Oil and Grease Test Procedures
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A clean flask is dried, cooled and weighed.
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A 1 Ltr wastewater sample is acidified (typically using hydrochloric or sulfuric acid) to a pH = 2.
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The acidified wastewater sample is then transferred to a 2 Ltr separatory funnel.
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30 mL of the extraction chemical (e.g., n-Hexane) are then added to the funnel and the funnel is shaken vigorously for two minutes.
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The wastewater/extraction chemical layers are allowed to separate in the funnel (the lighter water layer will be on the top and heavier extraction chemical layer will be on the bottom). The bottom layer of extraction chemical is drained into the flask prepared in Step 1.
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Steps 4/5 are repeated twice more to extract O&G.
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The contents of the flask (i.e., the extraction chemical containing O&G) are then heated so that the extraction chemical is distilled into another container.
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The flask (containing the extracted O&G) is reweighed. The original weight of the flask is subtracted and the total O&G weight in mg is calculated. The results provide the O&G concentration in mg/L.
APHA Standard Methods for O&G Measurement
5520 B. - Liquid-Liquid, Partition-Gravimetric Method ( EPA Approved )
5520 C. - Partition-Infrared Method
5520 D. - Soxhlet Extraction Method