present in the raw gas. International Research and Technology Corp. (1977, as
reported in USDOI/BLM, 1981c) considered the potential environmental
consequences of a gas separation plant built in the South Atlantic region, and
concluded that there would be no significant impact on local air quality.
The operation of both pressure booster stations and gas separation plants
must comply with applicable North Carolina and federal air pollution laws and
programs; see Cribbins (1981) for a detailed discussion of these. Three basic
programs will govern emissions from these facilities. First, a State Air
Quality Permit is required from the N.C, Division of Environmental Management
(DEM) to operate any air contaminant source in the state. Applications are
evaluated in terms of an area's ambient air quality standards and the emission
control standards set by DEM for various sources.
Second, under the Prevention of Significant Deterioration Program
established by EPA and now administered by DEM, a permit is needed in areas
attaining National Ambient Air Quality Standards (which includes the entire
coastal area) if a source either 1) emits more that 250 tons per year of a
listed pollutant, or 2) emits more than 100 tons per year if it is one of
several listed facilities, which pressure booster stations and gas separation
plants are not. Various criteria must be met for permit approval, including
demonstration that the emissions will not cause significant deterioration of
air quality (as defined in the regulations) , and that pollution controls
representing the "best available control technology" will be used.
New Source Performance Standards have been issued by EPA (40 C.F.R. §60)
for new emission sources in certain categories. Of the various processes and
equipment possibly associated with oil and gas pipelines, standards have been
established for stationary gas turbines and sulfuric acid plants, the latter
of which may be built to use sulfur recovered from the gas stream.
Water Use and Quality . Only gas separation and dehydration plants, among the
facilities being discussed, use and discharge substantial quantities of water.
Figures available from the gas separation industry in 1973 indicated a water
demand for gas plants ranging from zero to 750,000 gallons per day, with most
plants using less than 200,00 gallons per day (NERBC, 1976). How much water
is used depends largely on the gas throughput and the cooling process
employed. Modern air-cooled systems use far less water than water-cooled
systems, which themselves vary in their water requirements depending on
whether cooling towers or other recycling systems are used.
The water may be obtained from wells, surface waters or municipal
systems. The withdrawal of such large amounts of water from surface or ground
waters may create problems if surface flows are reduced or the water table
lowered substantially. Under N.C. General Statute §143-215 Part 2, the
Environmental Management Commission is empowered to designate "capacity use
areas," within which a permit is needed to withdraw 100,000 gallons or more
per day from surface or groundwaters. One capacity use area currently exists
in the coastal zone, covering all of Beaufort, Pamlico, and Washington
Counties and portions of the counties of Carteret, Craven, Hyde, and Tyrrell.
Several types of wastewater will be generated by gas separation and
dehydration plants. These are:
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