I got to share my journey of how I became interested in engineering, product design, and sustainability with the freshman Living Sustainably classes recently. I appreciated the opportunity to reflect on how I got to where I am today as an engineer and share that experience with others, as I am closing out my senior year and rapidly approaching graduation. It was an interesting experience because freshmen are not always known for their attention span or audience participation, even during a 10-minute presentation on a topic that they should be able to connect with easily. I had to do more work with the first class and call on students to get them to participate in sharing ways that we commonly associate with living sustainably (the topic of their course- ugh freshmen!). However, the second group was much quicker to volunteer ideas, which was greatly appreciated.

We often associate living sustainably with practices like veganism and walking instead of driving, but it was exciting to share technological and engineering-based ways that people are trying to make the world more sustainable, such as showers that purify and recycle water as they run and cars fueled by biogas (the type of gas I am working to produce with my toilet and biogas digester in the future!). I also discussed opportunities that the freshmen have to get involved with sustainability work and/or engineering during the rest of the time at the Upper School. Although I have no expectation that all of the freshmen found me entertaining, I hope that I got through to a few of them and they might consider pursuing similar work of their own.

I got the opportunity to share my project with the Upper School community this spring during the Independent Study assembly and talk about how a Jack Linger Explorer Grant supported my project. This was an exciting opportunity because my winter presentation was to a much smaller group. I loved sharing how composting toilets can have an impact on the global community with people who have never heard about them before and answering people’s questions about my project. Due to the, at times, silly nature of my project it was fun getting classmates and teammates interested in my toilet by making jokes each time I went to work on the toilet. A lacrosse teammate even caught me CADing on a bus ride to one of our games and made a video that spurred a conversation on our bus about the work I am doing.

Below is an excerpt from my second-semester interim reflection. I hope this all gives you some insight into my work.

What is exciting to you so far?

I have been enjoying the challenge of designing the churning mechanism for the toilet and coming up with how I will manufacture it. See next question for more detail.

What is surprising or frustrating?

The most challenging, I would not say frustrating, part so far has been figuring out how to build a churning mechanism that is located in the center of the solid waste container. The mechanism is used to churn the solid waste and coat it in peat moss, sawdust, coconut coir, etc. This mechanism is challenging to design because the crank used to churn the waste needs to be detachable, and the crank needs to function from the top of the toilet, not the side. Designing this system in a way that it won’t interfere with the user and stows in the housing for the toilet has been an exciting challenge. The churning mechanism also has to be easy to clean.

What are you learning about learning?

I am continuing to learn about learning from others. I had a great conversation with Tate Staples that lead me to brainstorm how to apply my project to larger infrastructure. Ella Simmons and Dave Chandler taught me how to use a lathe to round the bottom of the hex shaft that I plan on using for the main post of the churning mechanism. I have always been interested in learning how to use a lathe, but it was very cool to be taught by a friend who has a lot of experience.

Where are you recording information, ideas, questions, resources, etc.?  And how do you anticipate using this material, either in this project or in the future?

I have been documenting my project in an engineering notebook in OneNote. I either work on whiteboards, paper, OneNote, or OnShape (CAD) and document all my work with photos, videos, or links. I label, date, sign, and have Leyf Starling sign all of my work, so if I go forward with applying for a patent in the future I have documentation of all my designs.

I have been researching what parts to use for my toilet. My main focus has been finding what I am calling, “the pee reservoir,” which will collect the urine that is diverted when the user goes to the bathroom. The pee reservoir is a crucial part of my design because I am using the weight of the liquid that is stored in it to provide a low center of gravity and increased stability for my toilet. The toilets on the market have the solids stored next to the liquids (side by side). I am going to use a shelf system to store the pee reservoir below the solids chamber. This will allow the toilet to sit at a more optimal toilet height and will decrease the footprint of the toilet overall, which will put me ahead of the competitors in both areas.

The equivalent of my midterm for my independent study was a presentation that I gave to peers, mentors, and faculty on my project.

Below is the flyer that I sent to Durham Academy Upper School with the subject line “Come talk $h*t!”:

The subject line was my best attempt to get students to open my email because as a student who has also ignored many emails sent to the whole Upper School, I knew I needed to stand out. Sure enough, my plan did work because many people messaged me or came up to me asking why Mr. Wilson (Upper School Director) just sent them an email from me with “$h*t” in the subject line. 

The posted time for the presentation was 20 minutes, but it ended up running over this time because people asked questions. I enjoyed getting to share what I have been working on and felt very supported by the people who came. Many members of the audience were people that I interact with in other settings, and it was a unique experience to get to present to them in a situation where I was the specialist. For example, my teachers present to me for many hours a week on topics that they are passionate about, and it was cool to have those roles reversed.

The majority of the presentation focused on my goals for the project, my research, what I have been doing, and how I got interested in this topic because many of my audience members had limited knowledge of my composting toilet and biogas digester system. It was great getting to present to an audience that was interested in my work. The presentation was a great opportunity to use the skill that I have developed, over the course of the first semester, to talk about my project, which due to the subject can be challenging at times.

