COD relates to almost anything containing a carbon atom – in simple terms, this includes anything that has lived or is alive and therefore food and drink ingredients, paper, plastic, leather, pharmaceuticals etc.

There is always a consent level for COD when discharging trade effluent, this must be met to avoid potential prosecution and associated fines.

COD also forms part of the MOGDEN formula – the method used to calculate your trade effluent charges when discharging to a water company.

Therefore, reducing COD to meet consent has a direct cost saving against the MOGDEN formula.

There are two types of COD:

• Insoluble COD - which can be removed via filtration and/or flotation and/or settlement.
• Soluble COD – this is dissolved and cannot be seen by the naked eye and requires biological treatment to be removed from water.

Note – when discharging to a water course, Biological Oxygen Demand (BOD) is often quoted.