Document 6wV8Jx2Zx58Qd2kbNanmZVVw3

i ' ] i j i j 1i ' Distribution of Polychlorinated Diphenyls in an Aerated ltiological Oxidation Wastewater Treatment System by 1'. S. k. Cum. II. Nack. and J. K. Im.inn ii.hteu.i-: Colinn bus l.uborulorii-s Columbus, Ohio 1:1201 Polychlorinated biphenyls (PCB) have received con siderable attention over the last decade because of the slow biodegradability and the possible toxicity to various eco systems including human beings (HOLMES et al. 1970; RISEBROUGH et al. 1968; JENSEN et al. 1969; KOEMAN et al. 1969; PRESTT et al. 1970; BIROS et al. 1970; PEAKALL and LINCER 1970; WILDISH 1970; VOS and KOEMAN 1970; NIMMO et al. 1971; HANSEN et al. 1971; VILLENEUVE et al. 1971; REHFELD et al. 1971; KURATSUNE et al. 1971; M0SSER et al. 1971). PCB is distributed to the environment mainly through various water courses. PCB in waters, wastewaters, and coastal waters has been reported elsewhere (DUKE et al. 1970; AHLING and JENSEN 1970; HOLDEN 1970; SCHMIDT et al. 1971). However, the fate of PCB in water and wastewater treatment systems, especially in a secondary aerated oxidation system has not been studied. A knowledge of PCB distribution in this particular pathway to the environment is of interest from the standpoint of its ultimate control. This study aims at determining the PCB distribution in a secondary aeration system and examining the effect of the substance on the system's performance. Material and Method A secondary sewage treatment laboratory system con sisting of an aeration tank (volume: 2340 cm3 at normal opera ting conditions) and a clarifier (volume: 2450 cm3) was em ployed in this study (see Figure 1). The feed rate was adjusted to provide 5-10 hours mean residence time. The air flow rate was adjusted to keep the dissolved oxygen level in the aeration tank at about 4 ppm or higher. The wastewater employed for feed of the system was a natural wastewater collected from the effluent of primary treatment in a municipal sewage treatment plant (Jackson Pike Plant, Columbus, Ohio). A synthetic wastewater was not considered to be appropriate for use in the treatability study although it might give an advantage of reproducibility of experimental results. PCB spiking into wastewaters was carried 12 Bulletin of Environment*! Contamination & Toxicology, Vol 11, No. 1 1974 by Springer-Vrrlag New York Inc. DS^310?21 STLCOPCB4070707 t Wastewater Feed FIGURE 1. DIAGRAM OF A SECONDARY BIOLOGICAL OXIDATION SYSTEM out using an ultrasonic emulsifier; i.e., PCB (Aroclor 1254) was first dissolved in a certain amount of n-Butanol, and then, the mixture was emulsified in wastewater by treating with ultra sound at 0.2 - 0.3 ampere for 4 to 6 minutes. The quantitative analysis method for PCB has been delineated (REYNOLDS 1969; ARMOUR and BURKE 1970; ZITKO et al. 1971; ROTE and MURPHY 1971; SNYDER and REINERT 1971). A gasliquid-chromatographic method was employed in this study. Separation of PCB from other interfering substances was made by extracting it with methylene chloride in the presence of hydrochloric acid and sodium chloride, concentrating the mixture, and separating it through a silica gel column. A gas-liquid-chromatograph, utilizing an electron capture de tector and a 6' x 1/4" O.D. ('t 2 mm I.D.) glass column packed with 1.5 percent OV - 17/1.95 percent 0F-1 on supelocoport was employed under operating conditions as follows: column temp erature, 