Application of Polydadmac Zetag 8165 and Zetag 8125

1. Product Overview

Zetag 8165 and Zetag 8125 are high-performance cationic polydadmacs produced by BASF, designed for water and wastewater treatment applications. Polydadmac, or poly(diallyldimethylammonium chloride), is a strongly cationic, water-soluble polymer with permanent quaternary ammonium groups, giving it a pH-independent positive charge. This property allows consistent performance in a wide range of water qualities and treatment processes.

Both Zetag™ 8165 and Zetag™ 8125 are supplied as liquid formulations, making them easy to dose in municipal, industrial, and process water systems. The primary function of these products is electrostatic charge neutralization, which destabilizes negatively charged colloids, organic matter, and suspended solids, enabling effective flocculation and removal.

While Zetag™ 8165 generally has a higher charge density compared to Zetag™ 8125, both products are suitable for coagulation, flocculation, and sludge conditioning, with selection depending on raw water characteristics and treatment goals.

2. Mechanism of Action

The main mechanism of action of Zetag™ 8165 and Zetag™ 8125 is charge neutralization. Most suspended solids and colloidal particles in water carry negative surface charges, which prevent aggregation. When a cationic polydadmac is added:

• The positive charges neutralize negative particle surfaces

• Electrostatic repulsion is reduced

• Fine particles aggregate into micro-flocs

• These flocs can be removed by sedimentation, flotation, or filtration

Zetag™ products can also act as coagulant aids for metal salts like aluminum sulfate or ferric chloride, improving floc formation, settling rates, and filtration efficiency. The permanent cationic charge ensures stable performance over a wide pH range, which is particularly beneficial in variable water qualities.

https://youtube.com/shorts/5vgTFKIrYZo

3. Municipal Drinking Water Treatment

Zetag™ 8165 and Zetag™ 8125 are widely used in municipal drinking water treatment for:

• Turbidity reduction

• Removal of natural organic matter (NOM)

• Color reduction

• Algae removal

• Filtration aid

In many water plants, polydadmac is used upstream of high-rate filters or in combination with traditional coagulants. Compared with inorganic coagulants alone, Zetag™ polydadmac:

• Reduces sludge volume

• Improves filter run times and backwash efficiency

• Lowers residual aluminum or iron

• Enhances overall water clarity

These properties make it highly suitable for high-turbidity surface waters or sources with high colloidal content.

4. Municipal and Industrial Wastewater Treatment

In municipal wastewater, Zetag™ 8165 and Zetag™ 8125 are used to:

• Improve primary clarification

• Reduce suspended solids (TSS) and turbidity

• Enhance phosphorus removal

• Aid secondary effluent polishing

For industrial wastewater, these polydadmacs are effective in:

• Textile effluents (color and fine solids removal)

• Pulp and paper mill effluents

• Food and beverage processing wastewater

• Metalworking or electroplating wastewater

They help destabilize colloidal suspensions and emulsified oils, improving the performance of downstream dissolved air flotation (DAF) or sedimentation units. Their rapid action and strong cationic nature make them ideal for high-flow industrial systems.

5. Sludge Conditioning and Dewatering

Zetag™ 8165 and Zetag™ 8125 are frequently used in sludge conditioning prior to mechanical dewatering:

• Fine particles and organic matter in sludge carry strong negative charges

• Zetag™ neutralizes these charges

• Flocs become denser, releasing bound water

• Dewatering efficiency improves

When used ahead of cationic or anionic polyacrylamides, Zetag™ polydadmac can:

• Reduce flocculant consumption

• Increase cake solids

• Improve filtrate clarity

• Lower overall sludge management costs

They are compatible with centrifuges, belt filter presses, and chamber filter presses.

6. Papermaking Applications

In papermaking and recycled fiber systems, Zetag™ 8165 and 8125 function as:

• Fixatives for anionic trash and colloidal substances

• Retention aids for fines and fillers

• Pitch and stickies control agents

• White water clarifiers

By improving retention and drainage, polydadmac enhances:

• Paper machine runnability

• Product quality

• Water and chemical recycling efficiency

Permanent cationic charge ensures consistent performance, even in recycled fiber systems with variable anionic content.

7. Mining and Mineral Processing

Polydadmac Zetag™ products are also applied in mining for:

• Tailings water clarification

• Thickener feed conditioning

• Process water recycling

Fine mineral particles often resist settling due to high surface charge. Zetag™ 8165 and 8125 destabilize these particles, forming aggregates that settle faster, resulting in:

• Clearer overflow water

• Enhanced water recovery

• More efficient recycling in mineral processing circuits

8. Advantages

Key advantages of Zetag™ 8165 and 8125 include:

• Permanent, high-density cationic charge

• Fast and reliable coagulation

• Effective across a wide pH and temperature range

• Low dosage requirements

• Reduced sludge generation

• Compatible with other coagulants and flocculants

• Easy liquid handling and dosing

9. Conclusion