POWDERED ACTIVATED CARBON/ACTIVATED SLUDGE
TREATMENT OF CHEMICAL PRODUCTION WASTEWATERS
N. A. Leipzig, Environmental Engineer
Salsbury Laboratories
Charles City, Iowa 50616
M. R. Hockenbury, Regional Technical Director,
Engineering-Science, Inc.
Atlanta, Georgia 30329
INTRODUCTION
Salsbury Laboratories (Salsbury) has its corporate headquarters and the major portion
of its production facilities located in Charles City, Iowa. Activities at this location include
research and development, and production.  Products are specialty organic chemicals and
animal health products including biologies, feed additives and pharmaceuticals.
The chemical production division produces approximately 40 different cyclic organic
compounds. These compounds are used in the animal health products, textile, dye, plastics,
rubber, and metal finishing industries.   Typical chemical processes include: nitrations,
esterifications, oxidations, chlorosulfonations, amidations, acid chloride reactions, hydrolysis,
salts of carboxylic or sulfonic acids and diazotizations.   Chemical production is on a
batch-type basis with all except one of the 40 chemical compounds being produced on an
intermittent production schedule.
The batch-type reactions, frequent changes in production scheduling, and the diversity
and type of organic compounds produced, all present problems in effectively treating the
chemical-production wastewater.
Currently, Salsbury discharges its chemical-production wastewater to the local munci-
pal Wastewater Treatment Plant (WTP).   This WTP has secondary treatment capability in
the form of a trickling filter.  Salsbury's present pretreatment includes: neutralization, solids
removal, hydraulic and organics equalization of the total chemical-production wastewater
along with arsenic removal from a segregated process waste stream.
Cognizant of increasingly stricter regulations governing treatment of such wastewaters
Salsbury along with Engineering-Science, Inc. of Atlanta, GA. initiated an intensive investigation into the treatability of the chemical-production wastewater starting in September, 1976.
Briefly, the average wastewater can be characterized as an industrial wastewater
yellowish-orange in appearance and with a daily flow of approximately 0.5 million gallons. It
is of moderate organic and moderate to high ammonia strength.   It contains a variety of
organics which are present in widely varying amounts, and a number of inorganic and organic
arsenic forms.
Characterization of the wastewater over the period 1971-76 resulted in the pollutant
levels listed in Table I.
Table I. Characteristics of the Chemical Production Wastewater (1971-1976).
Parameters
Concentration
Total organic carbon (TOC), mg/1
410
Biochemical oxygen demand (BOD5), mg/1
486
Color, CPU-chloroplatinate units
8234
Ammonia as N, mg/1
73.6
Total arsenic, mg/1
6.1
Phenols, mg/1
25.7
Flow, mgd
0.45
195