Introduction
Because of the safety requirements, we have to eliminate all EcN-IL present in feces after SDZ degradation. In order to make our degradation process legal, friendly to the environment, and easy to apply in real life, we have designed a septic tank to fully eliminate the remaining genetically engineered bacteria and save financial costs for our product users.
Overall process I
First of all, we insert feces with SDZ and our freeze-dried powder into the main tank (see picture 1) with the holes on its lid (see picture 2) so that EcN-IL could function and gradually degrade SDZ. At the same time, with the help of the stirring blades (see picture 3), EcN-IL could be in full contact with SDZ and, therefore, better degrade it.
After the treatment of SDZ in the feces, they pass through the funnel on the bottom of the main tank to the storage tank (see picture 4) with the help of the tubes (see picture 5), and the feces were stored in the tank until the liquid layer, and the solid residues are separated.
The liquid and the remaining solid went through different treatment processes afterward. The liquid part, composed of water and genetically modified bacteria, was transported to the water tank (see picture 6) through the transparent tubes (see picture 7). In the middle of the transportation, strong ultraviolet lights would go through the transparent tube and kill the bacteria in the feces, avoiding the genetically modified organism’s unwanted exposure to the natural environment or crop fields. With the help of ultraviolet lights, water resources could be used for agriculture or simply discharged into the environment. The solid parts, the remained residues of the animal feces without the mass presence of water, could also be utilized as fertilizers after passing through the ultraviolet-surrounded transparent tube. And, of course, these processes that involve mass transportation of liquid and solid matter have to be facilitated by an electric generator (see picture 8)that pushes things to the wanted place.
At last, the marsh gas emitted during the stirring process could be used as fuel in households. Therefore, there is a tube connecting the main tank to the marsh gas tank (see picture 9) in order to collect these gases that could make financial profits.
A Potential Problem
From our interview with Professor Zekuan Yu from Fudan University, we found out that there may be a problem eliminating the EcN-IL remaining with the stationary transparent tube. For water, it’s relatively safe, but for the solid residues, it may be harder to ensure that there are no genetically modified organisms inside it. Therefore, we designed a spinning apparatus...
Overall process II
Summary of the overall process I + solution to the new problem
Future Plans
Although our design only exists in a 3D model, we are confident in the benefits that it will bring. Continuing on into the future, the septic tank is definitely a facility that we would want to spend more time and resources looking into and developing.
Summary
With the treatment of our septic tank, a swamp of dangerous, useless animal species with no economic benefits was transformed into reusable water resources, economically advantageous fertilizers, and gases that further regenerate profits for users of our project. At the same time, the cost of our equipment was rational: a bunch of concretes, an electric fan that does not have to work so fast, and ultraviolet lights that are relatively cheap. By the simple cost-benefit analysis, farmers would find our septic tank and freeze-dried powder appealing, therefore, apply the output of our project.