Biological filtration is a wastewater or water treatment process that uses microorganisms living on a filter medium to remove pollutants.
What is Biological Filtration?
Based on the definition, biofiltration (or biological filtration) is a specialized filtration process. It relies on a filter medium that is porous, such as sand, granulated active carbon (GAC), or various synthetic carrier materials. The crucial element is that this medium is actively colonized by indigenous microbial communities. These microorganisms are not just passive inhabitants; they are essential to the process because they perform at least one of the essential treatment functions.
Think of it as using natural biology to clean water or air.
How Does It Work?
In essence, contaminated water (or air) passes through the porous filter medium. As it does, the microorganisms living in the porous structure consume or transform the pollutants.
Key Components and Process
- Porous Filter Medium: Provides a large surface area for microbes to attach and grow. Examples include:
- Sand
- Granulated Activated Carbon (GAC)
- Synthetic polymers or ceramics
- Microbial Community: Diverse groups of bacteria, fungi, and other microbes that live on the medium, forming a biofilm. These microbes break down or convert contaminants into less harmful substances (e.g., converting ammonia to nitrates in aquarium filters).
- Contaminant Removal: As water or air flows through, pollutants come into contact with the biofilm and are metabolized by the microbes.
Applications of Biological Filtration
This process is widely used in various fields:
- Wastewater Treatment: Removing organic matter, nitrogen compounds, and other pollutants.
- Drinking Water Treatment: Removing taste and odor compounds, iron, manganese, and sometimes disinfectants.
- Aquariums and Aquaculture: Breaking down harmful ammonia and nitrite produced by fish waste into less toxic nitrate (known as the nitrogen cycle).
- Air Pollution Control: Removing volatile organic compounds (VOCs) and other gaseous pollutants from industrial emissions.
Benefits
- Environmentally friendly (uses natural processes).
- Often cost-effective for removing certain pollutants.
- Can handle fluctuating pollutant loads.
In summary, biological filtration is a technology where microbes living on a porous material clean water or air by breaking down contaminants.
