After completing our laboratory work, we faced a formidable challenge that is shared by all plastic degradation teams: How can we efficiently degrade plastics in the natural environment?

There is an urgent need for a simple and efficient device to address the escalating issue of microplastic pollution in the oceans. This device should be characterized by ease of operation, strong sustainability, high collection efficiency, and minimal impact on marine ecosystems. We aspire to utilize this device comprehensively to combat microplastic pollution in the oceans, thereby preserving the health and stability of marine ecosystems and leaving behind a cleaner and brighter marine environment for our future.

The device we've developed is designed to efficiently process microplastics in the oceans and surrounding rivers and lakes that are challenging to collect manually. Leveraging biotechnology, we immobilize genetically modified Escherichia coli on cellulose fibers, effectively capturing and removing microplastic particles from the marine environment. Furthermore, this device is highly efficient, environmentally friendly, sustainable, and reusable, aiming to minimize disruption to marine ecosystems to the greatest extent possible.

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At the outset, we considered directly adhering the engineered bacterial strains to cellulose fibers and releasing them into the water. However, our laboratory's safety supervisor, Professor Chao Shen from Wuhan University, cautioned us that this approach could potentially result in genetic leakage, thus raising significant safety concerns. Subsequently, we explored the possibility of using bacterial membranes to encapsulate the engineered bacteria before introducing them into the water. Nonetheless, experts pointed out that this method would significantly reduce the volume of water treated.

Consequently, we made the strategic decision to develop a hardware device capable of effectively preventing bacterial leakage while simultaneously optimizing water treatment efficiency. This design ensures that our engineered bacteria can efficiently degrade plastic waste in open water bodies.

In regions where wastewater flows at a sluggish pace, only a small portion of the water may pass through our device over an extended period. Unfortunately, this results in suboptimal wastewater treatment efficiency. To address this challenge, we opted to incorporate an impeller into our device to accelerate the flow rate of wastewater. The impeller requires an electrical power source, and after considering various factors such as cost-effectiveness and environmental sustainability, we determined that low-pollution, cost-effective solar panels were the most suitable choice for power generation.

To implement this, we replaced the top section of the device with solar panels, positioned the impeller within the device, and securely connected it to the solar panels. Recognizing the intermittent nature of solar power generation, particularly on overcast or rainy days, we incorporated a battery into the system, seamlessly linked to the solar panels. This ensures uninterrupted device operation, even when faced with adverse weather conditions.

The exterior of the cylindrical device is constructed from specially designed plastic, featuring a grid-like array of strip filters that effectively screen out impurities.

At the top of the device, solar panels are integrated. These solar panels are connected to a battery, which, in turn, powers the impeller to ensure a continuous flow of water for efficient filtration.

Located at the bottom are genetically modified Escherichia coli strains that have been immobilized onto cellulose fibers. This configuration is designed for the purpose of microplastic filtration.

After designing the initial device, during discussions with staff from the Wuhan East Lake Management Office, we identified several issues with the hardware.

Firstly, we failed to consider the stability of the hardware on the water's surface. In real-world testing, it frequently capsized. Secondly, some debris outside the hardware device was not effectively managed. Thirdly, the membrane-like filter cotton was prone to damage.

To address the feedback from users and draw inspiration from a swimming pool debris handler, we have designed the second-generation hardware system.

To address the first issue, we incorporated three floatation devices, significantly enhancing the hardware device's stability on the water's surface, as illustrated in Figure 2.

To tackle the second problem, we introduced a larger debris collection frame. This frame is capable of simultaneously capturing larger particulate pollutants, effectively addressing the challenges posed by both microplastics and larger debris, as depicted in Figure 3.

In response to the third issue, we modified the membrane-like filter into a porous structure. This alteration not only improves water flow permeability but also mitigates the likelihood of breakage, as shown in Figure 4.

The overall device consists of an enclosure, a water pump (1), floatation devices (2), a filter basket (3), and filter cotton (comprising cellulose fibers carrying engineered bacterial strains, 4).

In the operational process, we place the cellulose fibers containing engineered bacterial strains into the device and then deploy it into the water. Floatation devices ensure that the equipment remains afloat on the water's surface. Once connected to a power source, the water pump is activated. It draws in the upper-layer water (where plastic accumulates) into the device, and this water is treated by the cellulose fibers carrying the engineered bacterial strains. The engineered bacteria initiate the degradation of PET (a common plastic), and the purified water is discharged from the bottom of the device.

Note: We are fully aware of the importance of biosafety. Even under controlled conditions, taking engineered bacteria out of the laboratory is a highly irresponsible act. Therefore, in all videos demonstrating the operation of this hardware in open environments, engineered bacteria have not been included.

After designing this device and engaging in discussions with staff from the Wuhan East Lake Management Office, we identified certain issues and subsequently made improvements to the equipment.

1. Providing power sockets at every lakeside location is impractical. Therefore, we have integrated solar panels into the device, allowing it to operate independently and reducing its dependency on conventional power sources. We believe this innovation will make our device more sustainable and applicable to a wider range of environments.

2. When deploying the device on open water surfaces, without proper anchoring, the pollution treatment equipment itself might become a new source of pollution. To address this concern, we have implemented an anchoring system, allowing the device to be securely anchored within a specific range along the shoreline.

1. Anchor Rod Schematic

2. Actual Anchor Rod Photo

3. Rope

Procedure:

1. Insert the anchor rod into the ground.

2. Secure one end of the rope to the anchor rod.

3. Secure the other end of the rope to the hardware device.

This anchoring system ensures the stable positioning of the device and prevents it from drifting or causing any unintended environmental impact.

This cost breakdown presents an estimate of the expenses associated with the key components required to build a Microplastic Treatment Device. The device aims to address the issue of microplastic pollution in open water bodies while remaining cost-effective. Each component's cost range is provided, along with potential suppliers to help teams find the most affordable and suitable options. The total estimated cost falls within a budget of $47 to $85, ensuring that the device remains affordable for various applications.

This column provides potential sources where you can purchase each component for your hardware system. It's important to compare prices, quality, and availability from various suppliers to optimize your budget and ensure the best value for your project.

This User Manual is an essential companion for anyone utilizing our innovative microplastic treatment device. Our commitment to addressing microplastic pollution in aquatic environments goes hand in hand with ensuring that users can easily operate, maintain, and troubleshoot the device for optimal results.

This guide provides step-by-step instructions, insights, and valuable information on device setup, operation, maintenance, and troubleshooting. Our goal is to empower users to make the most of this technology in various environmental contexts, promoting a cleaner and healthier aquatic ecosystem.

We invite you to explore the contents of this User Manual and harness the full potential of our microplastic treatment device to contribute to a more sustainable future.

As part of our commitment to the success and reliability of our microplastic treatment device, we have developed a comprehensive guide to address common issues and provide troubleshooting methods. This section aims to equip users with the knowledge and tools necessary to maintain the device's optimal performance in various environmental conditions. We understand the importance of ensuring that our technology functions effectively, and this guide serves as a valuable resource for users to overcome challenges and maximize the impact of our solution in addressing microplastic pollution.

In creating our microplastic treatment device, we've effectively tackled the critical challenge of microplastic pollution in aquatic environments, aligning with iGEM's evaluation criteria. We've actively engaged with users, incorporating their feedback, and ensured that our hardware is practical and functional through rigorous testing. Our thorough documentation will enable other teams to replicate our work, fostering collaboration for a cleaner and healthier world.