Engineering Solutions To Combat Plastic Pollution

Plastic pollution is a pressing issue that poses a threat to the environment, wildlife, and human health. Engineers play a crucial role in addressing this global problem by developing innovative solutions to reduce, reuse, and recycle plastic waste. From designing technologies for ocean clean-up to creating biodegradable alternatives, engineers are at the forefront of combating plastic pollution. This introduction will explore the various ways in which engineering can help tackle the detrimental effects of plastic waste on our planet.

Designing technologies to remove plastic from oceans

Engineers are developing a range of technologies to remove plastic from the oceans, with the goal of not only addressing the current pollution but also preventing future plastic from entering the marine environment.

One such technology is the Seabin, a barrel-like structure submerged under water with its opening at water level facing upwards. It is designed for use in coastal areas, where it moves up and down with the tide to collect floating rubbish. An electric pump creates a vortex that pulls in water and floating debris, while a filter bag made of coarse material collects the rubbish, allowing water and tiny organisms to pass through. Each Seabin can hold up to 20 kg of waste and can catch up to 1.5 kg of rubbish per day.

Another innovative solution is the BeBot, a beach-cleaning robot developed by 4Ocean. The BeBot mechanically sifts sand to remove plastic waste and other debris without harming the environment. It operates on two 12-volt batteries and a solar panel, making it 100% electric and environmentally friendly. The robot can clean 3,000 square meters of beach per hour, which is equivalent to the size of seven basketball courts. It collects various types of plastic fragments, such as bottle caps, cigarette butts, and food wrappers, that would otherwise end up in the ocean and harm marine life.

The Ocean Cleanup, a non-profit organization, has developed System 002, a floating trash collector that uses wind and wave action to guide it to areas with the most trash. This U-shaped floating device moves with ocean currents and skims garbage off the surface of the water. It captures plastic debris in two wings and transports it to a central collection area called the retention zone, where it is later separated and sent for recycling.

In addition to these technologies, engineers are also exploring the use of drones, barriers, and advanced filtration systems to combat plastic pollution in our oceans. These efforts demonstrate the commitment of engineers to address the pressing issue of plastic pollution and protect marine ecosystems.

Developing biodegradable plastics

Plastic pollution is a pressing issue, with plastic waste finding its way into oceans, shores, and landfills, threatening marine life and human health. A potential solution lies in developing biodegradable plastics, which can break down in landfills within months or years, reducing plastic waste and its harmful impact on the environment.

Benefits of Biodegradable Plastics

Biodegradable plastics are derived from natural sources such as corn or wheat starch. They offer an eco-friendly alternative to conventional plastics, which can take decades or even centuries to decompose. Biodegradable plastics can be metabolized by microorganisms into CO2, CH4, and biomass, leaving no environmental footprint at the end of their life. This is particularly valuable in situations where recycling and reusing conventional plastics is not feasible.

Challenges and Concerns

While biodegradable plastics show promise, there are challenges and concerns to address. One challenge is ensuring proper disposal and full biodegradation. In natural environments, factors like heat, humidity, and bacterial activity may vary, impacting the degradation process. Additionally, the generation of micro- and nanoplastics during biodegradation has raised concerns about potential environmental impacts before they completely degrade.

Improving Biodegradable Plastics

To address these challenges, researchers are working on several strategies. One approach is to develop standards and certifications for biodegradable plastics, ensuring they meet specific degradation criteria under controlled conditions. Another strategy is to focus on the types of biodegradable polymers used. For example, polylactic acid (PLA) is widely used for packaging, but it only degrades effectively in industrial composting and thermophilic anaerobic digesters. By selecting the right biodegradable polymers and managing their disposal, we can improve their effectiveness.

Using 3D printing to create rock pools and crevices for marine life to colonise seawalls

Marine life, including rock oysters, limpets, snails, starfish, anemones, kelp, and other seaweeds, can be adversely affected by the construction of seawalls, which cover up their natural habitats. To mitigate this, researchers at the Reef Design Lab in Melbourne and the Sydney Institute of Marine Science, in collaboration with Volvo and Fibercon, have designed a 3D-printed seawall for Sydney Harbour.

The seawall features complex geometries that create rock pools and crevices, enabling marine life to colonise the walls. This is in contrast to traditional seawalls, which are completely flat and do not provide any habitat for marine organisms.

The 3D-printed seawall is designed to mimic natural shorelines, with each panel digitally designed by industrial designers at Reef Design Lab. Measurements are taken from features on natural rocky shorelines to inform the size and shape of the rock pools and crevices. This level of detail allows for the recreation of the fine details found on natural shorelines.

