BOD Efficiency between Conventional and Extended Aeration Plants

To determine the biochemical oxygen demand (BOD) in effluent, you can follow the standard procedure outlined by regulatory bodies such as the American Public Health Association (APHA) or the International Organization for Standardization (ISO). Here is a general overview of the procedure: 1. Collect a representative sample of the effluent in a BOD bottle. The sample size should be chosen based on the expected BOD concentration and the capabilities of the laboratory. 2. Measure the initial dissolved oxygen (DO) concentration using a dissolved oxygen meter or probe. This represents the initial oxygen content in the sample. 3. Incubate the BOD bottles in the dark at a controlled temperature (usually 20 °C) for a specific period (typically 5 days). This allows microorganisms in the sample to consume the organic matter, depleting the dissolved oxygen. 4. After the incubation period, measure the final DO concentration in the BOD bottle using the same method as step 2. 5. Calculate the BOD by subtracting the final DO concentration from the initial DO concentration. This represents the amount of oxygen consumed by the microorganisms during the incubation period. To compare the efficiency of extended aeration and conventional treatment in terms of BOD removal, you need to calculate the percent removal for each process. Here's how you can do it: 1. Determine the initial BOD concentration (BODi) in the influent of both treatment systems. 2. Measure the final BOD concentration (BODf) in the effluent of each treatment system. 3. Calculate the BOD removal efficiency for each system using the formula: BOD removal efficiency = ((BODi - BODf) / BODi) * 100 By comparing the BOD removal efficiency of extended aeration and conventional treatment, you can assess which process is more effective in reducing BOD levels in the effluent.