BushProof Biosand Filter

Target SDGs

Market Suggested Retail Price

$1,687.00

Target Users (Target Impact Group)

Household

Distributors / Implementing Organizations

BushProof

Competitive Landscape

Direct competitors include PurAll Water Purification, DHAN Biosand Filters, Ideas at Work Biosand Filter, and Hydraid® BioSand Filter.

Manufacturing/Building Method

Individual production by artisans and trained builders using locally available materials such as sand, water and cement. BushProof sells metal moulds for casting concrete housings in which the biosand is placed. There are also guidelines for producing moulds.

Intellectural Property Type

Open-source

User Provision Model

BushProof Biosand filters are sold through trained artisans and builders. BushProof trains individuals to make the systems and sells the moulds required to manufacture the filters.

Distributions to Date Status

As of March 2004, BushProof has sold 670 units in Madagascar, Africa: 600 for rural households and 70 in urban households.

Design Specifications

BushProof Biosand filters work according to the principles of a general BioSand Filter (BSF) whereby layers of sand and gravel are housed in a concrete container. The water level is maintained above the sand layer by setting the height of the outlet pipe. This shallow water layer allows a bioactive layer to grow on top of the sand, which contributes to the reduction of disease-causing organisms. A diffuser plate with holes in it is placed on the top of the sand layer to prevent disruption of the biolayer when water is added to the system. To use the BSF, users pour water into the BSF, and collect finished water out of the outlet pipe into a bucket. The BushProof Biosand Filters relies on intermittently operated BSF technology. In this design, the drain pipe is raised 1-8 cm above the sand level, which ensures that the water level is just above the sand. Even when water is not continually added to the filter, oxygen can still permeate into the water to reach the bioactive layer by diffusion across this shallow layer of standing water. When the flow rate becomes unacceptably low, the filter can be cleaned by removing accumulated dirt from the top few centimeters of sand. There are several ways to do this, but all disturb the biological layer which results in less effective filtration for some time. Some methods are less disruptive than others.

Product Schematics

Technical Support

BushProof-trained artisans provide technical support, and an instruction booklet can be accessed online.

Replacement Components

All materials are locally available and can be sourced by the builder.

Lifecycle

About 4 years according to research conducted by Medair, Kenya

Manufacturer Specified Performance Parameters

Intermittently-operated slow sand filters can be made as small units that supply clean water for a family. Under ideal conditions, a biosand filter of this size produces 1 liter of clean water per minute. Even at a much slower flow rate, however, the filter can be practical. A filter that fills a 20-liter jerry can in two hours can be convenient to a family, even though this equals a flow rate of only 0.16 liters per minute.

Vetted Performance Status

Safe Household Drinking Water via Biosand Filtration Pilot Project Evaluation and Feasibility Study of a Biosand Pitcher Filter Water, advocacy, sanitation and hygiene: Lessons learnt from Tearfund’s global water, advocacy, sanitation and hygiene programme 2007–2012. Written by Murray Burt and Bilha Joy Keiru.

Safety

Concrete filters can be heavy and difficult to move and transport.

Complementary Technical Systems

Safe water storage containers.

Academic Research and References

Compliance with regulations

Although Biosand filters have been tested to reduce pathogen load in drinking water, they do not consistently comply with WHO standards for drinking water.

Evaluation methods

Field evaluations. Examples include, Medair Kenya – Biosand filter project evaluation report Results showed that filters were still performing very well, producing drinking water of acceptable purity to the majority of households that bought one 4 years prior.

Other Information

In 2005, BushProof received the World Bank global Development Marketplace award.