Biochemical oxygen demand (BOD) provides a measure of the impact of wastewater on the oxygen content of the receiving water body, and is an “estimate” of the “food” available in the sample. The more “food” present in the sample, the more oxygen is required, and the higher the BOD, the faster the oxygen is depleted from the water column. This means that less dissolved oxygen is available for aquatic life, which is subsequently stressed, suffocated and killed.
What is Biochemical Oxygen Demand (BOD)?
BOD (Biochemical Oxygen Demand) is the amount of dissolved oxygen required for microbial decomposition of organic matter contained in 1L of water under aerobic conditions, generally expressed in mg/L. The higher the BOD value, the more serious the pollution of the water body by organic matter.
COD and BOD
Like BOD, chemical oxygen demand (COD) can be used to estimate the amount of organic loading in a water sample. COD describes the amount of oxygen required for chemical decomposition of pollutants, while BOD indicates the amount of oxygen required for microbial decomposition of pollutants.
Why measure Biochemical Oxygen Demand?
BOD is an important water quality parameter that is widely used in the water treatment industry and environmental monitoring. When effluents are discharged into the environment, they introduce pollution in the form of organic matter into receiving waters. Biological Oxygen Demand (BOD) is commonly used in wastewater treatment plants as an indicator of the level of organic contamination in water. High concentrations of organic matter can deplete dissolved oxygen levels in water, leading to negative environmental and regulatory consequences.
To help determine the impact and ultimately limit the amount of organic pollution in water, BOD is an essential measurement. Total Organic Carbon (TOC) can also be used when related to BOD or COD.