Drinking water production with oxygen
Waterworks that treat groundwater must almost always remove iron and manganese to prevent deposits in the pipelines. To this end, iron and manganese are oxidised with oxygen and retained as insoluble oxide particles in filters. Stoichiometrically, the oxidation of iron and manganese requires only small amounts of oxygen. This is therefore often carried out with air oxygen unless the ground water is already oversatured with nitrogen. If groundwater also contains ammonium, this can also be oxidised in the filters if sufficient oxygen is dissolved in the water. However, aeration rapidly reaches its limits here.
Many waterworks use pure oxygen instead of compressed air. Pure oxygen has an almost five-fold higher solubility in water then air-oxygen (see figure). Therefore, it is easy to achieve high oxygen enrichments of 20 mg/l and more with pure oxygen, and increased ammonium contents can also be safely oxidised.
Oxygen and the Oxysolv process from Messer have many advantages compared to pressurised aeration:
- High oxygen enrichment possible; increased ammonium values can also be safely oxidised
- Longer filter life
- No “white water“ at customer
- Good for drinking water quality: pure oxygen is cleaner than air
- Unwanted stripping of CO2 from groundwater is avoided
- Low investment and operating costs
For the rapid and complete dissolution of O2, Messer supplies diverse, widely tested technologies, varying from fine-bubble feed directly into the main water stream to complete dissolution in a side stream under hydraulically defined conditions. In each project, we specify the feed method that best fits the local conditions.