FEASIBILITY OF ZERO AROMATIC HYDROCARBON DISCHARGE
FROM A STYRENE MONOMER FACILITY
David E. Bruderly, Senior Engineer
John D. Crane, Division Manager
Jack D. Riggenbach, Senior Engineer
Environmental Science and Engineering, Inc.
Gainesville, Florida 32604
INTRODUCTION
Environmental Science and Engineering, Inc. (ESE) investigated advanced wastewater
management and treatment techniques for removing aromatic hydrocarbons from wastewaters generated by a styrene monomer plant in the Southwest. The wastewaters are contaminated with benzene, ethylbenzene, diethylbenzene, styrene and toluene and are currently
treated in a dissolved-air flotation unit prior to being discharged.
Work to eliminate aromatic discharges was executed in four phases:
1. In Phase 1, an in-plant wastewater survey was conducted to determine the major sources
of hydraulic and organic loading and to evaluate the operation of the existing treatment
system.
2. In Phase 2, potential treatment processes were screened by bench-scale laboratory tests.
3. Treatment efficiencies, costs and design criteria of promising unit processes were developed from onsite pilot plant studies during Phase 3.
4. Recommendations for storm water and process wastewater collection and treatment
were developed in Phase 4.
In-Plant Survey
The wastewater survey revealed eight significant wastewater sources and further showed
that a considerable portion of the wastewater now being treated consisted of storm water.
These sources and the existing wastewater treatment system are shown in Figure 1.
Present Treatment
The present treatment system consists of continuous neutralization with sulfuric acid.
Polyelectrolyte is then added to the neutralized wastes which are then pumped to the dissolved-air flotation (DAF) unit for oil and grease removal.  Effluent from the DAF then
passes through a surge tank where boiler blowdown is added prior to discharge to the river.
A pH monitor in the river discharge stops flow to the river if the pH is not between 6.1 and
8.9 units.
Bench and Pilot Studies for Hydrocarbon Removal
Laboratory bench-scale investigations of activated carbon, biological stabilization, coagu-
lation-flocculation, polymeric resin adsorption, solvent extraction and steam stripping were
conducted on synthetic waste streams.  Based on these investigations, field pilot tests for
steam stripping, air stripping, solvent extraction and activated carbon adsorption were conducted.  Results of the pilot investigations were favorable for each of these techniques. Steam
stripping was selected as the most versatile and cost-effective hydrocarbon removal unit process. This is indicated in Table I which shows capital and operating costs for the processes
investigated.
726