We conducted our human practice though visitation a sewage plant of Hanghua Property of China Merchants located at China World Trade Center, in Beijing. Since investigating this plant mainly uses the biology method to decompose sewage and takes it as a main method for a long time, while they also had used other ways, including chemical and physical methods, and evaluated as a precursor in sewage disposal. Our team believes in that the process and details of either daily-sewage or factory-sewage are similar, thus it is the best choice to find out the specific information of techniques used and practical problems faced in sewage disposal as a critical method for ensuring and improving our project' feasibility of dealing with problems in the present treatment.

During the interview, we found out the situation of each current methods

First of all, they talked about their previous chemical and physical techniques such as Activated carbon adsorption technology and oxidation method, both of them have a same defect that is expensive cost, which stimulate them the idea of using the biology treatment.

After touring us to view their disposal machine, which contains plenty of bacteria used for decomposing sewage, we begin to discuss about its advantage and defects. Because special treated bacteria are able to reproduce themselves rapidly, factory is able to process waste water with relatively lower financial requirement. However, since the bacteria release a toxic gas when they are disposing sewage, the plant has to continue turning on aeration pumps, which need a huge number of money to support, and harm their employees' hearing caused pump-noises. As time goes by, the advantage of lower cost is offset by its electricity bills, and the higher payment for their workers because of the unfriendly work environment.

Moreover, traditional biological treatments have some factors that keep it from extensive using. For most of the cases, traditional germs are directly injected into the waste water. In this case, single germ are unable to fully act because the thin concentration, and the death of bacteria caused by aeration pump equipment that contains these bacteria is easily eroded and short lifespan can added up, which is even higher than the reproducing rate, and lead to a decreasing in its effectiveness. The statistics show that the plant could dispose eighty tons of sewage in 2003, but it only disposes twenty tons in 2018, which declines about 60% effectiveness

Fortunately, based on these clues, we conceived to use biofilm and laccase as the problem solver and received the positive feedback of our project. Since biofilms may form and firmly attach to living and non-living surfaces, the bacteria living in biofilms organize themselves into a coordinated functional community in which lots of living organisms can share nutrients and are sheltered from the possibility of being erased, which means that the problem of lower bacteria density, and death caused by erosion are solved successfully.

Moreover, the laccase is capable of processing the sewage without releasing any toxic substance, which eliminates the unnecessary cost of using aeration pump and extra employee payment, which means to utilize biology treatment' biggest advantage-lower price.

Though our project is capable of dealing with the issue of current biology treatments, inspired by the human practice, we notice some critical factors that is worth to consider and adjust our project based on it, the effect of speed on effectiveness and the competition among bacteria. The most crucial one is the speed of sewage, since the higher speed of sewage means the lower time of contacting with our bacteria, which would have a serious influence on effectiveness of bacteria. Therefore, we draw a method of using physical facilities to either increase the contact area or control the run-off of sewage. Therefore, there are three adjustments for it. The first one is to use proper signal peptide to enable bacteria to secrete laccase outside of it and fix secreted laccase by adding the spy-catcher with it and spy-tag on the surface of biofilm, since under this method, the laccase is able to directly contact with sewage to encompass more effective units on the same surface. Secondly, based on research of some archetypes, we plan to design our own machine to control the run-off of sewage and gathering particles for effectiveness.

Furthermore, the another challenge we need to deal with is the competition between wild bacteria and ours. Through human practice, we realized that the realistic condition of sewage disposal is complicated, which means that there are usually more than one or two colonies of bacteria in the same area. Since once the biofilm of our bacteria forming, they share nutrients and defend the intruder together, which is able to compete with any wild type bacteria, another key adjustment is to ensure our bacteria that have a nutritious and comfortable environment for growth and formation of biofilm. Our team decide to provide a suitable environment, and we focus on the particle Bluepha capsule. since this particle is made of carbohydrate, and when we plant the modified bacteria onto its surface, the rate of growth and formation of biofilm would increase significantly to help our bacteria compete with the original germsunder that environment.

In conclusion, this human practice investigates the details of current methods disposal, and their defects. As for the biology method, the expensive cost and decreasing effectiveness are two main problems required to address, and could be solved by our project theoratically. Therefore, we believe in that with further improvement, adjustments inspired by the human, our project is able to work under realistic condition and have better effect of practical application in larger scale-factory-sewage disposal.

Our public education includes two sections: on campus and off campus activities.

On campus, we design and implement a layered education system, starting from series of lectures to all students, interviewing some students and evaluating their potential of being iGEMers, then our synthetic biology club offering them training in genetic engineering.

Off campus, we established the collaboration with sewage plant for exchanging the instructive information including biology, plant and policy. We strongly believe that the practicability of our project would attract more plants even business companies to cooperate with us.

We conducted lectures of iGEM projects and synthetic biology techniques to students on Tuesday and Thursday weekly. At the start of our education program, we briefly introduced our project's purpose, effectiveness and future potential contribution to the environment. We also invited students who were interested in improving the environment by synthetic biology technologies. After that, we held a series of lectures explaining the molecular mechanism, and prove practicability of our project to the students who followed up our project.

For the whole process of education, we put a high value on the effectiveness of lecture. Therefore, we required students who is willing to cooperate our work to register their WeChat account, and asked randomly 75% of students each time to share their perspectives, so we could adjust and improve the content of our lecture. We also interviewed students to find future iGEMers.

Furthermore, in our synthetic biology club, we introduced some basic methods and techniques of genetic engineering such as DNA extraction, restriction enzyme digestion, Primer design, and PCR, reserving talented students for our further iGEM projects.

In general, our on-campus education program comprehensively passed on our experience in iGEM and synthetic biology knowledge. Our program had also triggered students’ concern on environmental problems, as well as their passion for learning synthetic biology and becoming a qualified iGEMer.

During the visit of a sewage treatment plant, we briefly introduced our project to work leaders, then we showed reliability of our project and resolution to protect the environment. On one side, sewage treatment plant helped us conduct the design of our program by providing first-hand information of sewage plant. On the other side, we offered more information of our modified biology treatment. As a result, both sides were looking forward to establishing a long-term collaboration.