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<br />""'" <br />~ <br />w <br />ao <br /> <br />The next major trea~~ent step is removal of crganics. Here ~e have <br /> <br />selected biological oxidation in prefer~nce to adsoC?tion. Certainl~ biological <br /> <br />treatment will ~e more economical than car=on adsorption at t~e ~igh BOD and <br /> <br />COO levels. However, resin adsorption may prove to be a viable precess, <br /> <br />particularly for those waters containing high COD/BOD raeics. !ns~f:icie~t <br /> <br />i~formation is avai~able on resin adsorption characteris~ics fc= modifiec in <br /> <br />situ oil shale waters to compare costs. The design and costing of t~e biological <br /> <br />unit has to be based on kinetic data obtained using coal conversion wastewaters <br /> <br />since ~~is data is not available fer in situ retort wa~ers. In our example ~e <br /> <br />selected an oxygen syst~~ since indications are that costs will be lower :or <br /> <br />the high (> 1000 mg/l) BOD waters. Also, o~ygen systems ope~ate ~cre s~ably <br /> <br />and some measure of control oVer stripped volatile va?ors is available. <br /> <br />The bicar~onate levels may =e high enough to require eithe~ acicifica~ion <br /> <br />or li~e 3often~~g prior to use in ~ie cooling tower. Such trea~~ent is sca~card <br /> <br />and ~ay be considered as part of ~he cooling wa~er system. <br /> <br />In Section 2.7 the cost of biological trea~~e~t E~r ~~e BCD =e~oval t~at <br /> <br />~ould be required for the water of Table 4-8 is S2.3/1000 gal (= SiSO/acre- <br /> <br />ft). From our ammonia strip9inq stucies (?e:. 6, Se=tion 2) we conclude t~at <br /> <br />after taking a c=edit of S120jton for the a~9roximately 100 tons 0= ~onia <br /> <br />recovered per day =~e stripping cost for ~~e retort ~ate: would be, a~ ~ost. <br /> <br />SO.40/1000 gal (= S130/acre-f~). ?rL~arl ~~d secondarj oil-wa~er se?ara~i=n <br /> <br />may be esti..l1ated at SO_15/1eCO gal (= S49/acre-ft), alt~oug~ this is cnlj 'lsed <br /> <br />for about. ha.l: the '#later. .jl.d.dir.g these :03tS toget.;,e.!." t.he ~ost of t=eati.ng <br /> <br />the retort wate~ for ~euse is S2.B/IJOO gal 1= S913/acre-ftl. <br /> <br />It can!lOt., <br /> <br />however, be emphasizec too strongly t~at this is for an ass~ec ~e~ort water <br /> <br />for ~hich data u?on which to base ~~ accu~ate cesign is not available at ~~is <br /> <br />I <br />I <br />-----I <br /> <br />time. <br />