STATISTICAL DISTRIBUTION OF BIOLOGICAL WASTEWATER
TREATMENT PLANT EFFLUENT DATA
David G. Hutton, Process Associate
Environmental Control Division
E. I. Dupont Company
Deepwater, New Jersey 08023
INTRODUCTION
All operators of wastewater treatment plants in the United States are now covered
by NPDES permits, which limits the amount of pollutant that can be discharged. Most
plants have a monthly average limit and a daily maximum limit to attain. Many of us
have biological systems which we have noted give characteristic non-normal distribution
of effluent data. This paper will discuss specific examples using quantitative data.
DU PONT'S CHAMBERS WORKS
Chambers Works, Du Pont's largest and most complex manufacturing facility has now
been operating its wastewater treatment plant to meet NPDES permit requirements for
well over a year. On this site, over 2000 processes manufacture more than 2500 products,
most of which fall into the organic chemicals category. Included in the product lines at
this site are "Freon" fluorocarbons, organic intermediates (mainly substituted aromatic
compounds), dyes and dye intermediates, petroleum additives, isocyanates and elastomeric
products, general industrial chemicals (particularly paper and textile-treating chemicals),
sulfuric acid, and miscellaneous other products. The wastewater from the plant is colored
and strongly acidic. Since most of the plant processes are batch, the wastewater receives
slug discharges of organics which results in a highly variable organic load, both in terms
of dissolved organic carbon (DOC) concentration and concentration of specific organic
compounds. Feed to the wastewater treatment plant had the composition shown in
Table I during the first year of operation.
Table L Chambers Works Wastewater Treatment Plant Feed, June, 1977-May, 1978
Flow, gallons per minute
27,000
Total dissolved solids, mg/1
3,200
PH
2.07
DOC, mg/1
183
Total Acidity, mg/1
950
Total BOD5, mg/1
177
Total suspended solids, mg/1
112
This wastewater treatment plant consists of neutralization and settling for primary
treatment followed by combined powdered activated carbon-activated sludge (Du Pont
PACT Process) for secondary/tertiary treatment. The wastewater, varying from 23 to
50 mgd during the first year of operation, is fed to the process without equalization
(Figure 1). Wastewater is pumped into the neutralizes where lime is added for neutralization. Polyelectrolyte is added to the neutralizer effluent to aid in coagulating the fines
prior to clarification. Primary sludge settles and thickens in the clarifiers, is pumped to
storage, and finally is pumped to a filter press for concentration before disposal in a
lined landfill
Powdered activated carbon and return PACT sludge are added to the primary effluent
as it is fed to the aeration tanks. Polyelectrolyte is added to the aerator effluent to aid in
coagulating fines in the final clarifier. Treated effluent combines with other plant streams
in a settling lagoon and is discharged to the Delaware River.
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