Industrial dust abatement: how to solve the problem

What they are and how to reduce dust emissions with water mist barrier technology

In recent years, the management of industrial dust emissions has become an issue of increasing importance, both due to the increase in regulations imposed by competent authorities and the increased awareness of environmental issues.
Dust abatement has therefore become a priority for companies with a view to protecting people's health and mitigating impacts on the environment.

In this article we will examine the importance of industrial dust abatement and the various strategies and technologies available to effectively address this challenge.

What is dust?

Dust in the air, also referred to as atmospheric particulate matter (PM) or suspended particulate matter (SPM), are solid or liquid microscopic substances suspended in the earth's atmosphere. These particles can vary in size, shape, color, chemical composition and physical properties. Although some are too fine to be visible to the naked eye, they can have a significant impact on health and the environment. 

Understanding the sources and characteristics of dust is critical to developing effective abatement strategies and mitigating its negative impacts.

Dust types and their importance in occupational safety

In the context of occupational safety, it is essential to understand the characteristics of different types of dusts and their potential health impacts on workers. Dusts can be divided into several categories based on their size and ability to penetrate the respiratory tract:

  • inhalable dust, capable of entering the nose and mouth, with a size of less than 100 µm, can be invisible and pose a health threat if inhaled during work activities.
  • thoracic dust particles with sizes between 5 and 10 µm capable of reaching the upper respiratory tract. Although they do not penetrate to the alveoli, the smallest branches of the lungs, they can still cause respiratory problems and irritation.
  • respirable dust particles with a particle size of less than 4 µm per particle can cross undisturbed to the alveoli, posing a serious health risk to exposed workers. It is important to take effective preventive measures to protect workers from these dusts, including safe work practices and the use of appropriate personal protective equipment.

Effects of dust on health and safety

Studies conducted by organizations such as IARC (International Agency for Research on Cancer) and WHO (World Health Organization) confirm that dusts have a number of adverse effects on human health and occupational safety.

Continuous exposure to these dusts can cause severe respiratory disorders, lung diseases and increase the risk of lung cancer. Heavier dusts can also have harmful effects on vision.

In addition, contamination of work tools and equipment by dusts can lead to deterioration in operation and shortened service life of the tools and equipment.

Therefore, it is essential to take preventive measures to protect workers' health and mitigate the impacts of dust on work safety and quality.

Origin of dust

Dust originates from a variety of sources, both human and natural.
Anthropogenic activities, such as agriculture, industrial processes, construction work, demolition, and vehicular traffic, make up a significant portion of the sources of airborne dust.
Natural sources, such as windblown dust and forest fires, also contribute to the overall problem of dust in the atmosphere.

Solutions to abate dust

Industries can adopt several strategies to significantly reduce dust emissions and improve the environmental sustainability of their operations. These strategies include:

Application fields of misting systems

Misting systems for dust abatement are widely used in various industries. Here are some of the main fields of application:

Thermal power plants and contribution plants
In combustion processes of fuels such as coal and lignite, the use of loading and unloading equipment that minimizes the height of fuel drop can reduce the generation of diffuse dust. In addition, the use of water misting systems to reduce dust formation from coal stocks is a recommended practice, especially in climatic conditions below zero °C.

Mining and quarrying industry
Misting systems are used for dust control in various stages of mining and mineral processing in quarries. These include transfer points of belt conveyor systems, crushing processes, drying, screening, and loading of trucks or rail cars. Water misting prevents dust from becoming airborne, thus reducing the impact on air quality and worker health.  

Construction and demolition
During earthmoving, demolition, and leveling operations, water misting can be used to reduce the dispersion of dust into the air. In addition, washing construction and transport vehicles before leaving the construction site area helps to keep dust levels in the surrounding environment low.

Waste recycling centers
At waste recycling centers, the use of misting equipment is essential to control dust dispersion during the different stages of the recycling process. These systems are used during the transport, sorting, shredding and handling operations of recyclables, ensuring a safe working environment and reducing environmental impact through dust containment

Other industries
Misting plants are also used for dust suppression during loading and unloading of bulk materials, dust control at conveyor transfer points, and air pollution mitigation in outdoor areas subject to material disturbance from various industrial activities.

Dust abatement with water mist: how it works

In misting systems used to reduce dust, the water mist acts as a filter that traps dust particles. When these particles come into contact with the water droplets produced by the system, they become heavier and precipitate to the ground. This process, known as agglomeration, encourages the dust particles to join the water droplets, increasing their mass and allowing them to fall to the ground under the effect of gravity. 

