What exactly is anthracite?
Anthracite is a type of coal with the highest carbon content, exceeding 95 percent by weight. Anthracite, like most minerals, forms over millions of years of deposited plant layers combined with pressure and temperature.This black and rather shiny mineral is the hardest of all carbon materials.
Why is anthracite used as a filter medium for water?
Filter media, in simple terms, are materials that enable raw, untreated water to pass through while keeping any impure particle matter behind and allowing cleaner water to pass. Each filter medium has its own set of features, including size, weight, whether it is activated or not, gravity, and so on. All of these qualities result in varying operating performance for specific filtration jobs; often, a compromise is attempted to deliver the most durable system or a system at a lower price point.
Why is anthracite used as a filtering media?
Anthracite is a popular choice because of its broad contamination tolerance and ease of shaping it into a filter grade product.
Anthracite has ideal properties for purifying and clarifying drinking water, wastewater filtration, and industrial water, especially when used in conjunction with other sand filters or as a component of a dual- or multi-media filtration system.Anthracite is one of the most widely used water filter mediums in the world due to its ideal properties, relative ubiquity, and ease of use.
Anthracite is a type of coal with a high carbon content that is compact and hard. These properties make anthracite useful for more than just energy production, despite the fact that it is one of the cleanest and most energy-producing types of coal. Anthracite, unlike its relative bituminous coal, is not commonly used as a source of activated carbon, primarily because it is not as easy to activate as bituminous coal.
What are the benefits of Anthracite Carbon Media?
1: It is possible to incorporate it into existing sand filters
There are times when a municipality begins to experience problems with an existing water treatment system. Unfortunately, the cost of replacing those systems with new ones can be prohibitively expensive.However, in the case of sand filters, the addition of Anthracite carbon media may be possible to retrofit these filters. Whether the problem is excessive back washing or head loss, inefficient treatment, or changes in the influent water quality or flux, adding anthracite to the filter bed can be a simple and economical remedy. Depending on how the bed was originally built up, some altering of the structure may be required. The best case scenario, however, is to simply add anthracite to the top of the filter system. It has a lower specific gravity than sand.
Uniformity is an enemy of filtration system. It affects the flow of fluid through the bed and how particulate matter is collected within the granular voids, example sand. Anthracite is typically produced with a uniformity coefficient less than two. The lower the coefficient, the smaller the difference in granule size. Smaller granules in coarse filter media (such as anthracite) can capture smaller suspended solids. This prevents deeper penetration into the filter bed and accelerates media clogging. Sand has a higher uniformity coefficient and thus clogs more frequently when used in a singular media filter configuration.
Sand particles are more spherical in shape, whereas anthracite particles are sharp and angular. According to research, more angular structures result in more effective back washes. This could be because it agitates the backwash water, causing particulate matter to be dislodged from the media surfaces. Back washes that remove all or most of the captured suspended solids are critical to increasing filtration run times and improving treatment quality.
During the course of their operation, filter Medias may be exposed to a variety of pollutants as well as erosion. Each of these events has the potential to degrade the media in question over time, resulting in media loss as well as changes in the gradient and stratification of multimedia filters. Degradation will also affect the rate of blockage by reducing the size of the media particles. Anthracite is a tougher type of coal that is recognized for its long life. It can withstand the presence of corrosive chemicals as well as erosion over time.
5: Can carry biofilm
To enable sand filters to remove bacteria from the influent stream, it is advantageous to allow the formation of a biofilm on the surface of a portion of the media, typically the top. When it comes to biofilms, the effective surface area is everything. More surface area means more biofilm to accumulate on. Fortunately, anthracite has a high specific surface area and a high void percentage. The void percentage is calculated as a ratio of the empty volume in a filter matrix to the volume of solid media. A high percentage means more space between the anthracite granules, which is important for biofilm formation and prevention of clogging.