In the rural areas of Madagascar only 29% of the population has access to clean water and 10% has access to improved sanitation. It has been estimated that environmental risk factors, such as inadequate access to clean drinking water and proper sanitation, are responsible for 94% of the diarrheal disease burden. This study was focused on testing a point-of-use technology called the Tulip filter, which is a siphon ceramic candle filter impregnated with silver. The purpose is to assess its feasibility for implementation in rural regions of Madagascar through a laboratory study performed at the University of South Florida.

The study tested the Tulip filters for turbidity, total coliform, and E. coli removal for various types of water. Each filter processed synthetic water classified as control (tap water, <1 NTU), low turbidity (5-7 NTU), medium turbidity (25-35 NTU), or high turbidity (60-80 NTU). Approximately once every 100 L the filters processed pond water to test coliform removal. Furthermore, the particle size distribution was measured to analyze the effectiveness of filter to remove various particle sizes. Two of the seven Tulip filters tested had some quality control issues with the glue connecting the ceramic candle to the plastic cap and failed at 350 L.

Of the functioning filters, the turbidity removal ranged from 93% to 98% with none of the 779 samples taken from 4 filters above the WHO recommended 5 NTU for drinking water. The log removal of total coliforms was about 3.90 to 4.16 and achieved an average of 1 CFU/100mL of E. coli in the filtered water. WHO guidelines consider water with 1-10 CFU/100 mL a "low risk" and all but one of the working filters had E. coli and total coliform concentrations within, or below, this range for all samples (n=20 for each filter). The filters also showed an average of 96% removal of particles of all size ranging from 0.5 to 10 μm.

This study finds that the Tulip filter is an appropriate of point-of-use technology that enables rural areas access to "low risk" water, at a low cost and with minimal maintenance. This study also reinforces the importance of adding silver or another biocide to ceramic filters because particles of sizes up to 10 μm are able to pass through the filter. This is particularly a problem because pathogens can range from 0.01 μm to 100 μm.