Once the panel design is finalised, it is 3D printed using the latest technology. A reusable mould is then created from the 3D-printed panel, and concrete panels are cast from this mould. Each panel design undergoes a series of tests to ensure they are able to withstand marine conditions.

The 3D-printed seawall provides an eco-friendly alternative to traditional concrete seawalls, which can be harmful to marine life. By creating habitats for marine organisms, the 3D-printed seawall helps to enhance the underwater ecosystem while also providing the structural benefits of a traditional seawall.

Creating advanced recycling technologies to break down plastic waste

Engineers are developing advanced recycling technologies to break down plastic waste and address the growing problem of plastic pollution. This involves creating innovative solutions to improve recycling rates and promote a more circular economy. One approach is advanced recycling, which converts plastic waste into its molecular building blocks, which can then be used as raw materials for new products. This process, also known as chemical recycling, uses heat, chemical reactions, or both, to recycle used plastic into virgin-equivalent plastic, fuel, or other chemicals.

Chemical recycling offers several benefits over traditional mechanical recycling methods. It can handle a wider range of plastic types, including complex and contaminated plastics, and produce higher-quality recycled materials. Additionally, it reduces the need for fossil resources and helps keep plastic out of landfills and the environment. The advanced recycling process can also be used to create transportation fuels and other valuable products from plastic waste.

One specific example of advanced recycling technology is pyrolysis, which involves heating plastic waste to high temperatures in a low-oxygen environment. This process breaks down the plastic into smaller molecules, such as synthetic crude oil, which can then be refined into diesel fuel, gasoline, heating oil, or waxes. Another technique is gasification, where plastic waste is heated to high temperatures to produce synthesis gas, or "syngas," which can be used for power generation or converted into other fuels or chemicals.

Another promising solution is chemolysis, which uses chemicals to break down plastics into monomers, the building blocks of plastic. Selective solvent extraction is another technique that uses solvent baths to dissolve plastics and separate specific polymers from one another. These chemical processing techniques aim to separate plastic polymers from chemical additives, allowing for the recovery of "virgin" polymers that can be reused repeatedly.

The development and adoption of these advanced recycling technologies face challenges such as high startup costs and limited incentives for innovation. However, with increasing private investments and initiatives, there is potential to revolutionize plastic recycling and significantly reduce plastic pollution.

Advocating for plastic pollution solutions

Engineers play a crucial role in advocating for and implementing plastic pollution solutions. Here are some ways in which they can contribute:

Policy Advocacy and Government Pressure

Engineers can use their expertise to advocate for policies that address plastic pollution. They can pressure governments to ban unnecessary single-use plastics, such as straws and plastic bags, and provide subsidies or tax breaks for companies that use biodegradable alternatives like bioplastics or compostable packaging. Engineers can also push for mandatory access to proper waste streams for compost, plastic, and metals, ensuring that recycling and disposal processes are more effective and environmentally friendly.

Public Awareness and Education

Engineers can educate the public about the impact of plastic pollution and the importance of recycling. By raising awareness, engineers can influence consumer behaviour and encourage people to reduce, reuse, and recycle plastic products. This can include promoting the use of reusable items, such as water bottles, coffee mugs, and shopping bags, instead of their single-use plastic counterparts.

Collaboration with Industry and Consumers

Engineers can collaborate with industries and consumers to reduce plastic waste. They can provide practical solutions, such as advanced recycling technologies, and work with companies to incorporate these technologies into their processes. Additionally, engineers can develop standards and guidelines for plastic products and their disposal, ensuring that products are designed with sustainability and recyclability in mind.

International Cooperation

Plastic pollution is a global issue, and engineers can contribute to international efforts to address it. They can participate in or support initiatives like the Commonwealth Clean Oceans Alliance, which brings together multiple countries to tackle marine plastic pollution. By sharing knowledge, technologies, and best practices across borders, engineers can help create a more coordinated response to plastic pollution.

Technological Innovations

Engineers can develop and implement innovative technologies to combat plastic pollution. This includes creating biodegradable plastics derived from corn or wheat starch, which decompose much faster than conventional plastics. They can also explore chemical processing techniques to separate plastic polymers from chemical additives, creating closed-loop recycling systems. Additionally, engineers can design technologies to remove plastic waste from the ocean, such as the Seabin, which collects floating rubbish in coastal areas, or the Ocean Cleanup's u-shaped floating booms.

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