Treatment of a High Strength Phenolic and
Ammonia Wastestream By Single And Multi-Stage
Activated Sludge Processes
CARL E. ADAMS, Jr., President
Associated Water and Air Resources Engineers, Inc.
Nashville, Tennessee 37215
INTRODUCTION
This project comprised evaluation of the potential of biological treatment for a weak
ammonia liquor from a coke plant which had been pretreated by multi-stage flash
evaporation. The evaporator condensate, which contained only ammonia and phenolic
compounds, comprised the wastewater which required final treatment. The coke plant had
engaged the Westinghouse Corporation to design the evaporator on a turnkey-type project.
When Westinghouse realized that the evaporator condensate contained high
concentrations of ammonia and phenolics, they prepared a preliminary cost estimate for
steam stripping of the ammonia and sorption of the phenols by activated carbon. Since
these costs were exceedingly high, Westinghouse then retained Associated Water and Air
Resources Engineers, Inc. (AWARE) of Nashville, Tennessee to develop and design a
biological treatment system to meet anticipated effluent quality criteria for both ammonia
and phenol removal. These effluent criteria were estimated to be:
BOD = 100 mg/1
Suspended Solids = 20 mg/1
Total Phenols =        0.002 mg/1
Ammonia-Nitrogen = 10 mg/1
After reviewing the characteristics of the waste and the desired effluent quality,
AWARE recommended that activated sludge be examined as the most promising biological
system. It was also emphasized by AWARE that steam stripping of ammonia to levels
required for BOD removal (approximately 3 to 5 parts of ammonia-nitrogen required per
100 parts of BOD removed) might be more economical than biological nitrification. It was
also recommended by AWARE that some form of phenol polishing, possibly by activated
carbon or ozonation, would be necessary to meet the two parts per billion of phenol.
However, due to Westinghouse's request, only biological treatment was examined during
the first phase of the investigation which is reported herein.
WASTE CHARACTERISTICS
Since the evaporator had not been installed prior to this study, a synthetic wastewater
was prepared according to Westinghouse's estimates of the composition of the evaporator
condensate. The desired composition of the wastewater is shown in Table I. Since the
quantity of waste needed for the investigation was substantial, a reverse osmosis unit was
used to prepare a water similar to the evaporator condensate. The reverse osmosis unit was
capable of generating considerably more water in the laboratory than a still and was
therefore selected for the water supply. Based on AWARE's experience with phenolic
materials in other coke plant wastewaters, the wastewater was synthesized with several
forms of phenol including para, ortho and meta-phenolic compounds which included
creosols. The actual characteristics of the synthetic feed are shown in Table II.
The concentration of total phenol averaged 3,270 mg/1 with an average BOD
concentration of 6,370 mg/1, an average COD level of 8,230 mg/1 and an average TOC level
of 2,260 mg/1. Since phenol was the only organic compound in the raw waste, the
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