4.15 INDUSTRIAL COOLING WATER SYSTEMS - SUBPROJECT 15 



OCS-related facilities , in which the use of cooling water and its 

 associated environmental impacts are of major importance, include (1) gas 

 processing and LNG plants, (2) refineries, (3) petrochemical plants and 

 (4) power plants dependent on CCS facilities. Impacts associated with 

 extraction of cooling water from surface water bodies include impingement 

 and entrainment of aquatic organisms, contamination of the cooling water 

 by a variety of chemicals, and thermal effects associated with the 

 higher temperature of the discharged cooling water (Figure 42). 



4.15.1 Summary 



A variety of water uses are associated with OCS-related activities. 

 The most important byproducts, from the standpoint of damage to fish and 

 wildlife and their habitats, are cooling and processing waters. 



Since the cooling system is an integral part of the physical plant 

 system, and construction activities are relatively minor threats to the 

 environment, this section focuses on the operational aspects of the 

 cooling water system. 



Waste heat from a variety of processes is removed through the use 

 of water or air cooling. Water cooling is preferred because of the high 

 costs and large energy demands required for air cooling. Perhaps 40 per- 

 cent of the total water use in OCS-related processing industry (70 to 95 

 percent in gas processing plants) is for cooling purposes [7]. Also, 

 electric power plants generating power for OCS facilities consume massive 

 amounts of cooling water and thus create an extremely high potential for 

 adverse effects in coastal waters. Because most electricity will be 

 purchased from a local utility (except in remote areas), the effects 

 on the cooling water system will be at a power plant site, which may not 

 be in the immediate vicinity of the OCS facility. As a specific example, 

 a refinery complex with a capacity of 250,000 B/D will use 100,000 kilo- 

 watts [7]. 



Many problems for the aquatic environment are posed by large- 

 volume cooling systems. The suspended life in natural waters of estu- 

 aries and rivers may be injured or destroyed while passing through plant 

 cooling systems. Larger fishes can be drawn against the intake where 

 they may be crushed against the entrance screens (Figure 42.) Plant 

 cooling systems tend to become fouled with algae and plankton forms. 

 The popular treatment for destroying these organisms is flushing with 

 a periodic dose of hypochlorite ( chlorine), which destroys most forms 

 of aquatic life. 



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