What is Chemical Oxygen Demand?

 

Chemical Oxygen Demand (COD) is used as a measure of organic pollutants in water and is expressed in milligrams per litre (mg/L) or parts per million (ppm).

The most common application of COD is in quantifying the amount of oxidisable pollutants found in water. A COD test can be used to decipher the level of organics in water.

Regulators enforce limits on the maximum amount of COD allowed in wastewater before it enters the environment and the local utility provider stipulates levels for effluent going to sewer. Businesses which use water in their manufacturing processes must be mindful of the level of COD in their wastewater, or risk being forced to pay strict fines.

COD can be split into two types – non-biodegradable and biodegradable.

The Nyex™ processes specialise in the non-biodegradable category, as the biodegradable type tend to be broken down using a simple biological treatment process. Non-biodegradable compounds tend to be recalcitrant in nature, requiring a more advanced tertiary process to remove.

 

Chemical Oxygen Demand

 

 

 

Non-biodegradable COD

 

Biodegradable COD (BOD)

 

Pharmaceuticals

 

Persistent organic pollutants

 

Industrial chemicals

 

Pesticides*

 

Organic additives

 

Aliphatic compounds**

 

Aromatics**

 

Fatty acids

 

Proteins

 

Alcohols

 

Sugar

 

 

 

 

*Agrichemical companies are making strides to produce biodegradable pesticides, but the majority are still non-biodegradable.

**There are a few non-biodegradable aliphatic compounds and aromatics – the Nyex™ process is suited to both types.

 

What products do Arvia offer?

 

Nyex Rosalox

Nyex Ellenox

What are the benefits of COD reduction?

 

Reducing COD levels positively affects the environment by reducing the amount of contamination which enters our water supplies. It also helps organisations avoid fines from utilities or regulatory bodies.

Manufacturers must also adhere to strict limits of Chemical Oxygen Demand (COD) for wastewater which is to be discharged into the environment. Failure to comply with local limitations set for colour and/or Chemical Oxygen Demand (COD) can result in loss of permit, operational downtime, limited production volume and severe fines, not to mention reputational and environmental damage.

By adopting a wastewater treatment process which has the ability to remove low to trace levels of organics, you can meet regulations and prove commitment to the protection of the environment.