A beautiful head belongs to a well pulled draft beer. Workers in sewage treatment plants like foam but only in the beer glass. In their sewage treatment plants foam always causes great technical problems.

Foam is formed when the surface tension of the water is reduced and air is incorporated by turbulence, when ventilated or when gas-forming reactions occur in the treatment process. Surface foam is easily recognized by foam bubbles. Enclosed air and gas bubbles are usually only noticed by their disrupting impact on the operational processes.

DefomStar® defoamers / deaerators are highly effective products available in various settings adapted to the application purpose. They positively support the wastewater treatment and sludge treatment process by foam prevention or foam control. In this process, the surface-active defoamer particles destabilize the foam bubbles on their surface and thus make them burst. The deaerator brings gas particles together to form larger bubbles, which easily rise to the surface and escape. Depending on composition each defoamer also has a more or less powerful deaerating effect, which must be taken into account when used in the various areas of waste water treatment plants.

Our special defoamer for wastewater treatment plants DefomStar® 300 L is a very effective defoamer and deaerator. It is very stable in its efficacy, so usually only one dosing point is sufficient to achieve a good defoamer effect throughout the whole system. The dosages are usually 5-50 ppm.

Usually DefomStar® 300 L is used either pure or as a highly diluted solution, whereby the optimum effect is only achieved at proper resolution and mixing. ACAT offers suitable dissolving and dosing systems for the optimal product preparation.

APPLICATION

The selection of the metering point is extremely important for the optimum effectiveness of the defoamer/deaerator. In gas-bearing treatment stages (due to technological reasons) defoamers / deaerators are only to be used after preliminary trials. Dosing points can be:

• Biology
• Effluent from the final clarification
• Digestion tank
• Spraying
• Dosing into the circulating line
• Sedimentation tank to vent before sedimentation
• Collecting pond

A distribution of the total metering quantity on several metering points might be advantageous. The most appropriate dosage is to be determined by operating tests. In the case of increased foam attack the dosage should be increased only in small steps.

Experience shows that overdosing does not increase the effect, but it can adversely affect the operating process. For carrying out laboratory and operational tests to select the right product for your individual application, our technical service is at your disposal at any time. This also applies to project planning and delivery of suitable manual, semi- and fully automatic dissolving and dosing systems.