Subproject: Industrial Wastewater Systems (SP-14) 



Disturbing Activity: Wastewater disposal 



Hydrocarbon levels in the cooling and process waters in an LNG 

 liquefaction or regasification plant usually increase as the water is 

 utilized. These wastewaters should be treated as appropriate for 

 specific LNG plants following EPA requirements. 



Subproject: Industrial Cooling Water Systems (SP-15) 



Disturbing Activity: Circulation of cooling (heating) water 



A water cooling system for an LNG liquefaction plant or a gas-fired 

 LNG vaporization process may be a once-through or a recirculating system. 

 Water demands for cooling depend on the plant capacity, and the type of 

 cooling system used. A combination air and water closed cycle cooling 

 system would minimize water demands. The temperature of the water passing 

 through the plant rises significantly in some cooling processes and types 

 of plants. Chemicals added to the cooling water as biocides and to 

 reduce corrosion in the system, such as hypochlorite, are highly toxic 

 and require collection and treatment prior to release. 



The cooling operations of LNG liquefaction plants need large amounts 

 of water. The 3 BCFD liquefaction plant proposed for Alaska would require 

 more than 1 million gallons of cooling seawater per minute [29] and a 

 1 BCFD capacity regasification plant would need 140,000 gallons of heating 

 water per minute [30]. At the regasification plant, the estimated drop in 

 water temperature would be "70°F between inlet and outlet" [16]. It is 

 highly unlikely that these enormous water volumes could be supplied by 

 groundwater. Seawater would probably be used for all but boiler water 

 and domestic needs. When withdrawing groundwater for these uses, 

 precautions must be taken to avoid environmental disturbances, such as 

 saltwater intrusion and land subsidence. 



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