When to Choose Anionic PAM

Anionic PAM is commonly used when wastewater contains a high level of inorganic suspended solids. These particles often need polymer bridging to form larger and stronger flocs.

Anionic PAM is suitable for clarification and sedimentation systems where the main purpose is solid liquid separation.

Typical Applications

• Mining wastewater
• Coal washing wastewater
• Sand washing wastewater
• Stone processing wastewater
• Construction wastewater
• Paper making process water
• Some alkaline industrial wastewater

In these applications, the main purpose is usually solid liquid separation, sedimentation, clarification or thickening.

Anionic PAM can improve floc size, accelerate settling speed and reduce suspended solids in treated water.

When to Choose Cationic PAM

Cationic PAM is commonly used when wastewater or sludge contains a high level of organic matter.

Many organic particles, biological sludge particles, bacteria and colloids carry negative charge. Cationic PAM can neutralize these charges and help particles bind together.

Typical Applications

• Municipal sewage sludge dewatering
• Food factory wastewater treatment
• Printing and dyeing wastewater treatment
• Paper mill sludge dewatering
• Fermentation wastewater treatment
• Slaughterhouse wastewater treatment
• Chemical and organic wastewater treatment

In these applications, the main purpose is often sludge conditioning, dewatering, organic solids capture and reduction of sludge volume.

Anionic PAM for Neutral and Alkaline Conditions

Anionic PAM usually performs better under neutral to alkaline conditions.

When the pH is above 7, the molecular chain can extend more effectively, which improves adsorption and bridging performance.

In some applications, anionic PAM can still work well under strong alkaline conditions, such as pH 10 to 12. This makes it suitable for mineral processing, coal washing and sand washing wastewater systems.

Cationic PAM for Neutral and Acidic Conditions

Cationic PAM is usually more suitable for neutral to acidic conditions.

Its positive charge can effectively interact with negatively charged organic particles and sludge solids.

For strong alkaline wastewater, the performance of cationic PAM may be affected. In this case, pH adjustment or another PAM grade may be required.

Anionic PAM

Anionic PAM usually requires a longer dissolution time, especially for high molecular weight products. The common stirring time is about 40 minutes to 1 hour.

Cationic PAM

Cationic PAM usually dissolves faster, and the common stirring time is about 30 minutes.

Step 1

Use clean water and start the mixer first.

Step 2

Slowly add PAM powder into the moving water.

Step 3

Do not pour the powder directly in large amounts.

Step 4

Use a low concentration solution for easier dissolution and more uniform dosing.

For Sludge Dewatering

Choose cationic PAM in most cases. Cationic PAM can improve sludge floc strength, release water from sludge and help form a drier sludge cake.

It is commonly used for municipal sludge, biological sludge, paper mill sludge and organic industrial sludge.

For Sand Washing and Coal Washing Wastewater

Choose anionic PAM in most cases. Anionic PAM can help suspended solids settle quickly and improve water recycling efficiency.

It is suitable for wastewater with high suspended solids and mineral particles.

For Food Wastewater

Cationic PAM is often used because food wastewater usually contains organic matter, oil, protein, starch and biological solids.

It can help capture organic particles and improve solid liquid separation.

For Paper Making

Both anionic PAM and cationic PAM may be used depending on the process.

Anionic PAM can be used for retention, drainage and fiber flocculation. Cationic PAM can be used for sludge dewatering or charge adjustment.

For Oilfield Applications

Anionic PAM is commonly used as a viscosifier, thickener, drilling fluid additive and enhanced oil recovery polymer.

It can help improve fluid viscosity and support oilfield production processes.

Is anionic PAM or cationic PAM better?

There is no universal answer. Anionic PAM is better for many inorganic suspended solids and alkaline wastewater. Cationic PAM is better for organic wastewater and sludge dewatering.

Why does PAM form lumps during dissolution?

PAM may form lumps when the powder is added too fast, the concentration is too high, or the mixing is not uniform. PAM powder should be added slowly into moving water.

Can cationic PAM be used for alkaline wastewater?

Some cationic PAM grades may work in mildly alkaline conditions, but strong alkaline wastewater may reduce performance. Jar testing is recommended.

What is the best PAM for municipal sludge dewatering?

Cationic PAM is usually selected for municipal sludge dewatering because it can neutralize negatively charged sludge particles and improve water release.

What information is needed to select the right PAM?

Important information includes wastewater type, pH value, suspended solids content, organic content, treatment process, sludge type, target result and current chemical dosage.

Can one PAM product be used for all wastewater?

No. Different wastewater types require different PAM products. The suitable ionic type, molecular weight and ionic degree should be selected according to actual wastewater conditions.