PHARMACEUTICAL WASTEWATER TREATMENT:
A CASE STUDY
Dewey R. Andersen, Professor
Department of Civil Engineering
University of Nebrasksa
Lincoln, Nebraska 68588
INTRODUCTION
Pharmaceutical products manufactured and the associated wastewater characteristics
vary from plant to plant. In addition, because of the seasonal use of many products, production within a given pharmaceutical manufacturing plant often varies throughout the year.
The latter situation exists at the facdity studied, the Dorsey Laboratories plant at Lincoln,
Nebraska. Products produced at this drug mixing and formulation plant, which are primarily
of the nonprescription type, include medications for arthritis, coughs, colds, hay fever,
sinus and bacterial infections, sedatives, digestive aids and skin sun screens. As indicated,
production at this plant is adjusted to meet the seasonal demand for many of these products.
The Dorsey Laboratories facdity at Lincoln, Nebraska, employs approximately 275
full-time employees. Generally, production is limited to a single work shift of eight hours
per day five days per week. However, an additional night shift is employed as needed in
the packaging and shipping areas. Morning and afternoon coffee breaks and the noon meal
are served in a plant cafeteria. Although the plant is connected to the municipal water
system for the City of Lincoln, it does not have access to the sewerage system and therefore
has its own waste treatment facdity. This system has been studied periodicaUy since 1968
by graduate students from the Department of Civil Engineering at the University of Nebraska. The results of these studies are presented in this chapter.
DESCRIPTION OF WASTEWATER TREATMENT SYSTEM
Initially, the treatment plant consisted of a factory-buUt extended aeration system.
In 1973, the system was expanded to include a comminuter, basket screen, equaUzation
basin and biological tower preceding the activated sludge system and disinfection and
fUtration for the plant effluent (Figure 1).
The equalization basin has a volume of 76 m3 (20,000 gal), which is equal to the design
daily flow for the system. Mechanical mixing and aeration are provided in this unit. Rate
of pumpage from the equalization basin to a 3.7-m (12-ft)-diameter, 4.2-m (H-ft)-deep,
plastic media, biological tower is approximately 250-265 liter/min (65-70 gpm). Tower
effluent is discharged to a splitter box where a portion of the flow, 45 liter/min (12 gpm),
is diverted to the extended aeration system. The remainder of the flow is returned to the
Figure 1. Flow diagram of the wastewater
treatment plant at Dorsey Laboratories.
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