(12) Gamson, B. W., Thodos, G., Hougen, 0. A., Trans. Am. lnst. Chem. Eng., 39, 1 (1943).
(13) Hougen, 0. A,, Marshall, W. R., Jr., ibid., 43,197 (1947). (14) Marshall, W. R., Friedman, S. J., “Chemical Engineers Handbook”, 3rd ed., pp 877-84, J. H. Perry, Ed., McGraw-Hill, New York, N.Y., 1950. (15) Zelen, M., Severo, N. C., “Probability Functions”, “Handbook of Mathematical Functions”, Abramowitz and Stegun, Eds., Chap. 26, Dover, N.Y., 1965. (16) Brunauer, S., “The Adsorption of Gases and Vapors”, Vol I, pp 474-97, Princeton Univ. Press, 1943. (17) Darnall, K. R., Lloyd, A. C., Winer, A. M., Pitts, J. N., Jr., Enuiron. Sci. Technol., 10,692 (1976). (18) Carter, W. P., Darnall, K. R., Lloyd, A. C., Winer, A. M., Pitts, J . N., Jr., Chem. Phys. Lett., 42,22 (1976). (19) Dimitriades, B., “On the Function of Hydrocarbon and Nitrogen Oxides in Photochemical Smog Formation”, U S . Bur. Mines Rep. Invest. 7433, Pittsburgh, Pa., 1970. (20) Altshuller, A. P., Cohen, I. R., Purcell, T. C., Science, 156,937 (1967). (21) Purcell, T. C., Cohen, I. R., Atmos. Environ., 1,689 (1967). (22) Dimitriades, B., Wesson, T. C., J. Air Pollut. Control Assoc., 22, 33 (1972). (23) Kopczynski, S. L., Altshuller, A. P., Sutterfield, F. D., Environ. Sci. Technol., 10,909 (1974). (24) Altshuller, A. P., Bufalini, J. J., ibid., 5,39 (1971). (25) Pitts, J. N., Jr., Winer, A. M., Darnall, K. R., Doyle, G. J., McAfee, J. M., Quarterly Progress Report, California Air Resources Board Contract No. 4-214, March 31,1975. (26) Demerjian, K. L., Kerr, J. A., Calvert, J. G., Adu. Enuiron. Sci. Technol., 4, 1 (1974). (27) Niki, H., Daby, E. E., Weinstock, B., Adu. Chem. Ser., 113,16 (1972). (28) Sylvania Technical Bulletin No. 0-306,Lighting Center, Danvers, Mass., 1967. (29) Calvert, J. G., Pitts, J. N., Jr., “Photochemistry”, pp 368-9,377, Wiley, New York, N.Y., 1966. (30) Zafonte, L., Rieger, P . L., Holmes, J. R., “Some Aspects of the Atmospheric Chemistry of Nitrous Acid”, presented at 1975 Pacific Conference on Chemistry and Spectroscopy, Los Angeles, Calif., October 28-30,1975.
