How to eliminate foam in wastewater?

I. Causes of Foaming in Wastewater:
Surfactants in water are prone to foaming.
Excessive growth of filamentous bacteria can cause bacterial flocs to entrain large amounts of air, forming a stable, difficult-to-remove scum foam on the water surface. Excessive growth of filamentous bacteria has been shown to be the primary cause of foaming.
Excessive fatty acids in wastewater, long sludge retention times, low sludge return rates, and low F/M ratios can lead to excessive growth of filamentous bacteria, resulting in foaming.

II. Hazards of Foam in Wastewater

It can affect the normal display of instruments, especially in wastewater treatment plants using DCS automation, and can cause system malfunctions. Ultrasonic level gauges can cause false liquid levels, and in severe cases, can cause pumps to run dry. Open channel flow meters used at the wastewater treatment plant's main outlet can lead to errors in the total outlet wastewater flow rate.
Large amounts of wastewater foam can form and spread onto the walkway slabs, disrupting normal maintenance. In winter, wastewater foam can freeze, making cleanup difficult. In summer, it can be blown by wind, creating unpleasant odors and seriously polluting the environment.
In processes using surface aeration equipment, the sticky nature of wastewater foam can prevent proper aeration and oxygenation, reducing the dissolved oxygen content of the mixed liquor.

Some wastewater foam can also enter the secondary sedimentation tank, increasing pollutants such as SS and CODcr in the discharged water. 

III. Wastewater Foam Solutions

Wastewater defoamers are composed of polyether, silica, dispersants, and stabilizers. They disperse quickly in water, offering excellent instantaneous defoaming and long-lasting foam suppression. They effectively eliminate and suppress foam generated during wastewater treatment without altering the water's oxygen content, preventing secondary water pollution. Even a minimal amount is required to achieve effective defoaming and suppress foam regeneration, making them a highly stable wastewater defoamer.