Disinfecting Urine and Being “Claire Twa”
Hello! My name is Claire or, as I was known around the office, “Claire Twa” (meaning Claire Three), since there were two other women named Claire working there at the time. I am a Master of Public Health student in Environmental Health at Emory University, and I worked with SOIL this summer to study various inexpensive and easy ways to disinfect urine before disposal. I tested the addition of different levels of ashes, vinegar, and Clorox since these three materials are accessible and inexpensive.
SOIL’s style of Ecological Sanitation (the safe re-use of the nutrients in human waste) utilizes a urine diversion toilet which separates the urine into a front container to be dumped by the user, and the feces into a bucket to be covered and collected by SOIL for treatment. SOIL diverts urine due to the high cost of transporting liquid to the waste treatment site. This leads to the difficulty of figuring out what to do with the urine that is diverted within the toilets. Currently, users simply dump the urine container out when it becomes full. While the vast majority of diseases are contained within the feces, some diseases can be transmitted through urine, and urine is often cross contaminated with fecal matter. The only WHO approved way for the disinfection of urine is to store it for 6 months. While effective, this is not something users can do easily in their homes.
For most of the summer, I worked in Atlanta, completing background research and planning the project. However, for 2 weeks in late June to early July, I was in Cap-Haitien completing my data collection.
While I did not have the ability to test directly for pathogens within the lab, I used pH and ammonia levels as a proxy for disinfection power. Urine is disinfected naturally by the ammonia it contains and raising the pH releases more of this ammonia and increases the disinfection rate. I tested this idea by adding different amounts of vinegar, Clorox, and ash to small samples of urine in the lab and adding ash directly to the toilets in the office to see how they would affect the pH of the urine.
Since vinegar is an acid, it lowered the pH of the urine. In order to lower the pH to a level effective enough to reduce pathogens, I discovered I needed a 1:1 mixture of urine and vinegar, which is not feasible for users. Vinegar did not turn out to be a feasible disinfection additive.
Clorox did not alter the pH of the urine at amounts likely needed to disinfect (20-100 ppm chlorine). At 1000 ppm chlorine, it significantly lowered the pH of the urine by approximately 0.2. While it did not show an increase in pH, according to the literature, these levels of Clorox likely disinfected the urine, I just did not have the ability to test for it.
Finally, adding ash to the urine raised the pH significantly in all of our trials in the laboratory. When I treated the toilets in the office, on the 2 days I added 500 ml of ashes to the 1 gallon bucket of urine, the pH was significantly higher by between 0.5-2.5. However, on the one day when I only added 200 ml of ashes, the pH of the urine from the treatment toilet was lower than that of the control toilet. These results show that adding ash to toilets or urine could potentially increase the disinfection rate, however more tests quantifying the change in disinfection rate and the amount of ashes needed will need to be done. We are hoping that this project will help guide future research to develop an easy way for users of urine diverting toilets to dispose of their urine safely.
While I was working hard collecting data for most of my time in Haiti, I was able to play tourist during my one full weekend there. On Saturday, we went to Paradis, which is a beautiful beach you can only reach by boat. We first took a moto to Labadee, which is where the cruise ships dock and then from there took a boat to the beach. It was amazing to how different the area where the cruise ships dock is from Cap-Haitien. It made me wonder if the tourists who dock there think this is what “normal” Haitian life is like and especially grateful for my experience with SOIL living in Cap-Haitien and meeting and working alongside Haitians daily.
On Sunday, I took a taptap out to Milot and hiked up to the Citadel. The hike was a lot longer than I anticipated, however we did stop often along the way and even bought coconuts to drink. The Citadel was breathtaking. It rivaled the forts I’ve visited San Juan, Puerto Rico in both size and beauty. There were also beautiful views of the Haitian mountains, and you could see all the way to Cap-Haitien on the coast. It was without a doubt one of the most impressive places I have ever been.
Living in Haiti for two weeks was a constant adventure and learning experience. I loved the adventure of taking a moto, a ti bus (a 12 seater van), and a taptap to and from work every day, even if they were sometimes extremely uncomfortable rides. I loved walking around Cap-Haitien, even when I couldn’t understand 95% of what people were saying around me. I met so many wonderful people in Haiti, and I cannot thank SOIL enough for being wonderful hosts and helping me constantly throughout this project!