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Fall 2010 Research
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Stacked Rapid Sand Filtration

The

Introduction

A stacked rapid sand filtration unit filter is preferable to a conventional rapid sand filtration unit as it requires less water to back wash since the filters are stacked, and use the same water for all filter layers to back washa novel self-backwashing filter invented by the AguaClara team. Its unique stacked geometry allows it to use the same flow rate for the filtration and backwash cycles, without the expensive pumps or elevated tanks required to backwash conventional rapid sand filters. In addition, a stacked filtration system requires a much smaller footprint to achieve the same level of filtrationthan a conventional filter to treat a given flow rate.

A vertically stacked filtration system meets many of the AguaClara Project constraints. Both normal filtration and back wash backwash operations are gravity driven and require no electricity. In additon, it is an open system. The required construction materials (PVC pipes, sand, concrete, brick, and rebar) are relatively cheap and available in Honduras. Most importantly, stacked rapid sand filtration is proven to consistently lower the effluent to below 1 NTU. the US EPA standard of 0.3 NTU.

Further Reading

Proof of Concept Paper
General Filtration
Current Challenges
Past Challenges