the air or soak into the ground and contaminate both surface water and groundwater. Some of the most deplorable cases of environmental pollution in the last century have been associated with one or the other of these two methods of hazardous waste disposal. 

A primary limitation of phytoremediation is that it takes time, and several growing seasons may be required to achieve treatment goals. Phytoremediation is also limited by the depth of the roots. The contaminants to be treated must reside in the top 3 to 6 ft of soil or, in the case of groundwater, the water table can be no more than 10 ft below ground surface. The creation of a process waste stream may also be seen as a limitation. In cases where the plant takes up and stores the contaminant, the plant may be considered a hazardous waste (depending on the contaminant type and concentrations in the plant matter). 

Barlaz, M. A., Shafer, M. B., Borden, R. C. Wilson, J. T. (1993). Rate and extent of natural anaerobic bioremediation of BTEX compounds in ground water plumes. Symposium on Bioremediation of Hazardous Wastes Research, Development, and Field Evaluations. May 4-6 Dallas, Texas. 

Sims, R. G, Sims, J.L., Sorensen, D. L., Stevens, D. K., Huling, S. G., Bledsoe, B. E., Matthews, J. E. Pope, D. (1994). Performance evaluation of full-scale in situ and ex situ bioremediation of creosote wastes in ground water and soils. In Proceedings, Symposium on Bioremediation of Hazardous Wastes Research, Development and Field Evaluations, pp. 35-9- EPA/600/R-94/075. Cincinnati, OH US EPA. 

USEPA, Hazardous waste clean-up information, U.S. Environmental Protection Agency, Ground-Water Remediation Technologies Analysis Center, Remediation Technologies, www.gwrtac.org/htm/tech topic.htm, 2003. 

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