Fracturing
Overview
Fracturing is a way to crack rock or very dense soil, like clay, below ground. It is not necessarily a cleanup method in itself. Rather, fracturing is used to break up the ground to help other cleanup methods work better. The cracks, which are called fractures, create paths through which harmful chemicals can be removed or destroyed.
Hydraulic fracturing uses a liquid—usually water. The water is pumped under pressure into holes drilled in the ground. The force of the water causes the soil (or sometimes rock) to crack. It also causes existing fractures to grow larger. To fracture soil at greater depths, sand is pumped underground with the water. The sand helps prop the fractures open and keep them from closing under the weight of the soil.
Pneumatic fracturing uses air, to fracture soil. It also can help remove chemicals that evaporate or change to gases quickly when exposed to air. When air is forced into the soil, the chemicals evaporate and the gases are captured and treated above ground.
Air can be forced into the ground at different depths within a hole. When air is forced near the ground surface, the surface around the holes may rise as much as an inch, but will settle back close to its original level. In both pneumatic and hydraulic fracturing, equipment placed underground directs the pressure to the particular zone of soil that needs to be fractured.
Blast-enhanced fracturing uses explosives, such as dynamite, to fracture rock. The explosives are placed in holes and detonated. The main purpose is to create more pathways for polluted groundwater to reach wells drilled for pump and treat cleanup.
4.38 Hydrofracturing (In Situ Ground Water Remediation Technology)
In Remediation Technologies Screening Matrix and Reference Guide, Version 3.0. Federal Remediation Technologies Roundtable.
4.6 Fracturing (In Situ Soil Remediation Technology)
In Remediation Technologies Screening Matrix and Reference Guide, Version 3.0. Federal Remediation Technologies Roundtable.
Artificially-Induced or Blast-Enhanced Fracturing to Improve Groundwater Recovery for Treatment and Migration Control: Technology Overview Report
1996. Ralinda R. Miller, Ground-Water Remediation Technologies Analysis Center. TO-96-01, 13 pp.
The report introduces the principles and techniques associated with fracturing and discusses the advantages and disadvantages of the technology in remediation applications.