(31) Chan, W. H., Nordstorm, R. J., Calvert, J. G., Shaw, J. H., Chem. Phys. Lett., 37,441 (1976). (32) “Chemical Kinetic and Photochemical Data for Modeling Atmospheric Chemistry”, NBS Technical Note 866, R. F. Hampson, Jr., and D. Garvin, Eds., June 1975. (33) Campion, R., Esso Research Laboratories, private communication (1971). (34) Doyle, G. J.,Lloyd, A. C., Darnall, K. R., Winer, A. M., Pitts, J . N., Jr., Enuiron. Sci. Technol., 9,237 (1975). (35) Lloyd, A. C., Darnall, K. R., Winer, A. M., Pitts, J. N., Jr., J. Phys. Chem., 80,789 (1976). (36) Wmer, A. M., Lloyd, A. C., Darnall, K. R., Pitts, J. N., Jr., ibid , 80,1635 (1976). (37) Darnall. K. R.. Carter, W.P.L..Winer. A. M.. Llovd, A. C Pitts. J. N., Jr., ibid., 80, 1948 (1976). (38) Lloyd, A. C., Darnall, K. R., Winer, A. M., Pitts, J. N., Jr., Chem. Phys. Lett., in press (1976). (39) Pitts, J . N., Jr., Winer, A. M., Darnall, K. R., Doyle, G. J., Bekowies, P. J., McAfee, J. M., Long, W. D., unpublished results. (40) Pitts, J. N., Jr., Winer, A. M., Darnall, K. R., Doyle, G. J., McAfee, J. M., “Chemical Consequences of Air Quality Standards and of Control Implementation Programs: Roles of Hydrocarbons, Oxides of Nitrogen and Aged Smog in the Production of Photochemical Oxidant”. Final Reoort. California Air Resources Board, Contract No. 3-01’i, July 1975. (41) Kondrat’ev. V. N.. “Rate Constants of Gas Phase Reactions”, Science Publ.,’Moscow, USSR, 1970. (42) Breen, J . E., Glass, G. P., lnt. J. Chem. Kinet., 3, 145 (1971). (43) Greiner, N. R., J. Chem. Phys., 53,1284 (1970). (44) Herron, J. T., Penzhorn, R. D., J . Phys. Chem., 73, 191 (1969). (45) Morris, E. D., Niki, H., ibid., 75,3640 (1971). (46) Leighton, P. A., “Photochemistry of Air Pollution”, Academic Press, New York, N.Y., 1961.
.
Received for review March 11, 1976. Accepted June 14,1976. Work supported by the California Air Resources Board (Grant No. 5067-1).The contents do not necessarily reflect the views and policies of the California Air Resources Board, nor does mention of trade names or commercial products constitute endorsement or recommendation f o r use.
Collection and Analysis of Organic Gases from Natural Ecosystems: Application to Poultry Manure Morgan S. Smith, Arokiasamy J. Francis’, and John M. Duxbury” Department of Agronomy, Cornell University, Ithaca, N.Y. 14853
Combined gas chromatography-mass spectrometry was used to identify volatile compounds generated from chicken manure and collected in Poropak QS-Carbosieve B traps. Various alcohols, ketones, esters, and carboxylic acids together with dimethyl sulfide and dimethyl disulfide were detected when the wastes were incubated in an argon atmosphere. Significant amounts of dimethyl sulfide and dimethyl disulfide but few other compounds were found when the manure was incubated in air. Several investigations have been made of the volatile compounds responsible for the odor of animal wastes. These studies have often been motivated by the conflict between agricultural operations and neighboring residential areas disturbed by the unpleasant odors arising from the storage and handling of large quantities of manure and by the belief that
Present address, Brookhaven National Laboratory, Upton, N.Y. 11973.
a knowledge of the chemicals responsible might lead to a method of control. Inorganic gases, particularly ammonia and hydrogen sulfide, may be significant components of manure odor ( 1 ) ; however, organic volatiles have more frequently been associated with the problem. Most of the information available on the identities of the volatile organic products in animal manure is derived from studies of cattle and swine wastes (1-3). Deibel ( 4 ) , however, found that butyric acid, ethanol, and acetoin were the chief volatile components in accumulated poultry manure, whereas fresh manure was devoid of these compounds. Burnett ( 5 )found mercaptans, sulfides, and diketones in the head space of accumulated liquid poultry manure, and volatile organic acids, indole, and skatole in the liquid. Burnett and Dondero (6) detected amines in partially dried poultry wastes and volatile organic acids in liquid wastes. Banwart and Bremner (7) reported that hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide were the sulfur compounds evolved from poultry manure, and they found much greater amounts under anaerobic compared to aerobic conditions. Many of the studies of the volatiles evolved from manures Volume 11, Number 1, January 1977
51
