Ozon Biofiltration
High-molecular-weight organic humic substances contribute to increased discoloration of water. These compounds consist primarily of carbon, hydrogen, and oxygen, with traces of nitrogen and sulfur. Their chromophoric structures absorb specific wavelengths of visible light, resulting in a yellowish to brownish tint.
Ozonation followed by biofiltration has proven to be an effective method for the targeted removal of these color-causing substances.
Ozone biofiltration is a proven method for treating water containing humic substances. The process is based on natural mechanisms.
Under the influence of ozone as a strong oxidizing agent, high-molecular organic carbon compounds are broken down into low-molecular fragments. Some of these degradation products are biologically available and can be further degraded in the downstream biofiltration stage by microbiological processes.
Simultaneously, the change in the chromophoric structures leads to a significant reduction in color, as shown in the graph. The blue curve shows the raw water color, the red curve shows the purified water.
Natural organic matter
The content of natural organic matter (NOM) is important if water is to be used for drinking water supply. The NOM concentration is analytically determined as the sum of dissolved organic carbon (DOC). DOC is also responsible for the coloration of water.
Water with elevated DOC levels should not be used for drinking water supply without water treatment. Even supposedly stable waters can be prone to high levels of contamination after oxidative water treatment (e.g., dosing of disinfectants). Relevant parameters for the dimensioning of a treatment plant are DOC/TOC. In turbidity-free water, TOC is almost identical to DOC.
Coloration
The coloration of the water depends on the DOC, but does not correlate with it. Thus, water with low DOC can show high coloration, while water with high DOC can show comparatively low coloration. Ozonation breaks down the coloring substances and reduces the coloration of the water by 80 to 95%. Decolorization occurs very quickly and is directly dependent on the ozone dose.
The particular advantage of the ozon biofiltration process is the high level of environmental friendliness, since unlike with nanofiltration systems and reverse osmosis, virtually no environmentally harmful substances must be used.
However, neither can the process be used for all water, and it may have to be treated in two stages.
We would be happy to assist you in designing a system. In addition to the specification of the hydraulic values, a complete water analysis is essential for the project planning. A question sheet checklist is available in the download area.
Further information is available on request or can be found in the specialist reports on drinking water treatment in the Media Centre.