Our drinking water

Team Flocculators coagulate with mucilage from chia seeds.

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Our team, the Flocculators, did our STEM project this year on the chemistry of our drinking water. Studies have shown that Lake Erie microplastics, those tiny pieces of broken-up plastic debris, absorb pharmaceuticals, pesticides, and metals on their surface.

Fortunately, our source of drinking water from Lake Erie is far out in the lake and at a depth such that very few micro or nano plastics reach us.

To quote Scott Moegling, the Chief Water Quality Manager at Cleveland Water, “There is not much in the raw; very, very little in the finished water we drink. In fact, we have fewer microplastics than bottled water does.” 

That is because aluminum sulfate is used as a coagulant to gather the few plastic particles and sediment into clusters that can be easily filtered out. But by removing one health hazard, is not another being introduced? Many health agencies now recommend minimizing aluminum intake; we no longer cook with aluminum pots and pans in our homes.

Our project was to find an effective plant-based coagulant that could replace aluminum sulfate. We focused on plants that have mucilage and sticky secretions, such as aloe, prickly pear cactus, candelabra cactus, chia seeds, and okra.

After soaking in distilled water overnight to remove the mucilage, the chia seeds gave the most promising results. The mucilage from only one gram of seeds was mixed with 1,500 ml of water containing microplastics. After passing through a screen, only 2.1% of the particles remained. Further filtration through sand resulted in no plastics being visible in the water sample when viewed under a microscope.

While further experimentation needs to be done, using a natural plant-based coagulant proved feasible, removing the need for aluminum sulfate.

Our team, sponsored by Bay Sea Scouts, is entering our project in the eCyberMission STEM competition sponsored by the U.S. Army Education Outreach Program.