INDUSTRIAL AND ENGINEERIXG CHEMISTRY
August, 1928
of Fumigants on Food Products UNSWEETPOWENED SHELLEDWALNUTDERED CHOCOFUMIGAXT PRUNES ALMONDSMEATS COCOA LATE BACOK Calcyanide 0 0 0 0 0 e,3 Chloropicrin i.1 e,l i,3 i,2 i,4 e,4 Ethylene dichloridecarbon tetrachloride 0 0 i,3 e,l i,6 e,2 Ethylene oxide 0 0 0 e,l i,3 r,3 Lethane 23 e,1 r,l e,2 e,? 7,4 i,aa Lethane 22 0 0 e,l 0 i.3 . b Trichloroethylene ~?,1 e , l i,3 e,2 r,4 i,? Table 11-Effect
0 = No taste or odor of fumigant detected. i = Tastes or smells mildly of fumigant. edible but not palatable. i = Tastes or smells strongly of fumigant'; inedible. 1, 2, 5 , etc. = Days aeration required to remove all obvious taste and odor of fumigant so t h a t product was edible and palatable. a Tested after 2 weeks' exposure to air; still inedible. b S o bacon included in this fumigation, by error.
Table 111-Effect
of F u m i g a t i o n on G e r m i n a t i o n of Seeds WHITE SHE:LLED OATS WHEAT BEANS PEANUTS CLOVER
FUJIIGAXT DOSAGE Lbs./M c u . jt. Blank, not fumigated None Calcyanide 0.5 Chloropicrin 0.8 Ethylene dichloride-carbon tetrachloride 14 0 Ethylene oxlde 2 0 Lethane 23 15 Lethane 22 0 5 Trichloroethylene 7 0
85 89
93 81
77
86 88 84
85 85 85
74 58
42 60
44
63
86 86 81
83 30
58 20 53 61 34
62
85
41 05
88 86 88
61 55
78 83 80
as
Laboratory experiments with vinyl ~ h l o r i d e ,a~ liquid boiling a t -14" C. and whose vapor has peculiar garliclike odor, indicated that it had only low toxicity. A fumigation based on a dosage of 8 pounds per 1000 cubic feet equivalent to a concentration of about 7.5 per cent by volume of the vapor in air, with a contact period of 48 hours at 75-80' F., killed only 30 per cent of TrrboEium cofzfusum confined in flour. Effect on Metals
I n the fumigation tests with seven different fumigants in the Plymetl vault in which different polished metal surfaces 3
Dana Burdick, anc-l Jenkins J
A m Chem Soc , 4 9 , 2801 (1927).
837
were exposed no corrosion whatever was detected and the only discoloration noted was a "red" tarnish on the copper after fumigation with calcyanide. Effect on Food Products
Table I1 indicates the effects of the seven fumigants used on six different food products. In this 24-hour fumigation in a tight room, chloropicrin was found to be absorbed and retained to a much greater degree than had previously been noted in large-scale fumigations with chl~ropicrin.~Hydrocyanic acid gas appears to be little absorbed by various food products and the U. S. Department of Agriculture5 has indicated that removal of meats and other food products during fumigation of premises with hydrocyanic acid is unnecessary. The absorption and retention of fumigants, which are themselves good fat solvents, by food products rich in fat, such as bacon, unsweetened chocolate, and walnut meats, are noteworthy. Shelled almonds, though rich in fat, have a rather thick protective skin and appear t o resist absorption of the fumigant. Pastry flour exposed to these seven fumigants acquired their characteristic odors to varying degrees but lost these odors again after relatively short exposure t o the air. I n the case of calcyanide and ethylene oxide less than 24 hours were required, while with the other fumigants from 2 t o 4 days' exposure was necessary. Effect on Germination Power of Seeds
K i t h the exception of ethylene oxide, which seems to have distinctly deleterious effect on germinating power, particularly of wheat and beans, none of the six other fumigants had any consistent effect on germinating power of five varieties of seeds exposed to fumigation in the Plymetl vault. (Table 111) The germination tests were run simultaneously under identical conditions and hence are strictly comparable. Hoyt and Ellenberger, IKD.ENQ.CIIEM.,19, 461 (1927). Bur. Animal Industry, Service and Regulatory Announcements, January, 1921. 4
5
Treatment and Disposal of Distillery Slop by Anaerobic Digestion Methods' S. L. Neave w i t h A. M. Buswell STATEWATERSURVEYDIVISION,URBANA, ILL.
