How Industrial Wastewater Pretreatment Systems Work?

Figure 1 Industrial Wastewater Pretreatment Systems

In industries where wastewater is a natural byproduct of day-to-day operations, businesses must ensure safe and environmentally responsible disposal of wastewater. However, unsafe and untreated wastewater disposal will have severe environmental consequences. In addition to harming human life by contaminating nearby drinking sources, aquatic and animal life will suffer from contact with untreated wastewater.

Because of that, governments impose laws and regulations for the safe disposal of industrial wastewater. So to avoid hefty fines that could put you out of business, it’s crucial to implement effective industrial wastewater pretreatment systems.

This article will explore industrial wastewater pretreatment systems. We will also provide a step-by-step guide that explains the industrial wastewater pretreatment process

What Is Industrial Wastewater?

Before we explain what wastewater pretreatment is, we must answer what industrial wastewater is. Industrial wastewater is a natural byproduct across many industries. Since water is a core component in the production process, it is used in varying degrees and for various operations. 

Plants and production facilities that create wastewater must discharge it based on local regulations and laws. Therefore, they can treat the wastewater to meet these laws and regulations and avoid hefty fines for compromising the environment and public health. Even if these plants decide to reuse the water, it still must be treated. 

What Is Pretreatment of Wastewater?

Wastewater pretreatment is a crucial step in the overall wastewater treatment process. It involves the removal of contaminants and pollutants from industrial wastewater before it is released into the environment or further treated in a municipal wastewater treatment facility. The goal of pretreatment is to reduce the concentration of harmful substances to levels that meet regulatory standards. But how does the pretreatment in the water treatment process work?

What is Industrial Wastewater Pretreatment

How Does Industrial Wastewater Pretreatment Work?

Industrial wastewater pretreatment is typically done using specialized wastewater treatment equipment. The process involves several steps that work in tandem to remove pollutants and contaminants from the water. While the specific processes may vary depending on the type of wastewater, the following steps are commonly employed in industrial wastewater pretreatment systems:

Step 1: Coagulation

Coagulation is the first step in the wastewater pre-treatment process, where a coagulant (alum or poly aluminum chloride) is added to the wastewater. The coagulant destabilizes the suspended particles and colloids in the water, causing them to combine and form larger particles called flocs. This process helps to aggregate fine particles and contaminants, making them easier to remove in subsequent steps.

Coagulation is especially effective in color removal from industrial wastewater. 

Step 2: Flocculation

After coagulation, the wastewater enters the flocculation stage. During flocculation, gentle stirring or agitation is applied to the water, allowing the flocs to collide and form larger, more settleable masses. This process aids in forming larger flocs that are easier to separate from the water.

Step 3: Sedimentation

Once the flocs have formed, the wastewater enters a sedimentation basin or clarifier. In this step, the flow velocity of the water is reduced, allowing the flocs to settle to the bottom of the basin. The sedimentation process relies on gravity to separate the flocs from the water, forming a sludge layer at the bottom. The clarified water is then separated from the sludge layer and moved to the next stage.

Step 4: Filtration

Filtration is employed to further remove any remaining suspended particles and impurities from the water. The clarified water passes through various filters, such as carbon sand or industrial-activated carbon filters, which trap and remove fine particles. Filtration ensures that the wastewater is free from any solid contaminants and prepares it for the final step of the pre-treatment process.

Applications of Water Filtration Systems

Step 5: Disinfection

In the final step of the industrial wastewater pre-treatment process, the water is disinfected to eliminate any remaining harmful microorganisms. Industrial wastewater treatment methods for disinfection include chlorine, ozone, or ultraviolet light water sterilizers. These processes neutralize or kill bacteria, viruses, and other pathogens present in the water, ensuring that it meets the required safety standards for discharge. 

Step 6: Distribution or Reusage 

Plants and production facilities don’t necessarily have to discharge the water following the wastewater pretreatment process. In some cases, facilities might still use the treated wastewater for other operations. In that case, the treated wastewater will be pumped into tanks where the facilities can reuse it. 

However, if the facility decides to discharge the wastewater, it will go into specialized water tower distribution systems. These systems are found at most production plants and facilities that create industrial wastewater. 

Other Steps to Treat Industrial Wastewater

Some industrial wastewater pretreatment systems fail to achieve optimal water treatment. In that case, the facility might take other possible steps before the final step. One possible step is introducing an ion exchange water treatment system. These are specialized deionized water systems for water softening and deionization applications. 


Industrial wastewater pretreatment systems are vital in ensuring the safe and responsible disposal of wastewater generated by production facilities and plants. Industrial wastewater pretreatment systems are effective in removing contaminants and pollutants from wastewater.

These systems help production plants and facilities comply with laws and regulations and prevent environmental and public harm. 

The sequential steps of coagulation, flocculation, sedimentation, filtration, and disinfection work together to transform wastewater into a clean, treated effluent that can be discharged without causing harm to the environment or public health. Therefore, implementing and maintaining an industrial wastewater pretreatment system is a necessary investment in industries where wastewater is a byproduct of normal operation. 

Can NEWater Help With Industrial Wastewater Pretreatment Systems?

With over 20 years of experience, NEWater is a trusted provider of professional industrial wastewater treatment systems and services. We specialize in designing and implementing customized pretreatment solutions tailored to your specific needs and regulatory requirements. Our team of industry experts will cooperate closely with you to develop a system that effectively removes contaminants and pollutants from your wastewater.

Feel free to get in touch with us for any inquiries regarding our industrial wastewater treatment systems and solutions.


How Does Industrial Wastewater Treatment Work?

Industrial wastewater treatment works by removing contaminants and pollutants from industrial wastewater. It is done using a number of steps performed in tandem to ensure the proper discharge of wastewater based on local laws and regulations. 

● What is the Pretreatment Process of Wastewater?

The pretreatment process of wastewater is crucial in removing pollutants and contaminants from wastewater before it is discharged into the municipal sewage system or reused for other operations. 

● What are the Six Steps in Industrial Wastewater Pretreatment? 

The six steps in industrial wastewater pretreatment include the following:

  • Step 1: Coagulation
  • Step 2: Flocculation
  • Step 3: Sedimentation
  • Step 4: Filtration
  • Step 5: Disinfection
  • Step 6: Distribution or Reusage
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