Oxygen for Water Treatment
Oxygen is the most important oxidizing agent in water treatment. It plays a central role in the oxidation of iron, manganese, and other reduced substances in water. Furthermore, an adequate oxygen content is crucial for drinking water quality as well as for system stability and corrosion prevention. To form a sufficient protective layer (calcium carbonate scale layer) in the piping system, the oxygen content of the water should generally not fall below 5 to 6 mg O2/l.
The atmosphere consists of approximately 21% oxygen, 78% nitrogen, and about 1% other gases. Due to gravity, each of these gas components exerts its own pressure, known as the partial pressure. The sum of all partial pressures results in the total pressure of the gas mixture.
The solubility of a gas in water depends directly on its partial pressure. Since the partial pressure of oxygen in the air is only about 21% of the total pressure, the maximum achievable oxygen concentration during water aeration is also limited.
During aeration, oxygen and nitrogen are in equilibrium exchange with the water due to their different partial pressures and solubilities. The maximum achievable oxygen saturation with atmospheric aeration is approximately 12 mg O₂/l (8 °C) or 10 mg O₂/l (15 °C), depending on the water temperature. As the temperature rises, the solubility of oxygen decreases, resulting in lower saturation concentrations.
For applications with increased oxygen requirements, the use of oxygen
- can achieve up to 4.5 times higher saturation
- eliminates the need for energy-intensive mixing systems and large oxidizer tanks
- enables faster oxidation
- allows the aeration system to be significantly smaller in size.
For this reason, we use only technical oxygen for oxygen enrichment. This is produced on-site in high quality from compressed air using oxygen generators. The gas mixture is finely filtered through several stages of filtration and contains only a small amount of nitrogen. The correct dosage is achieved using a mass flow controller.
Oxygen mixing
Oxygen is mixed into the water with high efficiency using special Venturi/injector units. Oxygenation systems can be installed upstream of oxidizers or filtration systems, upstream of reaction tanks, or for pre-aeration in open-loop systems.
Oxygen generators are also used to produce oxygen for ozone generation.
Oxygen generation systems in three lines
Oxygen generators produce high-purity oxygen from conditioned compressed air. To ensure cost-effective operation, oxygen generation systems must always be designed to meet actual demand and specific process requirements.
High-quality compressed air treatment is essential for reliable oxygen production. In addition to drying the compressed air, this also includes the multi-stage separation of solids, oil components, and gaseous impurities.
We would be happy to assist you in calculating your oxygen requirements as well as in the design and configuration of an oxygen generation system optimally tailored to your process.
Please contact us — we will find the right solution for your application.