Application of Polydadmac AF 4120 and AF 4140

1. Introduction to AF 4120 and AF 4140

AF 4120 and AF 4140 are cationic polydiallyldimethylammonium chloride (PolyDADMAC) polymers, widely employed in municipal and industrial water and wastewater treatment. Polydadmac is a high-charge-density cationic coagulant that functions primarily through charge neutralization. This mechanism enables it to destabilize negatively charged colloidal particles, natural organic matter (NOM), algae, fine suspended solids, and emulsified contaminants.

Unlike high-molecular-weight polyacrylamides, which primarily act via bridging mechanisms, AF 4120 and AF 4140 are highly effective in destabilizing small colloids and fine particles, making them ideal for both drinking water clarification and industrial effluent treatment. These polymers are supplied as liquid concentrates, which facilitates easy dosing and integration into various water treatment processes.

2. Municipal Drinking Water Applications

2.1 Raw Water Clarification
AF 4120 and AF 4140 are widely used as primary coagulants in municipal water treatment plants. Surface waters often contain fine clay, silt, algae, and NOM that carry negative charges, making them resistant to settling.

• When dosed in rapid-mix or inline-mix zones, AF 4120 and AF 4140 neutralize colloidal charges, forming microflocs that settle efficiently in sedimentation basins.

• Turbidity is reduced, and downstream filtration is enhanced, improving water clarity and plant reliability.

2.2 Coagulant Aid

• Often used with alum, ferric chloride, or polyaluminum chloride (PAC).

• Enhances floc formation, reduces inorganic coagulant dosage, and minimizes sludge production.

• Provides denser flocs and faster settling rates, improving clarifier performance.

2.3 Color and Organic Matter Reduction

• Effectively removes humic and fulvic acids, which contribute to color and act as DBP precursors.

• Reduces formation of trihalomethanes (THMs) and haloacetic acids (HAAs) during disinfection.

2.4 Seasonal Turbidity and Algal Control

• AF 4140, with higher charge density, is particularly effective during algal blooms or seasonal turbidity spikes.

• Reduces filter headloss and ensures stable water treatment operations.

3. Municipal Wastewater Applications

3.1 Primary Clarification Enhancement

• AF 4120 and AF 4140 enhance primary clarifier performance by accelerating the settling of suspended solids, fats, oils, and grease (FOG).

• Polymers neutralize colloidal charges, forming denser, faster-settling flocs, which improve overall sedimentation efficiency.

3.2 Sludge Conditioning and Dewatering

• Applied upstream of gravity thickeners, belt filter presses, or centrifuges.

• Neutralizes particle charges in sludge, promoting aggregation and improving free water release.

• Often used in combination with high-molecular-weight polyacrylamides to optimize cake dryness and reduce overall polymer consumption.

3.3 Secondary Clarification Support

• Enhances the removal of fine suspended solids escaping primary treatment.

• Reduces load on biological treatment units and improves plant stability.

4. Industrial Wastewater Applications

4.1 Food and Beverage Industry

• Clarifies wastewater containing proteins, fats, oils, and fine suspended solids.

• Destabilizes emulsified oils and organic matter, facilitating separation and reducing chemical oxygen demand (COD) prior to biological treatment.

4.2 Pulp and Paper Industry

• Removes fiber fines, fillers, inks, and dissolved organics from effluent streams.

• Enhances dissolved air flotation (DAF) efficiency, reduces residual turbidity, and improves water recovery.

4.3 Textile and Dyeing Industry

• Neutralizes negatively charged dyes and surfactants, improving color and solids removal.

• Promotes sedimentation of colloidal solids, supporting downstream clarification processes.

4.4 Oil, Gas, and Petrochemical Effluent

• Breaks emulsified oils and destabilizes fine suspended solids.

• Supports the performance of API separators, flotation units, and secondary clarifiers.

5. Key Operational Advantages

• Rapid coagulation due to high cationic charge density.

• Versatility: effective across a broad pH range and varying water qualities.

• Reduced sludge volume compared to inorganic coagulants.

• Improved downstream operations: enhances filtration, dewatering, and sludge handling.

• Ease of dosing as a stable liquid concentrate compatible with standard injection systems.

• Environmental compliance: reduces the use of metal salts and associated residuals.

6. Typical Dosing and Integration

• Typical dosage range: 0.5–10 mg/L, depending on raw water or wastewater characteristics.

• Can be applied alone or in combination with inorganic coagulants.

• Injection points include rapid-mix basins, inline injection systems, or pre-clarifier feed.

• Often paired with anionic or nonionic flocculants for enhanced floc formation and improved sludge dewatering.

Grade Selection Guidelines:

• AF 4120 – Medium-charge polymer for routine municipal water and wastewater clarification.

• AF 4140 – Higher-charge polymer suitable for high turbidity, color, or algae-impacted waters.

7. Summary

Polydadmac AF 4120 and AF 4140 are high-performance cationic polymers that improve water and wastewater treatment by rapidly destabilizing colloids and organic matter. They are suitable for municipal drinking water clarification, municipal wastewater treatment, and industrial effluent applications. By selecting the appropriate grade, operators can optimize sedimentation, filtration, and sludge dewatering processes, reduce chemical usage, minimize sludge volume, and achieve consistent water quality. Their liquid formulation ensures easy handling, flexible dosing, and compatibility with existing treatment chemicals, making them reliable solutions for a wide range of treatment scenarios.