In the water treatment process, granular media filtration plays an important role as a crucial stage to ensure the quality of the final water meets standards.

This system is designed to remove various suspended particles, flocs, metal deposits such as iron and manganese, and acts as a polishing stage (tertiary treatment) before the water is used further in industrial or domestic processes.

Purpose of Granular Media Filtration in Water Treatment

The main purpose of granular media filtration is to:

Remove filterable solids that remain after initial processes such as coagulation, flocculation, and sedimentation.
Lift flocs formed from previous chemical reactions or results from the softening process.
Filter iron and manganese deposits formed due to oxidation, especially if the raw water contains both metals in high concentrations.
Act as a tertiary treatment process in the water treatment system, to improve water clarity and reduce turbidity significantly.

With this multifunctional role, granular media filtration becomes an element that cannot be ignored in the design of a reliable and sustainable water treatment system.

Granular Media Filtration Working Mechanism

The filtration process through granular media does not only depend on one mechanism, but rather a combination of complex physical and chemical processes. Some of the main mechanisms include:

Straining: Particles larger than the pores of the filter media will be directly retained on the surface or between the gaps in the media.
Adsorption: The surface of the media has the ability to attract micro particles or dissolved molecules through molecular attraction.
Flocculation: In the media layer, small particles can collide and form larger flocs, facilitating the capture process.
Sedimentation: Particles with a higher density can settle between the pore spaces of the media due to local gravitational forces.

The synergy of these mechanisms makes granular media filtration capable of producing water with consistently high clarity.

Types of Granular Media Filters

In its application, granular media filter systems are developed in various types based on the direction of flow and operational pressure, including:

1. Gravity Filter

This system utilizes gravity as the driving force of water flow. Water flows from top to bottom through the media layer slowly. Generally used in systems with large capacities and low filtration rates, such as city-scale drinking water treatment plants.

2. Pressure Filter

Uses pump pressure to push water through the filter media in a closed vessel. Suitable for applications with limited space or high filtration speed requirements. Pressure filters are widely used in the manufacturing industry and boiler water treatment.

3. Upflow Filter

In contrast to conventional systems, in upflow filters the water flows from bottom to top. This design minimizes clogging and is suitable for raw water conditions with high solids concentrations.

Each type of filter has its own advantages and disadvantages, so its selection must be adjusted to the process needs and characteristics of the raw water.

Common Media Types in Granular Media Filtration

The success of a granular media filtration system is highly dependent on the type of media used. The following are the most commonly used granular media:

1. Silica Sand

The most popular media used to filter large particles and flocs. Silica sand has a uniform size and shape, making it ideal for initial filtration.

2. Anthracite Coal

This media is used to capture fine particles and has high resistance to physical damage. Due to its lower specific gravity, anthracite is often used as the top layer in dual media systems.

3. Garnet Sand

Garnet has a high density and is used as the bottom layer in multimedia filter systems. Its function is to filter microscopic particles that are not captured by the media above it.

The selection of media not only considers filtration efficiency, but also compatibility with the backwash system and operational life.

Types of Filter Media Layers

The structure of the media layer also determines the effectiveness of the granular media filtration system. There are several types of media layer configurations that are commonly used:

1. Single Media Filter

Using one type of media, usually silica sand. This system is simple, but less effective at filtering micro particles because there is no layer gradation.

2. Dual Media Filter

Consists of two different layers, usually anthracite on top and silica sand below. This system increases filtration efficiency and extends the time between backwashes.

3. Mixed Media Filter (Multimedia)

Has three or more media layers with different size and specific gravity gradations, such as anthracite, silica sand, and garnet. This system allows filtration of particles of various sizes in one pass.

Multimedia filters are the main choice in water treatment systems that require high clarity and long-term performance stability.

Optimal Support for Better Filtration Performance

Lautan Air Indonesia is present as a trusted partner in procuring high-quality granular media, including silica sand, anthracite coal, and others. We understand that every water treatment process has its own challenges, and therefore, we provide solutions tailored to the specific needs of our clients.

In addition to providing materials, we also offer comprehensive technical services, such as:

Consultation on media type selection and filter media layer configuration.
Recommendation of solutions for common problems in granular media filtration systems, such as decreased efficiency, increased backwash frequency, and media fouling.
Technical support related to maintenance and regular media replacement to ensure optimal performance.

As a company with more than four decades of experience in the water treatment industry, Lautan Air Indonesia is committed to providing comprehensive, accurate, and sustainable solutions to each of our partners.

Trust Your Filtration Media Needs to Lautan Air Indonesia

If your granular media filtration system requires media replacement, performance evaluation, or filtration performance improvement, Lautan Air Indonesia is ready to help.

Granular Media Filtration: An Effective Filtration Solution in Water Treatment