T
H E increasing importance of industrial wastes in riverpollution and sewage-disposal problems makes desirable more information regarding the behavior of many wastes in the ordinary sewage-treatment processes. Distillery slop, resulting from the production of industrial alcohol, seems to have received little attention in this country, though a number of patents dealing with the recovery of its potash are to be found in the literature; the feasibility of this recovery evidently depends upon market conditions and an abundant supply of slop. The British Royal Commission on Sewage Disposal2 has satisfactorily treated the diluted neutralized wastes from a whisky distillery on a percolating filter and used the effluent to maintain a salmon hatchery. S o reference has been found t o the anaerobic treatment of such wastes. As collected from the alcohol stills, the slop has a deep brown color and an inoffensive caramel odor; on dilution and exposure to the air, however, it is highly putrescible with the production of foul odors. I 2
Received April 13, 1928. Littlefield, Chemistry & Industry, 3, 860 (1925).
Experimental
Anaerobic digestion tests have been made under conditions resembling those used for sen-age sludge to determine the extent of bacterial degradation, the quantity and nature of the gases evolved, and the character of the resulting sludge. Through the courtesy of the T;. S. Industrial Chemical Company, of Baltimore, a sample of slop, showing the following composition, n-as obtained: Total solids: Ash (20.7%) Organic matter
J l g . per liter 126,338 27,415 98,923
Mg.p e r liter Ammonia nitrogen Organic (Kjeldahl) nitrogen Acidity (as acetic acid)
24 1,920 9,360
I n accordance with the technic followed in this laboratory, all digestion mixtures were made up to a volume of 1 liter to fill completely a 1-liter brown-glass bottle connected to a gas reservoir filled with saturated salt solution. Dilutions were made with settled domestic sewage and de-oxygenated tap water, and mere inoculated with well-digested Imhoff tank sludge, thus:
INDUSTRIAL A N D ENGINEERING CHEMISTRY
838 (A) water (B) water (C) water (D) water
+ 200 cc. sludge + 400 cc. sewage + 3CO cc. cc slop + 200 cc. sludge + 400 cc. sewage + 200 cc. +2001 gram CaC03 300 cc. slop + 200 cc. sludge + 400 cc. sewage + 100 cc. Control 200 cc. sludge + 400 cc. sewage + 400 cc. 100 cc. slop
The progress of digestion was judged by the gas evolution; this criterion indicated practically complete digestion in bottle (A) after 73 days, as shown in the accompanying graph, and the tests were discontinued at this time, although bottle (B) was still actively fermenting. Bottle (C), containing 300 cc. of unneutralized slop, failed to ferment. The quantity of gas given by the control (D) was small and no correction of the other gas volumes has been made for it. At the conclusion of the tests, the resulting sludges and liquors were separated by vacuum filtration and analyzed separately. The following summary shows their characteristics :
Vol. 20, No. 8
The liquors from the anaerobic digestion have a pronounced color equal to 50 to 60 per cent of the initial color of the diluted slop; these coloring matters are, therefore, only partly attacked under anaerobic conditions. Aerating the liquors for 24 hours in the presence of about 20 per cent by volume of activated sludge also failed to remove this residual color.
,-
7 m
6CCO 6500
1
TOTAL DRYSOLIDSIN BOTTLE Loss of Over-all slop Bottle Initial Final loss alone Per Per Grams Grams Per cent Grams Grams cent cent (A) 15.5 16.0 3.2 (increase) 28.13 22.28 20.8 55.4 (B) 15.5 17.3 5.2 (increase) 41.77 33.17 20.6 68.3 (C) 1 5 . 5 1 9 . l ( ? ) = (?) 40.77 40.77 0.0 0.0 (D) 1 5 . 5 14.7 5.2 (loss) 15.90 15.50 2.5 a (C) could not be filtered. DRYSLUDGE IN BOTTLE Initial Final Change
..
