Institutional Energy Solutions (IES)
A biomass-fueled water pasteurizer that is designed for institutions such as schools, dormitories, or refugee camps.
Originally designed by Institutional Energy Solutions (IES) (previously InStove) the water pasteurizer is a gravity-fed unit that kills microorganisms by heating water to the pasteurization temperature of 71 ºC and cooling it back down to safe drinking temperature. The system is housed in a 60 L pot and is designed to work with 60 L and 100 L cookstoves, but could potentially be used with other heat sources. The flow rate depends on the water inlet pressure, ranging from 3-8 L/min. Interview with designer
This technology is currently not available on the market.
East Africa, with field trials underway in Uganda and Zambia
The IES 60-L Stove retails at 895 USD and the estimated cost for producing the water pasteurization unit is an additional 1500 USD (for a total cost of 2395 USD).Interview with designer
Goal 6: Clean water and sanitation
Communities, institutions, organizations, hospitals, refugee camps, and schools
The product is in the prototype phase and is not yet manufactured.
The product is in the prototype phase and is not yet distributed.
Primary water purification method
Manufacturer-specified water treatment rate, measured in liters per hour
Laboratory-evaluated log scale removal rate of bacteria
Laboratory-evaluated log scale removal rate of viruses
Laboratory-evaluated log scale removal rate of protozoa
Reduction levels of heavy metals and/or arsenic through this treatment system
Manufacturer-specified maximum level of inlet turbidity (NTU)
Range or value of outlet turbidity levels (NTU)
Is there safe water storage integrated into this product?
The water pasteurizer comprises of heating coils, a heat exchanger, and regulating thermostatic valve – all housed in a 60 L pot, and is designed to work with 60 L and 100 L cookstoves but could potentially be used with other biomass heat sources. Water is gravity fed from an elevated tank (3-4.5 m) and enters into the hot-side of the heat exchanger, then it passes through a coil where it increases in temperature. Next, a thermostatic valve regulates the system by only opening if the temperature of the water is above 71 °C. Water then flows through additional piping before re-entering the heat exchanger and cooling down to room temperature as it exits the system.
Contact the designer
Some components can be available in local hardware stores, otherwise, contact the manufacturer.
Estimated 10 yearsInterview with designer
The product meets WHO requirements for drinking water while using up to 97% less wood per liter compared to boiling over an open fire.Interview with designer
Laboratory testing was conducted by Oregon State University and found a 99.9999% reduction in E. coli through the pasteurization unit in all samples and an average clean water production rate of 6.7 L per minute. The steady-state production of clean water required an average of 5.5 g of dry wood equivalent per liter of water pasteurized or 106 kJ of energy per liter. When accounting for system startup, it required 9.1 g of dry wood equivalent per liter of pasteurized water produced or 175 kJ of energy per liter.
Handling firewood and feeding the stove presents a reduced burn hazard compared to a typical open cooking fire. The pasteurization unit is designed to cool the water down using a heat exchanger so that the water at the outlet does not exceed 20 °C and does not present a burn hazard.
The designer specifies that off-the-shelf or purpose-built filters can be connected in-line with the pasteurizer to remove non-microbial contaminants present in a particular water source such as sediments, metals, or synthetic organic compounds.
Burleson G, Caplan D, Mays C, et al., 2020, Computational Modeling and Empirical Analysis of a Biomass-Powered Drinking Water Pasteurization Technology, MDPI.
Burleson, G., Tilt, B., Sharp, K. and MacCarty, N., 2019. Reinventing boiling: A rapid ethnographic and engineering evaluation of a high-efficiency thermal water treatment technology in Uganda. Energy Research & Social Science, 52, pp.68-77.
Burleson, G., MacCarty, N., Sharp, K. and Tilt, B., 2018, August. An Interdisciplinary Mixed-Method Approach to the Evaluation of a Novel Water Treatment Technology in Eastern Uganda. ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference.
MacCarty N, Burleson G, Moses N, et al., 2017, Design and Testing of a High-Efficiency Rapid Throughput Community-Scale Water Pasteurization System, ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference.
Meets WHO requirements for drinking water and US-EPA regulations for coliform and virus reduction.Interview with designer
Testing of the fuel usage and pasteurization performance, including following standard protocols for MS2 bacteriophage and E. coli reduction, was conducted at Oregon State University in controlled laboratory conditions. Additionally, field trials were conducted in Uganda and Zambia.Interview with designer
Received the Impact Invention Award from the Lemelson Foundation in 2017.
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