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<br />~."" <br />fjJ <br />U1 <br />po.. <br /> <br />on Table 2-5 it was shown t~at the flow rate of dirty condensate was very <br />variable wit~ process and, for some precesses, with ~oisture in the coal. In <br />addition, some of L~e dirty condensate will be taken for purposes other than <br />cooling system makeup. One possible use is makeup to a flue gas desulfurization <br />system if L~e plant boilers are coal fired rather than gas fired. For this <br />purpose additional removal of organic material is probably not required. <br />Because i~ is low in salt, treated condensate is suitable for spraying on <br />roads to control dust. For this purpose good organic removal helps. Still in <br />most plants most of the process condensate will be used in the cooling system <br />and will be treated just enough to permit this use. This level of treatment <br />is for ttis report, an internal treatment ~~at must be done for adequate plant <br />operaticn rather than for environmental control. T~e cooling blowcown will <br />contain concent:ates derived from process condensate and if these are unacceptable <br />then additional treatment of concensate (before mixing into the cooling sys~em <br />feed) or of cooli~g system blowcown is re~uired. <br />Approximately 20-50' of the ~akeup to t~e cooling system ~ay be treated <br />condensate, with 30-70 lb conde:lsat.e/106 9tu requiring at least enough treatrne:1t. <br />fer use in the cooling tower. Based en L~e above discussions, the =oncensate <br />may require additional treatment for ~~e safe disposal of the blowdcwn ~ic~ <br />30-70 lb ccndensate treated for eve~J 11 lb of blowdown. <br /> <br />If treated condensate had t~ice tne organic concentrations shown en Table <br /> <br />2-9, if this ~ater ~ere 20-50\ of the tower makeup, if the tower concentrated <br />tenfold, except for ammonia; and if 50\ of the feed BOD and 9B\ of the feed <br />phenol were removed in the tower, then the concentration of the blowdown might <br />be as shown on Table 2-12. The blowdown ccntains appreciable organic concamination. <br />ala~down from many gasitica~ion processes will have less organic contamination. <br />This table will be used for discussion of the cost of blowdown treatment. <br />... .. 1 1 . 30 <br />Please rem~er that ~t ~s arge y conJecture <br />The total dissolved solids shown on Table 2-12 depend mostly on the <br />quality of the river water taken into the plant. Furthe~ore, the blowdown is <br />likely to be supersaturated in scale forming salts so treatments into12rant of <br />precipitation, such as reverse osmosis or electrodialysis, are unlikely to be <br />suitable for desalting this water. <br />We will discuss trea~ent and its cost, but first disposal must be mentioned. <br /> <br />46 <br />