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The Purpose and Practice of Industrial Water Treatment

Given the more immediate threat of the Covid-19 pandemic, it is easy to forget that South Africa and most of the world’s nations face a far greater crisis. The three years of limited rainfall that, in early 2018, led to Cape Town’s “Day Zero” drought is an event that is now five to six times more likely to repeat than a hundred years ago. The need to practise water conservation has never been greater and industrial water treatment is one of several activities that can help reduce the mounting pressure on the planet’s declining reserves.

industrial water treatment

Whether purposely or accidentally, discharging wastewater that contains toxic chemicals or other contaminants that might prove harmful to the environment is illegal, and perpetrators could face heavy penalties. Before any contaminated effluent can be disposed of, it must first undergo whatever processing may be necessary to ensure that it will pose no threat to underground or surface water sources, wildlife, crops, livestock or nearby inhabitants. However, environmental concerns are not the only reason to implement industrial water treatment.

In an attempt to encourage consumers to reduce their consumption, the price of water has been increasing at regular intervals. Many companies whose usage is unavoidably high have found that these successive price hikes have led to a marked rise in their operating costs. To counter that rise, some now choose to recycle their wastewater and find ways to reuse it rather than simply disposing of it. In addition to cutting a company’s costs, this practice can, over time, significantly reduce its total usage.

However, industrial water treatment is not only for wastewater. Water for use in boilers and cooling towers will often require pre-treatment. Let’s examine some common pre-and post-treatments.

Scaling and corrosion can cause major damage to boilers. Dissolved and suspended solids, organic materials, dissolved gases and excessive alkalinity can all pose problems. While individual treatment regimens may vary, they usually include preliminary filtration to remove the solids and ion-exchange resins for softening and dealkalisation. Where exceptional purity may be necessary, including a reverse osmosis step in the industrial water treatment process will ensure removing microorganisms and anything larger than a water molecule.

The regimens to render wastewater safe for reuse or to discharge it to the environment or a municipal treatment plant also vary, but will generally include clarification, disinfection and softening stages. The clarification step might consist of sedimentation followed by filtration aided by the addition of flocculants or coagulants. The chemical responsible for hardness may be precipitated out with soda lime or removed by ion exchange.

Equipment for these and other industrial water treatments and expert advice on their use are available from WaterIcon.