Filter Matters
Gabbie Lee
Prince of Wales Secondary
Floor Location : J 181 R

Filter Matters is an investigation on the filtration ability of tree bark fibre as compared to sand, in efforts to identify a low-cost water filtering material that can be used in emergencies. Flow rate, turbidity and bacterial microbe count were determined and used to evaluate the effectiveness and merit of each material.

Many people worldwide live without access to safe, drinkable water and many more have faced some water related emergency. I wish to help to solve this water problem with filtration. I want to see if some materials in nature, such as cedar bark, would provide inspiration or a solution.

I hypothesize that bark fibres will filter out more particulates and microbes compared to sand. The dense fibre structure of mashed cedar bark, microscopically, will arrange itself like a maze with lots of dead ends which provide room to hold suspended particles or microbes measuring 1 to 10 μm. Whereas, the arrangement of sand in a filter would be more like a pinball machine, where the dirt or small particles, simply tumble and bounce around the gaps between grains of sand and eventually having lower chance of getting trapped.

By capturing digital pictures of Secchi disc for turbidity and through microscope for bacterial activity, images were processed in Photoshop, then data were acquired and analyzed. The results agree with my hypothesis and provided meaningful insight for future development of a functional water filter.