Engineers' Innovative Solutions To Combat Plastic Pollution

Plastic pollution is a pressing issue that poses a threat to both human and animal life. Engineers are at the forefront of efforts to combat this problem, developing innovative solutions to reduce, reuse, and recycle plastic waste. From designing technologies that prevent plastic from entering oceans to exploring chemical processes for recovering polymers, engineers are crucial in the fight against plastic pollution. This paragraph introduces the topic of how engineers are tackling plastic pollution, acknowledging the significance of their contributions in addressing this global challenge.

Developing technologies to trap/break down plastic particles in wastewater

Engineers are developing technologies to trap and break down plastic particles in wastewater to prevent them from entering our waterways and affecting marine life.

One approach is to use wastewater treatment plants (WWTPs) that employ a range of primary, secondary, and tertiary treatment technologies. These include grease and grit treatment, primary settling, A2O, biofilters, bioreactors, biologically active filters (BAFs), disc filters (DFs), and rapid sand filters (RSFs). The choice of treatment technology depends on the amount of influent and effluent discharge. While these treatments can remove a significant amount of microplastics, they may not be able to completely eliminate them. For example, the secondary treatment of wastewater treatment plants can remove 78.1 to 100% of microplastics, but the specific removal rate depends on the treatment technique.

Another challenge in removing microplastics from wastewater is the "sticky and messy" nature of sludge, which can make it difficult to filter out plastic particles. Additionally, other pollutants, especially metals, can adhere to microplastics during sewage treatment, leading to potential health risks for ecosystems and humans.

To address these challenges, engineers are exploring innovative technologies for the removal of microplastics. One promising discovery is the use of bacteria common in wastewater, such as Comamonas, to break down a common type of plastic called PET (polyethylene terephthalate). These bacteria can use plastic as a food source, breaking down the plastic into smaller pieces that can be consumed. While the rate at which they break down plastic is slow, it could still be a potential solution for removing microplastics from wastewater.

Overall, the development of technologies to trap and break down plastic particles in wastewater is an ongoing area of research and innovation, with engineers working to create effective solutions to combat plastic pollution and its impact on the environment.

Using bacteria to eat away at plastic waste

Plastic pollution is a pressing issue, with plastic waste polluting oceans and shores, clogging landfills, and fostering dependence on fossil fuels. A potential solution to this global crisis lies in the use of bacteria to eat away at plastic waste, a method that has garnered significant interest from researchers worldwide.

In 2001, Japanese scientists led by Professor Kohei Oda discovered bacteria that could break down plastic fully and process it into basic nutrients. These bacteria were found in a rubbish dump, feasting on plastic bottles, toys, and other discarded items. The bacteria harvested carbon from the plastic for energy, enabling their growth and reproduction. This discovery sparked a quest to find and engineer microbes that can efficiently break down plastic.

Researchers have since found bacteria that produce enzymes capable of breaking down certain plastics, such as those used in water bottles and clothing. These enzymes act as proteins that accelerate the chemical reactions involved in plastic degradation. Enzymes offer a greener approach to recycling as they require less energy and can target specific plastics mixed with trash.

In a laboratory setting, scientists have developed a process where plastic nurdles (small plastic pellets) are placed in a sealed steel tank containing a water and enzyme solution. Over time, the plastic erodes, dissolving into a greyish liquid. This process has been scaled up by a French company, Carbios, which uses a bacterial enzyme to process about 250 kg of PET plastic waste daily, breaking it down into precursor molecules that can be reused.

Additionally, researchers have engineered a strain of E. coli bacteria that can transform terephthalic acid, the main component in PET plastics, into valuable compounds like muconic acid and adipic acid, which are used in various everyday products. This process offers a way to recycle plastic waste into useful starting materials for other products, reducing our dependence on fossil fuels.

Creating robots to clean up shorelines

Plastic pollution is a pressing issue that is poisoning water bodies, killing marine animals, and contaminating the marine food chain. Engineers are developing innovative solutions to tackle this global crisis, including the creation of robots to clean up shorelines and waterways. One notable example is the Clearbot Neo, an AI-enabled robotic boat that autonomously collects tons of floating garbage and trash from harbors, canals, and rivers, preventing them from reaching the oceans.

The Clearbot Neo, developed by Open Ocean Engineering, is a sleek and compact robotic boat that utilizes smart technology and AI to recognize and collect trash. It measures just three meters long and is powered by a solar battery-electric motor, allowing it to navigate designated sections of water efficiently. The robot skims the surface, scooping up floating trash with an onboard conveyor belt into a holding bin. It can collect up to a metric ton of refuse per day, including plastic pollution and oil spills, making it a versatile tool in the fight against water pollution.

