Team:Nanjing-China/Human Practices
Human Practices
Introduction
Our projects are closely related to environmental protection and resource reuse, so we must think carefully and pathologically about the impact of our work from multiple perspectives of society. First, the Background, we introduced the natural cycle of nitrogen, phosphorus cycle in circulation problems, and accordingly put forward the solutions. Through trips to typical cities with phosphorus pollution for more typical spot investigation and the first line of data and views, we optimize the design of experiment to ensure the feasibility of the scheme. Integrated Human Practices shows the continuous progress of our program as we communicate with the expert community in different regions.
At the same time, we actively communicate with other teams and organizations. We have cooperated with the team from Southeast University. We participated in the iGEM Nanjing Summit in Nanjing in April and got a lot of suggestions on experiments. This has important guiding significance for our project experiments and modeling. We participated in the 6th CCiC in Shenzhen in August and exchanged experiences with other teams to understand the aspects that the project can improve.
Background
As time goes on, the phosphorus cycle and the nitrogen cycle are gradually coming into our view. The phosphorus cycle in nature is a sedimentary cycle, deposited at the bottom of riverbeds, lakes, etc., waiting for geological changes or human activities to bring them to light again. Our project is mainly about the process of enriching phosphorus in domestic sewage with high phosphorus content by bacteria, and then releasing and adding industrial ammonia nitrogen sewage under specific conditions to transform it into struvite, a slow-release fertilizer.
We focus on investigating cities in arid regions, industrial cities and population-intensive cities. Through field visits, big data analysis and looking for cooperation with other teams, we further understand the existing sewage indicators and treatment schemes, adjust experimental schemes and strive to make some changes to the world.
Ordos
For Northwesten industrial city, we chose Ordos as an example.Ordos is located in the plateau of Inner Mongolia, with little precipitation and rich mineral resources. Considering the amount of factories, the treatment and recycling of all kinds of sewage is the foundation of the city.
Xingtai
For industrial city, we selected Xingtai as a representative. In recent years, the government of Xingtai has made great progress in sewage treatment. We mainly visit the environmental monitoring centre of this city and two sewage treatment plants in Xingtai.
Nanjing
For cities with intensive population, we chose Nanjing among the cities with effective methods of sewage processing.We mainly investigated the Nanjing Institute of Water Environment and laboratory of environmental assessment and pollution control of environmental protection pesticides.
Integrated Human Practices
Ordos, a city in arid area
We interviewed government officials, technical personnel of enterprises and sewage treatment plant in this city to learn about the methods and standards of sewage treatment, and consulted them about their opinions and suggestions on our project.
According to one of the officers of the environmental protection bureau of the city, being in dry areas has become a driving force for working on sewage treatment technologies, as well as that the interim policy is to reward enterprises for their own treatment, the level of reaching environmental standards stands out among cities. He stressed that for such technology, the state will certainly give strong support, giving our project very good expectations for the future.
In front of the Ecological Environment Bureau
With officials from the bureau
With the support of the policy and the public, we wanted to know whether our plan could meet the approval of experts. With doubts, we came to a large chemical enterprise. A technician said that most of the treatment technologies adopted by enterprises are still in the stage of chemical treatment, and he was very surprised by our plan. At the same time, he put forward some suggestions for improvement: in the actual industrial sewage treatment process, the environment is often with high COD, where the bacteria we designed may have difficulty growing as well as in the environment we simulated in the laboratory. Research students recorded the problem and went on with hope.
With the administrators and technicians from the factory
Next, we visited the sewage treatment department of this large factory. The process is similar to what we investigated before. It mainly depended on the biochemical reaction to process the sewage. Meanwhile, the factory has a device which can monitor the important indexes to ensure the operation of the system. This visit inspired us a lot.
The sewage treatment system of this factory
Moreover, we visited the sewage treatment plant in Ordos to do research for the technology that most sewage treatment plants now utilize in daily routine. In general, the procedure mainly include the following steps: 1. Primary Filtration: Via the two filter units, they can remove the relatively large waste matter in the sewage, for example, the plastic, thrown vegetables or something like this. 2. Biochemical reaction and sedimentation: In this part, they construct a long pool where the water can move smoothly and utilize the aeration device which can wash off the organic matter on the surface of sludge in the water. The most important reaction pool constructs a circulatory reaction environment where the nitrobacteria and phosphorus-accumulating bacteria work in the anaerobic pool to remove the phosphorus and ammonia nitrogen. Finally, in the aerobic pool most phosphorus can be cleared. After the reaction, the sewage will enter the second sedimentation pool where the sludge precipitate from the water. 3. Flocculation and further filtration: Add flocculant into the pool and carry out the further filtration with special pump and filter membrane. 4.Sterilization: Add sodium hypochlorite to wipe out pernicious matter in the water. Then, the processed sewage turn into water which can be transported to be reused. Nowadays, the criterion for the sewage process mainly focus on the value of total phosphorus, total nitrogen and COD. The technician in the plant thought that the project of our team have great potential to make effect in the process of sewage in the future. He suggested that we should take the efficiency into consideration, thus made our bacteria and device more attractive.
