Taste- and Odor-Producing Components In Refinery Gravity Senarator uents C. C. RUCHHOFT, F. RI. WIIDDLETON, HARRY BRAUS, AND A. A. ROSEN U. S . Public Health Service, Environmental Health Center, 4676 Columbia Parkway, Cincinnati 26, Ohio Gravity oil separator effluents from five refineries were studied to determine the types and quantities of materials present that contribute to taste and odor when discharged into surface drinking water sources. The organic materials in the effluents were concentrated by adsorption on active carbon and by liquid-liquid extraction. Examination of the recovered extracts indicated the neutral materials, largely aliphatic and aromatic hydrocarbons and cyclic sulfur compounds, to be the principal source of odorous components i n these wastes. Phenolic materials are less significant i n causing odor. Threshold odor tests were employed t o estimate the magnitude of the odor contribution from such wastes.
T
HE control of tastes and odors in drinking waters obtained from surface water sources is a major problem in water puri-
fication. Tastes and odors in surface waters may come froin aquatic plants such as algae, natural land drainage, and the discharge of domestic sewage and industrial wastes. The odor bearing materials, largely organic, may undergo physical and chemical changes as a result of sedimentation, vaporization, oxidation, temperature and light effects, and biochemical action. This study was undertaken to determine the types and quantities of materials present in petroleum refinery gravity oil separator effluents that contribute to taste aiid odor when discharged into surface waters used as drinking vvater sources. Petroleum refineries universally separate slop oils from waste waters by gravity differential-type separators. Such waste oils originate from processing operations, spills, leaks, tank dramoffs, and maintenance and repair activities. Operating experiences with gravity oil separators have been adequately described in the literature (7, 10). Although the purpose of the separators is to break emulsions and separate the oil, this separation is not complete and oil separator effluents contain materials in solution, emulsion, and suspension. The effluent is usually discharged without additional treatment. 1
Present address, National Distillers Products Corp., Cincinnati, Ohio.
OPERATION DATA TABLE I. FILTER
Sample NO. E-1
E-2
E-3
Type Sand Granular carbon
Prefilter Rate of Depth fiow, gal./ of sq. ft./ filter, min. inches 6 2-1
...
..
4
24
..
..
.4SD
Samples were collected froin fire pctroleum refineries, all operated by different companies, selected to represent a reliable cross section of the refining industij-. S o attempt was made t o correlate the types of crude oil processed or the products m:inufactured with the waste materials in the 01%separator efflucnts. Refinery A is a very large, complete refinery, Refinery E is the smallest of the five and performs only theiinal cracking. I11 sddition, certain of the stronger wastes at refinery E are not dispoqed of through the oil separator. Refineries R,C, and D arc intrimediate in size. APPARATUSANUPROCEDURES
Carbon Filter Method. Most of the samples were collcctctl i>y passing 100 or more gallons of oil ecparator effluent through a sinal1 active carbon filter (2, 3) a t a rate of 2 to 6 gallons per square foot per minute. The inat'erials adsorbed on the carbon were elut,ed by means of chloroform in a Soxhlet-type extractor and recovered by distillation of the solvent, One filter system consisted of 4-inch iron pipes, 3 feet in length, filled with granular active carbon (Cliffchar 4-10 mesh, Cliffs Dow Chemical Co., Marquette, Mich.), The carbon filter was preceded by a sand f i h r v,-hich \=,-asbnckrvashed a t intervals to prevent clogging of the carbon. Losses on backmashing and mechanical entrainment of oily materials in the sand filter resulted in l o a recoveries by this met>hod.
RECOVERY O F ORGANIC CHEMICALS
FROM OIL
SEPARATOR I
