Water Filtering Systems

What is a Water Filtering System?

An essential water filtration system comprises four key elements necessary for effective filtration. These include a filtering medium, a liquid containing suspended solids, a driving force typically generated by pressure differences between two locations, and the filter mechanism itself that holds the medium and the liquid while facilitating the driving force. During the filtration process, a byproduct known as 'cake' is produced. The system is equipped with features to manage the removal, cleaning, and drying of this cake byproduct.

Components of a Water Filtration System

To function effectively, a fundamental water filtration system relies on four essential elements. These are the filtering medium, a liquid containing suspended solids, a driving force typically generated by pressure differences across two points, and the filter apparatus that houses the medium and liquid while facilitating this force. The filtration process generates a byproduct known as 'cake,' and the system includes specific features for its extraction, cleaning, and drying.

Filter media can be categorized into two primary types. The first category includes thin barriers such as filtration cloths, screens, or standard laboratory filter papers. The second category consists of thicker barriers, including sand beds, porous ceramics, coke beds, porous metals, and filter aids commonly used for fluids containing gelatinous precipitates in industrial applications. For more information on filter media, visit this resource.

Thin filter media consist of a single barrier with openings that are smaller than the particles intended for separation from the liquid. In contrast, for situations where a gelatinous cake might obstruct the pores of the filter medium and disrupt the filtration process, a sand bed can be employed. Thick filter media, like sand beds, can have significantly larger dimensions compared to the particles being filtered out. As the liquid flows through the medium, the particles navigate through a convoluted path and are eventually captured in the smaller voids within the filter material.

The filtering force drives the fluid to be filtered and makes it pass through the filtrate medium. The filtering force is brought by the force of gravity or by a generated centrifugal force or application of a vacuum below the filter to create the pressure difference. Centrifuges with a bowl with a permeable filter medium can be considered as the centrifugal force replaces the gravitational force which is significantly greater than gravity. For the case of a laboratory filtration process, a partial vacuum is applied at the bottom to boost the rate of the filtration.

How a Water Filtering System Works

In most cases, the water filtering system works by capturing the undesirable elements and impurities inside the water and thereby allowing only clean water to pass through.

Residential water filtration systems often use thin film composite membranes designed to filter out even the tiniest microscopic bacteria while allowing purified water to pass through. These systems capture sediments and contaminants due to their extensive surface area as the water moves through the medium. Activated carbon functions to attract and hold lead and other volatile substances, similar to how a magnet attracts metal. Additionally, the chemical reactions within the filter help to decrease and neutralize substances such as chlorine.