I also printed the first prototype of my funnel that I have been CADing. I talked about the engineering design process starting at coming up with my success criteria for the project and the funnel itself. I then showed the first sketches and notes I have from the night I came up with the funnel design. Following that, I displayed my CAD and the evolution of the design. Finally, I allowed people to come up and interact with the funnel and answer questions. I also talked about the technology I used to create the funnel, such as dissolvable filament. It was great getting to answer questions one-on-one after the larger group Q&A. Overall, the presentation was a great way to end the first semester of my project.

I have made a lot of progress in my funnel CAD! I learned how to get the shape and dimensions I want with a lot of trial and error, online lessons, and help from my friends on the robotics team (THANK YOU!). I look forward to printing the funnel once I finalize the design and prepare the file to be printed.

Also, stay tuned for details on my project presentation and Q&A next week to wrap up the work I have done this semester.

I hit a roadblock with the CAD software that I had been using (Tinkercad) and made the decision to invest the time to learn a new CAD software called Onshape. Tinkercad had worked for previous projects of mine, but its tools did not offer me the level of detail that I needed for this project. I was already slightly familiar with Onshape from being a member of 6502 DARC SIDE, the robotics team at Durham Academy; however, I did not know how to operate many of the tools I needed to build my funnel in Onshape. Onshape offers many free online courses to learn the platform, which I have been using to teach myself in addition to attending CAD workshops through DARC SIDE and watching youtube videos over the past few weeks. CAD has a steep learning curve, but I am making progress and with another lesson, I should be able to extrude my prototype funnel. Extruding is the process of converting your sketch (2D) to a 3D model.

I took the following lessons through Onshape:

• Intro to Sketching
• Understanding Curves

Through robotics, I have also familiarized myself with all the equipment in the lab again. I practiced my skills by designing and building a catapult for a challenge.

Yesterday, I made my first trip to Lowe’s to get supplies! I needed to purchase my solid waste receptacle and a toilet seat to inform the design of my funnel. I had a plan of what I needed going into Lowe’s, but I also explored the store for about an hour looking for other parts. Wandering around was entertaining and helped me practice talking around toilets. For example, instead of saying, “I am looking for a rectangular 2ish gallon pee reservoir,” I said, ” I am looking for a rectangular liquid/gas/water tank that holds about 2 gallons.” I saved myself from concerning the employees at Lowe’s who were kindly helping me and strange looks from the people around me. Although I did not purchase any other parts, looking at what was available and exploring new pricing was very helpful. Since making my project/grant proposal, there have been changes in the supply chain and pricing of materials, so I have been monitoring what is available for my project.

My main focus of this week has been continuing to research the likes and dislikes of composting toilet users, alternative designs, and pee splatter. I have found studies on pee splashback that I will use to influence my funnel design and toilet layout. One struggle that I am working through is finding a consistent unit of measurement. I initially planned on using metric units for simplicity; however, most of the products I am purchasing are in imperial units, so I am thinking of switching over. Getting back into CADing has definitely been an adjustment, but with some more practice over the next few workdays, I should return to higher efficiency CADing. For those of you who are not familiar with CAD, each program has similar tools, but different ways to use those tools (e.g. keyboard shortcuts, selection methods, etc.), so it takes a bit of time to get used to a program if you have not used it in a while.

As I get ready to 3D print my first funnel design, I have been planning my first experiment. I will be testing the effectiveness of my funnel prototype by seeing how well it achieves my success criteria.

Success criteria:

• No splash back
• No overflowing

I will test the prototype by mounting my funnel and a hose with consistent water pressure. The funnel will be tested from angles that mimic using the bathroom. I will then observe how the funnel performs and take notes on how I can improve my design.

My passion project is designing and building a composting toilet and biogas digester system. The system will allow people to produce biogas for cooking and running generators; compost; and liquid fertilizer all using My passion project is designing and building a composting toilet and biogas digester system. The system will allow people to produce biogas (for cooking and running generators), compost, and liquid fertilizer all using what is collected in the toilet. The system will complete the human nutrient cycle replacing of the disaster of a system and wasteful cycle that we have today. I became fascinated with composting toilets by researching tiny houses. Toilets are an easy way to get people to live sustainably because everyone goes to the bathroom. The current composting toilets on the market are neither user-friendly nor part of a system with a biogas digester. My goal is to design a composting toilet that has a familiar user experience and requires no instructions, unlike the competitors. It is crucial for the toilet to be easy to use to get a global audience to switch to this system. My composting toilet is also waterless thereby reducing the large volume of freshwater being wasted on flush toilets. Separating liquids from solids also has the advantage of reducing smell and allows everything collected in the toilet to be used as a renewable resource. This technology has an application on a global scale because in areas without an established toilet system it can provide sanitation, a source of electricity, and agricultural resources. On the other hand, in areas with established toilet systems it can reduce freshwater usage, artificial fertilizer usage, and the harm done to natural ecosystems by sewage treatment plants.