Definition

Chemical oxygen demand

The chemical oxygen demand (or COD) is the consumption of oxygen by strong chemical oxidants to oxidize organic and mineral substances in water.

The concentration at the end of the treatment process must be less than 125 mg/L.

Biological oxygen demand

Biochemical oxygen demand (BOD) is the amount of oxygen required to oxidize organic (biodegradable) matter by biological means (oxidation of biodegradable organic matter by bacteria).

On average, a person consumes 150 L of water per day and generates 60 g of BOD per day.

The concentration at the end of the treatment process must be lower than 25 mg/L.