21    ENVIRONMENTAL SOLUTIONS BASED ON RECYCLING OF
WATER, OIL, AND SLUDGE AT AN INTEGRATED OIL
REFINERY
Noah Galil, Professor
Menahem Rebhun, Professor
Environmental and Water Resources Engineering
Technion - Israel Institute of Technology
Haifa, Israel
INTRODUCTION
A research and development project was carried out at an oil refinery in Haifa, Israel. The refinery
is located less than two miles from municipal, recreational and agricultural areas, close to other
industrial sites and a river. The production processes include distillation, catalytic cracking, visbreack-
ing, oil and waxes, ethylene, sulphur recovery and other processes. Due to national and regional water
shortage (low fresh water consumption) as well as the variety of production processes, the wastewater
(8,400 mVday) is characterized by relatively high concentrations of pollutants and include several
periodical streams from gasoline and other product washeries, containing up to 12% phenols, most of
them cresols and xylenols.
The implementation of the environment quality regulations, regarding discharge of effluent to the
river, imposed a revision of the old, existing, wastewater treatment facilities. The new waste management solutions were based on the following concepts: (a) lowering the level of pollutants to the values
required by regulations, the treated effluent and some of the separated pollutants could be considered
for recycling by the refinery and by adjacent industries, minimizing the discharge outside the industrial zone; (b) maximal utilization of the existing facilities; (c) the solutions have been developed and
executed step by step.
Effluent recycling in this case means saving more than 2.5 million cubic meters per year and has a
real importance for a semiarid country with very limited fresh water resources.
The research project included the following subjects: characterization of the main wastewater
stream, as well as lateral streams generated by specific production processes; feasibility studies of
general treatment of all the wastewater streams versus separate treatment of concentrated streams; a
comparative study of three alternative processes for the biological treatment stage; a survey of the
processes occurring in the recirculated water cooling system of the refinery; characterization and
considerations regarding sludge treatment and disposal.
Following the conclusions of the research, the new wastewater facilities include: separate storage
and treatment of concentrated spent soda streams; storage and regulation of the main refinery
wastewater stream; API type oil-water separator (OWS) chemical flocculation and dissolved air
flotation (DAF); biological treatment; sludge collection, treatment and disposal.
FLOW REGULATION
The main wastewater stream could be influenced by factors as rain floods and spills caused by
unexpected accidents at the production units. For minimizing these influences, a 15,000 m3 tank was
built and connected to the system. The operation of this tank, having a capacity of about two days of
maximal flow, could enable the operators to avoid sudden hydraulic or pollutants loads on the
treatment units.
CONCENTRATED PHENOLIC WASTEWATER
These wastewater streams used to be discharged periodically to the refinery sewerage system.
Studies carried out for the development of biological treatment by Rebhun and Galil1 revealed severe
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