A bio-sand filter is a simple household water treatment device that improves upon traditional slow sand filters. It removes suspended solids and pathogens from water through physical and biological processes occurring within the filter media, which is covered by a biofilm. This filtration method effectively reduces turbidity, protozoa, viruses, bacteria, and heavy metals. Studies have shown that using a bio-sand filter helps reduce waterborne diseases such as diarrhea.

EcoConcern has developed an innovative filtration method utilizing different layers of sand. The bio-sand filter consists of key components, including a metal frame, filter media, and a 1,000-liter HDPE tank. It has a filtration capacity of 180 liters per hour and operates through a system of four HDPE heavy-duty tanks. The first unit is the sedimentation tank, which is topped by an aeration tower made of four buckets. The aeration tower is fitted with a steel mesh to prevent bird entry. A fiberglass rolled sheet is placed in the middle of the sedimentation tank, with a washout valve at the bottom. Water is then transferred to the reservoir tank through a 50 mm CPVC pipe.

A ball valve and a pipe guide in the reservoir tank allow decanted clear water to pass into a 500-liter pre-filtration tank, which contains gravel as the filter media and a metal screen to separate the sludge zone. This tank can be placed on metal stands or brick masonry for leveling. After passing through this stage, the water moves to the filtration tank, which contains fine sand and gravel as filter media. All four tanks are supported by a metal frame measuring 8x4x6 feet, constructed using 25x25x5 equal-angle metal sections and 8 mm rods. The filtered water is then tested to ensure it meets the Nepal Drinking Water Quality Standards before being used for drinking and other household purposes. This improved bio-sand filter effectively removes iron concentration, turbidity, and E. coli, providing a reliable and sustainable water treatment solution. The design is based on test reports supplied to various customers, ensuring its effectiveness in different settings.

For more details: Bio-sand Filter Brochure