Chemicals used in the water treatment industry

Chemicals used in the water conditioning (water treatment/processing) sector are usedto improve the physical and chemical properties of water,to protect the system against corrosion, scale, and biological fouling. These chemicals are used for different purposes in drinking water, industrial process water, boiler water, cooling water, and wastewater systems.

Main Chemicals Used in the Water Conditioning Sector

1.Coagulants (Agglomerating Agents)

They bring together fine particles suspended in water and enable them to settle.

• Aluminum Sulfate (Alum)

• Polyaluminum Chloride (PAC)

• Iron(III) Chloride (FeCl₃)

• Iron Sulfate

Application Area:Drinking water treatment, wastewater pre-treatment

2.Flocculants (Flocculating Agents)

They turn the small particles formed after coagulation into large flocs, facilitating settling or filtration.

• Polyacrylamide (PAM)– In anionic, cationic, or nonionic forms

• Organic polymers

Application Area:Wastewater treatment plants, sludge dewatering

3.pH Adjusters

They regulate the acid-base balance of water and ensure chemical reactions are efficient.

• Caustic Soda (NaOH)

• Sodium Carbonate (Na₂CO₃)

• Lime (Ca(OH)₂)

• Sulfuric Acid (H₂SO₄)

• Hydrochloric Acid (HCl)

Application Area:Boiler water, process water, wastewater

4.Scale (Deposit) Inhibitors (Antiscalant)

They prevent minerals such as calcium, magnesium, and silicates from depositing in the system.

• Phosphonates (HEDP, ATMP)

• Polyacrylic acid derivatives

• Organophosphorus compounds

Application Area:Reverse osmosis systems, cooling towers, boilers

5.Corrosion Inhibitors

They prevent corrosion (rusting) that may occur on metal surfaces.

• Sodium Nitrite

• Sodium Molybdate

• Phosphates and polyphosphates

• Zinc compounds

Application Area:Closed-loop systems, boilers, cooling systems

6.Biocides (Microbial Inhibitors)

They keep the growth of bacteria, algae, and fungi under control.

• Isothiazolinone

• Glutaraldehyde

• Bronopol

• Chlorine, bromine derivatives

• Peracetic acid,hydrogen peroxide

Application Area:Cooling towers, reverse osmosis, wastewater

7.Disinfectants

They ensure the water is microbiologically safe.

• Sodium Hypochlorite (NaClO)

• Chlorine Gas

• Chlorine Dioxide (ClO₂)

• Used in conjunction with UV systems

Application Area:Drinking water, process water

8.Oxygen Scavengers

They prevent corrosion by removing dissolved oxygen in boiler systems.

• Sodium Sulfite (Na₂SO₃)

• DEHA (Diethylhydroxylamine)

• Hydrazine (N₂H₄)– Toxic; its use is declining.

Application Area:High-pressure boilers

9.Cleaners and Washing Chemicals

Used to clean scale and dirt that have formed in the system.

• Acidic cleaning products (citric acid, HCl)

• Alkaline cleaning products (NaOH + detergents)

Application Area:Reverse osmosis membranes, boiler tubes