Use of slow-flow sand filtration to remove nanoplastics from water

Microplastics are small particles that are < 5mm (0.2 inches) in diameter. They are of 2 types: primary and secondary.

Primary microplastics are used in cosmetics, cleansers, etc. Secondary microplastics are obtained vy breaking down larger plastic items, such as water bottles.

Microplastic contamination and its danger to ecosystems and human health have become a major concern. Its presence in water bodies and human and animal organs has lately been on the news and social media.

A new terminology, “nanoplastic,” is increasingly being used, which makes “microplastic” a bit redundant. Nanoplastics measure less than one micrometer in length. They are so small that they can enter the lipid membranes of living cells, affecting their natural functions and causing stress responses in organisms. Worryingly, they have even been found within human organs and blood, although their long-term risks remain unclear.

Addiction to plastics

Plastics are used abundantly for their many advantages like heat resistance, brittleness, and longevity. A plastic bottle or tiffin box may last for a few months or years, but if it is disposed of carelessly and the remains end up in the sea, they may take anywhere from decades to thousands of years to degrade.

Recently, bioplastics derived from plant matter have gained traction owing to their biodegradability and ability to isolate atmospheric carbon. Polylactic acid is one such bioplastic that has seen increased use. However, its low heat resistance and brittleness make it less than ideal compared to plastics such as polyethylene terephthalate. Moreover, its vaunted biodegradability is very poor outside optimal conditions, such as in an industrial composter.

Bioactive sand filtration may be a vital innovation

It is an effortless and consistent process. It can be built without wasting money, but its operation requires trained operators. Raw water is poured on the surface of the filter, where it slowly infiltrates amidst a layer of permeable sand before being emptied from the bottom. It allows microbial biofilms on the aged sand to effectively retain these tiny particles, achieving 99.97% retention of nanoplastics across a multistep process.

This process is only one countermeasure against nanoplastic pollution, but it can be used to still undo some of the damage we have imposed on the environment and lessen our exposure.


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