As the fast fashion manufacturing industry continues to grow, textile factories have become increasingly prevalent. Traditional dyeing and printing wastewater treatment processes require substantial quantities of cleaning agents and chemicals for fabric production. These substances not only lead to the decay of plant roots but also contaminate rivers and the vegetation along their banks. Moreover, they can result in skin irritations and kidney ailments for individuals. Consequently, we aim to replace certain harmful chemical agents in the traditional dyeing and printing wastewater treatment facilities with a more environmentally friendly approach. In our laboratory, we have developed a product using synthetic biology techniques. Because we intend to deploy it in real-world settings, we have designed hardware that aligns with the practical environment and is compatible with our engineered bacterial strains.

Sewage simulation scheme

At the outset of our experimental apparatus design, obtaining untreated dyeing and printing wastewater proved challenging. Therefore, we used various laboratory materials to simulate dyeing and printing wastewater. We identified the key components to be pH levels, large particulate matter, fiber fragments, dyes, and oils. For the purpose of our simulations, we substituted acetic acid for potential acidic components, sand for large particulate matter, tissue paper for suspended fiber fragments, ink for dyes, and vegetable oil for oils that might be present.

Within our laboratory, we utilized our engineered bacterial strains to produce a sufficient quantity of bacterial cellulose, ensuring the functionality of our hardware components.

 During our investigation of the filtration process for traditional dyeing and printing wastewater, we recognized that it involved multiple steps to achieve effective filtration. Therefore, we aimed to enhance this device to increase the efficiency of wastewater filtration, simplify the dyeing and printing process, and reduce the need for manual labor and resources.

When considering a filtration device, our initial inspiration came from the common filters used in fish tanks. Therefore, we decided to put our conceptual ideas into practice by utilizing a filtration system commonly found in fish farms. We procured a small-scale filtration device, a water pump, plastic tubing, and wire. These components were set up in two separate glass tanks to simulate the containers before and after wastewater treatment.
First, we securely fastened the water pump using wire, allowing for precise adjustment of its placement height. Positioning the pump's intake below the oil layer and above sediment proved to be the most effective configuration. Transparent tubing was connected to both the intake and outflow of the water pump to observe the flow of wastewater. At the top of the apparatus, water flowed in, passing successively through layers of filter cotton, activated carbon, cellulose, and finally converged at the bottom before exiting. This design represented our first-generation device.

 The removal efficiency of large particulate matter, fiber fragments, dyes, and oils was notably effective. There was a noticeable reduction in color intensity.

 In our initial hardware setup, we utilized a 25W water pump with wastewater entering from the top opening and exiting from the bottom. During this process, the water flow rate was relatively high, resulting in less apparent filtration, and only minor changes in color intensity.

 Based on the challenges observed in the previous generation, we decided to replace the water pump with one of appropriate power to enhance filtration efficiency. Additionally, we addressed issues related to the less concentrated filtration due to a large filter area and the problem of loosely packed filter materials, which allowed wastewater to escape through gaps without undergoing thorough filtration. To tackle these concerns, we planned to improve both the filtration structure and arrangement, selecting alternative filter materials and configurations.

In the second-generation iteration, we initially employed a relatively sealed and concentrated filtration environment provided by mineral water bottles to address the issues observed in the first generation. We found that this approach effectively resolved the problems associated with gaps between filter materials and the instability of filtration due to the large surface area but insufficient thickness of the filter materials in the first generation. Additionally, we switched to a 5W water pump, and after a period of filtration, we noticed a significant improvement in the filtration performance compared to the first generation.

In the second-generation hardware setup, we began by placing a glass tank at the far left to simulate a settling tank. This was done because we observed the presence of oils and solid particles in the dyeing and printing wastewater. This initial step was primarily designed for the preliminary treatment of wastewater to facilitate sedimentation. Subsequently, we positioned a water pump above the glass tank to ensure it drew water from the upper-middle part of the tank. This choice was made to avoid drawing in surface-floating oils and the larger particulate matter settling at the tank's bottom.

