BIOLOGICAL WASTE STABILIZATION PONDS AT
EXXON'S BAYTOWN REFINERY AND CHEMICAL PLANT:
SYSTEM PERFORMANCE AND ALGAL ACTIVITY
R. J. Olsen, Graduate Fellow
C. H. Ward, Professor and Chairman
J. M. King, Research Associate
Department of Environmental Science and Engineering
Rice University
Houston, Texas 77001
S. M. Novak, Environmental Engineer
Environmental Engineering Section
Exxon Company, U.S.A.
Baytown Refinery
Baytown, Texas 77520
INTRODUCTION
Over the past 25 years there has been an increase in the number of investigations carried out on oxidation (waste stabilization) pond systems, ranging from pilot-plant and
laboratory studies to examination of full-scale, operating domestic and industrial ponds.
These studies indicate that oxidation ponds are generally able to provide a good-quality
effluent with relatively inexpensive capital and operating costs.   From some of the earliest studies [1-3], a "symbiosis" or mutually benefiting relationship was seen to exist
between the interacting bacterial and algal populations.   The result of this interaction is
a significant reduction in such water quality parameters as biochemical oxygen demand
(BOD), chemical oxygen demand (COD), total organic carbon (TOC) and total suspended
solids (TSS).   Recent concern [4-6], however, has focused on the algal component which
develops in these highly nutrified aquatic systems.   Under some circumstances nuisance
algal blooms may develop, resulting in a deterioration of water quality, but this is not
universally true; the impact of each effluent must be examined to determine its individual
effect upon receiving water quality.   Much is still to be learned concerning the factors
which control algal populations in oxidation ponds and the interrelationships of these to
overall pond performance.
This chapter reports on the performance of an aerobic lagoon-oxidation pond system
operated in series by the Exxon Co., U.S.A., in Baytown, Texas.   Characterization of the
algal component includes species and numbers present, biomass and chlorophyll a concentrations.   The role of algae in pond performance is discussed as well as algal periodicity
and factors controlling algal populations.
BACKGROUND INFORMATION ABOUT THE PLANTS
Humble Oil & Refining Company started construction of the 10,000-bbl/day Baytown
Refinery in 1919.   Capacity of the refinery has increased to the current capacity of
468,000 bbl/day (420,000 bbl/day crude oil and 48,000 bbl/day natural gas liquids).
World War II marked Humble's entry into the chemicals business at Baytown, primarily
through the production of toluene for TNT production and butyl rubber.   In 1966, Enjay
Chemical Company was organized to handle the then-expanded chemical business.   In
1973, Exxon affiliates underwent a name change, which replaced the Humble, Esso, Enco
and Enjay names with Exxon.   Today at Baytown there are two plants-Exxon Company,
U.S.A. Baytown Refinery and Exxon Chemical Company, U.S.A. Baytown Chemical Plant.
The plants share a wastewater treatment system.
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