Application of PRAESTOL 851

PRAESTOL 851 is a high-performance cationic polyacrylamide flocculant designed for efficient solid–liquid separation in municipal wastewater treatment, industrial effluent treatment, sludge thickening and dewatering, pulp and paper production, food processing, and other applications involving negatively charged suspended solids. With its balanced cationic charge density and high molecular weight, PRAESTOL 851 provides excellent floc formation, fast settling, strong floc structure, and enhanced water release, making it a reliable solution for demanding separation processes.

Flocculation Mechanism

The flocculation mechanism of PRAESTOL 851 is based on a combination of charge neutralization and polymer bridging. Most suspended solids present in wastewater and sludge systems—such as biological solids, organic matter, fibers, clay particles, and colloids—carry a negative surface charge. The positively charged polymer chains of PRAESTOL 851 adsorb onto these particles, neutralizing surface charges and reducing electrostatic repulsion.

Simultaneously, the long molecular chains of PRAESTOL 851 create bridges between multiple particles, forming large, dense, and shear-resistant flocs. This dual mechanism significantly improves sedimentation, clarification, thickening, and dewatering efficiency, even under high solids loading or variable operating conditions.

Municipal Wastewater Treatment Applications

In municipal wastewater treatment plants, PRAESTOL 851 is widely applied for:

• Primary sludge thickening

• Waste activated sludge (WAS) conditioning

• Mixed sludge dewatering

• Tertiary effluent clarification

PRAESTOL 851 improves floc strength and settling speed in gravity thickeners and clarifiers. When used in belt filter presses, centrifuges, or screw presses, PRAESTOL 851 increases cake solids content and produces clearer filtrate or centrate. These improvements reduce sludge volume, lower transportation and disposal costs, and contribute to stable, cost-efficient plant operation.

Industrial Wastewater Treatment Applications

PRAESTOL 851 is extensively used in industrial wastewater treatment systems with high concentrations of organic or mixed suspended solids. Typical industries include:

• Food and beverage processing

• Meat, poultry, and seafood processing

• Dairy, starch, and fermentation industries

• Textile and dyeing operations

• Chemical and pharmaceutical manufacturing

In these applications, PRAESTOL 851 efficiently flocculates organic solids, biological sludge, and colloidal matter, enabling rapid separation by sedimentation or mechanical dewatering. It is commonly used in combination with inorganic coagulants such as ferric chloride, aluminum sulfate, or polyaluminum chloride to optimize overall clarification and solids removal performance.

Sludge Thickening and Dewatering

One of the most important uses of PRAESTOL 851 is in sludge thickening and dewatering. It is suitable for use with a wide range of equipment, including:

• Gravity belt thickeners

• Rotary drum thickeners

• Belt filter presses

• Decanter centrifuges

• Screw presses and filter presses

PRAESTOL 851 enhances water release from sludge by forming firm, well-structured flocs that withstand mechanical shear during processing. Improved dewatering results in higher dry solids content, clearer filtrate, reduced polymer consumption, and lower overall sludge handling costs.

Pulp and Paper Industry Applications

In the pulp and paper industry, PRAESTOL 851 is applied for:

• Biological sludge dewatering

• Fiber and fines recovery

• Whitewater clarification

• Paper machine effluent treatment

The cationic nature of PRAESTOL 851 allows it to bind effectively with negatively charged cellulose fibers, fillers, and organic residues. This improves fiber retention, reduces solids loss, increases water reuse, and lowers the environmental impact of discharged effluent. Enhanced clarification also contributes to more stable paper machine operation.

Food Processing and High-Organic Sludge Treatment

PRAESTOL 851 is particularly effective for sludges with high organic content, which are often difficult to dewater due to their strong water-binding characteristics. In food processing and fermentation industries, PRAESTOL 851 improves floc cohesion and drainage behavior, leading to better dewatering efficiency and reduced sludge disposal volumes. This results in lower operating costs and improved environmental compliance.

Construction and Slurry Treatment

In construction, tunneling, and civil engineering projects, PRAESTOL 851 can be used to treat drilling and foundation slurries containing fine, negatively charged particles. The polymer promotes rapid aggregation and settling of suspended solids, allowing treated water to be reused on site. This improves water management efficiency and reduces the environmental impact of slurry discharge.

Compatibility and Process Integration

PRAESTOL 851 is compatible with most commonly used coagulants, pH adjustment agents, and other flocculants. It can be applied as a standalone flocculant or as part of a dual-chemical treatment program. Optimal performance depends on correct dosage, dosing point selection, adequate mixing, and sufficient reaction time. Excessive shear or over-mixing should be avoided to prevent floc degradation.

Dosage and Preparation

Typical dosage levels of PRAESTOL 851 range from 0.5 to 8 g/m³, depending on sludge characteristics, solids concentration, and equipment type. PRAESTOL 851 is usually prepared as a 0.05–0.3% aqueous solution using clean water. Adequate hydration time and gentle agitation are essential to fully activate the polymer and achieve consistent flocculation performance.