Nitrate Treatment of Lagoons
H. H. Young
Chief Engineer, Stokely Foods,  Inc.
Indianapolis, Indiana
The problem of waste treatment for canneries is obvious, and so far
the lagoon seems to be the best solution. Stokely Foods, Inc., has sixteen
lagoons in its plants in Wisconsin, Illinois, Indiana, Michigan, and
Ohio. Some of these are not much more than holes in the ground, and
in one or two instances the lagoons serve as preliminary settling beds
for additional treatment facilities; but there are a few lagoons that the
company can be quite proud of.
The first lagoon which the company used was constructed at South
Beaver Dam, Wisconsin, in about 1940. It was designed and built with
the assistance of the Engineering Department of the Wisconsin State
Board of Health. This lagoon is still doing a good job, although the
design specifications have been somewhat changed in recent years.
The figures given below on design are subject to the suggestions of
any of the State Board of Health engineers, but in general they conform
to state and federal specifications. The National Canners Association
has been very active in prevention of pollution by cannery wastes and has
done a lot in helping the industry work out waste-treatment methods.
Following is an outline of some of the more important points to
follow in lagoon construction:
1. Sufficient area of land is necessary. Area required depends
on the plant's maximum seasonal output. This will be explained
later.
2. Lagoons should be as close as possible to the plant. If possible, they should be on the side of town opposite the direction from
which prevailing winds come. They should be as close as possible
to the eventual discharge point, and they should be outside the corporation limits in a sparsely settled area.
3. Adequate capacity is important for proper lagooning. Good
results have been obtained in designing for a three- to four-foot
depth of liquid. For a three-foot depth, approximately one acre of
ground is required for the retention of one million gallons of liquid.
Provision should be made for the retention of 25% of the previous
season's waste in order to have seed sludge for the next season. For
example, in designing a lagoon for a season's waste of 12,000,000 gal-
208