Industrial water treatment entails a number of process steps, each with a very specific purpose. In this module we will go through the steps one by one to look at them in more detail.

The first step in the treatment process is aeration. Aeration gets rid of volatile components such as hydrogen sulphide, ammonia or carbon dioxide by bringing oxygen into the water.

The aeration process can also be used to oxidise iron or other water compounds and release them from the water.

There are various aeration methods available. Cascades, mixers or rotating discs made from porous materials are the most commonly used solutions for blowing air into the water.

The next step is flocculation.
The purpose of the flocculation process is to coagulate small particles and dissolved substances into bigger particles that can be filtered out in the next process step.

Two kinds of chemicals are used to coagulate the flocks: primary flocculants which are typically iron and aluminium salts and secondary flocculants which are long organic polymers.

Now, we want to remove all particular matter from the water. This is done by separating the water from the particles – a process that can be carried out by means of sand filters or membrane technology, using either micro- or ultrafiltration. Any dissolved substances can be removed
in a subsequent sorption step by adding powdered activated carbon and later filter the water with a sand filter.

Once all particles and substances have been removed from the water, it’s time to add content in the disinfection step. Disinfection can be achieved by applying physical methods, for instance UV, or by chemical dosing of a disinfectant. Which disinfection method to choose depends on the application in question and on the water quality.

Water with a pH value of eight or higher cannot for instance be treated with chlorine, as this disinfectant is not effective in this pH range.
Using UV in water with high turbidity won’t be effective either as the UV light cannot pass through the water properly.

Finally, a stabilisation step is necessary to balance the water chemistry after content has been removed and added during the treatment process.
Stabilisation typically involves pH adjustment, balancing the water with minerals like calcium or magnesium or removing ions.

The main purpose of balancing the water chemistry is to avoid corrosion in the pipes or of the materials used elsewhere in the industrial process.The stabilisation step is also where it is ensured that the water conditions comply with standards and regulations, for instance in wastewater treatment. This step is very important as it is the last stop before the water is distributed to the industrial process it is to be part of.

Throughout the entire water treatment process different measuring and control functions make sure that the results
required in every process step are accommodated and that all specifications are ultimately met.

In closing, let’s briefly take a look at the variety of pumps and disinfection solutions that help ensure a successful water treatment process – from centrifugal pumps and end-suction pumps to digital dosing solutions
and monitoring equipment.