Ground remediation, also known as land remediation, is the process of restoring land contaminated by hazardous materials to a usable state. The materials causing the contamination are usually dangerous and need to be neutralized so that people and animals aren't harmed. One way to achieve this is by containment so that people can't come in contact with harmful materials. The second method is treatment of the materials with agents that alter the chemical make-up so that they aren't dangerous anymore. Another ground remediation method is complete removal of hazardous materials from the affected area.
There are many materials and situations that can contaminate land and make ground remediation necessary, such as industrial waste, oil spills, gas line leaks, radioactive materials, and various chemicals. In the United States, the environmental cleanup efforts are regulated by the Environmental Protection Agency, commonly known as the EPA. The first step in the remediation process is to determine the cause and scope of the environmental contamination, usually by testing numerous samples. This information, together with knowledge about the future use of the site, helps to select the method of remediation to be used.
Containment is one type of ground remediation that can be used. This involves isolating the hazardous materials so that nothing can come in contact with them anymore and leaving them in place. If there's no danger of the contamination spreading to the air or water, land use controls can be used, essentially closing the site off and forbidding access. A cap can also be placed over the area to keep the contamination in, and to keep people from coming in contact with it. These are commonly used in landfills. Cut off walls can also be placed in the ground to prevent the spread of the contamination through groundwater.
Another type of ground remediation is treatment of the hazardous material, changing it into something less dangerous while still leaving it in place. This can be accomplished through the use of chemical oxidation, a process where chemicals called oxidants are pumped into the contaminated ground to mix with the hazardous materials. The oxidants change the hazardous materials chemically into harmless ones. Another treatment method is called bio-remediation, which uses tiny organisms called microbes to eat the hazardous chemicals. Through the digestion process, the chemicals turn into safer materials.
Complete removal of hazardous materials from the site is another option for ground remediation. This can be accomplished through a process called soil washing, where the hazardous materials are literally washed out of the soil and removed. Another way is excavation, where soil is actually dug up and removed to another location, then the area is filled in with fresh clean dirt. Sometimes the hazardous materials can also be completely destroyed and removed by burning them, also called incineration.
Depending on the ground remediation method used, it can be an ongoing process. Some methods will require monitoring, especially containment processes, to ensure that they are still working. Also, depending on the type and severity of the contamination, periodic testing of the site may be needed to ensure continued safety.