have not been quantitative, and in some instances, chemical identification has not been rigorous. Furthermore, the experiments are often conducted in a manner which is not representative of natural environments. Therefore, some doubt remains about which volatiles make important contributions to the odor of manure. This paper describes a convenient method for studying the gaseous organic compounds generated in natural ecosystems and reports on its application to chicken manure incubated in an argon or air atmosphere. Experimental The experimental apparatus is shown in Figure 1. Fifteen-gram samples of fresh chicken manure (75% moisture) were placed in 50-ml cylindrical glass vessels equipped with an inlet and an outlet tube. The inlet tube was connected to a gas manifold, and a stainless steel tube (2.0 mm i.d. X 15 cm) containing trapping material was connected to the outlet. Either compressed air or high-purity grade argon was constantly passed through the vessels to sweep volatiles into the trap. The flow was regulated at 1-2 ml/min by means of a needle valve placed after the trap and was visually monitored by bubbling the effluent gas through water. Contaminating volatiles were removed from the gas supply by placing a trap containing Carbosieve B (Supelco Inc.) in the gas line. No attempt was made to remove traces of oxygen from the argon. The trap contained approximately equal volumes of Poropak QS (Waters Associates), 150-200 mesh, and Carbosieve B, 100-120 mesh, with the Poropak comprising the first section. In some cases, a glass tube, 0.4 cm i.d. X 8 cm, packed with granular CaC12 was placed between the sample vessel and the trap to prevent accumulation of excessive amounts of water in the trap. There were two manure samples in each atmosphere: one with and one without a CaC12 drying tube. A third vessel, which was empty, was also included to demonstrate the absence of contaminating volatiles. The volatiles generated in the air atmosphere were continuously collected throughout a 90-day period. In argon, collection of volatiles was continuous only for the first nine days, after which the large quantities being formed caused a change to collection for an 8-h
MAN IFOLD
c$Ay
SWAGELOK
I
,
COLLECTING FLOW
~
~
ELUTING FLOW
Figure 1. Collection system
52
Environmental Science & Technology
......
DAY I
X 30
I
z
W
P v)
W
a a
2u W IW 0
x IO
DAY 16
W v)
z
2
Ea z
0
W 0
A
C D F G - I V J ' - ~
A A 8
M
I
I
1
I
I
I
I
I
4
8
12
16
20
24
28
32
MINUTES Flgure 2. Evolution of volatile products from poultry manure incubated for one day (without CaCI2 drying tube) and 16 days (with drying tube) under argon Compounds: (A) water, (B) methanol,(C)ethanol, (D)acetone, (E) dimethyl sulfide, (F) +propanol, (G)methyl ethyl ketone and 2-butanol, (H) acetic acid, (I) +propyl acetate, (J) ethyl propionate, (K)dimethyl disulfide, (L) unidentified, and (M) column degradation product. Figures above peaks are attenuator settings (X 30 most sensitive)
period immediately preceding analysis. The gas flow was, however, maintained throughout the experiment. The contents of the traps were analyzed on a Perkin-Elmer 270 gas chromatograph-mass spectrometer (GC-MS). The intervals between analysis ranged from 1to 4 days. A trap was placed in the injector port and connected to the GC column so that the He carrier gas flowed through it in the direction opposite to the collecting flow. The injector port was maintained at 220 "C to elute the contents of the trap into the GC column. The column was stainless steel, 2.9 mm i.d. X 1.83m, packed with Chromosorb 101 (Johns-Manville), 100-120 mesh. Various temperature programs were used depending upon the resolution desired. One satisfactory and frequently used program was to hold the column at 90 "C for 3 min after connecting a trap, followed by programming to 250 OC at 6.5 OC/min. Representative chromatograms are shown in Figure 2. Compounds were identified by comparison of their mass spectra and retention times with those of authentic compounds. Quantitative determinations were made by weighing traces of the chromatographic peaks, which were recorded from the ion monitor signal. Instrument response functions were determined for each compound; these were linear over the range of concentrations encountered. Corrections for changes in instrument sensitivity were made by determining the response to a standard solution of n-butanol a t a given analysis time. We did not correct for trapping efficiency. The minimum detectable quantity of a compound varied
Table 1. Recovery of Standard Compounds by Experimental Method % Recovery a
Compound
Methanol Ethanol +Butanol Acetone Acetic acid Dimethyl sulfide a
Wlthout CaCh trap 3 days 7 day. 105 38 96
107 b
Wlth CaCI2 trap, 1 day b
76 96
89 86
b
a0 0
b
b
b
b
88
Average of four replicates. Not quantitated.
