Application of Polydadmac (PolyDADMAC)

1. Product Overview

Polydadmac, short for poly(diallyldimethylammonium chloride), is a strong cationic, water-soluble polymer widely used as a coagulant and flocculant aid. Unlike many other cationic polymers, polydadmac carries permanent quaternary ammonium charges, meaning its positive charge is independent of pH. This property gives polydadmac highly consistent performance across a broad range of operating conditions.

Polydadmac is typically supplied as a clear liquid with low to medium molecular weight and very high charge density. Its primary function is charge neutralization, making it particularly effective for destabilizing negatively charged colloids, fine particles, organic matter, and emulsified oils.

2. Mechanism of Action

The effectiveness of polydadmac is based on electrostatic charge neutralization. Most suspended solids and colloidal particles in water systems carry negative surface charges, which cause mutual repulsion and prevent aggregation.

When polydadmac is added:

• Its quaternary ammonium groups rapidly neutralize negative charges

• Electrostatic repulsion is eliminated

• Particles aggregate into micro-flocs

• These micro-flocs can then be removed by sedimentation, flotation, filtration, or further flocculation using high-molecular-weight polymers

Because polydadmac acts very quickly, it is often used as a primary coagulant ahead of flocculants to improve overall treatment efficiency.

3. Drinking Water Treatment

One of the most important applications of polydadmac is municipal drinking water treatment. It is used to remove:

• Turbidity

• Color

• Natural organic matter (NOM)

• Algae and microorganisms

Polydadmac can be applied:

• As a stand-alone organic coagulant

• As a coagulant aid with aluminum or iron salts

Compared with inorganic coagulants, polydadmac offers:

• Lower sludge production

• Reduced residual aluminum or iron

• Improved filter performance

• Effective operation over a wide pH and temperature range

Due to its consistent quality and NSF/ANSI compliance in many grades, polydadmac is widely accepted for potable water use.

4. Municipal Wastewater Treatment

In municipal wastewater treatment plants, polydadmac is commonly used in:

• Primary clarification

• Secondary effluent polishing

• Tertiary treatment processes

It helps remove suspended solids, colloidal organic matter, and fine particles that escape biological treatment. Polydadmac is also applied for chemical phosphorus removal, where it improves the aggregation of phosphate-containing precipitates, enhancing settling and filtration.

5. Industrial Wastewater Treatment

Polydadmac is extensively used in treating industrial effluents from:

• Textile and dyeing industries

• Chemical manufacturing

• Pulp and paper mills

• Food and beverage processing

• Metal finishing and electroplating

In these applications, it is effective for:

• Color removal

• Reduction of COD and turbidity

• Destabilization of emulsified oils

• Removal of fine inorganic and organic solids

Its fast action makes it particularly suitable for high-throughput systems and dissolved air flotation (DAF) units.

6. Sludge Conditioning and Dewatering

Polydadmac is often used as a pre-coagulant in sludge conditioning prior to mechanical dewatering. In sludge systems:

• Fine particles and organic matter carry strong negative charges

• Water is tightly bound within the sludge matrix

By neutralizing these charges, polydadmac:

• Releases bound water

• Improves floc structure

• Enhances drainage characteristics

When used ahead of polymer flocculants, it can significantly reduce flocculant dosage while improving cake solids, centrate clarity, and overall dewatering efficiency.

7. Papermaking and Pulp Processing

In the papermaking industry, polydadmac is widely used as a fixative and coagulant. Key applications include:

• Neutralization of anionic trash

• Fixation of dissolved and colloidal substances (DCS)

• Pitch and stickies control

• Retention of fines and fillers

Polydadmac improves:

• Paper machine runnability

• Product quality

• Chemical retention

• White water clarity

Its strong, permanent charge makes it especially effective in recycled fiber systems, where anionic contaminants are abundant.

8. Mining and Mineral Processing

In mining operations, polydadmac is used for:

• Tailings water clarification

• Thickener feed conditioning

• Process water recycling

Fine mineral particles often remain suspended due to electrostatic repulsion. Polydadmac destabilizes these particles, improving aggregation and settling. This leads to clearer overflow water and more efficient water reuse.

9. Oilfield and Energy Applications

Polydadmac is applied in oil and gas operations for:

• Produced water treatment

• Oily wastewater clarification

• Drilling waste treatment

It helps break oil–water emulsions, aggregate fine solids, and improve separation efficiency in flotation units, separators, and settling tanks.

10. Advantages of Polydadmac

Key advantages include:

• Permanent positive charge independent of pH

• Rapid coagulation performance

• Low dosage requirements

• Reduced sludge production

• Excellent compatibility with flocculants and inorganic coagulants

• Consistent performance under varying water quality conditions

• Easy handling due to liquid formulation