Aerial photo of Convoy WWTP

Compliance with licence treatment standards

The urban waste water treatment directive sets the basic standard that discharges from waste water treatment plants must meet.  The EPA issue licences that are more detailed and may specify stricter standards where needed on a site specific basis to protect the local environment. 

41% of Irish Water’s treatment plants met the licence treatment standards in 2020, down from 45% in 2019.  The slight decrease in compliance may be due to more stringent emission limit values which commenced for a number of licences at the end of 2019.

  

 

Compliance with licence discharge limits

Ortho-phosphate compliance

Excessive amounts of nutrients such as ortho-phosphate can cause pollution in rivers and lakes. The EPA sets standards in our licences for the amount of ortho-phosphate that may be released into the water environment. If effluent doesn’t meet these standards it may lead to excessive and unwanted growth of algae and aquatic plants.

The graph below shows the percentage of Irish Water's treatment plants that complied with the ortho-phosphate standards in their licences. Almost two thirds (65%) of treatment plants met the standards in 2020, a decrease since 2019. The decrease in compliance may be due to more stringent standards which came into force for some licences in 2020.

Ortho-P Compliance

BOD

Biochemical Oxygen Demand (BOD) is one of the key parameters to assess the polluting potential of waste water. BOD measures the amount of oxygen used up (demanded) to break down and get rid of polluting matter in the effluent. The EPA sets standards in our licences for BOD that may be released into the water environment. If effluent doesn’t meet these standards it may lead to a drop in the oxygen levels in the receiving waters, which could harm aquatic life and biodiversity.

The graph below shows the percentage of Irish Water's treatment plants that complied with the BOD standards in their licences. Over three quarters (77%) of treatment plants met the standards in 2020, a slight increase since 2019.

 

BOD Compliance