What is wastewater pretreatment and why is it key in the industry?

El wastewater pretreatment originating from human activities (domestic, industrial, commercial or agricultural activities) is the first step towards cleaning, purifying and reusing this natural resourceand it is a crucial process for protecting public health and the environment.

But What is wastewater pretreatment? What does it consist of and why is it so important for the industry?

What is wastewater pretreatment?

Wastewater pretreatment is a generic term that It encompasses all procedures designed to condition water before it undergoes advanced purification and cleaning treatments.

It assumes, broadly speaking, eliminate its coarse solids, fats, oils and other toxic compounds that may damage the Treatment plants or violate environmental regulations.

From a practical point of view, wastewater pretreatment…

• Reduces manual intervention in the facilities

• Protects equipment, facilities, and automated systems.

• Optimizes the efficiency of subsequent processes.

• It guarantees a more effective, sustainable and economical treatment.
• It reduces the initial pollutant load of water treatment from industrial processes. 

What does wastewater treatment involve?

pretreatment prepares the wastewater for further treatment, protecting equipment and improving overall process efficiency.

However, to better understand what wastewater pretreatment involves, we must distinguish its main stages and techniques: 

Wastewater pretreatment phases

• Collection and driving 

In this first phase, It collects the water generated in the various industrial processes and transports it to the treatment plant. through pipes, channels or collectors. 

To design this conduction system, it is essential Get advice from specialist companies like SITRA, something essential to prevent leaks, blockages, etc. 

• Sieving or screening

The second phase of wastewater pretreatment consists of remove coarse solids and large floating materials from the water (plastics, rags, branches, wood or stones) to avoid mechanical damage or blockages in the pumps and equipment.

For this purposeGrids, meshes and sieves are used manual or automatic. 

• Desanding

The desanding process serves to separate sands, mineral particles and other heavy materials of wastewater using sedimentation chambers.

In these watertight chambers, and thanks to the reduction in water flow, The densest and heaviest particles settle to the bottom, which protects the equipment from blockages.

• Degreasing

In this stage of industrial water pretreatment Oils, grease, and other floating substances are removed. that may interfere with future biological or physicochemical processes. 

For degreasing water, the following are used flotation, aeration or density difference separation systems that facilitate the accumulation of fats on the surface to be removed. 

• Equalization or homogenization

The last of the phases of wastewater pretreatment in industry It serves to homogenize the flow and the pollutant load of the water.

The process is simple: In tanks, the flow is stabilized and variations in concentration, pH, and temperature are reduced.

The goal is to improve the efficiency of subsequent treatments, both physical and biological.  

Techniques for the pretreatment of wastewater

The techniques used in the pretreatment of wastewater from industry are: 

• Mechanical screening

It serves for retain large solids. 

It can be manual (plant personnel use simple grates) or automatic, using rotary sieves or grids with automatic cleaning mechanisms. 

Screening It reduces the polluting load and facilitates the handling of captured waste for disposal. 

• Preliminary sedimentation

Basically, it's about harnessing the force of gravity to separate particles such as sand, gravel, and inorganic solids of the water. 

In this process Sand traps or sedimentation chambers are used for to minimize the amount of solids suspended in the fluid.

• Dissolved air flotation (DAF)

The DAF system is a separation technique that removes suspended solids, oils and fats, for ourselves thanks to the generation of air microbubbles that They adhere to the particles and cause them to...The solids rise to the surface so they can be easily removed.

This technique is especially useful in the food, petrochemical and textile industriesAnd one of its main advantages is that it allows the recovery of useful or hazardous waste that can either be recycled or must be disposed of in a specific way. 

• API or CPI separators

The API separators (American Petroleum Institute) and the CPI separators (Corrugated Plate Interceptor) They separate hydrocarbons and light oils from wastewater: In the first case, the difference in density between water and oil is used; in the second, the contact surface is increased to separate oil droplets. 

Its use is very relevant in the oil and petrochemical industry, two sensitive sectors where close attention must be paid to environmental regulations when treating water. 

• Equalization tanks

The equalization tanks act as rwater flow regulators, avoiding sudden overloads that could affect the efficiency of biological or chemical systems.

This technique also helps to stabilize parameters such as pH and temperature, and facilitates the dosing of corrective chemicals used in the subsequent stages of wastewater treatment. 

• pH preset

En industries where wastewater has a pH outside the range suitable for biological treatment (for example, in metallurgy companies), it is necessary add chemicals (acids or bases) to neutralize the pH. 

This technique is known as "pH preset", prevents the inhibition of microorganisms in biological treatments and It protects system materials against corrosion and scaling.

In what types of industries is wastewater pretreatment essential?

Wastewater pretreatment It offers multiple operational and environmental benefits in those industries that generate effluents with high pollutant loads. 

The sectors that benefit most from wastewater pretreatment are:

• Food industryThis industry generates large quantities of wastewater containing fats, oils, and organic waste. The use of dissolved air flotation and grease separators is essential to prevent overloading subsequent stages of wastewater treatment. 
• Textile industry. Wastewater from the textile industry contains dyes, detergents, and suspended solids. In these cases, screening and pH adjustment are essential to reduce contaminants. 

• Ichemical and pharmaceutical industry. In these types of industries, it is common to discharge water with extreme pH, toxic compounds or hazardous reagents, so pH pre-adjustment and chemical neutralization are essential to protect biological processes and comply with current regulations. 
• Metallurgical industry. Wastewater from the metallurgical industry can contain heavy metals, oils, and solid particles. The use of sedimentation, API or CPI separators, and initial filtration systems will prevent environmental and technical damage.

What is the best system for water pretreatment?: At SITRA we adapt our solutions to all types of companies

The “best” system for the pretreatment of industrial wastewater is that which is custom-designed by engineers and specialized experts, combining the best available techniques according to the composition of the water.

For example, the combination of screening and degreasing is a generic solution, but one that works for many industries.

Furthermore, Choosing automated systems allows:

• Greater control. Its sensors regulate each phase of the pretreatment, preventing failures due to excess or deficiency.

• Less manual intervention. These types of systems reduce costs and minimize human error.
• Increased efficiency. Automating water treatment makes it easier to adjust the use of pumps, aeration systems, or chemical dosing.

In SITRA We design and build wastewater treatment plants and facilities. custom-made to the highest quality standards.

Energy efficiency, resource optimization and technological excellence are the pillars of our proposals.

What do you need?, We'll be with you through every phase

➡️ We adapt your current plant.

➡️We build custom-made water treatment plants

➡️ We regenerate wastewater.

➡️ We perform maintenance on your facilities.

➡️ We select the best systems and chemicals to comply with regulations.

📞 Contact Us.