BOD measures the amount of oxygen required by microorganisms to decompose organic material in wastewater over a specified time, typically five days. It is an indicator of the organic pollution level in water.
Microorganisms used in biological treatment thrive in a neutral to slightly alkaline pH range (6.5 to 8.5). Extreme pH levels can inhibit microbial activity and harm the treatment process.
Excess nitrogen in treated wastewater can lead to eutrophication, which causes algae blooms, oxygen depletion, and harm to aquatic ecosystems. Nitrogen is removed through processes like nitrification and denitrification.
In the activated sludge process, microorganisms break down organic matter, reducing BOD and converting it into water, carbon dioxide, and cellular biomass.
Chlorination is a common disinfection method that kills harmful pathogens in treated wastewater before it is discharged into the environment. Other methods include UV disinfection and ozonation.
