Grantee Research Project Results
2020 Progress Report: Ultra-Low-Cost Reusable Solar Disinfection Sensor
EPA Grant Number: SV839487Title: Ultra-Low-Cost Reusable Solar Disinfection Sensor
Investigators: Lacks, Daniel J , Mesiano, Sam , Maatouk, Christopher , Stanley, Sam , Kang, Lei , Lu, Elaine , MacDougall, Gordon , Augustine, Ashley , Ahorukomeye, Peter , Meyers, Abigail
Current Investigators: Lacks, Daniel J , Tippareddy, Charit , Maatouk, Chris , Stanley, Sam , Kang, Lei , Lu, Elaine , MacDougall, Gordon , Augustine, Ashley , Sinha, Annika , Pfau, David , Datta, Sanjit , Al-Serhaid, Sarah , Lundgren, Katherine
Institution: Case Western Reserve University
EPA Project Officer: Page, Angela
Phase: II
Project Period: April 1, 2019 through March 31, 2021 (Extended to March 31, 2022)
Project Period Covered by this Report: April 1, 2020 through March 31,2021
Project Amount: $75,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2019) Recipients Lists
Research Category: P3 Awards , P3 Challenge Area - Safe and Sustainable Water Resources
Objective:
The goal of the Billion Bottle Project is to provide reliable, cost-effective, and user-friendly alternatives for water sanitation to those in need. Our organization has chosen the avenue of solar disinfection, or SODIS, to accomplish this aim. SODIS has been proven to be the most cost-effective water disinfection technique for households in the developing world. The concept seems simple – a user exposes contaminated water to direct sunlight, and in a matter of hours the ultraviolet radiation is able to inactivate a sufficient amount of bacteria to yield drinkable water. In practice, this concept is complicated by the fact that weather conditions, the clarity of the water sample, and a myriad other conditions can affect the degree of ultraviolet light penetration into the sample, varying the time of exposure required dramatically. This degree of uncertainty has prevented SODIS from being used as widely as one might expect from such an efficient method of sanitation.
Rather than determining the safety of water treated using SODIS based on the length of time exposed to sunlight, we have developed reusable, low-cost devices which measure the dose of UV light that a sample is exposed to. The application of our devices, the OSPRI and SANTE, is user friendly. The OSPRI is a device that can be submersed in the container of drinking water; it contains a UV-sensitive dye that can be calibrated to change colors once the sample has been sufficiently irradiated. Similarly, the SANTE uses the same technology but in sticker form, and is even more cost-effective than the OSPRI and can be affixed to the outside of the container. Both devices provide an unambiguous endpoint to notify the user that the water is drinkable – a color change from blue to white which corresponds to a dose of UV light, not the time of exposure. The devices can then be placed in a dark space and will revert to their blue color, making them totally reusable. We aim for a production cost of under $1 per unit of the OSPRI and to make it reusable up to a year, thereby creating a high-accuracy and ultra-low-cost device that can help provide clean drinking water to our users.
Progress Summary:
Approximately two years of the Phase II project term has elapsed. In that time, we have developed an indicator formulation that changes color from blue to white in response to ultraviolet light. It is able to do so for at least 30 cycles without color degradation, and at least 90 cycles despite color degradation. We have mostly finalized the design of our OSPRI housing and now have a US patent application pending on our device. The primary objectives which remain for our device are finalizing our formulation, fine-tuning it to change color according to adequate doses of UV irradiation, and conducting field testing in areas of interest.
In the past year we have made significant efforts to finalize our formulation. We performed extensive experiments varying the concentrations of various components of the formula and documented their effects on transition times. This data will allow us to tune our formula to change color with adequate UV exposure to kill bacteria. We tested various storage and production techniques of the formula which will help us to provide a more consistent and reliable product. We experimented with different UV-sensitive dyes in order to determine which one can provide the clearest color change and survive longest.
We have made significant efforts to progress in our bacterial experiments as well. Our lab manager developed a serial dilution method to calculate the concentrations E. coli in water, serving as a cost-effective and efficient method of determining stock solution concentrations for quality control. Additionally, we showed that we were able to successfully implement the EPA method 1604 in our laboratory to approximate concentrations of E. coli accurately. Most importantly, we tested the ability of commercial kits, namely ColiScan, to accurately detect concentrations of E. coli in water samples. We compared our results using ColiScan to those with EPA method 1604 and found that it is a relatively accurate method of determining E. coli presence in the sample. However, the ColiScan method uses fewer materials and requires significantly less training than previously validated field testing protocols. This is important as it will allow us to conduct significantly more efficient field testing, which is one of the major components of our project that remains to be done.
Our work in the past year has been significantly impacted due to the COVID-19 pandemic, and was largely halted from March-June of 2020 due to state-wide shelter-in-place policies. Even after resumption of work, access to lab space was limited to maintain social distancing and we had limited access to spaces such as the campus solar simulator. In addition to a halt in laboratory testing, our planned field testing in Uganda, Kenya, and Zambia has been postponed indefinitely due to restrictions on international travel.
Future Activities:
Though several of our goals for the past year, particularly field testing, could not be accomplished due to the pandemic, we made progress towards finalizing our devices and facilitating future field testing. Our OSPRI device’s housing is largely finalized, and this year we were able to experiment with numerous iterations of our formulation to achieve an improved product. Our formulation will reliably cycle dozens of times without color degradation, making it ready for field testing. Additionally, we have validated an efficient and cost-effective commercial kit to detect coliform levels in water samples, which will facilitate future field testing tremendously. We anticipate successful completion of the specific aims during the extended project period.
Journal Articles:
No journal articles submitted with this report: View all 7 publications for this projectSupplemental Keywords:
Ultraviolet dosimeter, WASH, diarrheal disease, sustainable water management, drinking water treatment, water purification, water filtration, solar water treatment, water disinfection, pathogen removal, SODISRelevant Websites:
Progress and Final Reports:
Original AbstractP3 Phase I:
Ultra-Low-Cost Reusable Solar Disinfection Sensor | 2018 Progress Report | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
- Final Report
- 2019 Progress Report
- Original Abstract
- P3 Phase I | 2018 Progress Report | Final Report