An oxidant such as chlorine or potassium permanganate is added to the raw water – before it enters the treatment plant. This oxidant then oxidises metals such as iron and manganese in the water – and makes it possible to remove it down the line. The oxidant also acts as a disinfectant, killing any bacteria present in the raw water.

In cases where there are high levels of algae in the raw water – powdered activated carbon is used instead of an oxidant. The powdered activated carbon adsorbs tastes and odours caused by the algae and remove other organic compounds – that might be present.

After pre- treatment, coagulation, flocculation, sedimentation and dissolved-air floatation are used – to remove suspended particles present in the water. Coagulation is the process of adding a chemical to the water – to destabilise the suspended matter.

Coagulation is followed by flocculation. This is a mixing process that bounces the destabilised particles against each other – to form larger particles. These larger particles then settle to the bottom of large tanks called settling tanks (sedimentation).

The top water in the settling tanks then goes through a process known as dissolved-air floatation (DAF). Here, the water is saturated with air 0 in high-pressure vessels.

The small particles that were not removed in the sedimentation process cling to the air bubbles – and are transported to the top of the tank. They then form a scum layer – that is hydraulically removed and transported to sludge-storage dams.

Gravity sand-filtration is the next polishing step in water purification. The treated water gravitates through layers of different sizes of silica sand. Any remaining suspended matter, as well as microbiological organisms such as cryptosporidium – is removed in this treatment step.

At some of the treatment plants – there is an additional intermediate disinfection/oxidation step, in which chlorine is added – just before filtration takes place.

Finally, the water is disinfected using chlorine gas, which kills any remaining bacteria. Treatment plants with long distribution systems have added ammonia-dosing to this final disinfection step – as a way to maintain a residual disinfectant in the water for up to two weeks. This ensures that the water remains disinfected in the distribution system.

Magalies Water also offers a series of highly advanced preventative treatments – to proactively manage the deteriorating water quality.