What is the five-day BOD of normal domestic raw sewage?

The five-day biochemical oxygen demand (BOD) of normal domestic raw sewage is typically in the range of 200-250 mg/l. This measure reflects the amount of oxygen that microorganisms will consume while decomposing organic matter in a sample of water over a five-day period at 20 degrees Celsius. A BOD in this range indicates a moderate level of organic pollution present in domestic wastewater, making it a critical parameter for assessing the strength and treatment requirements for sewage.

Understanding this range is essential for wastewater treatment operations, as it helps in designing processes and predicting treatment efficiencies. This value also serves as a benchmark for comparing the organic content of various types of wastewater, allowing operators to develop appropriate treatment strategies based on the expected levels of pollution they will need to manage.