Even prior to producing natural gas, air pollution is generated by heavy construction activity including trucks and other equipment that emit air pollutants at well pads, pipelines, roads and compressor stations.
During the drilling of a well, air pollution is generated by diesel engines powering the drill rig, as well as by any natural gas emissions being vented from the hole in the ground. These emissions could include various toxic gases, including volatile organic compounds.
Waste from drilling, fracking, or production may be dumped into open air pits to allow some of the toxic material to evaporate into the air. This can result in significant air pollution.
|Located south of 49th St at 35th Ave, directly south of the DCP Midstream|
Gas Processing plant in Evans.
Land application (including land farming)
Waste from drilling, fracking, or production may be spread on the ground or otherwise applied to the land. This can result in significant air pollution.
Gas from wells is collected at central locations and compressed into smaller volumes at stations. Another type of compressor is located on the well site. Both types of compressors can leak and release a variety of toxic gases
Some well sites produce semi-liquid gases along with natural gas that are stored in tanks, which can leak various toxic gases into the air.
A condensate tank close to housing in Evans, east of 35th Ave, and south of Walgreens on 37th Street.
Dehydrators and Separators
These systems are needed to remove water from natural gas and can release toxic gases in the process.
Note: "...In refineries and processing plants, it is normal practice to inspect all pressure vessels and piping periodically for corrosion and erosion. In the oil fields, this practice is not generally followed and equipment is replaced only after actual failure...Oil and gas separators should be installed at a safe distance from other lease equipment. Where they are installed on offshore platforms or in close proximity to other equipment, precautions should be taken to prevent injury to personnel and damage to surrounding equipment in case the separator or its controls or accessories fail." ~ http://en.wikipedia.org/wiki/Separator_(oil_production)
Unwanted gases in the production process may be burned off in the open air through flares, which can produce other toxic gases as a result.
Flares (left), and separators at the U.S. 34 / U.S. 85 intersection.
Note the black pipes on the separators that 'vent' toxic fumes.
Fugitive emissionsLeaks in equipment such as pumps, valves, compressors, pipes and tanks can result in significant air pollution releases because of the number of components in gas processing.
During various stages of gas exploration, production and maintenance, gases are vented directly into the air rather than contained or flared. Venting can release large volumes of toxic gases.
Gas processing plant
The last stage of gas production involves the refining of the raw gas into the final product. This occurs at large gas processing plants, which have many sources of air emissions.
Additional waste disposal sites
Wastes from various stages of gas production and processing may be sent to treatment sources including landfills, injection sites and wastewater treatment sites, which can also release air pollution.
See more: Gassed! Citizen Investigation of Toxic Air Pollution from Natural Gas Development