Dive into the 2026 NY Wastewater Exam – Flush Away the Competition with Confidence!

The determination of Biochemical Oxygen Demand (BOD) is a critical aspect of wastewater treatment, as it reflects the amount of oxygen that microorganisms will consume while decomposing organic matter in a sample of water. The standard technique for measuring BOD involves placing a water sample in a BOD bottle, where it is sealed to restrict oxygen exchange with the environment. This setup is then incubated at a controlled temperature, typically 20 degrees Celsius, for a specified period, usually five days.

During this incubation, the microorganisms in the sample utilize the organic matter present, resulting in a decrease in dissolved oxygen levels. The change in oxygen concentration before and after the incubation period can then be quantified to provide the BOD value. This method is widely accepted and standardized, making it a crucial technique for assessing the organic pollution load in wastewater.

In contrast, the other options do not accurately measure BOD. Filtration is typically used for removing solids from water but does not assess biological activity or oxygen demand. Secchi depth is a measure of water clarity and is used primarily for assessing turbidity, not organic matter decomposition. Colorimetry, while useful for various water quality tests, is not directly applicable to BOD measurements in the standard procedure as it typically focuses