Disposal of Condensed Milk by DigestionAuthor(s): David P. BackmeyerSource: Sewage Works Journal, Vol. 21, No. 6 (Nov., 1949), pp. 1076-1077Published by: Water Environment FederationStable URL: http://www.jstor.org/stable/25031183 .

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1076 SEWAGE WORKS JOURNAL November, 1949

8. Kozma, Albert B., "Sludge Digestion?

Operation and Control." This Jour

nal, 16, 4, 700 (July, 1944). 9. Babbitt, Harold E., "Garbage Disposal

as a Sewage Problem." This Jour

nal, 16, 5, 861 (Sept., 1944). 10. McDonald, John D., "Sludge Disposal

Experiences at Springfield, Mass."

This Journal, 16, 5, 872 (Sept., 1944). 11. Daniels, P. N., "The Care and Operation

of Imhoff Tanks." This Journal,

17, 5, 995 (Sept., 1945). 12. Langford, L. L., "Theory and Operation

of Separate Sludge Digestion Units."

This Journal, 17, 6, 1235 (Nov.,

1945). 13. Schlenz, Harry E. and Buswell, A. M.,

"Important Considerations in Sludge

Digestion." This Journal, 19, 1, 19

(Jan., 1947). 14. Rankin, R. S., "Scum Control in Diges

ters." This Journal, 19, 3, 405

(May, 1947). 15. Rudolfs, W., et al., "A Critical Review

of the Literature of 1947 on Sewage and Waste Treatment and Stream Pol

lution." This Journal, 20, 2, 242

(Mar., 1948).

16. Rankin, R. S., "Digester Capacity Re

quirements. ' '

This Journal, 20, 3, 478

(May, 1948). 17. Walker, J. Donald,

' ' Sludge Digestion and

Methane Production." This Journal,

20, 3, 544 (May, 1948). 18. Kunsch, Walter M., "Sludge Digestion

Experiences with the External Heat

Exchanger." This Journal, 20, 6, 999 (Nov., 1948).

19. "Central States Sewage Works Associa

tion 1948 Operators' Breakfast For

um." This Journal, 20, 6, 1092

(Nov., 1948).

20. Rudolfs, W., et al., "A Critical Review

of the Literature of 1948 on Sewage and Waste Treatment and Stream Pol lution." This Journal, 21, 2, 240

(Mar., 1949).

21. Rudolfs, W., "Principles - of Sewage

Treatment." Bulletin No. 212, Na

tional Lime Association.

22. Doman, Joseph, "The Scum Problem

from the Operators' Standpoint." Water and Sewage Works, 94, 7, R211

(July, 1947).

DISPOSAL OF CONDENSED MILK BY DIGESTION By David P. Backmeyer

Superintendent, Water and Sewage Treatment Utilities, Marion, Ind.

An excellent example of how cooper ation between the municipal sewage treatment plant and industry can help to sidestep trouble for the operator is contained in the recent handling of a

heavy "slug" of otherwise troublesome

produce waste by the Marion, Ind., sewage treatment plant. The circum stances causing the incident were somewhat unusual, and called for an unusual although simple solution.

On August 5, 1949, a local produce plant was involved in a labor dispute and the workers went on strike. On hand was 11,000 gal. of condensed

milk, which the strikers would not allow out of the plant. The milk could not be held indefinitely, and if dumped into the sewers it would seriously upset the activated sludge treatment plant. Obviously, some means of disposal was needed.

With a total dry solids content of 24.5 per cent and a volatile solids con tent of 94.4 per cent, the total volatile solids involved in the 11,000 gal. of

TABLE I.?Gas Production Resulting from Addition of Condensed Milk to

Marion, Ind., Digesters

Date (1949)

Con densed Milk

Added (gal.)

Gas Produced (cu. ft.)

Total Normal From Milk Load

CO? Content

(%)

Aug. 3 4 5 6 73 8 9

10 11

11,0001

74,900 74,621 74,234

126,875 141,6304 87,000 87,000 84,000 76,000

74,900 74,621 74,234 69,500* 59,500? 68,000* 69,500? 71,500* 74,000*

57,375 82,130 19,000 17,500 12,500 2,000

35.6 36.0 36.6 36.2

34.4 34.6 33.8 34.2

1 Approx. 20,000 lb. volatile solids.

2 Estimated from past experience. s

Sunday. 4 Partly estimated by measuring cover drop

on release from dome.

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Vol. 21, No. 6 EXTRACTS FROM OPERATION REPORTS 1077

condensed milk amounted to about

20,000 lb. This was not considered to be too heavy an extra loading for the

plant digesters, as almost all of it would be quickly removed in the form of gas or supernatant.

Consequently, the entire volume of condensed milk was hauled to the treatment plant in the tank trucks

normally used for hauling liquid sludge. At the plant it was dumped into the ground-garbage well for pump

ing to the digesters. Hauling and

loading to the digesters was started on

August 5 and completed on August 6.

Digester temperature was 99? F.

throughout the entire operation. The resulting gas production was

rapid and spectacular. On August 6

it was nearly double the normal daily volume, and on August 7 was so great that the plant gas meters were inade

quate to handle it. Part of the volume

(Table I) was estimated by measuring the drop of the floating cover as the

gas was released directly from the cover dome. The previous gas produc

tion record for the plant (110,000 cu.

ft. per day) was set during the summer

of 1948, when cheese whey was being handled by the same method (see This

Journal, 20, 6, 1115; Nov., 1948). No increase in C02^ content of the

gas was apparent. In fact, no notice

able ill effects of any kind have re

sulted from the unusually heavy shock

load, the digestion system seeming to have taken the material in stride.

INTERESTING EXTRACTS FROM OPERATION REPORTS

? ' When your work speaks for itself, don yt interrupt.

'9

Attention operators! It will be appreciated if copies of all annual reports of both large and small plants are sent to the Federation ofi?ce for abstracting in this section of the

Journal. Carbon copies of typewritten reports will be promptly returned on request.

Please direct annual reports to: Federation of Sewage Works Associations, Room 325,

Illinois Bldg., Champaign, 111.

Seventeenth Annual Report of the Division of Sewage Disposal, Toledo, Ohio, for 1948 *

By A. H. Niles, Engineer-Superintendent

The sharp increase in sewage flow

experienced during the first half of

1947 continued throughout 1948, indi

cating that the flow represents firm

growth, both industrial and domestic.

Gas Engines

The gas engine driven pump, fueled

with digester gas averaged 31.8 m.g.d., or 363 gal. per cu. ft. of gas for the

year. This is the greatest amount

pumped and at the greatest efficiency

* For last previous extract see This Jour

nal, 20, 6, 1114 (Nov., 1948).

in the 12 complete years of operation of the engine. This speaks well for the quality of maintenance not only of the gas engine but also of the 36

m.g.d. rated capacity pump, which is over 26 years old. The 2 gas engines installed late in 1936 at an original cost of $41,075 have now saved a total of $170,909.51 in the cost of electric current used at Bay View Park.

Tol-E-Gro

The tonnage available for the spring of 1948 was the lowest in several years, due to the painting of the superstruc

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