77
BY-PRODUCTS AND TREATMENT OF BREWERY
AND YEAST WASTES*
Willem Rudolfs
Chief, Department Water and  Sewage Research
New Jersey Agricultural Experiment Station, New Brunswick, N. J.
As soon as by-products are made and utilized, their production
is a part of the industrial processes. By-products, which are in fact
new products for the specific industry, may themselves produce
wastes which are not much less objectionable, and may be even more
difficult to treat than the original wastes from which they are made.
The production of waste should be considered an integral part
of the manufacturing processes and the cost of treatment of indus¬
trial wastes must, therefore, be charged against the product.
Industries located in communities are tax payers and as such
are entitled to an equitable share in the waste treatment processes
of the community. Any additional cost of construction and opera¬
tion of the municipal treatment works should be borne by the in¬
dustry whose waste places the added burden on the city.
Utilization of Wastes
The recovery of waste products, the utilization of wastes for
new products as well as the use of waste as such for specific purposes,
is usually covered by the term "recovery" or utilization of waste.
In effect, the production of useful products from waste is frequently
a question of methods of procedure and economics. If the eco¬
nomical possibilities of recovery are considered in the light of reduc¬
ing the cost of waste treatment and disposal, they take an entirely
different aspect.
Results of experimentation and some practice resulting from
utilization of brewery and yeast wastes are available in the literature.
There is no doubt that considerably more experimentation has been
conducted than is reported. The examples cited are not a listing
of all that has been done, but rather an indication of the lines of
attack.
Evaporation of brewery waste by different methods and various
types of machinery is rather common and well known. Evaporation
of yeast wastes for the same purpose appears to be equally feasible
under certain conditions.
♦Journal   Series   Paper,   New   Jersey   Agricultural   Experiment,   Dept.
Water and Sewage Research, Rutgers University, New Brunswick, New Jersey.