Plant Scale Studies at Akron, Ohio
RICHARD P. BROWNELL, Project Engineer
JAMES P. HARRIS, Project Engineer
PAUL L. BUSCH, Vice President
Malcolm Pirnie, Inc.
White Plains, New York
LEWIS DEBEVEC, Manager
Water Pollution Control
City of Akron
Akron, Ohio
INTRODUCTION
Metropolitan Akron is situated on the Cuyahoga River, which flows into Lake Erie.
Akron has had secondary treatment for its municipal-industrial wastewater since the late
nineteen twenties. However, increasing quantities of wastewater and changing water
quality standards have dictated the need for higher quality effluents. In addition to
improved BOD5, suspended solids and phosphate removals, establishment of nitrification
was considered essential. The elimination of unsightly foaming conditions also was
considered important.
The existing activated sludge system provided the opportunity to study, on a large
scale, important aspects of the recommended program for improvements. The emphasis of
this paper is upon the results obtained from pilot and prototype studies of single-stage and
two-stage nitrification. Laboratory, additional pilot plant and other full-scale study results
have been used for supplementation as necessary.
WASTEWATER CHARACTERISTICS
The Akron Water Pollution Control Station receives an average flow of 80 MGD from
a sewerage system which is about 60 percent combined. Contributions made by local rubber
and associated chemical industries are estimated to be 25 percent of the flow, 30 percent of
the influent BOD5 and 20 percent of the influent suspended solids. Table I shows typical
average influent and secondary effluent characteristics for Akron wastewater.
TABLE I
AKRON WASTEWATER CHARACTERISTICS
Parameter
BOD5, mg/1
Suspended Solids, mg/1
Total Phosphate, mg/1
Ammonia, mg/1
(N02+N03)-N mg/1
Secondare
fluent
Effluent
126
24
214
50
17
10
15
15
1.2
0.7
An analysis of BOD5 and suspended solids data from the secondary effluent yields the
following equation:
BOD5 (mg/1) = 6 + 0.34 x Suspended Solids (mg/1)
207