Limits for drinking water: 3 mg/l (ppm) as COD, 5 mg/l (ppm) as TOC
- Green or brown coloration of the water, possible odor, foaming
- Promotes the growth of microorganisms
Removal of COD
- Principle: adsorption, ion exchange
COD (chemical oxygen demand) and TOC (total organic carbon) values represent the amount of organic substances dissolved in water. They can get there naturally as waste produced by the organisms, or from decomposition of their tissues. For this reason, they occur mainly in surface waters. Another source is industrial waste water (especially the food industry). Increased COD value may represent a large variety of substances, and the impact on health depends mainly on their composition. But overall, organic substances are food for microorganisms which can than easily reproduce in the water distribution system and cause other health problems.
In order to reduce the content of organic substances, multifunctional solutions (improving multiple parameters) are used.
