Spring Blog #2

Blog #2

Team: “Veggie Sticks”


Project Updates

The IEEE Conference is upon us! We went through several drafts of our poster and have come away with a nicely polished and elegant product(shown below). The goal of our poster was to showcase and pitch our idea of the “stand-alone” unit that we originally had planned on creating. Due to changes made to the project, we are not actually going to construct this “stand-alone” unit, however, we hope to pitch this idea to some companies at the conference. A second thought of ours is to inspire future EPICS teams to work on the replicable unit. The rest of the poster provides an overview to what systems we will be incorporating at Middlebrook Garden, with very brief descriptions of each. We then show the design of what we will be installing at the garden.  

The poster itself has minimal wording, and includes graphics that will hopefully spur questions from the viewers. The goal was to create a poster that looked exciting, and provided just enough information so the viewer had somewhat of an understanding of the project, yet, they would need to ask questions in order to find out more.

Aside from the poster presentation we have created an awesome semester plan as mentioned last time, and our awesome advisor Dr. Han has approved it!

Next Steps:

Our team has a few tasks that will begin this coming week. Lok and George are in charge of the electronic portion of the system. They are creating a board that will be a much cleaner setup of the sensors and digital display. Aaron, Chris, and Hector are dealing with the construction of a stand for the waste tank and will begin testing the barrel for leaks. They will also determine the flow rate through the automated valve which will be used as a fail safe if our turbidity sensors are not accurate enough to control when the valve closes.

We are currently waiting for a response from our community partner, so the installation will be on hold. This is fine for now, since we need to construct the stand and do some testing on the barrel before we install it. On top of this we can also begin to brainstorm ideas on how to incorporate an educational display into the project. 

Spring Semester Blog #1

Blog #1

Team: “Veggie Sticks”

Project Updates

Recap: We will be creating an autonomous system that combines the aquaponics and biogas unit at Middlebrook Garden in San Jose, California. Our project planning is finished; our design is complete and the assembly is 75% finished. Last semester, an automated waste delivery setup within a container was constructed as well as the majority of the piping system. The next steps will be to build and test the barrel setup with the solenoid valve; replace the current setup and install our prototype; analyze and store data recorded by turbidity, temperature, and PH sensors to refine our design.

Goals: Our goals for this semester include: completion of the assembly, installation at Middlebrook Garden, and subsequent testing and tuning of the system. We will also incorporate educational posters and activities at Middlebrook Garden to encourage the public to learn more about what we have installed.  

This semester is off to a good start! We are carrying the momentum from the end of the previous semester to hit the ground running. At the end of last semester the waste container was outfitted with a dual pipe drain on the bottom side. The wiring of the turbidity sensor, pH meter, thermometer, and solenoid valve were also completed. Both of these accomplishments can be observed in the pictures below. The rest of the piping network will be completed at Middlebrook Garden.

Barrel drain setup

Wiring setup

In the past week we have created a detailed semester plan, listing out each task that needs to be completed in order to finish our project. Our plan contains four sections: electronic setup, tank setup, data collection, and educational outcome. Within each of these sections we have several tasks that need to be completed, each with an estimate of how long it will take.

For electronic setup, the main goal is to create an electronic display so we, and the public, can easily see the readings from our sensor. As seen in the previous picture, the wiring is a little bit chaotic right now, and the design is not waterproof. For the tank setup, we will need to conduct leak tests and pressure tests to make sure we don’t run into problems after installment. We will also need to create a stand for the barrel that will allow easy access to the bottom of the waste container where the valves are located. Once the tank and piping has been installed, we will then be able to begin testing. The testing will consist of flow rates of the waste container, turbidity measurements, and several temperature tests. Our final step is to create educational posters and activities that will allow the public to gain a better understanding of what our project is and how it works.

We also have created a rough draft of a project poster that we will present at the EPICS IEEE gathering on February 18th. This is an expo that allows the EPICS program show off what projects we have been working on all year.

Stay tuned for more project updates as we begin installation!!

Blog #6

Blog #6

Team: Aquaponics/Biogas


Project Updates

Recap: Modifications have been made to a new 55-gallon barrel which can be seen in our previous Blog #5. This tank will replace the existing tank at Middlebrook Garden. It has been transported to the Maker’s Space on the SJSU campus so it can be further modified prior to taking it to the garden.


Our parts have been delivered!! We made our largest purchase so far, the combination of all of the PVC parts as shown below. Now we can get to work connecting and cutting the various lengths of the pipes!

As for the tank modifications…we have decided that a double drain at the bottom will work best for the most efficient fish waste removal. Similar to a double sink, there will be two holes in the bottom of the barrel, and these will both drain into a main pipe. A picture of the bottom of a sink is shown below to further illustrate this idea. The reason for the double drain is to minimize the amount of fish waste that will collect in areas of the barrel that do not drain easily. The bottom of the barrel is not completely flat, nor does it have a single low point.

