Application of Anionic Polyacrylamide (NALCO 7757)

NALCO 7757, also known as ULTIMER 7757, is an anionic polyacrylamide-based liquid flocculant formulated for water and wastewater treatment. It belongs to the Ultimer® series from Nalco Water (Ecolab), designed for fast inversion in water, easy handling, and high flocculation efficiency. As an anionic emulsion polymer, NALCO 7757 provides excellent clarification, solid–liquid separation, and sludge dewatering performance in municipal and industrial systems.

1. General Characteristics

NALCO 7757 is a liquid dispersion polymer with the following typical indices (from product data references):

• Physical form: White, opaque, oil-free emulsion.

• Ionic type: Anionic.

• Specific gravity: 1.19 – 1.22 g/cm³.

• pH (neat): 3.8 – 4.2.

• Viscosity: 300 – 1200 cP.

• Solubility: Fully soluble in water, rapid inversion.

• Active content: Approximately 35–40%.

The polymer’s high molecular weight and controlled anionic charge density make it particularly effective for flocculating negatively charged colloids and fine particles under neutral to alkaline conditions.

2. Application in Water and Wastewater Treatment

The main application of NALCO 7757 is in industrial and municipal water treatment as a flocculant or coagulant aid.

a. Raw Water Clarification

In raw water treatment (e.g., river or reservoir water), NALCO 7757 enhances particle aggregation and sedimentation when used after inorganic coagulants such as alum, ferric chloride, or polyaluminum chloride (PAC). It binds fine suspended solids and colloids, forming dense, fast-settling flocs. The result is improved turbidity removal and higher filtration rates in sand or multimedia filters.

b. Wastewater Clarification

In industrial wastewater, especially from chemical, food processing, textile, and mining industries, NALCO 7757 is applied to remove suspended solids, organic matter, and pigments. The anionic polymer acts through both charge neutralization and bridging mechanisms. It improves settling in clarifiers, flotation units, and thickeners, producing clearer supernatant suitable for discharge or reuse.

c. Sludge Thickening and Dewatering

NALCO 7757 is widely used for sludge dewatering in wastewater plants. It increases the size and density of sludge flocs, improving drainage in centrifuges, belt presses, and filter presses. By enhancing water release, it reduces sludge volume, disposal costs, and drying energy requirements. This property makes it particularly effective for biological and chemical sludges with moderate to high organic content.

3. Application in Industrial Sectors

a. Power Plants and Cooling Systems

In power generation plants, NALCO 7757 is used in cooling water and process water treatment systems. It helps remove suspended solids and metal oxides in make-up water and aids in the recovery of clear water from ash or sludge ponds.

b. Mining and Mineral Processing

The anionic polyacrylamide structure of NALCO 7757 makes it suitable for mineral processing applications, such as tailings thickening, clarification, and solid–liquid separation. It promotes the rapid settling of fine clays, silts, and metal hydroxides, leading to higher-quality process water recovery. It is particularly useful in coal washing, alumina production (red mud settling), and phosphate beneficiation.

c. Pulp and Paper IndustryNALCO 7757

In papermaking, NALCO 7757 acts as a retention and drainage aid. It improves the retention of fillers and fibers on the wire section and accelerates dewatering. It also assists in white water clarification and sludge thickening in paper mill effluent treatment systems.

4. Application Advantages

The use of NALCO 7757 offers several practical and operational benefits:

• Fast dissolution and easy feed: As an Ultimer® emulsion, it inverts rapidly in water without the need for external oil removal or surfactants.

• Enhanced floc strength: Produces robust, shear-resistant flocs that maintain integrity through mechanical handling.

• High efficiency: Requires lower dosages compared with inorganic coagulants or low molecular weight polymers.

• Wide pH tolerance: Performs effectively under neutral to alkaline conditions.

• Improved sludge dewatering: Lowers cake moisture content and increases throughput.

• Reduced chemical consumption: Works synergistically with alum, PAC, or ferric salts, minimizing overall coagulant dosage.

5. Application Methods

NALCO 7757 is generally applied as a 0.1–0.5% aqueous solution, prepared by inverting the emulsion into water under mild agitation. It can be fed continuously into clarifiers, thickeners, or dewatering units through a metering pump. The optimal dosage depends on system characteristics such as solids concentration, particle charge, and water chemistry, but typical use levels range from 1–10 mg/L for clarification and 1–5 kg/t DS (dry solids) for dewatering.

6. Environmental and Operational Safety

NALCO 7757 is non-toxic, non-corrosive, and environmentally safe when properly handled. It does not introduce hazardous residues into treated water. The product’s stability and long shelf life make it suitable for automated dosing systems and long-term industrial use.

7. Summary

In summary, NALCO 7757 (Ultimer 7757) is a high-performance anionic polyacrylamide emulsion designed for solid–liquid separation in water treatment, industrial effluent management, and sludge dewatering. Its balanced charge density, high molecular weight, and fast inversion properties deliver efficient flocculation, reduced turbidity, and improved sludge handling. The product is widely applied across municipal, industrial, mining, and papermaking sectors, where it consistently provides clearer water, lower chemical consumption, and enhanced operational efficiency.