clean water cleaned with anthracite filter media

Anthracite Filter Media, Water Filtration and Wastewater Treatment

In this article, we’re going to provide some detailed information regarding anthracite water filter media. We’ll be exploring the uses, the types and options you have regarding this product.

But before we do, let’s provide a high-level definition of what Anthracite Water Filter Media is, then we’ll dive into more detail.

What is Anthracite Filter Media? Anthracite media is a filtration medium mainly used for water filtration and wastewater treatment. It has benefits such as higher service flow rates, longer filter runs, reduced backwash rates, reduced head loss compared to single media filter beds and generally extends the life of the filter beds.

But before we continue, let’s just back up a little further and make sure we understand what Anthracite actually is. Then we’ll go on to discuss the various uses within water filtration and wastewater treatment

What is Anthracite?

Similar to coal, Anthracite is a high-hardness carbon content mineral. Like most minerals, anthracite is formed over millions of years of deposited plant layers, combined with pressure and temperature.

Of all the carbons, this black and rather shiny mineral is the hardest of them all - with a high carbon content of over 95%. In fact, Anthracite used for Water Filtration is usually specially selected from deeper mines, where, due to higher pressures, the carbon content is particularly greater.

Pot filled with milled anthracite

Why Anthracite Is Used as Water Filter Media

In simple terms, Filter media are materials that facilitate the passing of raw untreated water through them, while retaining any impure particle matter. Each filter media has specific characteristics such as size, weight, activated or non activated, gravity and more, all of which affect and impact their performance at certain filtration tasks - and this is why Anthracite is a popular choice.

For drinking water, wastewater filtration and water for industrial use, Anthracite has ideal properties for purifying and clarifying this type of water - when utilized in combination with other sand filters.

Because of this, Anthracite water filter media is one of the most widely used filtration media around the world. This is because it brings certain benefits...

Benefits of Anthracite Water Filter Media

Here’s a quick rundown of the benefits of using Anthracite as a Water Filter Media:-

● The shape of particles allows suspended particles to be retained over the depth of the filter bed
● It complements mixed filters very well, particularly Green and Manganese Sand filter media
● Allows for higher flow rate compared to sand
● Smaller pressure drop compared to sand
● Faster backwash rate compared to sand
● High resistance to a variety of chemicals
● Greater physical strength for use in industrial water purification.
● Prevents filtration blockage due to Synedra, Microcystin and more.
● Prevention of mad ball forming at the surface of the sand layer.
● Can easily transform from Single Media Filtration to Dual Media Filtration (sand)
● An ideal carrier for BioFilm Treatment

Water purification plant

Physical Properties of Anthracite

Dry Bulk Density800kg/m3
Specific Gravity1.6+ .05 g/cm3
Effective Size1.2 - 2.4mm
Uniformity Coefficient1.5 - 1.7
Bondwork Index20 - 22 BBW (KwH/mt)

Why Anthracite Is Used for Deep Bed Water Filtration

Deep bed filtration is a fast and very efficient method for removing small particles from liquid, and works particularly well with Water. This method of particle dispersion in liquids and water are common in a wide range of different industries and in particular the civil purification industries concerning water and wastewater purification.

Anthracite is perfect for this type of industry as the shape of the particles lend themselves extremely well to deep bed filtration uses. Their strength and other properties - as outlined above, make them an ideal source for these applications.

water treatment plant where acti-desolidex or anthracite could be used

What Exactly Is Multilayer Filtration?

Multilayer simply means there are a variety of layers in deep beds that provide filtration at different levels.

So in contrast to methods like cartridge filtration, the multi-layer filtration variant - which includes gravel in various sizes and forms, as well as anthracite, represents a deep-bed filtration.

With multi-layer filtration, the water passes through various layers of filter material with increasing fineness in the direction of filtration. Gravel filtration or multilayer filtration, in combination with flocculation, is particularly effective in the treatment of river water. When this process is followed, it usually also involves a process stage of sedimentation. Gravel and multi-layer filters are regularly cleaned by back-flushing.

Why Anthracite Media Is Good at Multilayer Water Filtration

We’ve already mentioned how Anthracite has strength and durability, and how particle shapes lend themselves well for Deep Bed filtrations. So with multi-layer filtration, any water requiring purification passes through a number and variety of layers of filter material - or filter media, with increasing fineness of media along the direction of filtration.

Having multiple layers allows the extraction of a variety of particle sizes and types passing through the layers. Thereby ensuring a purer outcome at the end of the process. Multilayer Filters can cover a large number of solids to be extracted.

Let’s explore a little more about Multi Layer Filtration for Water and Wastewater, as that is a popular and primary use for Anthracite carbon water filter media.

Anthracite Use in Multilayer Beds

A technique widely used for the purification of water and wastewater is the use of Multilayer beds. The main applications for this area - and for anthracite use within this area tend to be in urban wastewater purification stations, drinking water treatment plants and desalination plants.

Filtration is a process flowing through a single filter bed, or several that overlapping filter beds. In multilayer beds, usually the less dense filter media (like Anthracite) is placed on the upper layer of the bed. Before passing through to other layers such as Finer Sand, Coarse Sand, Fine Gravel, and Coarse Gravel. Each layer playing it’s part to remove particulate matter from the water.

Anthracite is used as it provides reliable improvements in turbidity extraction, mostly due to its capacity to effectively retain solids.


Why Is Gravel Used Alongside Anthracite?

In multi layer sand filters, the Anthracite is usually deployed on the top, above a number of sand layers that are designed to filter out finer particles from the water. Gravel normally forms part of the base layer and facilitates the purified water passing through to outlets. If sand were the base layer, these outlets would probably be clogged. Gravel helps prevent clogging from occurring.

So Finally...

We hope this article has been helpful in providing a greater understanding of Anthracite, it’s uses, qualities and benefits in Water Filtration, Water Filter Media and Water Treatment.

Here at African Pegmatite we specialize in the milling and processing of these exact kind of base materials and minerals, so if you’re in the water purification, wastewater or industrial water treatment industries, then we instinctively know what your needs are. So whether you already know your requirements, or indeed you need help in getting them right, then get in touch with us now and one of our experts will be happy to assist.