Anaerobic Digestion of Tomato
and Pumpkin Wastes
R. A. Canham
Sanitary Engineer, National Canners Association
Washington, D. C.
Don E. Bloodgood
Professor of Sanitary Engineering, Purdue University
Lafayette, Indiana
Tomato Waste
Experimental work on anaerobic digestion of food-canning wastes
was carried on in the Sanitary Engineering laboratory at Purdue University during 1947, following a preliminary survey and investigation
in 1946, and was reported by O. H. Hert in "Tomato and Pumpkin
Wastes," "Proceedings of the Third Industrial Waste Conference,
1947," Engineering Bulletin of Purdue University, Extension Series 64,
1947, page 244.
Other work on industrial waste predigestion has been reported by
Frederick G. Nelson, "Predigestion of Industrial Wastes," California
Sewage Works Journal, Vol. 17, No. 1, p. 27  (1945).
Results of the laboratory experiments on food-canning wastes in the
Purdue laboratory were such that it was deemed advisable to continue
the work on a larger scale. It was decided to conduct the digestion experiments on tomato and pumpkin wastes. The site of Ladoga, Indiana,
was selected for several reasons. Ladoga is a city of approximately 1,000
people, with the Ladoga Canning Company operating a canning plant
normally packing tomatoes and pumpkin. The city operates a trickling-
filter sewage-treatment plant, handling combined domestic sewage and
the canning-plant waste. During the canning season a substantial portion of the waste treated at the sewage-treatment plant is contributed
by the canning plant. During the 1946 season considerable information
was gathered on the canning-plant waste and on the sewage-treatment-
plant operation. This formed a valuable basis for experiments of the
type proposed. Some years prior to this study an attempt was made to
improve the existing sewage-treatment-plant operation by installing a
flocculation tank for chemical treatment. The flocculation tank was still
intact and provided an ideal tank for the planned digestion experiments.
Data from Hert's report indicate that during the 1946 tomato season
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