What is the best material to use to seed BOD water?

The best material to use to seed BOD (Biochemical Oxygen Demand) water is fresh settled domestic wastewater. This is because fresh settled domestic wastewater contains a diverse population of microorganisms, including bacteria, that are essential for the biochemical degradation of organic matter.

When performing BOD tests, it is important to seed the sample with microorganisms capable of effectively decomposing the organic compounds present in the water being tested. Fresh settled domestic wastewater approximates the typical composition of biodegradable organics one would find in municipal wastewater, making it an ideal source for seeding.

In contrast, industrial wastewater may have different characteristics, including extreme pH levels or high concentrations of toxic substances that could inhibit microorganism function. Distilled water lacks the necessary microorganisms for BOD determination, as it is essentially purified with no biological activity. Activated sludge, while rich in microorganisms, might not accurately reflect the microbial community in domestic wastewater and is more appropriate for use in active treatment systems rather than as a seed for BOD tests.

Using fresh settled domestic wastewater ensures that the seeding process mirrors conditions found in actual wastewater treatment scenarios, offering a more reliable measure of BOD in the test sample.