with molecular weight, chromatographic resolution, and instrument performance but in most cases was less than or equal to 1 pg. Evaluation of Trapping System The effectiveness of the trap was determined by injecting 2 p1 of an aqueous solution containing a mixture of methanol, ethanol, n-propanol, and n-butanol each a t the 2% (v/v) level, i.e., approximately 30 pg, into an empty vessel and analyzing the contents of the trap after allowing gas to flow through the system for varying lengths of time. Recovery was compared to injections directly into the GC-MS and to injections into a trap followed by 5-10 min of gas flow through the trap and GC-MS analysis. The trapping efficiency for other volatile compounds was evaluated by considering their chromatographic behavior, relative to the alcohols, on Poropak QS and Carbosieve B and by verifying that they were retained only on the first of two traps after a three-day collection period. The compounds tested in this way were acetaldehyde, acetone, acetic acid, n-butyric acid, dimethyl sulfide, and methyl acetate. The effect of the CaClz drying tube on the recovery of acetone, acetic acid, n-butanol, dimethyl sulfide, and ethanol was determined by the procedure used to test recovery of the alcohol mixture. Results and Discussion The procedure used to collect volatile organic compounds proved to be adequate for the purposes of the present study. Injection of standards into the GC or into a trap followed by GC-MS analysis gave identical results, demonstrating that the procedure used for sample transfer was sound. The data shown in Table I provide a representative picture of the effectiveness of the traps. All volatiles tested were retained quantitatively by the trap three days after their introduction into an empty vessel. After seven days, however, recovery of the more volatile compounds was decreased, indicating loss from the trap. As expected, the ability of the trap to retain a compound could be predicted from comparison of its retention time on Poropak QS or Carbosieve B with the retention times of the alcohols for which trapping efficiency had been determined. Retention increased in the order methanol < methane thiol < acetaldehyde < ethanol < methyl acetate < acetone < dimethyl sulfide < acetic acid < n-butanol < n-butyric acid. Increasing the quantity of ethanol introduced into a trap by a factor of 10,from 32 to 316 pg, did not reduce the recovery after three days. Use of the CaC12 drying tube, however, reduced the recovery of ethanol, acetone, n-butanol, and dimethyl sulfide by 11-20% and completely removed acetic acid. Methane thiol was partially converted to dimethyl disulfide in the process of collection and analysis. Injection of methane thiol into a trap led to the recovery of comparable quantities of methane thiol and dimethyl disulfide. Thus, formation of dimethyl disulfide may have been either chemical or biologi-
cal, or both. Higher molecular weight thiols did not form disulfides during collection and analysis. The combination Poropak QS-Carbosieve B trap was a significant improvement over a trap that contained only Poropak QS (8).Compounds which were readily lost from Poropak QS were held for a longer period on Carbosieve B. Poropak QS,which was an effective trapping material for compounds having four or more carbon atoms, was used in the first section of the trap because broad peaks were obtained when the higher molecular weight compounds were eluted from a trap containing only Carbosieve B. Before considering the data from the poultry manure experiments, it is important that the limitations of the method be recognized. First, the method is not capable of detecting the entire range of possible volatile products. Ammonia, hydrogen sulfide, and methane are among the compounds that would not be retained by the trap. Alcohols, ketones, and carboxylic acids with more than six carbon atoms, esters with more than eight carbons, and indole and skatole would not have been eluted from the GC column during the analysis period. Methane thiol was poorly separated from water and was easily converted to dimethyl disulfide; therefore, quantitation of this compound is questionable. Also, other compounds may have been present in'small amounts but masked by another compound from