Choosing the best type of water filtration system for an industrial cooling process can be a daunting task. Considerations regarding system footprint, ease of maintenance, materials of construction, cost effectiveness, waste disposal and performance are essential to help narrow the choices relating to the filtration system. The filtration systems themselves often are costly, and choosing the best suited system can help minimize costs while maximizing efficiency for the long term. Cost-effectiveness, maintainability, efficiency and sustainability are key features any engineer wants to apply to their industrial water filtration system.

Each of the options for industrial water filtration has its own advantages and disadvantages. Having a basic understanding of the common filtration system types and how they work can help users make the most effective choice for operational demands.

Bag Filtration Systems

Bag filters use different media solutions to filter solids from water. They are a low cost, effective option for smaller, low key performance demands. Bag filters tend to have a smaller surface area than other types of filtration systems, which can be a limitation on how large of an operation they can support. Things to consider with bag filtration systems are:

• The ease of maintenance.
• The time and financial cost required to maintain the system. The bag filters will need to be changed on a regular schedule to preserve filtration effectiveness.

In the instance of a higher performance demand, there is a higher frequency of disposal and replacement of bags in order to maintain system function. Changing the filter creates an inherent break in operation, and the process downtime adds the overall cost of using this filtration system. Furthermore, the costs associated with replacing the bags can accumulate, especially for larger operations. Although effective, it is important to consider the performance demands of your application to evaluate whether bag filtration systems are a good fit.

This filtration system is used on a cooling tower system.

Sand Filtration Systems

The most common type of media filtration system in industrial water treatment applications employs sand as the filtering agent. This type of media filtration functions by capturing solids as water passes through fine grains of sand. Sand filtration systems often are involved in a larger network of filtration processes for adequate treatment and end product cleanliness.

Keep in mind that this type of filtration system requires:

• A large footprint.
• A means to deal with high volumes of backwash water.
• The ability to perform regular maintenance.

Replacement of the sand or media used to run the system is important to prevent bacterial buildup and ensure that water is being filtered rather than contaminated. The cost of maintenance may be expensive in time and capital. The complexity, maintenance requirements and cost of performance are variables to consider.

Selecting the correct filtration system for the application – shown here is one for steel mill roll cooling – is essential for efficiency.

Cartridge Filters

Cartridge filters can be effective from a performance and economic standpoint in many situations. Materials such as synthetic or natural yarns, propylene yarn, microfibers or polyester variations are common mediums utilized in cartridge filtration systems. During operation, pressurized water passes through a single medium, where solids are captured. As solids buildup occurs, the cartridge will need replacement for optimal system function.

The obvious caveat to a cartridge filtration system is the need for cartridge replacement. Similar to bag filters, for larger operational demands, the time and material costs for cartridge replacement can reduce overall performance and cost efficiency.

Self-Cleaning Screen Filtration

There are two types of screen filters used for industrial water filtration: a regular screen filter or a self-cleaning screen filter. Both offer similar benefits, but the self-cleaning screen filter is more efficient and performs more effectively overall than a non-self-cleaning screen filter.

Sustainability, agility and efficiency are some of the most important factors when considering an industrial filter and, more specifically, a self-cleaning screen filter. The benefits of a stainless steel self-cleaning screen filter include:

• Uninterrupted flow of water during backwash. This allows the filtration process to continually operate.
• Ease of maintenance.

The self-sustainability via the automatic backwashing and self-cleaning processes, combined with the simplicity of design and ease of maintenance, make a self-cleaning screen filter extremely efficient. For example, some of these filters can be taken apart and reassembled in less than an hour without requiring special tools.

This power plant process cooling application in Florida includes an automatic filter.

Points to Consider for Any Filtration System

When considering a filtration system, the variables to consider can condensed into three primary categories:

• Filter footprint.
• Staff requirements.
• Waste levels.

The footprint of a filtration system can vary according to performance demands and space availability. If a smaller filter footprint can achieve the same result as a larger footprint, however, the smaller footprint option often is the more logical option. This is especially true if space is in high demand and low supply.

Inherently, a simple design and small footprint may provide an uncomplicated experience for staff members maintaining and operating the filtration system. When working with industrial water filtration companies, it is common for the maintenance staff to receive hands-on instruction regarding how to operate, maintain and troubleshoot the filtration system. Filters that are easier to maintain allow companies to operate more efficiently because of the low maintenance demands. This frees up time, energy and resources for other responsibilities and projects.

Finally, one of the most important considerations in selecting an industrial water filtration solution is the amount of wastewater produced by the system. Essentially, the volume and frequency of backwash can be associated with high levels of wasted water and, therefore, disposal costs. Also, there is the importance of environmental sustainability in limiting waste.

The self-sustainability via the automatic backwashing and self-cleaning processes, combined with the simplicity of design and ease of maintenance, make a self-cleaning screen filter extremely efficient.

Two important factors to evaluate with the backwash processes are the amount of water being used and the amount of time the system halts operation to complete the flushing process. Having a system that minimizes waste and operates continuously — even during a backwash — provides obvious efficiency and economic advantages. Thus, when searching for a filtration system, be aware that there exist filters capable of minimizing flow interruptions and maximizing water use.

Every situation is different: Each common filtration system requires a consideration of the pros and cons that the solution offers. Along with the filtration process, itself, there are maintenance, operational, troubleshooting and cost variables to consider.

What is most important, however, is that the best option is selected for the desired performance outcomes. What may seem most economical might actually end up costing more in the long run than the more expensive version. For this reason, it is always important to not only consider cost but energy, maintenance, time, personnel and sustainability aspects of the industrial filtration system for your organization as well. PC