Team:UMaryland/Engineering
The Engineering Cycle
Learn
Improvements
Based on the results and data collected from the testing phase, the design of the bioreactor was adapted to demonstrate the most effective agitator and housing of the silica beads. The improvements were then illustrated through the CAD assembly of the bioreactor.
Test
A sample of the water-tea mixture was taken from each test conducted in the prototyping phase and a spectrophotometer was used to measure which test created a higher concentration of tea solution. The test that produced a higher concentration was then deemed as the more effective method of agitating our polluted water in the bioreactor.
In order to examine how the silica beads should be housed in the bioreactor, our team created a MATLab simulation. We modeled the relationship between the volume of polluted water, the total surface area of the silica beads, and the period of time the solution needs to be agitated in order for all the environmental phosphate to be sequestered into the beads. For more information on modeling, see our model page here.
A sample of the water-tea mixture was taken from each test conducted in the prototyping phase and a spectrophotometer was used to measure which test created a higher concentration of tea solution. The test that produced a higher concentration was then deemed as the more effective method of agitating our polluted water in the bioreactor.
In order to examine how the silica beads should be housed in the bioreactor, our team created a MATLab simulation. We modeled the relationship between the volume of polluted water, the total surface area of the silica beads, and the period of time the solution needs to be agitated in order for all the environmental phosphate to be sequestered into the beads. For more information on modeling, see our model page here.
Design
Our UMaryland team began by investigating what devices are commonly used on farmlands and discovered that phosphorus bioreactors are typically used by farmers. So, we decided to accomplish our goal by constructing a bioreactor since it is familiar machinery for our intended customers.
To build a bioreactor, we had to first understand the nature of this technology. In our interview with Alicia Mulkey, the executive secretary to the State Soil Conservation Committee, we were informed that bioreactors are built to be buried underground, which conserves farming land.
The key features we desired in our final solution was a bioreactor that could pump in polluted lake water that would be cleaned using the E Coli injected silica beads developed by our wet lab team. The now clean water would then be returned to the lake, and the phosphorus encapsulated by the silica beads are then collected using the sugar water for later use.
For the design process, our team drew inspiration from the Purdue 2016 iGEM team’s bioreactor design. We agreed our bioreactor would consist of a 5-gallon bucket with water pumps attached to it, but the bioreactor team had an individual and a group brainstorming session to determine the other factors of its design.
The bioreactor team brainstormed three substantial designs that varied based on how they housed the silica beads, agitated the polluted water in the bioreactor, and extracted the phosphorus from the E. coli infused silica bead.
The team then selected the most favored components from each proposed solution and culminated them into one promising solution by accounting for supply availability, pre-existing technology, practicality, and efficiency.
Our UMaryland team began by investigating what devices are commonly used on farmlands and discovered that phosphorus bioreactors are typically used by farmers. So, we decided to accomplish our goal by constructing a bioreactor since it is familiar machinery for our intended customers.
To build a bioreactor, we had to first understand the nature of this technology. In our interview with Alicia Mulkey, the executive secretary to the State Soil Conservation Committee, we were informed that bioreactors are built to be buried underground, which conserves farming land.
The key features we desired in our final solution was a bioreactor that could pump in polluted lake water that would be cleaned using the E Coli injected silica beads developed by our wet lab team. The now clean water would then be returned to the lake, and the phosphorus encapsulated by the silica beads are then collected using the sugar water for later use.
For the design process, our team drew inspiration from the Purdue 2016 iGEM team’s bioreactor design. We agreed our bioreactor would consist of a 5-gallon bucket with water pumps attached to it, but the bioreactor team had an individual and a group brainstorming session to determine the other factors of its design.
The bioreactor team brainstormed three substantial designs that varied based on how they housed the silica beads, agitated the polluted water in the bioreactor, and extracted the phosphorus from the E. coli infused silica bead.
The team then selected the most favored components from each proposed solution and culminated them into one promising solution by accounting for supply availability, pre-existing technology, practicality, and efficiency.
Build
Prototyping
To imitate how the team could cycle the polluted water through the silica beads to be cleaned, we tested two methods of agitating the water: using a shaker table or a DC motor.