which they were not separated chromatographically. Second, the partial loss of the more volatile compounds when collection periods exceeded three days would lower the recovery of these compounds. It is felt, however, that errors of this nature are minimal and that the data estimate reasonably well the amounts of organic volatiles diffusing in the gas phase and indicate the sequence in which they appear. The evolution of volatile products from fresh poultry manure incubated in air is shown in Table 11. Since collection of compounds was continuous, daily production was calculated by dividing the quantity found by the number of days in the collection period. Small amounts of simple alcohols, ketones, and sulfur compounds and a trace of trimethylamine were found. With the exception of methanol, the alcohols and ketones were detected only in the first few days of the incubation period, and their generation may have been associated with a temporary deficiency of oxygen caused by microbial utilization of readily available substrate. Methyl ethyl ketone and 2-butanol were not resolved, but inspection of mass spectra indicated that they were present in approximately equal amounts. Methanol was detected for an extended period and most likely was the major product in the gas phase. Although recovery of methanol beyond day 9 was incomplete, it is evident that the quantity in the gas phase gradually decreased with time. It was usually impossible to detect methanol when a CaC12 drying tube was not used, because it was masked by the large water peak. Dimethyl disulfide was detected throughout the incubation period and was also a major product. Dimethyl sulfide was found after the first day of incubation but decreased rapidly thereafter. Trimethylamine was detected in trace amounts; it was the only nitrogen compound observed. A larger quantity of trimethylamine had been found in a preliminary experiment with a similar sample of manure. Data from the incubation of fresh poultry manure in an argon atmosphere are presented in Table 111. The daily production rate and total quantity produced were estimated through day 9 as described for the experiment in air. After this time, products were only collected for an 8-h period immediately preceding analysis; therefore, the amounts found were converted to a daily rate, and this value was then used for each day since the previous analysis. With gradually decreasing quantities, this procedure would give conservative estimates. Volume 11, Number 1, January 1977
53
Large amounts of alcohols, particularly ethanol, were detected during the first 45 days of the 90-day experiment. Methyl ethyl ketone production was approximately equal to that of 2-butanol and followed a similar pattern. A variety of esters representing all possible combinations of the alcohols and acids found were also detected, again mostly in the first 45 days. Only trace amounts of esters were detected in experiments where solutions containing alcohols and acids were placed in empty vessels, which indicates that the esters were generated almost entirely in the poultry manure. Carboxylic acids were not detected until the quantities of the alcohols and
esters had decreased considerably and then only from the sample without the CaClz drying tube. As noted previously, this desiccant completely removed organic acids. The delayed release of acids may have resulted from their conversion to esters in the presence of excess alcohol. Alternatively, their release could be associated with pH changes in the manure. The pH of the fresh manure was 8.3 (15 g wet manure in 25 ml 0.01 M CaC12), and after 90 days of incubation under argon, it was 5.8. Dimethyl sulfide and dimethyl disulfide were detected during the first nine days of the incubation, but the quantities
~~~
Table II. Organic Volatiles Evolved from Poultry Manure Incubated in Air Compound
1
2
4
6
1 2 1 2 1 2 1
40
40
20
40
Methanol Ethanol +Propanol 2-Butanol and methyl ethyl ketone Acetone
Dimethyl disulfide
Trimethylamine
13
+* +
7
+
4-
1
51
62
76
1
+
1
90
+
30 25 6
a
a
65 9
Estd total productlon, pg
320
t
30 25 6
2 1 2 1 2 1 2 1 2
Dimethyl sulfide
a
Rate of production (Wglday) on day 9 16 23 30 36 44
Sample a
0
20
1
a7
+ 4
6 2
100
+
5 7
8 4
3 4
Sample 1 had drying tube; sample 2 did not.
