consequences for its construction. If the process is carried out in such a way that the greatest of the xenon is removed before the low-temperature separation, the separation of the system Kr-N2 in the first column is determined. If the column is operated at constant pressure, pressures between 6 and 8 bar can be maintained. The temperature in the collection vessel must then rise with increasing enrichment of krypton to around 125 or 130 K. If it is desired to operate a t a constant temperature for the collection vessel, the temperature must be maintained a t about 115-120 K, which would result in pressures in the range of 20 bar and below for the nitrogen-rich region. The xenon fraction is only very slightly contaminated with krypton (Kr-85) when a preseparation is performed. One is then in the xenon-rich range. In this case, the column can be operated a t temperatures of 160-165 K and pressures about 2-3 bar. If the xenon is not separated before the low-temperature distillation, a Xe-Kr mixture becomes enriched in the collector vessel of the first column. For reliable estimation of operating conditions, above all the complete gas data for the systems with xenon and the multicomponent system (Xe + Kr)-Nn, as well as the corresponding liquidus lines, are still missing. However, from our last experiments and calculations, a high degree of enrichment of noble gases in the collection vessel requires temperatures to above 155 K and pressures far in excess of 20 bar. Furthermore, the xenon-krypton separa-
tion in the second column will also be able to function at relatively low pressures.
Acknowledgment The control calculations were made in cooperation with the Department of Chemical Engineering (Verfahrestechnik 11), H. Hartmann, Technical University Aachen. Literature Cited (1) Bundesanzeiger, Jahrgang 27, No. 132, Vol2, July 1976. (2) Prausnitz, J. M., Chueh, P. L., “Computer Calculations for High Pressure Vapor-Liquid Equilibria”, Prentice-Hall, Englewood Cliffs, N.J., 1969. (3) Stackelberg, M. V., Z . Phys. Chem. (Leiprig),170,262 (1934). (4) Fastovskij, V., Petrovskij, J., Zh. Fir. Khim., xxx, 74-6 (1956). (5) Thorpe, P. L., Trans. Faraday Soc., 64 (9), 2273-80 (1968). (6) Seemayer, D., P h D thesis, University Gijttingen, Germany, 1966. (7) Bohnenstingl, J., Heidendael, M., Laser, M., Mastera, S., Merz, E., International Symposium on the Management of Radioactive Wastes from the Nuclear Fuel Cvcle. Paoer IAEA SM-207/20. Vienna, Austria, Mar. 22-26, 1976: (8) Perry, R. H.. Chilton. C. H., “Chemical Engineers Handbook”, McGraw-Hill, New York, N.Y., 1975. (9) Mastera, S.G., P h D thesis, Technical University Aachen, Germany, 1976. Received for recieu: November 16, 1976. Accepted August 10,1977. Presented at the Division of Encironmental Chemistry, 172nd Meeting, ACS, Sun Francisco, C a i i f . , August 1976.
Organic Compounds in an Industrial Wastewater: A Case Study of Their Environmental Impact Gregory A. Jungclaus’, Viorica Lopez-Avila, and Ronald A. Hites’ Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Mass. 02 139
with the goal of identifying potentially toxic organic compounds so that possible serious chronic effects due to longterm, low-level exposure to dangerous organic chemicals may be averted. This paper reports on the detailed organic analysis of the wastewater and the receiving waters and sediments of a specialty chemicals manufacturing plant, Le., a plant that manufactures a broad range of chemicals, many of which are used by other chemical companies. Since little is known about the eventual fate of specific organic compounds after leaving a manufacturing plant, we have studied, in detail, the interaction of this plant with its environmental setting. Thus, we have been concerned with the identities of compounds entering the receiving waters and sediments, the compounds already present, and others that may be formed through in situ transformations.
w The wastewater and receiving waters and sediments from a specialty chemicals manufacturing plant are extensively analyzed for organic compounds. The concentrations of anthropogenic compounds range up to about 15 ppm in the wastewater and O.2‘ppm in the river (receiving) water, but up to several hundred ppm in the sediments. The composition of the river water reflects the composition of the wastewater except that some of the compounds appear to degrade or volatilize in the river. Many compounds accumulate in the sediments where they appear to be stable and build up to high concentrations. Some of the compounds are modified in situ. Various phenols are easily oxidized to quinones; these may be partially reduced back to phenols depending on the redox nature of the environment. Several compounds of known biological activity (herbicides, bacteriostats, and disinfectants) as well as some potentially toxic chemicals such as dichlorodibenzodioxin are present in the water. The long-term, lowlevel exposure to this wide variety of chemicals may have contributed to the lack of biota in this part of the river.
