Filters for Process Water Treatment Systems
Pure water is critical to the production of a wide variety of products and applications. Water in the pharmaceutical and biotech industries is used as an ingredient as well as for critical cleaning and other process applications. Water is used as an ingredient and is sometimes the product in the food & beverage industry. Several industrial and commercial operations use water as part of their processes or products. Desalination is used when source water in an area has a high level of dissolved solids as the result of salt water intrusion or lack of fresh water. Central water systems in healthcare facilities also use similar systems. The systems used to produce water for this wide variety of industries employ multiple treatment steps, including filtration. Most systems use reverse osmosis (RO) to consistently produce water of high purity.
The filters used may include particle removal filters, resin traps, carbon fines removal filters, system prefilters, tank vent filters, and bacteria control filters. Some of these are optional, but all are used in at least some facilities based on policies and conditions.
Below are schematics of three extensive treatment systems. The first is an example of a system used in the pharmaceutical industry. This system will generate purified water with the additional step of distillation for producing water for injection (WFI).
The second example shows a system that could supply pure water to a variety of other industries like food & beverage manufacturing, chemical processing and even car washes. It uses a reverse osmosis system followed by electrodeionization to remove both dissolved minerals and ions from the water. There are many other examples, but these show the location and function of filters used in high purity process water treatment in a variety of industries.
Finally, an ultra-high purity water system like that used in the electronics and semiconductor industry is shown. Ultra-pure water (UPW) is unique because of the very stringent water purity requirements for manufacturing computer chips, flat screen displays, storage media and other high-tech items. Visit our page on electronics/semiconductor water treatment for more information on those systems.
Not all steps shown in these systems are required, but they may be found in many industrial systems.
Removal of sediment and other suspended particles is critical to the efficient, cost effective operation of any water treatment system. Performed using depth filtration media, particle filters prevent fouling of the initial treatment steps by excess particles. Reverse Osmosis system prefilters preserve RO membrane performance and reduce the frequency of RO membrane cleaning.
Trap filters are used after process water passes through treatment equipment like tanks containing activated carbon powder or softening and deionization tanks contain resin beads. These powders or resins may break down, fracture and release small particles. Filters are used to trap the particles and prevent the contamination of downstream treatment process steps.
There are many possible bacteria and other organisms that could enter the treatment process, but all can be removed using membrane filters. Organisms can enter the system in a number of ways. One is with the source water, which itself often carries non-pathogenic organisms. System maintenance is another common way that bacteria can enter a system. As equipment is opened to replace parts or clean, the internal parts are exposed to environmental air, allowing the bacteria in the air to enter the system.
Bacteria control in pharmaceutical water systems is usually done using heat (maintaining the system at a temperature above 70°C) with additional methods, including filtration, optional. Both diagrams show UV lights followed by filters to remove “bacterial debris” created if bacteria are killed by the lights.Bacteria filters are membrane based with pore sizes of 0.10µm to 0.45µm, depending on the policies of the facility. They will capture most, if not all, of the debris and protect downstream processes.