195C; injector temperature, 220C; detector tempera ture, 210C; carrier gas, helium, carrier gas flow rate, 30 ml/ min; volume injected, 2pi. The calibration of the chromatograph was carried out and the chart was prepared for the quantitative measurement. v. In a typical experimental run, the secondary biological oxidation system shown in Figure 1 was operated for 5 to 11 days to reach a steady state condition, and then PCB was intro duced for a period of 2 to 3 days. Four to eight days of final 13 3 i DSW 310722 STLCOPCB4070708 i I operation was followed after the termination of the PCB intro duction. The operating conditions of the system were as follows: feed rate, 3.91 cm3/min; sludge return rate, 3.44 cin /min: sludge output rate, 0: feean residence time in aera tion tank, 9.98 hours. Results and Discussion Two experimental runs were conducted after completion of several preliminary runs needed for adjustment of the opera ting conditions. The results are shown in Figure 2 and in dicate that a considerable amount of PCB accumulated in sludge. 'For Experimental Run (1) concentrations in sludge of 6.14, 12,75 32.33, and 17.33 ppm were found 1, 2, 3, and 5 days after PCB introduction, respectively. The feed concentration was 1.63 ppm. For Experimental Run (2) concentrations in sludge of 36.2, 109.6, 152.0, 105.6, 112.0, and 84.0 ppm were found re spectively 1, 2, 3, 5, 6, and 10 days -after PCB introduction (l~r. T f~Xxd. I , (s /1 at the level of 16.88 ppm. Effluent solution, on the other hand, contained relatively small amounts of PCB. For Experi mental Run (1) the concentrations of 0.004, 0.0153, and 0.0225 ppm were found 1, 2, and 3 days after PCB introduction, re <L spectively. For Experimental Run (2) the effluents contained PCB concentrations of 0.006, 0.015, 0.042, 0.032, 0.022, and 0.015 ppm respectively, 1, 2, 3, 5, 8, and 10 days after the PCB introduction. PCB concentrations in feed, effluent, and sludge were 0.009, <0.001 and 0.07 ppm, respectively when PCB was not spiked into the wastewater. ( . .. . I / , /hv-fV.olLj'/*- 3 7 The interference of PCB on the system's performance in *7 terms of BOD, COD, and TOC removal efficiencies was not I clear. Microbiological studies are required to obtain further information on this matter. i Another view of the results involves consideration of I the dynamic concentration response of PCB in effluents and sludges for the impulse type PCB input. As shown in Figure 2, PCB concentration in effluents and sludges rapidly increased Tiii - with a step increase of PCB in feed, and then, decreased rather slowly with the same step size decrease of PCB in feed. The response of the system comprising a completely mixed tank and a tank without a stirrer could be approximated by a second f ~s> J.C. : or higher order dynamic model although the response was com 1 plicated due to the sludge return and a lack of knowledge on the (AAs) H.WU- degree of mixing in the second tank. According to the results, the secondary aerated bio logical oxidation system removes a high percentage of the PCB ; contained in wastewater. The treatment system, however, is 7 1 '' r 8', '' / ' _ tfu'+.J UJir K" 14 (X rcvJ-^j >/i d DSW 310723 STLCOPCB4070709 t to co UCuO e0) u co u u p* 0ft)) 30 T3 H3 (A O <U rH 0.024 o 20 0.016 10 0.008 J0 0 10 12 14 16 Operating Time, day (a) Experimental Run (1); Low Level PCB Introduction <u *6o0 3 4J c0) 0) <u M O 0.056 0.048 O0 E Co 0.040 CO 0.032 u c0o) 0.024 oco rt 0.016 o 0.008 (b) Experimental Run (2); High Level PCB Introduction FIGURE 2. PCB CONCENTRATION RESPONSES IN EFFLUENTS AND SLUDGES OF A SECONDARY AERATION TANK SYSTEM FOR A PCB INPUT (Symbols: ^ A, feed; 0, effluent; Q, sludge) . 