Can we rely on conventional water treatments to remove microplastics?

Concerned about microplastic in your water but don't know what to do? Come and learn with us how to remove MPs at home and on a large scale

Microplastic. Image created with Open AI

In my previous article, we explored the potential health risks of having microplastics in our bodies. In this one, we will explore how to reduce our annual dose, which ranges from 74,000 to 121,000 MPs, by treating our drinking water. Previous research shows the existence of MPs in ground, surface, tap and bottled water ranging from 0 to thousands of MPs/L depending on the location, climate and other factors. Although the lack of proper MP analysis, quality assurance and control methods, standards, etc. is results in hindrances in exploring the topic, Scientists still have been researching the effectiveness of various conventional methods as well as designing more advanced and feasible methods to remove MP’s from our drinking water.

A chunk of 550 million households were consuming bottled water globally in 2024; that's roughly more than 446 billion liters of water per year. With our lifestyle, we can only assume the number will potentially increase in 2025 and so on. In 2021, it was reported that the concentration of MP is significantly higher in bottled water than in tap water. The results showed MPs in bottled water from 0.0001 to 930 MPs/L, whereas MPs in tap water ranged from 1.4 MPs/L to 5.42107 MPs/L, making bottled water quite a big source of MPs in our bodies. There is very little that can be done on the provider’s side to remove MPs from bottled water, as the contamination is mainly linked to the decomposition of Plastic containers and a solid alternative to replace plastic is still a far-fetched dream. Even if we found one, adapting it on a global level would be another challenge. Hence, a more simple and doable thing is to remove them at home using our kitchens. Designing a method that is very affordable, effective, and reliable can only be expected from China. A team from Guangzhou Medical University and Jinan University in China experimented with the removal of MPs from both soft and hard water by boiling and then filtration. In some cases, they achieved up to 90% efficiency. While the removal of MPs was more effective on hard water due to the high concentration of calcium carbonates, the boiling water strategy still seems most promising as it removes even NMPs.

On a large scale in domestic water treatment plants, it has been observed that conventional water treatment methods, such as coagulation, sedimentation, sand filtering, and membrane separation, are effective in removing MPs to some extent. Activated carbon filtration removed only 6% of MPs, Coagulation-sedimentation processes were found 40.5–54.5% efficient, while air flotation, with coagulation/flocculation, flotation, sand filtration, and activated carbon filtration, removed the most MPs, up to 83%. While advanced processes like ultrafiltration, nanofiltration, and reverse osmosis have nearly 100% removal efficiency. This impeccability comes with a high cost and a drawback of choking filter media from a high concentration of MPs. Then, there are some other alternatives specifically built to only remove MPs from water, like magnetic nanoparticle composites. A study prepared Magnetic Polyoxometalate-Supported Ionic Liquid Phases (magPOM-SILPs), which resulted in 100% removal of 1 μm and 10 μm microplastic orbs. The good thing is that composites can easily be removed from water and are reusable, making them a sustainable choice in the long run.

The health effects of having microplastics in our bodies are still unclear; there is a need for further research to make sure the claims are not over- or underrated. Even if we do not have concrete data and results to show what damage plastic can do, past research shows that microplastic isn't the best at dealing with biological systems like human bodies. While up to 90% of the MPs ingested by humans are excreted naturally, we still need to reduce our uptake of MPs by treating our water and reducing contamination in our food sources.