BOD Loading

10/21/25

“How can we quantify the amount of organic matter entering a treatment system over time?”

Every day, wastewater treatment plants use microorganisms to break down organic matter in water. Plant operators need to estimate how much organic matter is entering a treatment system over time to design their system properly. But how can we do this? Well, we know that we already have a unit, biological oxygen demand, to estimate organic pollutant concentration. And we know that the influent water stream will contain a certain concentration of organic contaminants. So what if we were to multiply the influent volume flow by its BOD concentration (milligrams of oxygen microorganisms need to use to consume pollutants per liter)? Well, this will give us a variable called BOD Loading, measured in mass of oxygen needed for pollution cleaning per time, that plant operators can use for design calculations.