Industrial wastewaters are a major source of anthropogenic organic chemicals which enter the environment. Recently, the detailed organic analyses of the wastewaters of tire ( I ) , paper ( 2 ) ,and dye ( 3 )manufacturing plants have been reported. In addition, the Environmental Protection Agency will be analyzing the wastewaters of many other types of industries ( 4 )
8 L8LO”III.
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1
Figure 1. Map of the plant and its environmental setting
Present address, Ford Motor Co., Detroit, Mich. 48239. 88
Environmental Science & Technology
Sampling sites indicated; letters: water samples: numbers: sediment samples. Point C: clarifier at plant
0013-936X/78/0912-0088$01 .OO/O @ 1978 American Chemical Society
Many different analytical techniques were required to separate and identify the organic compounds found in these complex samples. The techniques included vapor stripping of volatile organic compounds, direct aqueous injection gas chromatography, computerized gas chromatographic mass spectrometry (GC/MS), high-pressure liquid chromatography (HPLC) with subsequent mass spectral analysis of the collected fractions using the direct introduction probe, and high resolution mass spectrometry (HRMS). Plant Description and Setting. A map showing the details of the plant location is presented in Figure 1.The plant location lends itself to a detailed study because the plant is the last on a small freshwater river which drains into a small brackish cove, then into a large brackish river which empties into an estuary. The plant operates in a batch production mode, generally following a weekly schedule. A wide range of compounds including pharmaceuticals, herbicides, antioxidants, thermal stabilizers, ultraviolet light absorbers, optical brighteners, and surfactants is produced. Water is used in synthesis processes, in the recovery of solvents, in steam jets, and in vacuum pump seals. The wastewater is neutralized in either of two 1 million-gal equalization tanks, passed through a trickling filter for biological degradation, and clarified in a 150 000-gal tank with a residence time of 3 h. The water spills over from the clarifier a t a rate averaging 1.3 X lo6 gal/day and enters the river through an underground pipe about 100 yards away. Only about one-fourth of the total BOD, which averages 12 000 Ib/day, is removed by the waste treatment system, and much of this is in the form of low molecular weight solvents.
Experimental Sampling, The water and sediment sampling sites in the vicinity of the plant are shown in Figure 1. Several samples were taken a t some of the more convenient locations such as a t the plant (site C) and a t bridges. Wastewater samples were collected on November 6, 1975, January 27, 1976, July 13, 1976, and September 8, 1976; river water samples were collected on November 6,1975, January 27,1976, March 8,1976, June 12,1976,June 23,1976, July 13,1976, and September 8, 1976; sediment samples were collected on January 27, 1976, March 8,1976, June 12,1976, June 23,1976, and September 8, 1976. Water samples were collected in 1-gal amber glass bottles with Teflon-lined caps. Wastewater samples were collected as the water spilled over from the clarifier. River water samples were collected both upstream and downstream from the plant by use of a small boat. Sediment samples were collected with a dredge-type sampler from the boat and also with the aid of a diver. About 300 mL of nanograde (Mallinckrodt) dichloromethane and 15 mL of 12 M hydrochloric acid were added to the water samples a t the collection site (except those used for volatile organic analysis) to minimize biological degradation and to start the extraction. One-quart glass jars were used for the sediment samples. They were covered with aluminum foil before replacement of the screwcap lids and placed in a box containing dry ice. The composition of the river bottom sediments varied from large gravel to an organic-rich black ooze. Generally, the bank area was quite silty, whereas the bottom became more gravelly toward the center of the river. Procedures. When returned to the laboratory, the sediment samples were placed in a freezer, and the water samples to be used for volatile analysis were placed in a refrigerator. A Teflon-covered magnetic stirring bar was added to each of the water samples containing dichloromethane for overnight extraction on a magnetic stirrer. Then most of the water was poured into another clean bottle, and the dichloromethane