We conducted two tests, one where we placed a tea bag in a bottle filled with water and a second one where we connected a tea bag to a continuous servo motor (meant to resemble a DC motor) that was attached to the head of a water bottle. The first water bottle was placed on a shaker to table to assess how well the tea bag, mimicking the beads filtering the water, was diluted in the water. The second water bottle evaluated the dilution rate by activating the servo to spin the tea bag in the water. Both tests were done for the same duration.
Prototyping
In order to show that our motor-based design can work to keep phosphorus suspended in water and keep it from settling at the bottom, we made a small prototype out of a continuous servo motor, a clear plastic jar, tea-bags, and an Arduino. Then, we took spectrophotometric readings to confirm that the prototype was suspending the tea in the middle of the reactor. Additionally, we compared the efficacy of a shaker table mechanism to our approach of spinning the beads in the reactor. Below are the models of the prototype and results of the absorbance readings for the two conditions:
Example of the motor-driven prototype, where the spinning of the motor causes the tea bags to move.
Shaker table approach, with the motor only serving to hold the bags in place, and the shaker table causing the device to move. The absorbance readings were derived by taking a sample of water from the black line shown in the image above.
Here is a video of the motor in action of the Arduino-controlled prototype
Testing: Results and Conclusions
As seen by the spectroscopy readings, the shaker table approach was less efficient in getting the tea to the middle area of the bioreactor, which is where it would need to be to work well with the beads. We have also shown that our prototype can work with real world limitations and allows phosphorus to remain from settling on the floor of the bioreactor, and thus can be uptaken by the beads.
CAD Assembly
While all our biological processes are essential to effective phosphorus uptake, an environment in which this process is controlled and operated is equally as important. We aimed to provide an overview of three potential bioreactor designs that are able to be constructed utilizing off-the-shelf parts. The goal is to be able to present these designs to a potential developer and have them directly translated into a working reactor. Each design comes equipped with a bill-of-materials, a list of specs, and a detailed CAD design. In theory, this would demonstrate how we can approach a customer (such as a farmer) and show them exactly what will be implemented on their property and what components are utilized.
It’s important to note that the materials proposed are sourced primarily from Mcmaster-Carr and are of a high standard. We chose to utilize large amounts of stainless steel as possible, yet when unavailable, selected aluminum due to rusting.
The reactors are ideally housed within a concrete shell that has been buried just below the surface. There are two lines that enter each vessel, an inlet that carries polluted water and any other required chemical components, as well as an outlet where treated water can be pumped directly back into the environment. The reactors are modular in that multiple can be implemented for increased filtration, as well as dotted along the banks of the polluted water source.
Polluted water is left within each reactor for a period of time, where it is agitated and filtered, before being released back into the environment.
Design 1
Overview:
The columns within the bucket represent the custom filters that are unique to this design. Every design centers around a common frame, pump, agitation and tubing system. The only difference is the shape and size of the filter section. The reactor sits within a 5 gallon bucket atop an aluminum frame. The water is pumped in via the right inlet pipe and pumped out on the left.
The columns are wrapped in a stainless steel mesh (not pictured), causing the silica beads to remain trapped inside. The lines shown are stainless steel rods attached to small 3cm wide stainless steel plates. There are also 12 columns per reactor, however only 4 have been shown for simplicity.
SPECS
Check out our bill of materials here.
Design 2
Overview:
Design 2 follows an identical approach to design 1, however it incorporates a different filter cartridge design. In this model, the filter layers the majority of the surface area within the vessel. It acts as a thin layer over which water can flow and contact the beads. This design also utilized stainless steel mesh that wraps around the steel bars.
Filter design that demonstrates where the beads will be trapped within the reactor. This filter design aims to maximize surface area and minimize volume.
SPECS
Check out our bill of materials here.
Design 3
Design 3 takes another unique approach. It utilizes an x shaped filter cartridge that aims to have a blend of high surface area and high volume. Water is still able to circulate around the x as it is also agitated by the motor that fits directly down the center. This design does require a larger quantity of materials, thus increasing cost by a significant amount.
This filter design requires more material but aims to increase the volume of beads being utilized. All materials are still stainless steel and sourced primarily from Mcmaster-Carr.
SPECS
Check out our bill of materials here.