Droplet size is very important for misting systems to work well. If the droplets are much larger than the dust particles, the dust particles will simply follow the airflow around the droplets. But if the droplets are almost the same size as the dust particles, the dust particles will stick to the water droplets and fall to the ground.

For optimal agglomeration, the size of the particles and water droplets must be approximately equivalent. The probability of collision increases with decreasing droplet size, so a smaller water droplet size promotes more collisions and effective removal of dust particles from the air.

Droplet size is affected by the number of nozzles, water pressure at the nozzles, and water flow rate. The greater the number of nozzles and the water pressure, the smaller the droplets will be.
Spray cannons, for example, produce a fine mist due to their high pressure and significant number of nozzles with very small orifices.

The operation of droplets in misting systems

The process of droplet generation, known as atomization, begins when a liquid is passed through a nozzle. The potential energy of the liquid, together with the shape of the nozzle, causes the liquid to be emitted in the form of small ligaments, which fragment into droplets or smaller liquid particles.

Each spray produces a variety of droplet sizes, which depends on the type of nozzle used and various factors such as liquid properties, nozzle capacity, pressure, and spray angle.

Nozzle quality and wear can significantly affect the performance of spray systems. Worn nozzles can alter the appearance of the spray and increase the flow rate and droplet size. As a result, there is a substantial difference in droplet size between new and used nozzles, which can affect the overall effectiveness of the spray system.

For this reason, once the dust suppression system has been designed and installed, we recommend a maintenance service to ensure that optimum performance is maintained over time.

Nozzle placement

The placement of nozzles in an area to be treated depends on the application and the characteristics of the dust pollution to be addressed. Some tricks include:

  • placing nozzles upstream of the point of origin of dust emissions so that water droplets can act on the dust before it disperses into the environment;
  • placing the nozzles at an optimal distance to ensure effective coverage while avoiding dispersion of droplets too far from the point of action due to air currents;
  • arranging the nozzles so as to maximize the residence time of the droplets in the air can increase the effectiveness in binding dust particles.

Indoor and outdoor dust suppression system: the differences

Dust abatement systems for indoor and outdoor environments have significant differences due to different environmental conditions and specific pollution control requirements.

In indoor environments, such as industrial plants or processing facilities, abatement systems must be designed to operate in confined and controlled spaces where nozzle distribution and airflow direction can be more precisely managed. These systems often use technologies such as high-efficiency filters and misting systems to capture and remove dust particles from the air.

In outdoor environments, such as quarries, construction sites, landfills, or outdoor industrial areas, abatement systems must deal with weather conditions and large-scale dust dispersion. In these situations, large-scale misting systems are often employed to reduce dust dispersion to the surrounding environment.

Water mist dust suppression systems can be installed both outdoors and indoors. Each context, however, has characteristics to which appropriate technical solutions must correspond.

Dust suppression cannons

Dust suppression cannons are an effective solution for dust management in outdoor environments and large areas where dustiness is high and covers large areas. These devices use water mist technology to generate a powerful jet of water mist that is sprayed into the air with high pressure. It is important to use these devices with weather and environmental conditions in mind in order to maximize their effectiveness and prevent any unwanted impacts.

Dust abatement systems with fixed lines

Water mist dust suppression systems are one of the most effective solutions for indoor industrial environments. These systems are based on the use of special pumps and nozzles that spray droplets of water mist, which bind to dust particles in the air.
The main advantages of such systems include their versatility of use, ease of application in various settings, and relatively low cost.
It is important to keep in mind that although misting systems are effective in saturating the air in a specific environment to break down dust, they are not able to act with a direct long-distance spray like spray cannons.
The specific choice of a system, its accessories, and the overall setup is influenced not only by circumstances but also by the chemical and physical nature of the dust to be abated.

How to choose the best solution for dust abatement

We offer advanced dust abatement solutions based on osmogenic spray/barrier technology. During the on-site technical survey, we carefully analyze the dust source and identify the most suitable solution for our customers' specific needs.

Our solutions include advanced dust abatement systems for both indoor and outdoor environments.

Our experience and technical expertise enable us to offer customized solutions to address dust pollution challenges in a variety of industrial and environmental settings.   

Dust abatement is essential to protect human health and preserve the environment. With the use of innovative technologies, we can significantly reduce the impact of dust on the air and ensure workplace safety.