Reducing plastic pollution with plants

by ZSL on

Today – Thursday 8th June – is World Ocean’s Day, a global celebration of all things under the sea and a time to think positively about tackling the challenges that face this underwater environment, which include the massive issue of ocean plastic. 

A recent study showed that between 5.5 and 14.6 million tonnes of plastic waste enters the ocean every year, and predictions are that if nothing changes, in 2025 there will be one tonne of plastic for every three tonnes of fish in the ocean.

So what better way for ZSL to celebrate World Oceans Day than by inviting students and advisors from the Institute for Advanced Architecture of Catalonia to showcase how their innovative solutions could help to both reduce plastic pollution in the oceans, whilst harnessing biological systems to meet the world’s energy needs? 

Recycled plastic bottle algae exhibit
The plastic bottles contain microalgae and shredded metal from a drinks can

These scientists and designers have been working on solutions that harness nature’s own engineers – plants – to capture energy from the sun through the process of photosynthesis and turn it into electricity that can power human technologies. 

This is done by combining them with electrodes to form biological solar cells, or Bio Photo Voltaic (BPV) cells – a concept developed by Paolo Bombelli and his research team at the University of Cambridge, which was then advanced by the Arribada Initiative to advance into a field-deployable solution capable of powering environmental sensors indefinitely.

The Bio Bottle Voltaic (BBV) project combines these cells with waste plastic by putting microalgae in waste drinks bottles. The organisms live and photosynthesise there, and with the simple addition of shredded metal from a waste drinks can, create a low-tech ‘anode’. 

Plastic bottles and electrodes
Electricity produced can be used for charging mobile phones and powering lights

A special lid with carbon paper and plastic from recycled bottles is created through 3D printing and added to create a ‘cathode’. The system is connected up in a specially designed architecture and the electricity produced can be used for charging mobile phones and powering lights. This is a hugely exciting project that could bring low cost bio-hack power to poor, isolated communities in rural areas. And for ZSL, it could be used to power camera traps, sensors and other technologies that are used to monitor our endangered wildlife in remote locations across the world.

Another project has used the same BPV technology to create algal cells that can adapt to their environment. The specialised architecture lays out the algae in a series of thin ‘leaf-like’ films in a structure that resembles a living plant, and uses a small motor to rotate the ‘leaves’ in changing light. This ensures maximum solar exposure without sun-bleaching the biofilms and increases the yield of electricity produced.

Biocatalytic cell
The algal cells can adapt to their environment using a small motor which rotates the ‘leaves’ in changing light

These two projects are a great way of getting users to appreciate the wonders of the natural environment, but algae are hardly the most charismatic of species…! So how do we get people to engage, care about and want to monitor the health of these systems? 

The final idea, ‘Algaegotchi’, is a fun project that takes the concept of the ‘Tamagotchi’ (remember them?!) and directly connects the user with the living algae through a mobile App. This App visually represents the needs of the algae – whether it is more heat, more light or more oxygen, the status of which is detected by sensors in the BPV cells – encouraging the user to respond, and creating an interaction with the ‘pet’. So now the algae is not only producing your power, it’s telling you what to do!

Learn about our marine and freshwater conservation projects 


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