1
+
+
2
+ 2 1
2 4
3 12
a
+
70 a0
+ 4 6
1 3
+ +
+ 1
+ +
2 +
5 9
4 9
3 7
+
4 6
230 390
3 4
+ +
Compound was detected but not quantified; generally less than 1 pg.
Table 111. Organic Volatiles Evolved from Poultry Manure Incubated in Argon Atmosphere Compound
Methanol Ethanol +Propanol
Samplea
3 4 3 4 3 4
2-Butanol and methyl ethyl ketone Acetone Dimethyl sulfide Dimethyl disulfide Acetic acid Propionic acid *Butyric acid Methyl acetate Ethyl acetate
5 Carbon esters 6 Carbon esters 7 Carbon esters
3 4 3 4 3 4 3 4 3 4 3 4 3 4 3 4 3 4 3 4 3 4 3 4
Rata of productlon (bg/day) on day 9 16 23 34
1
2
4
6
50
30
55
25
+*
75
25
440 65 95 17 140
300 160 140
50 175
500 125 95 iia 125
425 185 155 95 130
465 385 160 143 147
495 255 210 a5 150
150 795 72 525 51
300 570 ai 165 21
45
155
260
115
173
57 27 0
390
36
36 40 18 6 40 66 415 4 1 6 4 - 4 3 a + +
+
+
76
90
36
21
42
2 iao
195
150
36
69
42
14
28
17 920 21 470 5 ai0 a 650 2 990
44
62
585 39 165
+
15
6
+
+
72
+
+b
7 6
a
Sample 3 had drying tube, sample 4 did not.
54
Environmental Science & Technology
+ +
+ +
+
+
10 11 +
14 11
18 18
18 6
8
+
1
0 6
+ +
5 140
120 140 20 11
+
+
7 12 1 1
Ectd total production, pg
6 3
+
+ +
6 39 3 27
12 21 6 18
9 15 9 15
9
6
6
+ +
216
9 9 +
Compound was detected but not quantified, generally less than 1 pg.
175
175
18
90
3
+
6
+ +
219
+ + + +
750 960 260 620 1
22
were not large. Overall, more volatile organic sulfur compounds were found in the experiment under an air atmosphere. This is somewhat surprising since others (3, 7) have reported that aeration reduced the quantity of volatile sulfur compounds. The total quantities of organic volatiles collected upon incubation of fresh poultry manure for 90 days under air and argon are given in Tables I1 and 111, respectively. The total amounts were generally less from the samples with the drying tubes than from those without. This was expected because the CaC12 had decreased the recovery of standards by approximately 2090. The volatiles recovered from the argon incubated samples represented about 1%of the dry matter in the samples. Aeration of manure is generally considered to reduce or eliminate the odor problem; oxidation ditches are one means of handling manure to minimize odor (9).An extremely disagreeable smell arose from the manure under argon shortly after the incubation began, and this odor was maintained throughout the experiment; yet, at no time was the aroma of the manure in air either particularly intense or unpleasant. The data in Tables I1 and I11 do not adequately explain this difference. Sulfur compounds, which have frequently been associated with the odor of manures, were present in the initial stage of the experiments under both argon and air. Carboxylic acids, also odoriferous materials, could have contributed to the smell of the argon-incubated sample during the latter third of the experimental period. The only compounds detected during the bulk of the incubation under argon were alcohols, esters, and ketones, none of which are considered to have an offensive odor individually. It is possible that the mixtures of volatiles detected produced the unpleasant odor. However, some potentially important odor-causing compounds would not have been detected by the methods employed.
The technique used for the collection of volatiles should have wide applicability to the study of gaseous organic compounds. It is a mechanically simple method for the simultaneous collection and concentration of volatiles. Continuous slow flushing of a headspace with a gas stream is a more realistic model of most natural systems than is a sealed vessel. The accumulation or depletion of gases in the headspace is prevented, and disruptions caused by sampling are minimized. It should be possible to study volatiles outside the range detectable in this experiment by employing appropriate trapping materials and GC columns.
