Hydraulic fracturing or fracking is the method used by oil and gas companies to break up the rocks beneath the surface of the earth and release oil, gas and water that is often trapped there. The process of fracking is heavily reliant on large volumes of fresh water as well as chemical and sand which are pumped underground at very high pressure as far down as a mile. It is this high pressure combination that breaks up the rocks and the resulting gas, oil and water are then sent to the well where they are recovered for processing. One well uses between 4 – 6 million gallons of water.
The water that comes out of this process is known as produced water. It is contaminated water that needs to be cleaned out before it can be reused or discharged into the environment safely. It is important that the oil and gas produces demonstrate that they are indeed taken all the necessary steps to ensure that the public, water supply and even their investors are protected from any mishaps or accidents that could send this contaminated water out into the environment. Produced water treatment is a big deal for the gas and oil producers. They must of necessity find a way to make sure it happens in order to be environmentally sustainable.
Because most of the oil and gas wells tend to be located in water stressed areas, it is important that recycling and reusing of produced water become a priority. Often, the water in the said region will already be in heavy use from industries, municipalities and farms. It is therefore critical that some of the following techniques be employed for produced water treatment:
* Electrocoagulation – This method uses electrified plates in tanks. The water goes through the tanks and forms ions which then attach to the said contaminants. The contaminants become heavy and drop to the bottom of the tank. They may be large enough to filter or skim out.
* Oxidation – An electric field is created and oxygen passed through it to create ozone. The ozone is turned into hydroxyl radicals that are used to decompose contaminants which then take on the form of micro-bubbles that implode. It kills bacteria and strips hydrocarbons, polymers and more from the water.
* Desalination – is used to remove salt from produced water using a membrane based system and a distillation system as well that mimics boiling where water is heated and condensed.
There are several methods used in produced water treatment. They include electrocoagulation, oxidation and desalination. Oil and gas companies have to consider its treatment to be environmentally sustainable.
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