AIR SCRUBBERS

Scrubbers are used to help control emissions of sulfur into the atmosphere. This is of particular interest to those involved with electric power generation via combustion of coal. The gases that are emitted from the combustion process are passed through tanks containing a lime substance (often a limestone slurry) that can capture and neutralize the sulfur dioxide. Some types of dry scrubbers are in existence, but they are even more costly than slurry method scrubbers.

Aquaculture is the commercial production of fish. Often, this pertains to catfish farming.

A best management practice, often referred to simply as BMP, is a practice (or combination of practices) that is determined to be the most effective, practical, economical, and technologically sophisticated means to better manage wastes and prevent or reduce contamination of groundwater.

1. Wells used by generators of hazardous waste, or of radioactive waste, by owners or operators of hazardous waste management facilities, or by owners or operators of radioactive waste disposal sites to dispose of hazardous waste or radioactive waste into a formation which within one-quarter (1/4) mile of the well contains an underground source of drinking water.

2. Wells used by generators of hazardous waste or of radioactive waste, by owners or operators of hazardous waste management facilities, or by owners or operators of radioactive waste disposal sites to dispose of hazardous waste or radioactive waste above a formation which within one-quarter (1/4) mile of the well contains an underground source of drinking water.

3. Wells used by generators of hazardous waste or owners or operators of hazardous waste management facilities to dispose of hazardous waste , which cannot be classified under paragraph (a)(1) or (d)(1) and (2) of Section 144.7 (e.g. wells used to dispose of hazardous waste into or above a formation which contains an aquifer which has been exempted pursuant to section 146.4).

NOTE: Most Class IV Injection Wells are Illegal!

Often termed EOR, enhanced oil recovery injection wells are used to help prolong an oil field's life. Most commonly, salt water that is pumped to the surface is reinjected into the oil reserve. This forces the remaining oil into the pumping well. This process is known as secondary recovery. In contrast, tertiary recovery is the process of injecting gases, chemical additives, and sometimes even steam into a depleting well to prolong production.

Ethylene glycol is a component of antifreeze, and it also is a known carcinogen.

The Groundwater Education System is a hypertext educational program (very similar to the Injection Well Information Program). It attempts to inform the user as to what groundwater is, how it can be contaminated, the consequences of groundwater contamination, and why people should be concerned about groundwater.

For information on how to obtain this software, please contact

Prof. Bernard A. Engel
Department of Agricultural Engineering
Purdue University
West Lafayette, Indiana 47907-1146

This type of waste includes waste substances that are dangerous (or potentially dangerous) to sustaining life. Examples of hazardous waste include toxic or corrosive wastes or wastes created by specific industrial processes. It is generally defined by Subtitle C of the Solid Waste Disposal Act, as amended by the 1976 Resource Conservation and Recovery Act. EPA lists specific hazardous wastes and their pollutants in 40 CFR Part 261.

("HWM Facility") means all contiguous land, and structures, other appurtenances, and improvements on the land used for treating, storing, or disposing of hazardous waste. A facility may consist of several treatment, storage, or disposal operational units (for example, one or more landfills, surface impoundments, or combination of them).

A health advisory (HA) is a non-regulatory health-based reference level of chemical traces (usually monitored in parts per billion (ppb)) in drinking water at which there are no adverse health risks when ingested over various periods of time. Health advisory levels are established for 1 day, 10 day, longer terms, and lifetime exposure periods. These are based on data obtained from extensive laboratory studies. They also include a large margin of safety.

Heavy metals are found in used motor oil. Examples include barium, lead, and cadmium. These substances are considered carcinogenic.

Hydrocarbon storage wells are used to store liquified petroleum gas (LPG), crude oil, and various other liquid hydrocarbons. The same wells often are used to not only inject hydrocarbons, but remove them as well.

This is a waste product of an industrial process that does not meet the Federal definition of hazardous waste.

In situ leaching is used to mine metals such as copper, gold, and even uranium. In this process a neutral substance (water, carbon dioxide, oxygen, etc. - the substances vary according to what material is being mined) is injected into the Earth. The solution is circulated throughout the underground deposit. The liquid "leaches" the metal off of the sand particles that compose the ore of the mined substance. This is then pumped to the surface, and the mined particles are extracted from the solution.

