OIL AND GREASE: A PROPOSED 

 ANALYTICAL METHOD FOR 

 FISHERY WASTE EFFLUENTS 



The published procedures (American Public 

 Health Association 1971:407-413; Environmental 

 Protection Agency 1974) for determining oil and 

 grease in industrial wastes are generally unsuit- 

 able for fish-processing waste effluents, especially 

 for such high-load effluents as occur during the 

 processing of salmon for canning. These wastes 

 cannot be filtered satisfactorily by the method 

 described. In addition, a Soxhlet extraction of the 

 fish proteinlike material after drying for 30 min 

 gives low values because of the inefficient extrac- 

 tion of protein-bound lipids. 



These inadequacies of the published methods for 

 the analysis of oil in fish-processing waste streams 

 indicate a need for an alternate method that is 

 simple and accurate. Accordingly, a method was 

 worked out using portions of the published oil and 

 grease methods and using techniques developed 

 by Kelley and Harmon (1972) for the analysis of 

 carotenoids. The method involves a precipitation 

 of protein and particulate matter to allow easy 

 filtration and subsequent extraction of oil from 

 the residue under anhydrous conditions, using 

 2-propanol (IPA) and petroleum ether (PE). The 

 method is proposed as an alternate method for 

 determining oil and grease in fishery waste 

 effluents. 



Materials and Methods 



Reagents and Equipment 



Celite^ 503, Johns-Mansville (filter aid): For best 

 results, Celite should be washed with water and 

 solvents because a slight oil residue may carry over 

 into the oil fraction. Blend about 100 parts of 

 Celite by weight with 500 parts water, filter, 

 reblend with 500 parts (vol) IPA, filter, reblend 

 with 500 parts (vol) PE, filter and apply suction 

 until reasonably dry. Air dry and store in a jar. 

 Filter paper dispersion: Blend 20 7-cm filter paper 

 disks (Whatman 1 or 40) with distilled water in a 

 blender for 5 - 10 min. Bring volume to 2,000 ml. 

 Sodium hexametaphosphate in water: 250 mg/ml, 

 use 1 ml per analysis, i.e., 250 ppm. Other materials 

 required are: filter flasks (250 ml and 2,000 ml). 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



graduated cylinder (1,000 ml), filter pump (water 

 aspirator), filter funnel (fritted disc, 350 ml coarse, 

 150 ml medium), blender and jars (Virtis Model 23 

 and 200-ml blender jars), rotating evaporator with 

 250-ml flask, film to seal cylinder (parafilm "M" 

 American Can Company, Marathon Products), 

 50% acetic acid, anhydrous magnesium sulfate 

 (powdered), reagent grade IPA, and reagent 

 grade PE (bp 40°-60°C). 



Preparation of Filter Funnel 



Assemble filter flask and a 350-ml "c" sintered 

 glass filter funnel. Add about 3 g filter aid and 100 

 ml filter paper dispersion directly to the funnel. 

 Fill funnel with water, stir and allow to partly 

 drain without vacuum. Apply vacuum, rinse brief- 

 ly, and press down along edge of mat to ensure a 

 good seal. 



Preparation of Sample and Filtering Step 



Pour well-mixed sample of effluent to the 

 1,000-ml mark in the graduated cylinder. Add 3 to 

 6 g filter aid to aid precipitation. In its absence, 

 flotation and precipitation both occurred. Add 1 ml 

 hexametaphosphate solution, seal cylinder with 

 film, and mix by inverting cylinder about 12 times. 

 Add 2 ml acetic acid. The amount of acid will vary 

 with the type of effluent and is not critical provid- 

 ed enough is added; the pH must be lower than 4.2, 

 but precipitation works equally well at several 

 levels between pH 2.1 and 4.2. Invert three or four 

 times. Excessive mixing inhibits rate of precipi- 

 tation. Wait about 2 min and add more acid if top 

 inch or so is not clear. Solids in salmon waste 

 effluents are slow to settle and are best handled by 

 allowing the mixture to settle overnight in the 

 refrigerator. Salmon waste, after 2-h settling, can 

 be filtered but with difficulty. If filtration is 

 started too soon, the sample often must be dis- 

 carded because it will not filter. Shrimp and crab 

 waste usually can be filtered in 15 to 30 min. Filter 

 clear supernatant fluid under vacuum through the 

 prepared filter funnel (very rapid), and transfer 

 more slowly the precipitate (50-75 ml vol) and 

 rinsings to the funnel. Use about 200 ml water to 

 remove excess acid and to rinse graduate and 

 filter. Continue vacuum 5 to 10 min to remove as 

 much water as possible because the next step, the 

 extraction, must be anhydrous. 



Extraction of Oil 



Carefully transfer solid material, including 



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