CHEMISTRY AND APPLICATION
OF OZONE AND ULTRAVIOLET
LIGHT FOR WATER REUSE-
PILOT PLANT DEMONSTRATION
Jack D. Zeff, President
Eriks Leitis, Director of Research
Westgate Research Corporation
West Los Angeles, California 90025
John A. Harris, Director
Environmental Affairs
Occidental Chemical Co.
Lathrop, California 95330
INTRODUCTION
This evaluation of the UV-ozonation process for water reuse was conducted with the sponsorship of
the Office of Water Research and Technology (OWRT) of the Department of Interior, Robert
Madancy, Program Officer. The overall objective of the program was to demonstrate on a small pilot
plant scale at an industrial site the destruction of refractory and toxic organic residues in a slip stream
of a wastewater, which after treatment can be reused. The wastewater should be typical of a large
industrial consumer of water, and the water after treatment can be reused either in the plant or for
other purposes, nearby, such as irrigation or ground water recharge.
After contacting a number of chemical plants in the California area, the Agrichemical Plant of
Occidental Chemical Company in Lathrop, California, offered a wastewater site to Westgate
Research Corporation and OWRT to conduct these studies.
The chemical industry falls within the category of a large consumer of water, since it uses 13.5
billion gallons per day with the industrial organic chemical segment using 7.1 billion gallons daily [1].
The agricultural chemical companies within this classification withdraw 942 million gallons per day
[2]. The wastewater treated in this pilot plant evaluation is typical of many agrichemical industries in
that it is a rinse water collected from the wash down of formulation equipment and from rainwater
run-off. This wash water is collected and pumped to storage tanks, where periodically it is transported
by tank truck to a Class I landfill site. If the toxic and refractory organic compounds were removed,
the water could serve a useful purpose in the plant for cooling or other utilitarian purposes, or outside
the plant it could be used for irrigation.
Our purpose in this pilot plant study was to show that UV-ozonation would detoxify this water
economically in a treatment train with possibly other pretreatment and post-treatment processes.
BENCH EVALUATION OF THE WASTEWATER
Prior to the installation of the pilot plant at Lathrop, representative samples of the wastewater
were collected to determine the concentration of specific refractory organic compounds, total organic
carbon (TOC) and pH.
Also a series of bench scale UV/O3 evaluations were conducted on the water samples to obtain
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