Biological Utilization of Cellulose
L. B. POLKOWSKI, Professor of Sanitary Engineering
Univeristy of Iowa
Iowa City, Iowa
R. C. LOEHR, Associate Professor
University of Kansas,
Lawrence, Kansas
and
G. A. ROHLICH, Director, Hydraulic & Sanitary Laboratory
and
T. IWATSU, Research Assistant
University of Wisconsin
Madison, Wisconsin
INTRODUCTION
This paper presents the summary of the results of two independent proj-
ets: the utilization of cellulose by activated sludge and the anerobic digestion of domestic sludge with paper fiber sludge. The paper fiber sludge was
obtained from the save-all units of a paper making industry.
The utilization of cellulose by activated sludge has recently received
attention by the Greater Chicago Municipal Sanitary District because ofthe
occurrence of excess cellulose fiber in the dried sludge during certain seasons
of the year. Hurwitz (1) reported that the cellulose concentration of the
activated sludge in recent years was approximately 3.5 per cent on a dry
weight basis during the winter months, whereas concentrations of cellulose
during the summer months would be as low as 0.5 per cent. It was postulated
that the activity of celluloytic bacteria was affected by the waste temperatures and that the rate of utilization of cellulose was reduced greatly during
low temperature operation. Other factors were considered, such as suspended
solids concentration of the mixed liquor, sludge age, and the variation of
the cellulose concentration in the raw waste corresponding to seasonal
changes. Recent studies by the Chicago Sanitary District havelseen made to
evaluate the relative importance and relation of these variables to the utilization of cellulose in activated sludge treatment (1). The studies reported
herein are on the effect of temperature on the rate of utilization of cellulose
by activated sludge under laboratory conditions and on the effect of suspended
solids concentration and initial concentration of cellulose in the mixed liquor
on the rate of utilization.
Cellulose is the primary constituent of sanitary papers, the use of which
has increased significantly in the last 10 years in the U. S. The practice of
garbage grinding also increases the cellulose content of sewage by the addition of the cellulosic material of plants.
Cellulose, a polymer of glucose, has the assumed but generally accepted
formulation shown in Figure 1 which shows the anhydroglucose residues constructed with the betaglucosidic bonds.    The number ofanhydroglucose units
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