We have received feedback from a professional in the field!!  Kat Han, an environmental engineer who was at the design review helped our team brainstorm some ideas and gave us some tasks to do! Prior to this meeting with Kat, we did not know that we should have some baseline values of the system at Middlebrook Garden before we make any modifications. Now that she mentioned this, it seems like common sense! So, we we will start by collecting data in the form of: flow rate, temperature, pH, and turbidity from several different points within the system. These values will be recorded and compared to the measurements after our modifications to the system have been completed.

An illustration of the system was created by our team member Lok, shown below.

This diagram shows the system as a whole and where the outputs of each system go. Starting from the pond in the bottom right quadrant of the picture, the fish waste travels up (via pump) to the vertical drum barrel. Here the fish waste will accumulate at the bottom where it will be exported to the biogas unit (upper right quadrant). The clean, nutrient rich,  water will be drained from the top of the overflow tank to the plants. The plants will utilize the water soluble nutrients from this water, and then drain off back into the fish pond.

Blog #5

Team: Aquaponics/Biogas

Project Updates

As mentioned in the previous post we are going to be focusing our entire senior project at Middlebrook Garden. But first….

WE HAVE INOCULATED THE BIOGAS UNIT!! One of our team members, Aaron, took charge of inoculating the biogas unit at Middlebrook Garden. This was a messy process that involved picking up close to 100 pounds of horse manure, driving 70 miles, and then getting his hands (and clothes) dirty in the process of putting the manure into the biogas unit. Thanks again Aaron!

Now for the rest of the updates….

While brainstorming ways to combine the current aquaponic and biogas systems at the garden we have come to the conclusion that we will need to replace the current overflow tank from the fish pond. Currently, the level of the overflow tank is too low to utilize gravity to flush the fish waste from the barrel into the biogas unit. Aside from the height issue, the drain on the barrel is too high from the bottom of the tank. So, given these issues we have decided that a new tank would be necessary.

After much debate and testing we have also decided upon the type of sensor we will use to determine the level of fish waste in the overflow tank. This was originally designed to use a weight sensor, but we found that the difference in density between the fish waste and water is less than 1%. With such a small discrepancy in weight there is too much room for error with this method. We found that a turbidity sensor will work much better for our situation. A turbidity sensor measures the amount of light transmitted through the given medium, in our case this is water. When the water is dirty, (from the fish waste) less light will be transmitted through the sensor, which corresponds to a low number, while clear water will corresponds to a high number. The sensor will be attached to a microcontroller (Arduino) and the digital print out will be the turbidity level. A picture of the connection between the Arduino and the turbidity sensor can be seen to the right. 

We have also began construction of the replacement overflow barrel. We first thought a conical tank would be the best type of tank for our setup, but due to the incredibly high cost and marginal benefit, we decided that a translucent 55 gallon drum would work as well. We purchased a used 55 gallon barrel for only $25, what a deal!

The next step was cutting off the top so we will have easy access to the inside to place a swirl filter and the turbidity sensors at the bottom. Then to make a seal with the lid, that can be removed when necessary, we placed rubber housing(old garden hose) around the rim of the barrel. This will allow us to get a tight seal when the lid is tightened down with buckles/latches. This has still not been decided upon but that is one of the next steps. Below are pictures of the inside of the barrel and the rubber housing.


Our next goal is to place a drain on the bottom of the barrel and connect it to an actuated valve that will connect to the Arduino. The readings from the turbidity sensor will determine when the valve will open and close.

It was nice to finally get our hands dirty and start the construction of the project. We are excited to see our project taking off!

Blog #4

Blog #4

Team: Aquaponics/Biogas

Project Updates

After much back and forth we have decided upon what our final project will entail. We will be fully committed to working on our project at Middlebrook Gardens. As for our stand alone unit, which we were all very excited about, we will put this on the back burner for now and if time permits we will begin designing this in the second semester.

Our finalized semester goals are as follows:

  • First semester: connect aquaponics with biogas, and create sensor unit for pond
  • Second semester: connect stormwater to aquaponics, and make autonomous/least amount of user input required

We have also completed our budget and found that our spending will be relatively low, coming in at just under $400. Sensors will make up the majority of our expenditures. Below is a chart of our current budget.


Aside from establishing plans for the year and a clear budget we began the process of “starting up” the biogas unit at Middlebrook Gardens. Two of our team members, Aaron and Hector, volunteered to drive to a local farm, called Dario’s Ranch, to get horse manure to inoculate the biogas unit. This is where the essential bacteria come from that help turn the fish and food-waste into methane. The incubation time is two weeks so this was a crucial step in the process. Below is a diagram of how the biogas unit works. As pictured, the bacteria (from the horse manure) are very important for the breakdown of waste material.


We have began purchasing materials, and will begin working on the piping in the next couple of weeks!