Literature Cited (1) Muehling, A. J., J . Anim. Sci., 30,526 (1970). (2) Merkel, J. A., Hazen, T. E., Miner, J. R., Journal Paper No. J -
5826, Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, 1968. (3) White, R. K., Taiganides, E. P., Cole, G. D., in “Livestock Waste Management and Pollution Abatement”.,. D 110. Am. SOC. Aer. ” Ene.. St. Joseph, Mo., 1971. 14) Deibel. R. H.. in “Aericulture and the Qualitv of Our Environment”, N. C. Brady, E>., p 395, Am. Assol Ad;an. Sci., Washington, D.C., 1967. (5) Burnett, W. E., Enuiron. Sci. Technol., 3,744 (1969). (6) Burnett, W. E., Dondero, N. C., in “Animal Waste Management”, Proc. Cornel1 Univ. Conf. on Agr. Waste Management, 1969. (7) Banwart, W. L., Bremner, J . M., Div. of Soil Microbiol. and Biochem., 66th Meeting ASA, Chicago, Ill., Nov. 1974. (8) Adamson, J. A., Francis, A. J.,Duxbury, J. M., Alexander, M., Soil Biol. Biochem., 7,45 (1975). (9) Loehr, R. C., Anderson, D. F., Anthonssen, A. C., in “Livestock Waste Management and Pollution Abatement”, p 204, Am. Soc. Agr. Eng., St. Joseph, Mo., 1971. I
0
,
Received for review February 9,1976. Accepted June 25,1976. Work supported in part by Grant NGR-33-010-127 from the National Aeronautics and Space Administration.
Application of Weak Base Ion-Exchange Resins for Removal of Proteins David H. Foster*’, Richard S. Engelbrecht, and Vernon L. Snoeyink Department of Civil Engineering, University of Illinois, Urbana, 111. 61801
The increasing demands being placed on our water resources have resulted in a need for continually upgrading the quality of treated wastewater effluents before discharge into receiving waters. The organic matter portion of effluents is of concern because of the potential damage it may cause to the environment and the public health dangers it may present. These substances may be present because of their resistance to conventional biological waste treatment methods or may be metabolic end products. As a result, biological treatment should be regarded as only a partial solution to the problem of removal of organic matter from wastewater. The various treatment schemes for removal of residual organic matter from secondary water treatment plant effluents have focused principally on adsorption processes such as activated carbon adsorption. Activated carbon treatment may fail to remove large organic molecules, such as protein, which are unable to penetrate the carbon pores to take advantage of the large surface area carbon provides. In addition, carbon must generally be thermally regenerated. Recently, interest in the use of synthetic resins for complete or partial replace~~
Present address, Department of Civil and Architectural Engineering, University of Wyoming, Laramie, Wyo. 82071
ment of activated carbon treatment of wastewater has increased since the capacities of many of the resins for some substances are high and thermal regeneration is avoided. A large portion of the organic compounds in secondary effluents is thought to be high-molecular-weight organic anionic fractions which may contain up to 509/0of the organic nitrogen in the effluent ( I , 2 ) . Proteins and nucleic acids are present in high-molecular-weight fractions and may account for much of the total nitrogen present. Since many of the organic compounds present in wastewater in the normal operating range of pH values are anionic, this study focused on anion exchange resins as potential replacements for activated carbon in the treatment of wastewater from biological treatment units. The proteinaceous fraction of residual organic matter which would be removed by resin treatment is important from several standpoints. Treated wastewater effluents contain 2-8 mgh. of organic nitrogen, much of which is proteinaceous in nature ( 3 ) .Removal of organic nitrogen from effluents would be beneficial to the environment since its presence may contribute to oxygen depletion in receiving waters and may also provide a source of nutrients for algae and thus contribute to algal blooms. In addition, wastewater effluents contain viruses which are a special class of proteinaceous material. The virus particle is comprised of a nucleic acid core covered with a Volume 11, Number 1, January 1977
55