Karst topography is a landscape where the surface of the bedrock, usually limestone, has been dissolved by groundwater, forming an irregular surface and subsurface. Sinkholes and caves are also common in karst regions.

Low Input Sustainable Agriculture involves the reduction of runoff and the total amount of contaminant that could possibly cause groundwater contamination. This can be accomplished through improved chemical management, irrigation management, and planting techniques. LISA also involves organic farming practices as well. (United States Department of Agriculture, USDA).

A maximum contamination level, often referred to as an MCL, is an enforceable, regulatory standard for maximum permissible concentrations of contaminants in drinking water. They are established under the Safe Drinking Water Act of 1974. The MCL standards of purity are applied to the water distribution system after the water has been treated, regardless of a surface or groundwater source. These are health-based numbers which by law, must be set as close to the "no-risk" level as feasible.

Municipal waste, though not technically defined by Federal regulations, is considered to be sewage effluent that has at least secondary treatment. Currently, injection of municipal wastes is practiced in the state of Florida. This is because of the lack of available land, cost effectiveness, and surface water discharge limitations in Florida.

New Injection Wells means an "injection well" which began injection after a UIC program for the State applicable to the well is approved or prescribed.

Each Class V underground injection well has been given an abbreviated code name. For example, wells used by service stations are referred to as 5X28 wells, and injection wells used for storm water drainage are termed as 5D2 wells. The EPA is in the process of phasing out this nomenclature system, but it has been used widely in the past as a means of describing the various types of underground injection wells. These codes are listed as part of the well title in the list of wells found in Section Four [4. The Five (5) Classes of Injection Wells] of this program.

Owner or operator means the owner or operator of any "facility or activity" subject to regulation under the UIC program.

Permeability is a physical property of soil and rock. It is a measure of how easily a fluid, such as water, air, or liquid waste, moves through a porous rock or sand and gravel deposit. Two primary factors that contribute to permeability are the size of voids and their interconnectedness.

Plastic pigs consist of a chain and a bristled ball-like object. The ball is pulled through pipes to help remove any buildup that has accumulated on the inside of the pipe.

Porosity is a physical property of soil and rock. It is defined as the ratio of the amount of pore space present in a soil sample to the total volume of the sample. The voids or holes can be between grains of sand or gravel, in fractures or cracks in bedrock, or in larger voids where rock was dissolved by groundwater. Rock porosity varies from near zero to over sixty (60) percent.

RCRA is the Resource Conservation and Recovery Act. RCRA was established by Congress to regulate hazardous wastes. Its emphasis is on resource recovery and reduction of land disposal methods.

When crude oil is pumped to the surface, a large amount of salt water is pumped too. On the average, ten (10) barrels of salt water are produced for a single barrel of crude oil. This also occurs when extracting natural gas from the Earth.

Solution mining is used for the extraction of sulfur and salt from the Earth. To extract salt, water is pumped into the underground salt cavern. Here, the salt mixes with the water to form a brine solution. This solution is then easily pumped to the surface.

Sulfur mining is done by using the Frasch process. In this process, superheated water is injected into the sulfur deposit. The high temperature of the water melts the solid sulfur into a molten liquid. The liquid sulfur is then pumped to the surface (with the aid of compressed air).

UIC means Underground Injection Control program under Part C. of the Safe Drinking Water Act, including an "approved state program."

Waste exchange services match the waste products from one facility with another facility that can use the waste as a raw material in its process. Two exchange services are Pacific Materials Exchange (PME) in Spokane, Washington and Industrial Materials Exchange (IMEX) in Seattle, Washington. (Mention of these two services is not an endorsement by either USEPA or Purdue University. They are listed only as a sample of available technology.)

Waste minimization practices are measures or techniques that reduce the amount of wastes generated during industrial production processes. The term is also applied to recycling and other efforts to reduce the amount of waste entering into waste streams.

Well means a bored, drilled or driven shaft, or a dug hole, whose depth is greater than the largest surface dimension.

Well injection means the subsurface emplacement of "fluids" through a bored, drilled, or driven "well;" or through a dug well, where the depth is greater than the largest surface dimension.

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