Pharmaceutical residue

Removal of micropollutants such as pharmaceutical residue from wastewater

About a decade ago it became known that pharmaceutical residue in river water had caused fish to change sex. Recent studies show that pharmaceutical residue alters behavior of perch.

Many studies have concluded that waste waster contains micro pollutants like pharmaceutical residue. This water is released from our waste water treatment plants into the environment without proper treatment. Many countries in Europe are now taking political action to reduce the effects of the pharmaceutical residue. In Switzerland, for example, political decision will force 100 sewage plants to be equipped with systems to remove pharmaceutical residue.

Micropollutants in our waste water

Micropollutants are compounds of emerging concern that have been found in our waste water. All micro pollutants have in common that they are persistent and bioactive, examples include pesticides, hydrocarbones and biologically harmful metals (Pb, Hg, As) as well as PPCP’s (pharmaceuticals and personal care products like fragrances, cosmetics and sunscreen).

Why pharmaceutical residue in our waste water

Pharmaceuticals are not constructed to accumulate in the body – they are constructed to leave the body and are therefore released into the waste water. But they are also constructed to be persistent and break down very slowly in the nature. The bioactive nature of pharmaceuticals is another concern. Household sewage is the largest source of pharmaceutical effluent. Studies show that 70% of the pharmaceutical residue in our waste water comes from household use, while 20% comes from livestock farming and only 5% from hospital effluent.

Despite these facts, efforts are being made to reduce the effluent at hospitals. Primozone is part of a full scale project that is being conducted at the Herlev Hospital in Denmark where ozone is combined with other techniques to reduce pharmaceutical residue.

Ozone – the prevailing technique for pharmaceutical removal

Today most waste water treatment plants are not dimensioned to remove pharmaceutical residue. Estimates show that about 10% is eliminated at the treatment plants while 20% ends up in the sludge and as much as 70% ends up in the aquatic environment.

There are available techniques that efficiently reduce the level of pharmaceutical residue in our water. Conventional biological as well as mechanical treatment methods are not sufficient since a large part of pharmaceuticals are not degraded by these treatment methods. Ozone is a selective oxidant and primarily attacks electron rich structures in molecules, such as double bonds, and is therefore efficient in breaking down pharmaceuticals.

Ozone is a cost effective solution

With the Primozone ozone technology, ozone can be used to effectively remove pharmaceutical residue at a low cost. Many customers are positively surprised by the low cost per m3 water treated.

How efficient is ozone

Many studies show that up to 95% of the pharmaceutical residue can be removed with ozone, or even more depending on the dosage and retention time. A study performed by Primozone show that ozonation, preceded by filtration, will remove up to 95% removal with a 5 g O3/m3 water.

Studies also suggest that ozonation should be succeeded by sand filters to ensure an even more effective cleaning of the water.


  • Proven solution
  • Lowest carbon foot-print
  • Cost efficient treatment

Reduction of pharmaceutical residue

During the end of 2014 and the beginning of 2015 Primozone installed its pilot scale ozone system at 10 different wastewater treatment plants in the south of Sweden. The aim was to reduce pharmaceutical residue.

The unique approach of this study is that it was performed at 10 different waste water treatment plants with different process conditions and treatment methods as well as different population structure.

The results are unanimous with studies performed by others and confirms that ozone is a very potent solution for reduction of pharmaceutical residue (drugs residue) in waste water: up to 95% is removed.