Bio sand refers to the biosand filter (BSF), which is a point-of-use water treatment system adapted from traditional slow sand filters.
Biosand filters are a simple and effective technology used primarily in households and communities to improve drinking water quality. They work by removing pathogens and suspended solids from water as it passes through a column of sand.
How Biosand Filters Work
The effectiveness of a biosand filter comes from a combination of physical and biological processes:
- Physical Filtration: Suspended solids are trapped in the upper layers of the sand bed.
- Biological Processes: Biosand filters remove pathogens... using biological and physical processes that take place in a sand column covered with a biofilm. This biofilm, also known as the "schmutzdecke" or "biolayer," develops on the surface of the sand. It contains microorganisms that consume or inactivate pathogens and break down organic matter in the water.
- Adsorption: Pathogens and other particles can stick to the surface of the sand grains.
- Predation: Some microorganisms in the biolayer prey on pathogens.
Key Features of a Biosand Filter
Based on the reference and common understanding:
- Point-of-Use: Designed for use in the home or community, treating water immediately before consumption.
- Adaptation: Adapted from traditional slow sand filters, making the technology simpler and more suitable for intermittent use and decentralized settings.
- Components: Typically consists of a container (concrete, plastic, etc.) filled with layers of sand and gravel, with a diffuser plate at the top and a collection pipe at the bottom.
- Process: Water is poured into the top, percolates slowly through the sand bed and biolayer, and exits through the outlet pipe.
Why are Biosand Filters Important?
Biosand filters provide a practical solution for improving water safety in areas where access to treated water is limited. They can significantly reduce the presence of harmful bacteria, viruses, and protozoa, helping to prevent waterborne diseases.
