Biological contaminants pose a serious problem for water supplies, wastewater, and public health. These include bacteria, viruses, fungi, protozoa, biotoxins, and organic compounds resulting from biological degradation. Various methods are used to remove these harmful compounds, including chlorination, UV irradiation, reverse osmosis , and activated carbon adsorption .
Thanks to its porous structure, high surface area, and strong adsorption properties, activated carbon is ideal for removing biological contaminants and their byproducts. This article examines in detail the role of activated carbon in removing these compounds, its mechanism of action, advantages, limitations, and industrial applications.
What are biological contaminants?
Biological pollutants are substances of living origin or products of microorganisms. These include:
-
Pathogens such as E. coli, Salmonella, Legionella, etc.
-
Viruses such as rotavirus, norovirus and adenovirus
-
Fungi and mold
-
Protozoa such as Giardia lamblia and Cryptosporidium
-
Bioorganic compounds such as endotoxins, mycotoxins and microbial metabolites
These compounds can cause digestive problems, infections, respiratory diseases, and immune system disorders in humans.
The role of activated carbon in the removal of biological contaminants
1. Absorption of biological organic compounds
Activated carbon is very suitable for removing organic compounds produced by the activity of microorganisms, such as:
-
internal toxins
-
Mycotoxins
-
Phenolic materials
-
Odor-forming substances (e.g. sulfides)
-
Biopolymers
These compounds are commonly found in industrial wastewater, surface water, and biofilters.
2. Indirect removal of microorganisms
Activated carbon itself does not kill all bacteria and viruses, but it does the following:
-
Microorganisms can settle in its porous environment .
-
Absorbs nutrients and thereby reduces the growth of microorganisms.
-
In combination with silver or other antibacterial substances, it has a stronger antiseptic effect.
Types of activated carbon for removing biological contaminants
1. Powdered activated carbon (PAC)
-
Rapid absorption of bioorganic pollutants
-
Suitable for injection into process pipes or tanks.
2. Granulated activated carbon (GAC)
-
Formation of a stable layer for the passage of water or wastewater.
-
Suitable for industrial and household filters .
3. Modified activated carbon (e.g. Ag-GAC)
-
Silver-impregnated charcoal prevents bacterial growth.
-
For drinking water treatment and hospital systems
Mechanism of action of activated carbon in the removal of biocompounds
adsorption
Activated carbon, especially in medium and small pores, adsorbs biologically active compounds through van der Waals forces, hydrogen bonds and π-π interactions.
Ion exchange and deposition
Some biological compounds carry an electrical charge (e.g. toxins) that can interact with carbon groups on the surface and be absorbed.
Material trap
Viruses and small microorganisms can become trapped in the pores of the coal, especially in combination with mechanical filtration.
Industrial and environmental applications
1. Drinking water treatment
Granulated activated carbon is used in household filters and municipal water treatment systems to remove odors, flavors, organic compounds, and in some cases, viruses.
2. Wastewater treatment in hospitals
Hospital wastewater contains biological and organic compounds such as antibiotics, drug-resistant viruses, and pathogenic microorganisms. Activated carbon plays a crucial role in the final phase of wastewater treatment.
3. Food and pharmaceutical industries
In these industries, activated carbon is used to remove biological waste, mycotoxins, and unwanted metabolic compounds.
4. Biotechnology industry
In the production of enzymes , biopharmaceuticals and cell cultures, activated carbon is used to remove organic contaminants and biopolymers.
Benefits of using activated carbon to remove biological contaminants
-
Effective absorption of bioactive organic compounds even in low concentrations.
-
Non-toxic and environmentally friendly.
-
Higher efficiency when combined with other methods such as UV irradiation or chlorination.
-
Some types are recyclable.
Restrictions and important points
-
Doesn’t kill germs : Activated charcoal can absorb bacteria, but it won’t kill them unless combined with an antimicrobial agent.
-
Potential for biofouling on carbon surfaces (biofouling) : If not cleaned regularly, carbon surfaces can become a breeding ground for bacteria.
-
Rapid saturation with water with high organic load : must be replaced or replenished quickly.
Which activated carbon is best for removing biological compounds?
| Special feature | The right activated carbon |
|---|---|
| Virus removal | Medium opening, GAC Silver |
| Removes fungal toxins. | Polyaluminium chloride with high surface area |
| Removal of small bioorganic compounds | GAC or PAC from coconut shells |
| industrial and medical wastewater | Activated carbon has a strong adsorption capacity. |
Future research: Nanocarbon and biotechnology
Researchers are investigating the use of nanoactivated activated carbon or activated carbon modified with enzymes and biopolymers to improve the adsorption efficiency of biocomponents. Furthermore, the combination of activated carbon with photocatalysts such as titanium dioxide opens up new possibilities for the purification of microbial compounds.
Finally
Activated carbon, especially in powder and granular form, is one of the most effective methods for removing biogenic organic compounds from water and wastewater. While it doesn’t directly kill microorganisms, it can adsorb toxins, biopolymers, and (to a limited extent) even viruses, thus playing an important role in the health of aquatic systems. The selection of the appropriate type of activated carbon, careful design of the filtration system, and proper maintenance of the activated carbon bed are crucial factors for effectiveness.