Industrial wastewater contains high levels of contamination, including toxins, microorganisms, pathogens, and chemicals.

It’s therefore essential that industrial wastewater is treated before it’s discharged in order to protect the health of our waterways and the environment.

Every industry brings with it a different set of contaminants and with each one comes a different set of problems. For example:

  • The food industry creates wastewater containing a lot of organic particulates, agricultural chemicals, bodily fluids and flesh from animals, and bacteria, as well as oils and fats.
  • Industries that use a lot of metal, such as car manufacturers or appliance makers, will generate wastewater contaminated by heavy metals and chemical solvents.
  • Textile industries use any of a myriad of chemicals such as dyes, bleaches, waterproofing and flame retardant chemicals, and even insecticides.

If huge quantities of untreated industrial wastewater were to be discharged into the drainage system, wastewater treatment plants would grind to a halt, unable to deal with the sheer quantity of water that needs to be treated. There is an additional reason why pre-treating wastewater is useful for businesses - when water is untreated, water companies have to charge a lot more to treat it for them, so pre-treating it would avoid these additional costs.

Why treat wastewater?

The treatment of industrial wastewater is as essential to the environment as the treatment of domestic wastewater is. If we did nothing, our ecosystems would be devastated by oxygen depletion because of the huge quantities of pollutants and toxins. The pollution in the water would stop the light from getting to aquatic plants, preventing photosynthesis, and decreasing oxygen levels even further.

This is one of the reasons why different kinds of industrial waste require permits from the Environment Agency (EA). The EA permits to ensure that the sewerage system is not overwhelmed by the volume of wastewater or the number of toxins in the wastewater. The EA recently relaxed its rules on the number of chemicals needed in industrial wastewater treatment in order to deal with a national HGV driver shortage, but this is a temporary solution.

How is industrial wastewater treated?

There are various ways in which industrial wastewater is treated, including chemical treatments, biological treatments, and the physical removal of contaminants.

There are a number of processes that industrial wastewater must go through. The first is to filter out the large contaminants that may clog the drains, such as paper, plastics, metals, cloth, etc. The water passes into a sedimentation tank where inorganic and organic solids are left to settle at the bottom as sludge, and light materials, such as oils and grease, will float on the top as scum. The scum can be skimmed off and the sediment collected.

At this stage, the wastewater still contains suspended solids and toxic chemicals. It, therefore, needs to undergo a biological treatment process. The current method of doing this is through an ‘activated sludge’ process, where the water is mixed with air (for oxygenation) and sludge that contains bacteria which breaks down organic matter into a harmless by-product.

The treated water goes into another sedimentation tank where excess bacteria is removed. The wastewater is then disinfected with chlorine which kills at least 99% of the leftover bacteria before the water is discharged into the sewerage system. However, alternative treatments to chlorine are being explored, such as ultraviolet light or ozone.

As the UK’s leading independent business water supplier, we can help you with industrial wastewater treatment services. Working alongside our specialist partners, we can advise and assist you in finding the right solution for treating any wastewater that cannot be discharged into the sewer. Get an instant quote for all your water and wastewater services here.


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