Hidrológiai Közlöny 1975 (55. évfolyam)

7. szám - Dr. Csanády Mihály–dr. Gary S. Logsdon: Kísérletek kadmiumnak ivóvízből történő eltávolítására

296 Hidrológiai Közlöny 1915. 7. sz. Dr. Csanády M.—

dr. Gary S. Logsdon: Kísérletek kadmiummal vegyszer-fölösleggel (100 mg/l) 99%-ot meghaladó eredmény is elérhető. A kadmium-koncentráció növekedése a hatásfokot csak kis mértékben rontja. A pH beállítására általában szükség van, ami szóda vagy mész adagolását is szükségessé teszi. A meszes lágyítás csapadéka jól ülepedett. Az alumínium- és vashidroxid esetében viszont a rosszul ülepedő kis pelvhek szerepe jelentősnek bizonyult, ezért a derítést követő szűrés a kadmium-eltávolítás szempontjából is lényeges. A hazánkban leggyakrabban alkalmazott eljárás, az alumíniumhidroxidos derítés tehát önmagában általában nem alkalmas a kadmium eltávolítására. Aktív szén alkalmazása az eredményt javíthatja, a várható hatás kimérése azonban még további vizsgálatokat igényel. IRODALOM [1] Fleischer, M.: Natural sources of some trace előments in the environment, in: Cycling and Control of Metals. Proc. of an Environmental Resources Conf. 1972 Columbus EPA NERC, Cincinnati 1973. p. 3—10. [2] Durum, IV. H.

: Occurrence of some trace metals in surface and ground water. Sixteenth Water Quality Conf., University of Illinois, Febr. 12—13, 1974. [3 J Kroner, I'. C.

: The occurence of t race metals in surface waters; in

: Traces of Heavy Metals in Water" Removal Processes and Monitoring. Proc

. of a Symposium, Princeton University 1973. EPA, Reg. II. p. 311—322. [4] Hem, J. D.

: Chemistry and occurence of cadmium and zinc in surface water and groundwater. Water Reesources Research, 8 601

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679 (1972). [5J Csanády M.: Galvánüzemi szennyvíz által okozott talajvíz-szennyezések. Hidrol. Közi. 54. 62—65 (1974). [6] Csanádi) M.: A hazai felszíni vizek réz- és cinktartalma. Hidrol. Közi. 51. 90—93 (1971). [7] Logsdon, 0. S., Symons, J. M.: Mercury removal by conventional water-treatment techniques. J. AWWA, 65, 554—562 (1973). [8] Logsdon, G. S., Symons, J. M.: Removal of heavy metals by conventional treatment in: Traces of heavy Metals in Water, Removal Processes and Monitoring. Proc. of a Symposium, Princeton University, 1973. EPA, Reg. II. p. 225—256. [9] Linstedt, K. D., Houck, C. P., O'Connor, J. T.

: Trace element removal in advanced wastewater treatment processes. J

. Water Poll. Control Fed. 43. 1507—1513 (1971). [10] Maruyama, T., Hannah, S. A., Cohen, J. M.

: Removal metals by physical and chemical treatment processes. 45th Annual Conf. WPCF, Atlanta, Georgia, 1972. [11] Argo, D. G., Culp, G. L.: Heavy metals removal in wastewater treatment. Water & Sewage Work 1972. Aug. 62—65. és Szept.; 128—132. [12] Argaman, Y., Weddle, C. L.

: The fate of heavy metals in physical-chemical treatment processes. Report on Central Contra Costa (California) pilotplant investigations, 1973. [13] Posselt, H. S., Weber, W. J.: Removal of cadmium from waters and wastes by sorption on hydrous metal oxides for water treatment. In Chemistry of Water Supply, Treatment & Distribution, p. 89—108. [14] Standard Methods for the Examination of Water and Wastewater 13th Ed., APHA, New York, 1971. [15] International Standards for Drinking Water, WHO, Geneva, 1971. [16] Ga^diener, J.

: The chemistry of cadmium in natural water — II. The adsorption of cadmium on river muds and naturally occuring solids. Water Research 8, 157—165 (1974). OnbiTbi no YFLAJIEHHIO KA/TMUJI H3 NHTBEBOM BOÄM JJ-p yahiadu, M.

