We are so excited to share the preliminary results of our water testing. Using the water from San Francisquito Creek, we found that – before filtration – the water did not meet WHO standards in the following categories: iron, lead, total chlorine, fluoride, and pH. Interestingly, it did not possess any E. coli bacteria (as indicated by a negative test result) – something that we had been expecting and hoping to test the effectiveness of our filter on. This could be due to the way that we stored the water, the questionable quality of the test itself, the fact that the test blew over during the incubation period, or misinformation about E. coli levels in the creek. After the filtering process which took approximately 45 minutes, we retested the water and were pleased to find that our design dramatically improved the water quality. More specifically, it reduced the levels of all contaminants, bringing them within the range of WHO standards and thus making it drinkable with regard to these metrics. So awesome!
With the promising results, we want to continue our designs and testing in a few different ways. First, a sub-group of the team has turned their attention to the second filter prototype – the single-bucket gravity filter – and are beginning the construction phase today. Additionally, we want to test the first design with a more robust and credible test, such as the IDEXX ones described in an earlier blog. And lastly, in an effort to learn more about our filtration system's ability to remove bacteria, we are retesting the filter with new, more legitimate bacteria tests. We also plan to refrigerate our next batch of creek water – a step that will contribute to the health of the E. coli population. It seems weird to be promoting this type of growth but it is in the name of the safety of our users!
On the kiln side, we started sourcing materials for a larger, full-scale TLUD kiln. Our initial focus is the oil drum. We have found some options on Craigslist and Facebook Marketplace and are working on selecting the best drum – considering costs, presence or absence of paint, and distance from Stanford. We understand that our team may not finish building this design. Instead, we aim to set up the next ESW Biochar team for success!
Last week was huge for us! On the kiln front, we successfully created biochar from the cocoa husks. Not only did this feedstock light, it also resulted in % yield. We believe that the change in flammability stems from the husks having spent more time drier since they arrived from Ecuador, our team members learning how to block the wind and more effectively use the lighter, and Latifah provided critical advice on how to construct a tent of kindling around the husks. Moving forward, we plan to further test our kiln by continuing to burn both maize and cocoa husks and aiming to achieve 80% yield in at least three trials for each.
Moving to the water filter, we Zipcared to ACE Hardware to acquire a bucket and then headed off to the nearby Francisquito Creek – which is known to be contaminated by E. coli among other contaminants. After scaling a steep bank and rinsing the bucket multiple times as was recommended by a Stanford professor who focuses on water quality, we filled our bucket with creek water and transported it back to our workspace. Beginning today, we plan to work to eliminate the leakage in our filter system by connecting the holes between buckets with a Ziploc funnel that does not allow water to exit the system. Once implemented, we will test the creek water for E. coli and heavy metals prior to filtration and record results. For testing, we have purchased WaterSafe Bacteria Test Strips and an SJ-Wave Water Test Kit. Next, we will allow the water to pass through the filter and retest and re-record the E. coli and heavy metal readings. In order to gain insights on the filter's effectiveness, we will compare the readings. From there, we will likely iterate and repeat until our design removes contaminants and ensures that the water is in compliance with WHO water standards and that E. coli and chloroform levels are zero. If results are promising, we will invest more in certified water tests, such as those listed in our Bill of Materials – which includes the IDEXX Colilert test, IDEXX, Enterolert-E test, and Arsenic Low Range test. The water testing centers around the user and technical requirements of conformance to health standards. Drinking water is critical to human health, and thus our responsibility as engineers of this filtration system is at an all-time high. We must prioritize the well-being of potential users by testing rigorously.
husks to char – using the tent set up, drier
79% yield – 3 times
Hi again! In preparing for our Midterm Review presentation and prototype demo day last week, we took the time to reflect on our progress thus far. We are proud of our work over the past five weeks and see potential in both our biochar kiln and biochar-sand filter designs. At the moment, each possesses its own unique strengths and weaknesses. Going forward, we hope to capitalize on the former, while addressing the latter. Additionally, we plan to move into the test phase with our water filter, continue outreach to potential new partners, and begin to think of how we will provide guidance to next year's cohort.