15 O { STLCOPCB4070710 ' : ; ; ' i; ; ' i ; j i j 5 : V 1 : not believed to biodegrade or convert PCB to lower molecular weight or other types of chemical substances which are readily degradable. Instead, PCB is expected to be dissolved in fats present in sludge, adsorbed at the surface of the suspended material in sludge, or ingested by microbial cells in sludge. A combination of all of the above effects probably are opera tive in the concentration of PCB in sludge. Further study should be conducted to expand upon the results since this knowledge is essential in modifying current sludge handling methods. Simultaneously, landfill, land spread, and ocean dumping of sludge should be reexamined to keep PCB under con trol if the quantity of PCB discharge to streams increases. In addition, sludge incinceration should be reviewed to deter mine the fate of PCB in that system. Finally, a tertiary treat ment system such as activated carbon, should be studied to effect further removal of PCB from secondary effluents. References AHLING, B., and JENSEN, S., Anal. Chem. 44, 1483 (1970). ARMOUR, J. A., and BURKE, J. A., J. Assoc. Off. Anal.. Chem. 53; 761 (1970). BIROS, F. J., WAKER, A. M., and MEDBERY, A. Bull. Environ. Contam. Toxicol. 4^, 317 (1970). DUKE, T. W., LOWE, J. I., and WILSON, A. J., JR., Bull. Environ. Contam. Toxicol. 5_, 171 (1970) . . HANSEN, D. J., PARRISH, P. R., LOWE, J. I., WILSON, A. J., JR., and WILSON, P. D., Bull. Environ. Contam. Toxicol. 6_, 113 (1971). HOLDEN, A. V., Nature 228, 1220 (1970). HOLMES, D. C., SIMMONS, J. H., and TATTON, J. 0. G., Nature 216, 277 (1967). JENSEN, S., J0I1NELS, A. G., OLSSON, M., and OTTERBIND, G., Nature 224, 247 (1969). KOEMAN, J. H., TEN NOEVER DeBRAW, M. C., and DeVOS, R. H., Nature 221, 1126 (1969). - KURATSUNE, M., YOSHIMURA, T. , MATSUZAKA, J., and YAMAGUCHI, A., Health Serv. Mental Health Adm. Health Report. 8j3, 1083 (1971). 16 DSW 310725 STLCOPCB4070711 ( *MOSSER, J. L., FISHER, N. S., TF.NG, T., and WURSTER, C. F., Science 175, 191 (1972). NIMMO, I). R., BLACKMAN, R. R., WILSON, A. J., JR., and FORESTER, J., Marine Biol. _11, 191 (1971). PF.AKALL, D. B., and L1NCER, J. L., Biosci. 20, 958 (1970). PRESTT, J., JEFFERIES, D. J., and MOORE, N. W., Environ. Pollut. 1, 3 (1970). REHFELD, B. M., BRADELY, R. I.., JR., and SUNDE, M. L. , Poultry Sci. 50, 1090 (1971). REYNOLDS, L. M., Bull. Environ. Contam. Toxicol. 128 (1969). RISEBROUGH, R. W., RIECHE, P., PEAKALL, D. B., HERMAN, S. G., and KIRVEN, M. N., Nature 220, 1098 (1968). ROTE, J. W., and MURPHY, P. G., Bull. Environ. Contam. Toxicol. 6^, 377 (1971). SCHMIDT, T. T., RISEBROUGH, R. W., and GRESS, F., Bull. Environ. Contam. Toxicol. 235 (1971). SNYDER D., and REINERT, R., Bull. Environ. Contam. Toxicol. (1971). 385 VILLENEUVE, D. C., GRANT, D. L., PHILLIPS, W. E. J.,.CLARK, M. L., and CLEGG, D. J., Bull. Environ. Contam. Toxicol. 6_, 120 (1971). VOS, J. G., and K0EMAN, J. H., Toxicol. Appl. Pharmacol. IJ_, 656 (1970). WILDISH, D. J., Bull. Environ. Contam. Toxicol. _5, 202 (1970). ZITK0, V., HUTZINGER, 0., and SAFE, S., Bull. Environ. Contam. Toxicol 6, 160 (1971). 17 I 0SNN STLCOPCB4070712