began the first large-scale biological investigation of the impact 

 of desalination plants on the marine environm.ent. 



Previous researches (Le Gros et al 1968, Zeitoun et at 1969a) had 

 surveyed the literature for theoretical effects of heated brine 

 effluents and high levels of trace metals. Some experimental laboratory 

 studies and analyses of effluents had been conducted on the effects of 

 copper on the marine environment (Zeitoun et dl 1969b) . These works 

 contain excellent summaries of previous studies relating to biological 

 tolerances for excessive heat, salinity, and copper. 



The desalination plant at Key West is owned by the State of Florida 

 and managed by the Florida Keys Aqueduct Commission. It supplies 

 the City of Key West with about 2.4 million gallons of freshwater per 

 day. Additional water is pumped from the mainland of Florida to this 

 island community. Since the facility is located in subtropical areas, 

 the effects of added heat and salinity were expected to be more pronounced 

 here than in cooler waters. Since the plant was constructed by the 

 Westinghouse Electric Corporation, it was also felt that cooperation 

 between the plant operators and the researchers would be good, thus 

 facilitating the research. 



The objectives of the research program were to determine the biological 

 impact of the desalination plant effluent, to define the most toxic 

 elements of the discharge, to develop predictive capabilities on effects 

 of additional thermal, heavy metal, and organic loading of Safe Harbor, 

 and to establish possible methods for management of such stresses. 



In addition to reaching the planned objectives, Westinghouse Ocean 

 Research Laboratory assisted the Florida Keys Aqueduct Commission and 

 Westinghouse Electric Corporation in planning actual corrective measures 

 to improve the water quality of the effluent. 



The study showed copper discharge to be in excess of safe biological 

 levels. Reasons for the excessive corrosion were sought and engineering 

 methods were designed to overcome the corrosion problems. Westinghouse 

 Electric Corporation donated the engineering time involved in the corrective 

 measures, but the cost of the actual changes were still great. The 

 following steps were taken beginning in 1971: 



1. Large copper-nickel separatory trays were removed from 

 the deaerator and temporarily replaced with wood screens 

 (June, 1971). Stainless steel trays have been ordered 

 and will replace the remaining copper-nickel trays by 

 the spring of 19 72. 



2. An entire tube-bundle (1,200 tubes, 110 feet long) was 

 removed and replaced with titanium tubes (November, 1971). 



3. A new boiler was installed to prevent frequent shut-down 



15 



