SECTION VI 

 PHYSICAL PARAMETERS 



DESALINATION PLANT OPERATION 



Figure 10 shows monthly averages as well as high and low values for 

 various operating parameters of the Key West desalination plant. 

 The total volume of effluent discharged decreased during the study 

 period as did the number of operating days per month. Effluent tem- 

 perature averaged 35° C during the entire period. The pH averaged 

 7 with a range of 3.2 to 8.5. Salinity varied more than other 

 parameters, averaging between 48.00 and 53.00 o/oo with a range 

 of 40.00 to 55.00 o/oo. Copper discharge varied between 148 ppb 

 to 6,515 ppb. It increased from a mean of about 1,000 ppb in 

 June, 19 70 to a mean of 2,656 ppb in January, 1971. In June, 1971 

 engineering changes drastically lowered the copper output and in 

 August, copper concentration reached a minimum mean value of 425 

 ppb. Discharge of heavy metals is discussed further in the section 

 below on copper and nickel. 



AMBIENT CONDITIONS 



Temperature, salinity, and copper data from all stations were pooled 

 to present overall monthly averages (Fig. 11). Temperature steadily 

 decreased from August, 19 70 to February, 19 71 then increased again 

 through August, 19 71, Salinity declined in October and November, 

 1970 reaching a low of 34.60 o/oo in Novem.ber. From then until 

 May, 1971 salinity increased to high ambient levels with a peak of 

 38.00 o/oo in April. During that time South Florida experienced 

 a prolonged drought with little cloud cover. Lack of precipitatic 

 and long hours of sunshine (also plotted in Figure 11) explain the 

 high ambient salinities. 



Lon 



EFFLUENT DISTRIBUTION 



Distribution of the effluent was studied using Rhodamine B dye, 

 direct observation while diving, thermal mapping, salinity data, 

 and heavy metals distributions in the sediments (see Section IV 

 Methods and Procedures). 



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