The rough filtration
The reaction pool
The aeration device pool
Water taken from the second sedimentation pool
Water after the final step
With the technician
Xingtai, an industrial city
For industrial city, we selected xingtai as representative. In recent years, xingtai make great progress in sewage treatment. we mainly visit the environmental monitoring centre and two xingtai sewage treatment plants.
For the government, we mainly investigated relevant policy issues and the feasibility of our programs.
Environmental monitoring center said the wastewater composition is complicated, the main pollution elements is given priority to C, N, P. At present the mainstream of the sewage treatment is a method of AAO, the processing of C and N is relatively satisfactory, but the processing of P is really poor, so we usually use flocculant to precipitate phosphorus which may cost higher. .From a policy perspective, if our program can lower the cost of the process by using a kind of effective bacteria to remove phosphate from sewage, it will have very high application value. At the same time, we need to consider the recycling of sewage, the existing sewage treatment system has reflow process. If it is lack of reflow process, it will affect the AAO pool denitrifying bacteria.
Xingtai was established in industry, which has caused very serious pollution. However, their sewage treatment progress is fruitful in recent years, so to find out their treatment of phosphorus in sewage, we went to two of their sewage treatment plants to conduct research.
In one of the sewage treatment plant which uses the old technology, we have learned that their current process for treating phosphorus mainly relies on settling agent for settling, so here our phosphorus treatment scheme is relatively feasible.
Visit to the sewage treatment plant in Xingtai
Learn about the process of sewage treatment
Learn about the techonoly involved
In the other sewage treatment plant using biofilm method, we found that its treatment scheme is similar to ours, but its capacity is slightly weaker than ours. We have learned about the difficulties of using biological treatment in sewage treatment process, which provides valuable experience for our future application.
The model of the sewage treatment system
Learn about how the system worked
Nanjing, a population intensive city
For the population intensive cities, we chose Nanjing among the cities with excellent water environment and remarkable water treatment effect.We mainly investigated the Nanjing Institute of Water Environment and the National Key Laboratory of Environmental Assessment and Pollution Control of Environmental Protection Pesticides.
Technically, nitrogen and phosphorus pollution comes from agriculture. It accounted for more than sixty percent of phosphorus pollution, nitrogen pollution (fifty percent), nitrogen and phosphorus pollution from non-point source pollution, for example the agricultural fertilizer. Because the fertilizer can't completely absorbed by plants, it is caused the pollution, and people constantly produce fertilizer, fertilization can cause pollution again. The phosphorus pollution will lead to more of the abundance of algae growth, and excessive algae has a great influence on landscape and tourism. Therefore, the treatment of phosphorus pollution is vital for the ecological environment. Using flocculant can not be widely applied because it will cause secondary pollution, so the biological treatment has a good prospect.
The relevant technical and laboratorial personnel of the government all agree that the plan is in the right direction and will be of great help for the society to reduce pollution in the future. They are very confident about our plan.
Visit to the institute
Interview with the researchers
Consult the researchers about our project
Exchange and cooperation
We came to the Shenzhen Advanced Research Institute of the Chinese Academy of Sciences to communicate with other iGEM teams from China. We conducted a demonstration of poster and experimental modeling and presented and introduced our projects to other teams from China. Discussions related issues which is still in the project with other teams. We finally won the 6th CCIC best local problem solving award.
Trophy
Award ceremony of CCiC
Post-match photo
The Improvement of our project
After coming back, we carefully considered these practical problems in the experimental design, and constantly improved the experimental method by changing the original species of engineered bacteria. We choose the citrate frumenii as our engineering bacteria instead of E.coil, because it costs less COD and can remove more phosphorus. And we also designed a separate compartment device which can remove and reuse phosphate, so we can focus on specific places such as slaughter houses and municipal sewage which contain high concentrations of phosphate.