—d-p Jlozcdon, r. C. MccjieaoBaHHH 6unn HanpaBJieHbi Ha BbiiiBJieHHe CTeneHH YflaJieHHfl KaflMHfl H3 nHTbeBOH BOflbl TpaflHUHOHHblMH MeTOAaMH BOflOnOflrOTOBKH. OnbiTbi npOBOflHJIHCb B jia6opaTopHbix YCJIOBHSIX. YcTaHOBJiemie CTeneHH Y,AAJIEHH5I KAAMMI NP0H3B0.SH.N0CB PAÄH0H30TONHBIM cnocoßoM. noApoÖHbie pe3yjibTaTbi npeflCTaBJieHbi B BHfle ÄHarpaMM n B Taßjiuuax. IlpH CMilrieHHM ßOJIbmHM H36bITK0M H3BCCTH (pH11,3) KOHneHTpanHfl KaflMiiH coKpamaeTCíi, npHMcpno, na 3 nopíiflKa. B cjiynae HE06X0FLHM0CTII STOT cnocoß — B COqeTaHim c nocJieacTByiotuen aapauweW (pei<ap6omt3ahhji) — MOweT ßbiTb ycneuiHO npwweHeH ajiíi yflajiem-m KaflMHfl H3 nHTbeBOH BOflbl. OCBCTJlCHHe THflpOOKHCbK) ajlIOMHHHfl npH OßbIMHblX K0HneHTpanH5ix H pH aaeT pecbMa cjiaßbift 3<})(})eKT y«ajieHHii KaflMHH. YcTaHOBitB H^eajTbHoe 3HaqeHne pH (8,3) H pacxoayn H3JiHuiHee KOJiMMGCTBO pearema, 3(J)(J)ei<T y^ajienHfl BCii we He npeBbiuiaeT 50—60%. C p0CT0M KOHHeHTpanuH Kafl.vuiii He Bbi«ep>KHBaeTCH «a>i<e u Takoii ypoBeHb. Pe3yjibTaTbi ocBeTJiemifl iHflpooKHCbio 3-x BajiCHTHOrn >Kejie3a 3HamiTejibH0 Jiymne, XOTJI Towe ciuibHO 3aBHcstT ÓT pH. IlpHMeHjia npaKTHMecKii flonycTHMyio no3y peareHTa (20 Mr/ji) h npH pH-8, 3(J)(|)eKT y/iajiemifl cocTaBjiaeT npiiMepHO 80%; npu pH-8,5

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TpanHH nocjie ocBCTJieHHyi M0>Ker ßbiTb cymecTBeHHoií c TOMKH 3peHH5i yflaJieHMfl KaflMHH. Tai<HM oöpasoM, nan6ojiee LuiipoKO pacnpocTpaHeHHUH B narneii CTpaHe cnoco6 OCBETJIEHHH rH^pooKHCbio ajnoMiiHIISI caM no ce6e He noaxo

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. IlpMMeHeHiie aKTHBHoro yrjiji HecKOJibKO yjiyiuiaeT pe^yjibTaro, o/iHai<o KOJiHHecTBeHHoe onpe^ejieHHe o>t<nflaeMoro 3(j)(j)eKTa TpeöyeT aanbHeiínrax nccjie«OBaHi-iH. Experimenls for removal of cadmiuiü from drinking water M. Csanády, G. S. Logsdon The object of the investigation was to iearn the efficiency of conventional water treatment processes for cadmium removal. Bench-scale experiments were carried out using the jar test apparatus. Cadmium removal was measured by radioactive tracer technique. The initial cadmium concentration usually was 0.03 mg/1. Detailed results are shown in figures and tables. The concentration of cadmium may be decreased in excess of two orders of magnitude by the high lime softening process (pH=11.3). In an emergency the method may be used together with recarbonation to remove cadmium from drinking water. At typical pH values and alum concentrations, cadmium removal by alum coagulation was rather poor. At pH 8.3, the optimal value, 50 to 60 percent removal could be attained by using a high concentration of alum. When other conditions were constant, cadmium removal decreased as the initial cadmium content increased. Ferric coagulation was more effective than alum coagulation, b111: it was quite dependent upon pH. At pH 7 results were poor, but with a 20 mg/1 dose of coagulant, removal was about 80 percent at pH 8 and 89 to 94 percent at pH 8.5 — 8.7. Removal with 100 mg/1 of coagui