{ti (C) (D)
COMPOSITION OF FINAL SLUDGE Nitrogen Remarks Per cent 2.13 Drains and filters readily, faint tarry odor 1.76 Filters slowly; marked kerosene odor 2.38(?) Gelaiinous; failed to filter; putrid odor 1,92 Filters readily; faint tarry odor
Ash Per cent 56.7 52.9 46.5 59.7
COMPOSITION OF FINAL LIQUOR Dissolved Volatile acids solids Nitrogen as acetic pH M d l i t e r M R ./liter Mn./lifer
Remarks
Colorless
Since the solids in the slop are in solution, the usual liquefaction is lacking and a slight increase in sludge results from the precipitation of humus materials. A comparison of the total solids in the bottle, however, shows a decrease, and when these figures are corrected for the Imhoff sludge used, the actual decrease in slop solids is 55 to 68 per cent. The decrease in total solids approximately equals the weight of gases evolved, thus: Table I-Gases Evolved in Anaerobic Digestion of Distillery Slop ------PERCENTAGE COMPOSITION----DAYOF DIGESTION COz CZHI 0 2 CO Hz CHd CzHs NZ 1st 3rd 7th 15th 35th 73rd
31.5 53.7 53.1 32.4 24.0 30.3
1st 3rd 7th 15th 35th 73rd
32.2 53.2 80.0 84.1 51.7 28.3
15th 35th 73rd
11.9 14.8 21.9
BOTTLE (A) (B) (D)
... ... ... ... ...
0.0
... ... ... ... ...
0.0
... 0.0
0.0
COa Grams 3.87 6.02 0.17
BOTTLE (A)
1.9 0.5 0.0 1.4 0.3 0.0
... ... ...
...
3.3 1.0
3.0 16.8 6.7 2.4 1.3 5.6
... ... ...
43.0 22.6 40.1 42.7 54.0 62.3
5.8 5.3 1.1
BOTTLE (B)
1.2 0.0 0.0 0.0 1.7 0.0
... ... ... .. .
3.3 38.7 19.2 1.5 1.8 0.7 1.4 4.3
.. .
20.6 6.4 0.1 15.3 11.8 0.0 22.2 3.8 0.0
41.1 3.6 0.8 14.4 31.3 61.2
0.0 3.1 3.9
0.0
55.4 54.2 48.4
5.1 4.7 12.1
23.0 19.5 11.7
0.7
.. .
9.7 0.9
BOTTLE (D)
0.5 0.6 0.0
H2
Gram 0.03 0.06 0.002
...
2.0 0.3
1.1 4.2 5.6
TOTAL ACTUAL WEIGHT OF LOSS OF SOLIDS C H I + C ~ H B GASES
Gram 1.87 2.12 0.23
Grams 5.77 8.20 0.40
Grams 5.85 8.60 0.40
The complete composition of the gases is shown in Table I. The total volume of gas evolved is somewhat lower than Rudolfs’ value3 of 420 cc. per gram of organic matter: (A) 329; (B) 268+; (D) 82 cc. Considerable quantities of nitrogen were found in the gases, but since the analytical data showed no loss in total nitrogen during the digestion, this gaseous nitrogen must be attributed to diffusion through rubber connections on the gas reservoir. Conclusions
1-Without dilution the slop will not support a bacterial flora. 2--8 dilution of 1 part of slop to 4 parts of water still inhibits bacterial growth on account of acidity in the slop. 3-Such a dilution will ferment, though slowly, in the presence of an excess of calcium carbonate. 4--A dilution of 1 part of slop to 9 parts of water or sewage ferments smoothly and completely, giving an inoffensive, rapidly draining sludge and a destruction of 55 per cent of the total solids in the slop. 3
Fuller and McClintock, “Solving Sewage Problems” (1926).
Rising Italian Production of Sulfate of Ammonia Italian production of ammonium sulfate totaled 61,000 tons in 1926, or almost four times the 1913 figure and more than double 1925 production, according to reports to the Department of Commerce. The increase is to be attributed almost entirely to ammonium sulfate obtained from synthetic ammonia, it is said. Of the 61,000 tons of ammonium sulfate produced in 1926, 44,000 tons were synthetic ammonia sulfate; the balance, 17,000 tons, having been obtained from gas-works and coke-oven ammonia, from the gasification of peat and lignite, and from the decomposition of calcium cyanamide as follows: from gas-works ammonia, 5570 tons; coke-oven ammonia, 5460 tons; from peat and lignite, 4570 tons; calcium cyanamide, 1200 tons. Consumption of sulfate of ammonia in Italy in 1927 has been estimated a t 81,400 tons, compared with 65,000 tons in 1926 and 35,000 tons in 1913. The 25 per cent increase in the use of ammonium sulfate as between 1926 and 1927 is interesting, since it is the only fertilizer which registered a gain during 1927.
