Aerated Lagoon Treatment of Wastes from the
Dow Chemical Company, Zionsville, Indiana
GEORGE W. MANN, Waste Control Engineer
Dow Chemical Company
Zionsville, Indiana
INTRODUCTION
The facilities at Zionsville were originally known as Pitman-Moore Biological
Laboratories from 1913 until 1968. During part of this interim most wastes were
handled by open drainage (1913-1915), septic tanks (1915-1944), or collection tanks
known as "kill pits" (for infectious wastes) and septic tanks (1944-1953).
When the facilities were purchased by The Dow Chemical Company in 1962,
wastes were treated by four methods: 1) imhoff tank; 2) septic tanks; 3) kill pits; and
4) activated sludge system.
Effluent samples collected during the spring of 1963 from the above existing
treatment plants indicated these facilities to be inadequate (Tablel).
Date
3/21/63 	
4/03/63 	
4/11/63 	
5/02/63 	
5/09/63 	
A review of the above data and similar information from the other treatment
plants indicated a need for either repair or replacement of these facilities.
To provide the best solution, a study was initiated to find waste treatment
facilities which would meet the following criteria: 1) extreme flexible hydraulic
capacity; 2) immediate dilution of high organic concentrations; 3) continuous maintenance of aerobic conditions; 4) sludge disposal capacity; 5) maximum degree of
portability; and 6) effluent of less than 30 mg/BOD.
After considerable study, the most practical method was considered an aerated
lagoon due to the location of the plant and the availability of land. This plan was
submitted to the Indiana State Board of Health and was approved May 14, 1963.
The wastes requiring treatment include: 1) laundry wastes; 2) domestic sewage;
3) blood and blood-by-products; 4) bacterial and viral fermentation by-products;
5) animal wastes; and 6) chemical solutions.
-543-
TABLE I
IMHOFF EFFLUENT DATA
COD/mg/liter
BOD/mg/liter
                          1302
1200
                            656
300
                          1189
750
                          1521
1800
                          1509
1590