Application of Cationic Polyacrylamide PRAESTOL 851 DK

PRAESTOL 851 DK is a high-performance cationic polyacrylamide (CPAM) flocculant specifically formulated for advanced solid–liquid separation, sludge dewatering, and wastewater clarification. It is a dry powder product with high molecular weight and medium-to-high cationic charge density, which allows it to efficiently neutralize negatively charged particles and form strong polymer bridges. The combination of charge neutralization and bridging mechanisms provides rapid floc formation, excellent settling performance, and superior sludge dewatering capability. PRAESTOL 851 DK is widely applied in municipal wastewater treatment, industrial effluent clarification, sludge conditioning, papermaking, food and beverage processing, mining, and oilfield water treatment.

1. Municipal Wastewater Treatment

One of the primary applications of PRAESTOL 851 DK is in municipal sewage treatment plants, where it is used for clarification and sludge conditioning. Domestic wastewater contains colloidal organic matter, fine suspended solids, bacteria, and other negatively charged particles that settle poorly without chemical assistance. PRAESTOL 851 DK neutralizes these charges and aggregates the particles into large, dense flocs, enhancing sedimentation efficiency and producing clearer effluent.

In primary and secondary clarifiers, PRAESTOL 851 DK:

• Reduces total suspended solids (TSS)

• Improves turbidity removal

• Enhances settling rates

• Stabilizes effluent quality for downstream biological treatment

For sludge conditioning, PRAESTOL 851 DK is typically dosed ahead of mechanical dewatering equipment such as belt filter presses, centrifuges, screw presses, and plate-and-frame presses. It breaks the hydration layer around sludge particles, releasing bound water and forming dense, shear-resistant flocs. This leads to higher sludge cake dryness, lower sludge volume, reduced disposal costs, and improved operational efficiency of dewatering equipment.

2. Industrial Wastewater Treatment

PRAESTOL 851 DK is widely used in treating wastewater from textile and dyeing, chemical, pharmaceutical, electroplating, leather, metallurgical, and food processing industries. Industrial effluents often contain complex mixtures of dyes, surfactants, oils, colloids, and heavy metals that cannot be removed effectively through gravity settling alone.

Textile and Dyeing Industry

Textile wastewater contains reactive dyes, pigments, fibers, and surfactants that are negatively charged. PRAESTOL 851 DK promotes rapid aggregation of these particles into compact flocs, improving color removal, turbidity reduction, and overall effluent quality. The treated water exhibits lower chemical oxygen demand (COD) and higher clarity, which is essential for meeting environmental discharge standards.

Electroplating and Metal Processing

Electroplating wastewater typically contains heavy metals such as copper, nickel, chromium, and zinc. After chemical precipitation, fine metal hydroxide particles remain suspended and difficult to separate. PRAESTOL 851 DK effectively binds these particles, forming dense flocs that settle rapidly and improve filtration efficiency, ensuring compliance with stringent discharge limits.

Chemical and Pharmaceutical Industry

Chemical and pharmaceutical effluents contain fine organic particles, emulsions, and colloidal substances. PRAESTOL 851 DK enhances solid–liquid separation efficiency, reduces toxic and organic loading to downstream biological units, and stabilizes overall wastewater treatment performance.

3. Sludge Dewatering and Conditioning

Sludge dewatering is one of the most important application areas for PRAESTOL 851 DK. Activated sludge and industrial mixed sludge contain significant amounts of bound water, which is retained by negatively charged organic matter. PRAESTOL 851 DK works by:

• Neutralizing surface charges

• Breaking the hydration layer

• Forming dense, shear-resistant flocs

These effects result in faster filtration and centrifugation, higher sludge cake solids content, and reduced polymer consumption per ton of dry sludge. It is highly effective on activated sludge, biological sludge, oily sludge, and mixed industrial sludge, providing significant operational and cost benefits.

4. Papermaking Industry

In the pulp and paper industry, PRAESTOL 851 DK is used as a retention aid, drainage aid, and papermaking sludge dewatering agent. It improves the retention of fine fibers and fillers, such as calcium carbonate and kaolin clay, enhances drainage on the wire section, and contributes to improved paper strength, formation uniformity, and surface quality. For papermaking sludge, PRAESTOL 851 DK enhances dewatering efficiency, reduces energy consumption for drying, and lowers the cost of sludge disposal.

5. Food and Beverage Industry

PRAESTOL 851 DK is used in food and beverage wastewater treatment, including breweries, dairies, sugar and starch processing plants, and meat processing facilities. Wastewater from these processes contains high concentrations of suspended solids, proteins, fats, oils, and carbohydrates. PRAESTOL 851 DK aggregates these contaminants into flocs that can be efficiently separated using sedimentation, dissolved air flotation (DAF), or mechanical dewatering equipment. In DAF systems, it is often combined with inorganic coagulants such as polyaluminum chloride (PAC) to enhance flotation efficiency and scum removal.

6. Mining and Oilfield Applications

In mining, PRAESTOL 851 DK is applied to tailings thickening, mineral slurry clarification, and process water recovery. Fine mineral particles carry negative charges and remain suspended without chemical treatment. PRAESTOL 851 DK rapidly forms dense flocs, producing clear overflow water suitable for reuse and high-density underflow for tailings management. In oilfield water treatment, it effectively removes suspended solids, clay particles, and emulsified oils, facilitating reuse or environmentally compliant discharge.

7. Key Advantages

PRAESTOL 851 DK offers:

• High flocculation efficiency at low dosage

• Rapid formation of dense, shear-resistant flocs

• Superior sludge dewatering performance

• Broad applicability to municipal and industrial wastewater

• Compatibility with inorganic coagulants

• Reduced chemical consumption and sludge disposal costs

Conclusion

PRAESTOL 851 DK is a versatile and high-performance cationic polyacrylamide flocculant that provides outstanding performance in municipal wastewater treatment, industrial effluent clarification, sludge dewatering, papermaking, food and beverage processing, mining, and oilfield water treatment. Its strong charge neutralization, high molecular weight, and polymer bridging capabilities significantly enhance treatment efficiency, reduce chemical usage, and lower overall operating costs. With increasing environmental regulations and the need for sustainable water management, PRAESTOL 851 DK is a reliable and cost-effective solution for modern water and sludge treatment systems.