BIOLOGICAL TREATMENT OF REFINERY WASTES
Zahid Mahmud, Graduate Assistant
Department of Civil Engineering
University of Pittsburgh
Pittsburgh, Pennsylvania 15 261
Nguyen Cong Thanh, Chairman
Environmental Engineering Division
Asian Institute of Technology
Bangkok, Thailand
INTRODUCTION
The petroleum industry is one of the largest and fastly expanding industries, and
presents a variety of complex wastewater management problems.   With increased emphasis on the prevention of stream pollution, the petroleum industry is faced with ever
increasing demands for greater efficiency in wastewater treatment.
The stabilization of the complex wastes from the refineries and petrochemical industries is becoming a challenging job.    Biological oxidation of effluent waters has become
an established process in oil refinery practice in recent years.    It is usually the most
economical method of reducing its toxicity, organic content and objectionable appearance.
This paper presents the experimental development of parameters to stabilize the
petroleum refinery wastewaters.   This research was carried out at the Environmental
Engineering Division of Asian Institute of Technology (AIT), Bangkok, Thailand.
OBJECTIVES OF THE STUDY
It is recognized that each particular refinery poses its individual problems.   There is
a logical approach for evaluating refinery wastewaters problems and selecting the optimum system to produce the effluent desired.   While it is recognized that absolute statements on specific wastewater treatment systems are not possible, certain generalities
can be used as guides to biological treatment system selection.   The objectives of the
study were: (a) to determine the wastewater characteristics; (b) to estimate the waste
load basis for treatability study; (c) to determine the biological  treatability of the refinery waste; (d) to develop the design parameters for design of the units; (e) to develop
the design parameters for sludge production; (f) to develop procedure to predict the
waste effluent quality from the treatment units; and (g) to find a combination of processes for complete treatment and reduction of toxic effects of the effluent, if any.
MATERIALS AND METHODS
The first step in planning a biological wastewater treatment facility is to determine
the wastewater characteristics and to understand the importance of each of the constituents in the treatment system.
Composite samples were collected over the normal operational cycle of the refinery
to ascertain average wastewater characteristics.   Composite samples were analyzed for
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