We interconnected the bottoms of two mineral water bottles and connected one of them to the water pump via a flexible hose. This arrangement ensured that water could be drawn and transported to the mineral water bottles with the power of the pump. Within the bottles, we placed activated carbon, filter cotton, and cellulose in sequence. Additionally, we inserted a small quantity of filter cotton at two positions near the bottle openings to reduce water flow, thereby achieving a reduction in flow rate. This modification aimed to address the previous issue of decreased filtration efficiency due to excessive flow rate.
The activated carbon served to adsorb preliminary amounts of dyes and odors from the wastewater, while the filter cotton blocked the added cotton fibers, which simulated suspended particles in the wastewater, and also impeded the introduction of shredded paper that simulated fiber fragments. The design of these two layers primarily aimed to enhance the treatment of wastewater color and odor while separating other impurities in the wastewater.
Finally, at the endpoint of the apparatus, we connected a flexible hose to collect the ultimately filtered wastewater.

The table below illustrates a color comparison before and after treatment for both the treatment tank and the bacterial cellulose in our hardware setup. It is evident that the color of the treatment tank transformed from nearly pure black to a bluish hue, while the bacterial cellulose in the hardware device shifted from pure white to a light blue tint. This experimental result serves as compelling evidence that our hardware apparatus effectively functions to remediate dyes in dyeing and printing wastewater.

During the experimentation process, we observed the presence of some fibrous materials on the filter cotton. These were simulated fiber fragments using paper scraps, replicating the fiber fragments present in wastewater. This discovery inspired us to collect these used filter cotton materials and feed them into a shredder, adjusting the pH for further processing to transform them into usable non-woven fabric. Non-woven fabric production does not require weaving and holds various industrial values. We envision establishing contact with relevant procurement companies in the future to maximize the utilization of this resource, aligning with our ultimate goal of environmental sustainability.
However, considering that the current device lacks a mechanism for easy filter material extraction and replacement, we plan to adjust the structure to facilitate filter material replacement, thereby enhancing the device.

 In our third-generation design, we incorporated a replaceable structure where the three filter materials can be interchanged with one another. Additionally, we aim to explore more environmentally friendly filter materials in the future that are even more effective than activated carbon, making the entire device more efficient.

 In our most recent update, we introduced detachable screw heads in the spaces between each filter material, allowing for the replacement of filter materials. After some testing, we found that the efficiency of cellulose differed from our initial estimates. We researched and discovered that cellulose is a heat-sensitive material, which prompted us to consider using insulating materials like brass as the primary material. We envision collaborating with manufacturers capable of providing better insulating and more biodegradable materials in the future to enhance the overall environmental friendliness of the device.

 During experimentation, we observed paper scraps, used to simulate fiber fragments, adhering to the surface of the uppermost filter layer. Upon extensive wastewater filtration using the device, the accumulation of filtered-out fiber fragments will become substantial. With this in mind, we are considering recycling these fiber fragments into industrial materials such as non-woven fabric. When replacing the entire filter cotton layer, our plan involves using a shredder to process the material and adjust the pH, followed by selling it to relevant manufacturers. This approach would significantly contribute to environmental sustainability. We have already established contact with non-woven fabric manufacturers and have learned that they can indeed reprocess our raw material into industrial-grade materials using pressing and other processes.

Hardware Materials and Costs Summary

The "Total Cost" row summarizes the overall cost in both Chinese Yuan (¥) and US Dollars (USD). Please keep in mind that these are estimated costs, and the actual expenses may vary based on your specific requirements and negotiations with suppliers.

In order to better assist dyeing and printing wastewater treatment plants in the potential future use of our innovative hardware, we have created a user manual tailored to the specific needs and circumstances of such facilities. This manual has been developed based on the practical realities of the dyeing and printing wastewater treatment industry, with the aim of providing valuable guidance and support to these facilities.

We are well aware that implementing this technology in wastewater treatment plants for practical use will require a comprehensive long-term planning approach. As a result, we have prepared a detailed timeline for the future.

For teams that remain interested in pursuing this direction in the future, they can follow this timeline for continued progress.

We've developed an innovative hardware solution for dyeing and printing wastewater treatment, complete with a comprehensive user manual. This manual equips wastewater treatment plants with the knowledge they need for efficient operation and maintenance.
We've also created a detailed project timeline, organized in quarters, to guide the implementation of our hardware. This timeline covers research, development, testing, and eventual full-scale deployment, ensuring a clear path to success for interested organizations.
Our hardware and manual serve as a foundation for future enhancements and innovation, encouraging teams to adapt our timeline and commit to ongoing research and development.
In conclusion, our mission is to offer a sustainable solution for wastewater treatment, contributing to a greener textile industry. We remain dedicated to innovation and collaboration as we work towards this goal.