extract was separated from the remaining aqueous phase in a separator funnel. A plug of preextracted glass wool was used to aid in phase separation for those samples developing emulsions. Much of the emulsion remained on the glass wool which was then washed with additional aliquots of dichloromethane. These extracts and washings were combined and rotary evaporated to the desired volume. The decanted water from the acidic extraction was rendered alkaline with a preextracted, concentrated KOH solution and extracted with an additional 200 mL of dichloromethane to recover the basic compounds. The exact concentrations of some of the volatile solvents in the wastewater were determined using direct aqueous injection of 2-pL aliquots onto a 2 m X 0.32 cm i.d. stainless steel column packed with 0.4% Carbowax 1500 on Carbopack C (Supelco, Inc.). Qualitative analyses of the volatile organic compounds were performed using vapor stripping. About 2 L of a river water sample or about 200 mL of a wastewater sample were put into a 3-L glass stripping vessel similar to that described by Novotny et al. ( 5 ) . The water temperature was maintained a t about 80 "C. Purified helium was passed through the sample from a glass frit located a t the bottom of the apparatus a t a rate of 120 mL/min. Helium and the stripped organics were passed through a water-cooled condenser into two glass sampling tubes connected in parallel. These tubes were glass injection port liners from the gas chromatographs and were packed with about 40 mg of precleaned 60/80 mesh Tenax-GC porous polymer adsorbent. The liners were conditioned a t 250 "C for at least an hour in the injection port of the gas chromatograph prior to use. After vapor stripping for the desired length of time, the precolumns were removed and stored in Teflon-lined screw-cap test tubes until analysis by GC and GC/MS. The sediment samples were allowed to thaw at room temperature and then sieve-washed through a 2-mm stainless steel screen to remove pebbles and extraneous debris. Excess water was decanted, and the wet sediment was Soxhlet extracted for several hours with nanograde isopropyl alcohol. A further extraction with nanograde benzene was then necessary to isolate the polycyclic aromatic hydrocarbons. The isopropanol extract was evaporated to dryness on a rotary evaporator a t 30-40 "C; the benzene extract was freed of elemental sulfur by passage through a column of colloidal copper (6). Some of the sediment and water samples were also liquid chromatographically separated into hexane, benzene, and methanol fractions on a column containing about 1 g of 5% water-deactivated silica gel. I n s t r u m e n t a t i o n . Preliminary gas chromatographic analyses were carried out on a Perkin-Elmer 900 gas chromatograph equipped with a flame ionization detector and on a Hewlett-Packard 5730A gas chromatograph equipped with flame ionization and electron-capture detectors. The columns used were 180 cm X 2 mm i.d. glass columns packed with 3% SP-2100 (a methyl silicone fluid) on SO/lOO mesh Supelcoport; we also used 25 m X 0.25 mm i.d. glass capillary columns statically coated ( 7 ) with SE-52. Approximate quantitation was based on external standards made with the compounds identified. Liquid chromatographic separations were performed on a Waters Model ALC/GPC 204 liquid chromatograph equipped with two Model 6000 pumps, a Model 660 solvent programmer, and a Model 440 dual absorbance detector. Low resolution (-800) mass spectra were obtained with a Hewlett-Packard 5982A GC/MS system with a dual EI/CI source and interfaced with a H P 5933A data system. The quadrupole mass spectrometer was coupled to the gas chromatograph via a glass-lined jet separator held at 300 "C. The mass spectrometer was operated in the electron impact mode, Volume 12, Number 1, January 1978
89
Table 1. Summary of All Compounds Found in Wastewater, River Water, and Sediment Compound no.
Compound name
Wastewater
Concn range, ppm River water
Sediment
Present in tar balla
N-Containing heterocyclics
6 7 8 9 10 11 12 13 14 15
Acetyl pyridine Dibenzo [ b,f] azepine 10,lbDihydrodibenzo [b,f]azepine‘ 5-(3-Dimethylaminopropyl)-10,l l-dihydrodibenzo [b,f] azepine 4-n-Butyl-l,2-diphenylpyrazolidine-3,5-dione’ 2-(2’-Hydroxy-5’-methylphenyl)-2H-benzotriazole’ 2-(Hydroxy-t-butylphenyl)-2H-benzotriazole” 2-(Hydroxy-di-t-butyIphenyl)-2H-benzotriazole 2-(Hydroxy-butyl-t-amylphenyl)-2H-benzotriazole 2-(2‘-Hydroxy-3’,5’-di-f-amylphenyl)-2H-benzotriazole 2-(Hydroxy-f-butylphenyI)-chloro-2H-benzotriazole* 2-(2’-Hydroxy-3’,5’~i-f-butylphenyl)-5-chloro-2H-benzotriazole 2-Methoxy-4,6-bis-isopropylamino-s-triazine 2-Chloro-4,6-bis-isopropylamino-s-triazine Benzothiazole
16 17 18 19 20
Aniline Acetanilide Di- f-butylcyanophenol Azobenzene N-phenyl-1-naphthylamine
1 2 3 4
5
0.05