Let's start with the kiln! We love our little paint-can stove. It has held up quite well after five burns, in which the temperature surpasses 300 degrees C. On top of this durability, it meets our other key user requirements of affordability, locally-sourced materials, and energy independence. More specifically, the fact that it is made from cans, requires minimal development work, and does not need lighter fluid or other means to start are key, facilitating our mission. Additionally, the small-scale nature allows us to iterate constantly, testing new theories about burn times, changing the type or form of feedstock, and gaining new insights each day. On the contrary, our prototype is not realistic, as its yield is minimal; a community would require a larger design in order to meet their needs and enhance their quality of life – whether it be in the form of soil amendment or water filtration. We must scale up to reach our user requirement of quantity. Further, we hope to implement Latifah's advice and successfully burn the cocoa husks – another current weakness – as we are struggling to effectively harness the wastestream.
Next up, the water filter! Last week, we finished constructing our first water filtration design. Its strength lie in its ease of construction – it only took us two classes! – and the affordability of the buckets. According to our research, in Malawi, one 20 L bucket costs the equivalent of two cartons of eggs. Going forward, we plan to focus on the leaking that we witnessed in our first trial run. We will acquire and add PVC pipes to the prototype. This, along with the use of cheesecloth, presents an issue, as the materials may not be accessible in the community. Thus, we will do more contextual research on the topic and potential adjust materials. Additionally, we need to test the water filter rigorously and scientifically to protect human health and demonstrate the utility of the design.
Lastly, we want to provide a recap on our filter's preliminary performance. Talking to former team members who advised that biochar often turns water black when it runs through it in a filter, however our water came out clear. While not a super scientific result, it is anecdotal promising that our water isn’t coming out looking super dirty. We are going to spend the next week working on a more rigorous testing plan and are contacting professors on campus as we speak to see if we can use their labs for water testing.
Further, we are doing more research on lakeside communities in Central Malawi to determine what kind of contaminants we need to focus on removing. This will center our work and propel us in the right direction!
Enjoy the photos from the past two weeks ~ biochar in pics!
Last week, we met as a group to discuss and update our direction, goals, and individual responsibilities. We are feeling purposeful and energized as we head into the last six weeks of the quarter (how time flies!). In their weekly meeting, Isabelle and Ananya received exciting news from Ayisha – a member of our Biochar team who is currently working remotely (we miss you!). Ayisha successfully met with two potential partners on the Malawi side – Pam Haigh, a General Manager at Ripple Africa, an established organization that aims to empower Malawian communities toward a sustainable future – and Rodger Makwinja – a groundwater and quality researcher from the Addis Ababa University who has worked on the ground in southern Malawi. Haigh expressed interest in our work, offering to host us in the future and support and collaborate with our biochar production and water filtration efforts. Makwinja provided useful insights about community attitudes and preferences as well as the importance of a preliminary, exploration-based survey. Based on this information, we decided to simultaneously focus on testing the biochar kiln, building and evaluating the water filter, and conducting more contextual research about Malawi while reaching out to stakeholders. We divided our group into 3 sub-teams in order to streamline work and accomplish our goals efficiently. The biochar production group (Julia and Sebastian) will test the kiln with various feedstocks (husks – the wastestream in Ghana – and corn – that in Malawi) as well as different shapes and sizes of these inputs. They will document results using our newly-purchased scientific instruments as well as observation. The water filter group (Nomunzul and Bryana) will first construct the filters (as referenced in the last blog)with the acquired materials. On this note, another milestone last week was acquiring all the necessary materials for our sand filter from Home Depot. After a successful trip, we found storage for our materials and can begin prototyping the filter in the PRL over the next few weeks. Once built, the filters will be tested with local creek water, known to be contaminated with E. coli. We plan to use water tests like the Colilert kit to see how effective our filters are. Lastly, the research group (Isabelle and Ananya) will continue to develop a clear picture of the reality in Malawi as well as the different partners in the area. We hope to create a draft of a User Study by the end of the quarter that will address important concepts such as distance to available water and daily schedule, which will inform our designs and conceptualization of potential solutions. Many group members are motivated to travel to Malawi at the end of the summer; we are currently looking into the opportunity as well as sources of funding. And, lastly, next week, we plan to meet with Johannes Lehmann – a soil fertility and biogeochemistry professor, well-versed in the research and use of biochar – to discuss basic methods to assess the quality of the biochar that we produce in our kiln. Overall, we are excited to be working on this project with a newfound sense of direction and local connections that will help us build a useful and meaningful product.
