Aeration of Pumpkin Cannery Wastes
F. J. DREHWING, Sanitary Engineer
Stearns and Wheler
Cazenovia, New York
N. L. NEMEROW, Professor of Civil Engineering
Syracuse University
Syracuse, New York
Several proven methods exist for treating cannery wastes, starting with a preliminary application of screening for the removal of large solids and possibly followed by biological treatment, lagooning, or spray irrigation. A decision for the
application of one method for a specific waste problem cannot be made without
completing a preliminary investigation. This includes a study of the background
and economy of the cannery.
Since most canneries contemplate inexpensive treatment, one of the most
popular methods of waste disposal for canneries in the past decade has been lagooning where sufficient land area is available. Lagoons hold the wastes for a designated period of time. During this period of time, treatment of the waste is accomplished in five ways: biological action, both anaerobic and aerobic; sedimentation; soil absorption; evaporation; and dilution. The treatment accomplished in
a lagoon is mainly due to biological action during which micro-organisms break
down the organic constituents of the waste whereby the ultimate result is the separation of the colloidal and soluble organic material from the waste waters. Under
aerobic conditions, the end products are primarily carbon dioxide and water.
Odorous gaseous end products result when oxygen is not present. Because of the
absence of these nuisances in aerobic treatment this method was selected for laboratory investigation.
Pumpkin cannery waste was chosen for this study because of its specific characteristics of strength, high solids, and lack of nutrients. It afforded an opportunity for establishing the characteristics of a little-known waste and for initiating
a laboratory aeration study of this waste on a small scale. Its parameters could
then be ascertained for predicting results of full scale pilot plant operation.
Some criteria for design of an effective aeration system are based on the following factors:
1. Flow
2. BOD Loading
3. Efficiency Required
4. Detention Time
5. Depth of Basin
6. Air Rate
7. Suspended Solids under Aeration
Having reviewed all premises and limitations of the foregoing factors it appeared that the most significant and controlling elements for a proposed aeration
study are defined by loading, detention time, and air rate, which in turn deter -
mines the efficiency of the system. Although depth is a definite factor for the
transfer of oxygen in a large installation, it must be utilized only as a means of
controlling the detention time at the laboratory level, since it would prove im-
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