Harvest Your Future: Ace the 2025 Agricultural Engineering Exam!

The acceptable range of Biochemical Oxygen Demand (BOD5) for wastewater reuse in irrigation is less than 50 mg/L. This threshold is crucial because BOD5 measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water over a specific period, typically five days. When using wastewater for irrigation, particularly in agricultural settings, maintaining a low BOD5 is vital to ensure that the water is of good quality.

A BOD5 level lower than 50 mg/L indicates that the wastewater is treated adequately and contains minimal amounts of organic material. High levels of BOD can lead to environmental issues such as eutrophication, where nutrient overload causes excessive growth of algae that deplete oxygen in water bodies. Additionally, irrigation with high BOD sewage could harm plants and soil health due to potential pathogen risks and toxicity from organic compounds. Thus, establishing this low BOD5 limit promotes sustainable agricultural practices and safeguards public health.