Ozone Strong Water Dosing: High-Efficiency Micropollutant Removal

The removal of anthropogenic micropollutants (pharmaceutical residues, micro-contaminants, and pesticides) is a major goal of modern wastewater plants. However, direct ozone (O3) gas injection häufig faces physical limitations: large bubbles lead to non-uniform gas entry, high off-gas losses, and local concentration spikes that trigger carcinogenic bromate formation. The innovative “Ozone Strong Water Dosing” process solves these challenges by separating the ozone dissolution stage from the target pollutant reaction.

The Chemical Engineering Principle

In classical ozonation, an ozone-oxygen gas mixture is directly diffused into the wastewater. Since ozone has limited solubility in water, a portion of the gas escapes unutilized into the exhaust air. Under the “Strong Water Dosing” scheme, pure oxygen (LOX-based) is ozonated and dissolved in a small, pressurized side-stream of clean water or filtered effluent. This creates a highly concentrated liquid ozone stream (concentrations of 50 to over 80 mg/L of dissolved ozone).

This “strong water” is then dosed into the main wastewater stream via static mixers and multi-port injection nozzles. Since the ozone is already completely dissolved, the gas-liquid mass transfer limitation in the main flow is entirely eliminated. The reaction with dissolved micropollutants occurs almost instantaneously and homogeneously.

Advantages Over Direct Gas Diffusion

1. Suppression of Bromate Formation

A major concern in bromide-rich wastewater is the formation of carcinogenic bromate (BrO3-). At the boundary layer of rising ozone gas bubbles, extreme concentration spikes oxidize bromide rapidly. Because Strong Water Dosing introduces no gas bubbles into the main stream, these local hot-spots are avoided, reducing bromate formation by up to 70%.

2. High Gas Efficiency and Lower Operating Costs

Since gas dissolution occurs under optimal, pressurized conditions in a closed sidestream, nearly all generated ozone dissolves in the water. Off-gas losses are minimized. This significantly reduces the oxygen demand of the generator, saving substantial power and reducing the cost of residual ozone destructors.

3. Simplified Retrofitting

Traditional ozone contact basins require deep concrete tanks (often > 5–6 meters water depth) to achieve sufficient hydrostatic pressure for gas dissolution. Strong Water Dosing does not require deep basins and can be easily retrofitted into existing pipelines or shallow contact tanks, lowering capital expenditure by up to 40%.

Conclusion

The Ozone Strong Water Dosing method developed by Dr. Markus Meier represents a milestone in industrial gas applications for environmental engineering. It combines highly efficient pollutant barriers with maximum process safety and resource efficiency, offering a scalable alternative for municipal and industrial plants planning a quaternary treatment upgrade.