Pictures of the team at home depot >.<
Having detailed our prototype and operations in the previous two blogs, we will provide a testing update this week! For easy access, our procedure for building our prototype can be found in this previous blog post and in this video. The clam chowder can mentioned in the previous blog was the perfect fit for our inner chamber as it created an airtight seal when placed inside the larger paint can. After finishing the drilling, we were able to complete our first prototype!
Pictures of the completed prototype. Things to note: the sealed fit between the two inner cans and that the bottom of the inner can will not touch the ground (allowing airflow through the bottom holes).
Last Thursday, we completed a preliminary test of our small-scale TLUD biochar kiln. Initially, we hoped to use the "husks'' that we received through a donation in the winter. However, based on their appearance and chocolatey aroma, we suspected that the organization sent us the husks of the cocoa beans and not the pods. The initial attempt confirmed our suspicions, as the bean husks failed to ignite. As a result, we pivoted to wood chips, sticks, and leaves as feedstock, collecting them from around the PRL courtyard area. Here is a brief recap of our results, observations, and key takeaways! It was a huge moment of growth and learning for our team.
The sequence of our first burn! First picture shows us lighting the feedstock with a match, with a high density of dry leaves at the top to ensure the feedstock catches. Second picture shows the fire in action, and the third picture shows the final product.
Next Steps on our Sand Filter:
The team has identified two potential designs for our sand filter. Below are sketches of what we are envisioning:
The first design utilizes three different buckets, one with gravel, one with sand, and one with sand, gravel and biochar. We have made a plan to acquire materials and hope to make a trip to Home Depot by the time this blog is submitted. We will also consult with teaching team member Emily Wong since she worked on a similar filtration mechanism last year.
Biochar 2022 Team: Nomunzul, Isabelle, Ananya, Bryana, Sebastian, Ayisha, Julia
Picking up from where we left off in winter quarter, the 2022 Biochar Team is eager to continue prototyping our biochar kiln and begin the prototyping process for our water filtration system! Connecting to our last blog post, our current kiln design is a small-scale prototype of a TLUD (Top-lit Updraft gasifier) made with a paint can, soup can, and tuna can. Last week, we reached a small roadblock, realizing that the dimensions of our soup can did not align with those of the paint can. This left a gap between the two cans, impacting the air flow. After hunting through local grocery stores, we believe that we have located the perfect candidate for our project: a Progresso Clam Chowder can from Stanford's very own Munger Market. Now, we are drilling the last few holes in our prototype (more detailed instructions here) at the PRL. Through this initial design, our team hopes to meet the critical user requirement of making safe-to-use biochar – not charcoal. After burn tests, we will test the output to assess the effectiveness of our prototype based on the quality of biochar produced, looking into the chemical composition of the biochar as well as its toxicity. A subset of our cohort is currently researching available testing kits for this step. Following a successful testing phase, our team anticipates scaling up (given positive test results) and focusing on ways to locally-source required materials for our partner communities in Ghana and Malawi. Furthermore, for the water filtration system, our team will use the biochar produced from our kiln or biochar that we purchase to develop the sand filter design. Through this, our team hopes to build cohesion between the Ghana and Malawi sides of our project by working on both simultaneously and consistently discussing the ways our partner organizations are both similar and different. Such conversations may affect the kiln and water filtration prototypes. By the end of the quarter, our team aims to build and design a large-scale biochar kiln and prototype a few filtration systems that possess the ability to produce safe drinking water.