Application and Selection Tips of Defoamers in Industrial Wastewater Treatment

In industrial wastewater treatment processes such as papermaking, textile dyeing, chemical production, electroplating, and food processing, foam generation is a common issue. Excessive foam not only affects equipment operation but also reduces sedimentation, filtration, and biological treatment efficiency. Defoamers (Antifoam agents) play a key role in solving this problem. This article explains the application principles, common types, and selection tips of defoamers in wastewater treatment.

Why are defoamers needed in wastewater treatment?

     √ Prevent foam overflow in aeration tanks, flotation units, etc.

     √ Improve sedimentation efficiency by reducing foam interference with coagulants.

     √ Ensure effluent quality compliance by preventing foam from carrying pollutants.

Common types of industrial wastewater defoamers

Silicone-based defoamers

     √ Features: Low surface tension, fast defoaming, heat resistance.

     √ Applications: Papermaking wastewater, textile wastewater, chemical effluent.

Polyether defoamers

     √ Features: Good dispersibility, suitable for high-temperature and alkaline conditions.

     √ Applications: Electroplating wastewater, coal chemical wastewater, fermentation wastewater.

Mineral oil defoamers

     √ Features: Cost-effective, general wastewater treatment.

     √ Applications: Food processing wastewater, municipal sewage.

How to select the right defoamer for wastewater treatment?

     √ By wastewater type: Polyether defoamers are better for high-temperature/alkaline water; silicone-based defoamers for surfactant-rich wastewater.

     √ By process stage: Aeration tanks require persistent antifoam effects, while sedimentation tanks need fast defoaming.

     √ By cost-effectiveness and safety: Choose eco-friendly defoamers that do not inhibit microbial activity.

     √ Jar test validation: Always test dosage and type in small-scale trials before full application.

FAQ

Q1: What is the suitable dosage of defoamers in wastewater treatment?

A: Typically 10–100 ppm, depending on foam severity and water quality.

Q2: Do defoamers affect biological treatment?

A: High-quality defoamers do not inhibit microbial activity; choose eco-friendly, dispersible types.

Q3: What are the common types of industrial wastewater defoamers?

A: Silicone-based, polyether, and mineral oil defoamers.

Q4: Which industries commonly use defoamers in wastewater treatment?

A: Papermaking, textile, chemical, electroplating, and food processing.

Q5: What is the best method of dosing defoamers?

A: Continuous online dosing or key-point dosing ensures both effectiveness and cost efficiency.