Human Practice

I. Overview

In order to find out specific details of techniques used in sewage disposal and information of practical problems faced in that aspect for ensuring that our project' feasibility of dealing with them in the present method, we visited to a sewage plant of Hanghua Property of China Merchants located at China World Trade Center, in Beijing. The reason for investigating it is that this plant mainly uses the biology method to decompose sewage and reuse it for a relatively long time, while they also had used other ways, including chemical and physical methods, and evaluated as a precursor in sewage disposal. Therefore, our team believes in that they could provide their precious information of experience of using them.

II. Silver

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

a. Chemical and Physical 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.

b. Biological Method

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

IIT. Integrated Human Practice

a. Effectiveness of our project

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.

b. Adjustments inspired by the human practice

After this human practice, to compensate the loss of bacteria's natural death, we decided to apply the biofilms on to small plastic balls in a hardware and different signal peptides to secrete the laccase protein outside the bacteria to increase the contact area with high-speed sewage.

c. Conclusion

In conclusion, this human practice investigates the current methods of sewage disposal, and their defects. Our team believes that the defects appeared in daily-sewage disposal system would be nearly the same in factory-sewage disposal system. Therefore, we believe in that by these adjustments inspired by the human practice project would generate strikingly improvement for better effect of practical application in larger scale-factory-sewage disposal.