1 August 2017

Water and wastewater treatment chemicals

Types of chemicals used in the treatment of water

There are a number of chemicals used in water treatment regimens to purify water into a usable state. Drinking water, in particular, requires a full treatment process to make it safe for human and animal consumption.

Defoamers – organic matter in water decays to form surfactants. These surfactants on the surface of the water allow air and water to mix, causing bubbles on the surface of the water. Anti-foaming agents are added to the water to treat and prevent the formation of foam in water or wastewater treatments.

Biocides – anti-microbial biocides are used as anti-fouling agents to remove viruses or bacteria from wastewater.

Corrosion inhibitors – corrosion occurs in water systems and pipes where metallic surfaces are exposed to water and air. Corrosion inhibitors are used to reduce corroded particles or flakes from the water.

Oxidants – oxidants, such as chlorine, are used to remove organic or inorganic materials from the water by a process called oxidation.

Scale inhibitors – when minerals such as calcium and magnesium dissolve in water, the residue left behind accumulates as limescale. Scale inhibitors are used to slow down or stop the build-up of limescale in water systems.

Coagulants and flocculants – coagulants are used to remove small particles in wastewater treatment (that could not be removed by filtration). Flocculants are used alongside coagulants to bind smaller particles together to produce floc. The floc is denser and heavier in nature and gravity pulls the floc to the bottom of a water tank, making it easier to remove.

Disinfectants – Drinking water in particular needs to be at a very high standard to be safe for consumption. Therefore, a powerful disinfectant should be employed to eliminate harmful contaminants.

Neutralizing agents and pH adjusters – untreated water can often be too acidic or too alkaline. Therefore, neutralizing agents are required to balance the pH levels and pH conditioners are added to help control the acid levels so that the water is neutral.

NCH Asia provides a wide range of water treatment solutions designed to minimize energy, water and maintenance costs. Speak to one of our experts for advice on the correct water treatment process for your application.


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