Activated carbon for eliminating trace substances in wastewater treatment plants

Protecting our water resources is an essential task and vital for our society. On 1 April 2020, the first limits on pharmaceuticals were imposed in the water protection laws.

The challenge: Expanding the 4th treatment stage by 2035

In order to meet these legal requirements, the Cantons now have to knuckle down and push ahead with the expansion of the so-called 4th treatment stage or micropollutant elimination. No surprise, therefore, that the topic has become increasingly present in the ARA world in recent years. By 2035, up to 185 wastewater treatment plants in Switzerland will be busy equipping the 4th treatment stage.

The official site of the Federal Office for the Environment FOEN has more information about the selection criteria, financing and the Wastewater Fund. There are two processes that come into question above all: ozonation and activated carbon (or a combination of both).

These processes have to remove ≥ 80% of the 12 indicator substances listed below from the raw wastewater:

• Amisulpride - psychotropic
• Carbamazepine - antiepileptic
• Citalopram - antidepressant
• Clarithromycin - antibiotic
• Diclofenac - painkiller
• Hydrochlorothiazide - diuretic
• Metoprolol - beta blocker
• Venlafaxine - antidepressant
• Benzotriazole - corrosion inhibitor
• Candesartan - antihypertensive
• Irbesartan - antihypertensive
• Methylbenzotriazole – corrosion inhibitor