Ideas at Work Biosand Filter

Target SDGs

Target Users (Target Impact Group)

Household, Community

Distributors / Implementing Organizations

Ideas at Work

Manufacturing/Building Method

The Round Bio Sand Fil­ter is manufactured on demand via a mould unit. The main parts of the mould unit are shown in the exploded view below are: 1) the puller, 2) an inner mould, and 3) outer mould. The mould is bolted together, turned upside down and fit­ted with a cop­per out­let pipe. A con­crete mix is then poured in the mould and com­pacted down. After sev­eral hours the puller is used to remove the inner mould after which the outer mould can be removed reveal­ing the fin­ished fil­ter shell. The fil­ter is then filled with sand and gravel layers. The mould is bolted together, turned upside down and fit­ted with a cop­per out­let pipe. A con­crete mix is then poured in the mould and com­pacted down. After sev­eral hours the puller is used to remove the inner mould after which the outer mould can be removed reveal­ing the fin­ished fil­ter shell. The fil­ter is then filled with sand and gravel layers.

Intellectural Property Type

Select Type

User Provision Model

No longer available for purchase.

Distributions to Date Status

Unknown.

Design Specifications

The IaW Round BSF is based on a design by MedAir and has a ‘round’ form instead of a ‘square’ form typical of most BSF units, reducing the mass and material costs of the unit. This design also makes it easier to move the unit by rolling it on its bottom edge. This is achieved by relatively simple modifications to a standard round cement drain pipe moulds. To operate the IaW BSF, con­t­a­m­i­nated water is poured into the unit at the top. The water passes through the dif­fuser plate and the sand and gravel layers. Head pressure pushes water through the copper pipe in the base to the outlet point. Biological con­t­a­m­i­na­tion is reduced through the actions of adsorp­tion; mechan­i­cal fil­ter­ing, pre­da­tion (bio­log­i­cal layer) and nat­ural die off. The typ­i­cal flow rate of the unit is around 60 L/hr. Dimen­sions of the fin­ished BSF: Outer diam­e­ter: 35 cm; Inner diam­e­ter: 30 cm; Height: 95 cm; Weight: 60 kg Dimen­sions of the fin­ished BSF: Outer diam­e­ter: 35 cm; Inner diam­e­ter: 30 cm; Height: 95 cm; Weight: 60 kg

Product Schematics

Technical Support

Users are responsible for maintenance and repair.

Replacement Components

This is no longer in production.

Lifecycle

Unknown.

Manufacturer Specified Performance Parameters

The typ­i­cal flow rate of the unit is around 60 L/hr.

Vetted Performance Status

The Biosand Filter (BSF) is a proven technology, which removes pathogens such as bacteria, protozoa and helminth. BSFs are also somewhat effective for the removal of virus (CAWST 2009). Physical parameters such as turbidity and iron are also eliminated from drinking water. However, dissolved chemicals (such as organic pesticides or arsenic) are not removed. The treated water generally has an agreeable colour, taste and odour. The table below shows the biosand filter treatment efficiency in removing pathogens, turbidity and iron (adapted form CAWST 2009). Additional BSF evaluations have been aggregated by CAWST and include randomized controlled trials and field studies. Additional BSF evaluations have been aggregated by CAWST and include randomized controlled trials and field studies.

Safety

No cited hazards.

Complementary Technical Systems

Safe water storage.

Academic Research and References

Compliance with regulations

Although Biosand filters are known to reduce pathogen load in drinking water, this technology does not consistently meet WHO requirements.

Evaluation methods

Evaluation methods for this specific design of Biosand filter has not been evaluated. However, Biosand filters have been evaluated both in field and laboratory settings across the globe.

Other Information

None.