The development of Clearbot Neo was inspired by the manual trash collection efforts witnessed in Bali, Indonesia. Its creators, Sidhant Gupta and Utkarsh Goel, sought to automate this slow and laborious process. They started with a basic aluminum prototype and eventually created the advanced Clearbot Neo, overcoming challenges in AI model development and computing power. The robot uses AI to detect, identify, and log the types of trash it collects, providing valuable data for its target customers, including companies, governments, and environmental organizations.

The Clearbot Neo represents a significant step forward in shoreline cleanup efforts. Its compact size and AI capabilities make it ideal for use in harbors, canals, and rivers, where it can prevent trash from reaching the oceans. By addressing pollution at its source, the Clearbot Neo and similar technologies can play a crucial role in protecting marine environments and the species that depend on them.

In addition to robotic boats, engineers are also developing bio-inspired robots to clean up the ocean floor and hard-to-reach areas like coral reefs. These robots, such as the jellyfish robot developed by the Max Planck Institute for Intelligent Systems, combine soft robotics technologies with traditional "hard" robotic joints, allowing them to swim, walk, and crawl. These innovative designs aim to minimize disturbance to underwater fauna and provide flexible solutions for underwater cleanup and data collection.

Using solvent baths to dissolve plastics and separate polymers

The ever-growing plastic pollution problem is a pressing issue that requires immediate attention. Chemical engineering presents a promising solution, with selective solvent extraction as a key technique. This method employs solvent baths to dissolve plastics and separate specific polymers, offering a refined approach to tackling plastic waste.

Solvent baths provide an effective means to dissolve plastics and separate polymers, a process known as selective solvent extraction. This technique is currently being refined by chemical engineers at UW-Madison, who are making significant strides in addressing plastic pollution. By dissolving plastics, engineers can separate specific polymers from one another, facilitating the creation of valuable products from plastic waste.

The process of using solvent baths involves dissolving polymers in a solvent, optimizing the mixture to increase polymer mass fraction, and scissioning the polymers in the liquid matrix. This results in hydrocarbon-rich combinations, which provide the necessary carbon feedstock for producing new high-value materials. The dissolution process can be enhanced by creating plastic-solvent combinations from various sources, which are then streamlined through a single process stream.

Polystyrene (PS), polypropylene (PP), high-density polyethylene (HDPE), and acrylonitrile butadiene styrene (ABS) are among the most challenging plastics to work with, especially in a mixed-waste stream. These plastics are commonly used in construction, textiles, consumer products, and electronics. The selection of the right solvent is critical, as it can significantly accelerate dissolution, and different plastics have varying affinities for different solvents.

The goal of using solvent baths is to efficiently dissolve plastics and separate polymers, ultimately creating recycled plastic products. This process, known as dissolution or physical recycling, involves sorting plastic waste, dissolving it using solvents, separating additives from polymers, and recovering the polymers. During dissolution, the polymer structure remains intact, and heat may be applied to facilitate the process.

Converting mixed plastics into oil, then into virgin polymers

Engineers are working on innovative solutions to combat the growing problem of plastic pollution, which is poisoning water bodies, killing marine life, spreading diseases in coral reefs, and contaminating the marine food chain. One promising technique involves converting mixed plastics into oil and then into virgin polymers.

The process, known as pyrolysis, involves heating waste plastics in the absence of oxygen, which breaks them down into smaller pieces and eventually converts them into hydrocarbon gases. These gases are then concentrated and distilled into products, including oils. The oil produced through this method has a reduced wax content, making it more fluid and advantageous during winter.

The pyrolysis oil has properties similar to clean fuel and can be used as a substitute for virgin oil in the production of new plastics. This approach addresses the challenges of waste plastic disposal and reduces the demand for virgin oil. It is particularly suitable for recycling contaminated and laminated consumer-derived plastics, such as food packaging.

Additionally, chemical recycling technologies aim to convert waste plastics back into high-quality virgin plastics. This process involves breaking down the plastics into their basic molecules, called monomers, and then reforming them into long chains called polymers. Chemical recycling has the potential to reduce the polymer production industry's reliance on fossil fuels and meet regulatory requirements for the integration of recycled content in consumer products.

Overall, the conversion of mixed plastics into oil and virgin polymers is a complex and evolving process that holds promise for addressing plastic pollution and reducing our dependence on fossil fuels.

Frequently asked questions