Veolia Water Technologies & Solutions

Coagulants & Flocculants for Water Treatment

Coagulant and flocculant treatment for suspended solids, organics and oil removal, sludge dewatering, and lime softening

During influent water and effluent wastewater treatment, clarification aids like coagulants and flocculants help remove suspended solids, including oil, organics (TOC and color) and hardness. In turn, this allows our customers to prepare their influent raw water for efficient use as process water, meet wastewater discharge regulations reliably, all while allowing for cost-effective water reuse.

Our experts at Veolia provide customers with the peace of mind that can only come from working with professionals who have treated influent and wastewater clarifiers of all types for decades. 

Featured Products

Types of coagulants and flocculants

Veolia offers a comprehensive portfolio of coagulants and flocculants that aid in the clarification process. Whether you need coagulants or flocculants, liquid, emulsion or powders, cationic or anionic products, Veolia has a cost-effective solution for your raw water and wastewater. Our application expertise ranges from operational optimization to selecting and applying chemical treatment programs while providing your lowest total cost of operation for your solids separation and color removal needs. 

KlarAid* coagulants – highly charged inorganic, organic and blended coagulants for clarification of industrial water and wastewater

KlarAid products are ready to use water-soluble coagulants, ranging from polymeric inorganic and organic coagulants to single container blends. They are designed to function in a variety of industrial water and wastewater treatment applications, including use as a primary coagulant for removal of colloidal turbidity and color for raw water clarification, as a demulsifier to facilitate liquid solids separation in dissolved gas flotation units for primary wastewater treatment, and settling and filter aids used separately or in conjunction with organic flocculants.

The KlarAid product line encompasses a comprehensive portfolio of chemistries ranging from classic inorganics to modified natural products, such as amphoteric tannins and starches, to modern synthetic organic chemistries. They encompass relatively low to high cationic charge densities.

One of the highest costs in many water and wastewater treatment plants is residuals (sludge) disposal. Veolia works with their customers to choose coagulants that can minimize sludge production, which is a high cost to the plant (i.e., we always work with customers to minimize their total cost of operation).

For more information on our KlarAid technology program benefits, download our fact sheet.

Novus* flocculants – high molecular weight polymers for use as clarification, flotation and dewatering aids

Novus products are cationic, high molecular weight water-soluble polymers provided as liquid emulsions, providing the right balance of ease of use and cost-effectiveness. They are designed to function in a variety of industrial water and wastewater treatment applications.

The Novus product line provides a comprehensive portfolio with a broad range of cationic charge and molecular structure, thereby allowing Veolia to produce products for both raw and wastewater clarification, flotation enhancement and sludge conditioning (for thickening and dewatering).

For more information on our Novus technology program benefits, download our fact sheet.

PolyFloc* flocculants – high molecular weight clarification, flotation and dewatering polymers

PolyFloc products are high molecular weight water-soluble polymers. They are designed to function in a variety of industrial water and wastewater treatment applications. Depending on customer preference, they are available in concentrated powder form, cost-effective emulsion liquids and convenient, easy-to-feed liquid solutions.

The PolyFloc product line encompasses a broad range of charge types, ranging from low to high anionic or cationic charge, thereby allowing Veolia to produce products for raw and wastewater clarification, flotation enhancement and sludge conditioning (for thickening and dewatering) on a wide variety of substrates.

For more information on our PolyFloc technology program benefits, download our fact sheet.

Features & Benefits

Coagulation and flocculation features & benefits

The Veolia approach to providing a solution is to perform an in-depth system audit, incorporating customer needs and full cost analysis. The results of which are used to design a treatment program incorporating Veolia’s coagulant and/or flocculants together with the application and operational recommendations. This approach will provide the following benefits:

  • Cost-effective clarification and flotation operations
  • Optimal unit operation and effluent quality (lower effluent turbidity)
  • Influent clarification operations optimized to reduce ionic loading and fouling on downstream treatment processes
  • Improves downstream filter performance
  • Reduces sludge volume in clarifier blowdown and DAF float
  • Cost-effective thickening and dewatering applications for increased sludge dryness
  • Reduced solids generation when converting from inorganics to organic products
  • Lowest total cost of operation

Inorganic, organic and blended coagulant types exhibit unique properties. See the table below for a summary. 

coagulants & flocculants


Case Studies


What is clarification?

Suspended matter in raw water supplies is removed by various methods to provide water suitable for domestic purposes and most industrial requirements. The suspended matter can consist of large solids, settleable by gravity alone without any external aids, and non settleable material, often colloidal in nature. Removal is generally accomplished by coagulation, flocculation, and sedimentation. The combination of these three processes is referred to as conventional clarification.

What are the steps of clarification?

Finely divided particles suspended in surface water repel each other because most of the surfaces are negatively charged. These colloids can be said to be stabilized and can stay in suspension for a long time. The goal of clarification is to make them bigger so that they settle faster. The following steps in clarification are necessary for particle agglomeration:

  • Step 1: Coagulation can be accomplished through the addition of inorganic salts of aluminum or iron. These inorganic salts neutralize the particles' charge and hydrolyze to form insoluble precipitates, which entrap particles. Coagulation can also be affected by the addition of water-soluble organic polymers with numerous ionized sites for particle charge neutralization.
  • Step 2: Flocculation can be enhanced by the addition of high-molecular-weight, water-soluble organic polymers. These polymers can increase floc size by charged site binding and by molecular bridging.
  • Step 3: Sedimentation

Therefore, coagulation involves neutralizing charged particles to destabilize suspended solids. In most clarification processes, a flocculation step then follows. Flocculation starts when neutralized or entrapped particles begin to collide and fuse to form larger particles. This process can occur naturally or can be enhanced by the addition of polymeric flocculant aids.

What is coagulation?

Coagulation water treatment is the process of particle destabilization by charge neutralization. Once neutralized, the particles no longer repel each other and can be brought together. Coagulation is necessary for the removal of the colloidal-sized suspended matter in wastewater.

What is flocculation water treatment?

Flocculation water treatment is the process of bringing together the destabilized, or “coagulated,” particles to form a larger agglomeration, or “floc.”

What is sedimentation?

Sedimentation refers to the physical removal from suspension by settling that occurs once the particles have been coagulated and flocculated. Sedimentation or subsidence alone, without prior coagulation, results in the removal of only relatively coarse suspended solids.

What is jar testing?

Jar testing is the most effective way to simulate clarification chemistry and operation. A multiple-paddle gang stirrer permits the comparison of various chemical combinations, all of which are subjected to identical mixing conditions. The effects of rapid and slow mix intensity and duration may also be observed.

Our field representatives and our corporate support engineers are trained in the art of product selection using jar testing and will tailor your treatment to meet your specific water quality and application conditions. Reliability of operation is our number one objective.