Floquat FL4520 and Floquat FL4820 are liquid polydadmac (poly diallyl dimethyl ammonium chloride) cationic polymers widely used as organic coagulants in water treatment, wastewater treatment, papermaking, mining, and industrial separation processes.
These products belong to the Floquat series, which are high-charge density polymers designed for strong charge neutralization, fast coagulation, and efficient removal of suspended solids, color, and organic matter.
Because of their high cationic charge, FL4520 and FL4820 are often used as primary coagulants or coagulant aids together with PAC, alum, ferric salts, or polyacrylamide.

Below is a detailed explanation of the applications of Floquat FL4520 and Floquat FL4820 (about 889 words).

1. Drinking water treatment

One of the main applications of Floquat FL4520 and FL4820 is in drinking water purification.
These polydadmac polymers are used to remove turbidity, natural organic matter, algae, and fine suspended solids from raw water.

Typical water sources:

• River water
• Reservoir water
• Lake water
• Surface water
• Groundwater

Functions:

• Neutralize negatively charged particles
• Improve coagulation efficiency
• Reduce turbidity
• Remove color
• Remove organic matter
• Improve sedimentation

FL4520 and FL4820 are often used together with:

• PAC (polyaluminum chloride)
• Aluminum sulfate
• Ferric chloride
• Polyacrylamide

Advantages:

• Fast reaction speed
• Low dosage
• Works at wide pH range
• Less sludge production
• Stable performance in low temperature water

Because of high charge density, these polymers are very effective for raw water with high organic content.

2. Municipal wastewater treatment

Floquat FL4520 and FL4820 are widely used in municipal sewage treatment plants for primary clarification and tertiary treatment.

Applications:

• Primary sedimentation tank
• Secondary clarifier improvement
• Tertiary polishing
• Phosphorus removal
• Effluent clarification

Functions:

• Coagulate suspended solids
• Remove COD / BOD
• Remove oil and grease
• Improve settling
• Improve filtration

Typical treatment sequence:

1. Floquat FL4520 / FL4820 → coagulation
2. Polyacrylamide → flocculation
3. Sedimentation / filtration

Benefits:

• Larger flocs
• Faster settling
• Clear effluent
• Reduced chemical cost

These products are suitable for wastewater containing:

• Fine particles
• Biological sludge
• Colloids
• Organic matter

FL4820 usually has higher charge density and is often used when stronger coagulation is required.

3. Industrial wastewater treatment

Floquat FL4520 and FL4820 are widely used in industrial wastewater treatment, especially when water contains color, oil, or high organic load.

Industries:

• Textile and dyeing
• Paper mills
• Chemical plants
• Petrochemical plants
• Steel industry
• Electronics factories
• Pharmaceutical plants
• Food processing

Functions:

• Decolorization
• Suspended solids removal
• Oil removal
• COD reduction
• Heavy metal removal (with coagulant)

Polydadmac is very effective for dye wastewater because dye molecules are usually negatively charged.

Advantages:

• High efficiency
• Low dosage
• Fast coagulation
• Works at low temperature
• Compatible with PAC / PAM

FL4820 is often selected for high-color wastewater because of stronger charge.

4. Sludge conditioning and dewatering

Floquat FL4520 and FL4820 are commonly used for sludge conditioning before dewatering.

Used in:

• Belt filter press
• Centrifuge
• Screw press
• Filter press
• Gravity thickener

Functions:

• Neutralize sludge charge
• Improve floc formation
• Reduce sludge volume
• Increase cake dryness
• Improve filtration speed

Often used with cationic polyacrylamide.

Process:

1. Floquat → coagulation
2. CPAM → flocculation
3. Dewatering → dry cake

Benefits:

• Better dewatering
• Lower polymer consumption
• Faster filtration
• Stable operation

Suitable for:

• Municipal sludge
• Paper sludge
• Chemical sludge
• Food sludge
• Biological sludge

5. Paper and pulp industry

Floquat FL4520 and FL4820 are widely used in the paper industry as fixing agents and charge control agents.

Applications:

• Retention aid
• Fixing agent
• Trash control
• Pitch control
• Fiber retention
• White water clarification

Functions:

• Fix fines and fillers
• Improve drainage
• Improve paper strength
• Reduce chemical loss
• Improve machine efficiency

Used in:

• Tissue paper
• Kraft paper
• Packaging paper
• Recycled paper
• Printing paper

Polydadmac is especially useful in recycled paper systems because it neutralizes anionic trash.

These polymers are often used together with:

• Polyacrylamide
• Bentonite
• Starch
• PAC

6. Mining and mineral processing

Floquat FL4520 and FL4820 are used in mineral beneficiation and tailings treatment.

Applications:

• Tailings clarification
• Thickener overflow
• Slurry coagulation
• Water recycling
• Clay removal

Functions:

• Neutralize fine particles
• Improve settling
• Improve flocculation with PAM
• Clarify water

Typical combination:

Floquat + anionic polyacrylamide

Benefits:

• Faster settling
• Clear overflow
• Less water loss
• Better thickening

Used in:

• Coal washing
• Iron ore
• Gold processing
• Phosphate beneficiation
• Sand washing

FL4820 is often used when particles are very fine.

7. Textile and dye wastewater treatment

One of the most important uses of Floquat FL4520 and FL4820 is decolorization of dye wastewater.

Functions:

• Remove dye color
• Reduce COD
• Remove suspended solids
• Improve clarification

Advantages:

• Strong charge neutralization
• High color removal
• Low dosage
• Fast reaction

Used in:

• Printing wastewater
• Dyeing wastewater
• Pigment wastewater

FL4820 is commonly used for strong color removal.

8. Oilfield and refinery wastewater

Floquat FL4520 and FL4820 are used in oil & gas and refinery wastewater treatment.

Applications:

• Produced water
• Oily wastewater
• Drilling fluid treatment
• Refinery wastewater

Functions:

• Break emulsions
• Remove oil droplets
• Remove solids
• Improve separation

Often used with:

• PAC
• PAM
• Demulsifier

Polydadmac works well because oil droplets are negatively charged.

9. Food, sugar, and beverage wastewater

These polymers are used in food processing wastewater treatment.

Applications:

• Sugar factory
• Brewery
• Starch plant
• Beverage plant
• Meat processing

Functions:

• Remove solids
• Reduce COD
• Improve settling
• Reduce odor

Advantages:

• Works at high organic load
• Fast coagulation
• Low dosage

Conclusion

Floquat FL4520 and Floquat FL4820 are high-charge polydadmac cationic coagulants widely used in drinking water treatment, municipal wastewater, industrial wastewater, sludge dewatering, papermaking, mining, textile, oilfield, and food processing industries.
They provide strong charge neutralization, fast coagulation, and excellent removal of turbidity, color, oil, and suspended solids.
FL4520 is commonly used for general coagulation, while FL4820 is often selected for higher charge demand, stronger color removal, and difficult wastewater conditions.
Because of their high efficiency and low dosage, these products are widely used in modern water treatment systems.