Determination of Biochemical Oxygen Demand (BOD5)

5. Transfer 203 ml of sample into a white 500 ml casserole dish and titrate with 0.0250N sodium thiosulfate to a pale straw color. Add 1-2 ml of starch solution and continue to titrate to first disappearance of the blue color. (200 ml of original dilution water is equal to 203 ml of dilution water plus reagents.) Titrate two of the three samples. ................
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