3rd meeting of young researchers at UP 1 - IJUP - Universidade do ...

Self-powered water purification module
P. Coke 1,2 , R. Pereira 1 , Cândido Duarte 1,2 , Vítor Grade Tavares 1,2 ,
and Pedro Guedes de Oliveira 1,2
1 Microelectronics Students’ Group, Department of Electrical and Computer Engineering, Faculty of
Engineering, University of Porto, Portugal.
2 INESC Porto, Faculty of Engineering, University of Porto, Portugal.
In a world with an ever increasing population, climate changes and contamination, potable
water shortages are now one of the many problems that plague developing countries, which
many times cause health problems, malnutrition and poverty.
Several water-purifying solutions exist, ranging from low-tech, low-performance to highenergy,
high-cost implementations.
In this project we have evaluated simple, basic principles and combined them in a single
solution: a particle filtering process and ultraviolet (UV) treatment. The reasons behind these
choices are high-cost effectiveness, simple operation, and low maintenance.
Our device is a 60x50x80cm block that consists of a water tank with a capacity of about 150L
with a filtering system that cleans the water as it is manually pumped out. The filtering system
is comprised of a coarse filter at the tank input, a high density filter and UV light for
disinfection. As the water is pumped, it passes through the high-density filter and then through
a transparent helicoidal tube with an array of UV LEDs in the center, enclosed in a reflective
cylinder.
Since this solution is targeted primarily to developing countries or emergency scenarios, where
little or no infrastructures exist, the device needs to be self-sustainable. The device requires a
source of mechanical energy for pumping the water through the filter, and electrical energy for
powering the UV LEDs. By using a manual pump to produce water flow and a solar panel
together with a sealed lead-acid battery, these requirements can be fulfilled.
Filtering is achieved using a high-density design, this is essential to eliminate foreign particles
in the water that can be prejudicial and also reduce the effectiveness of the UV treatment. The
amount of pressure required to pump the water through the filter, from the tank to the output, is
provided by small manual water pump.
Based on existing studies [1], we concluded that UV LED lighting has enough fluency to
disinfect water as it is pumped through the helicoidal tube. Although these types of LEDs have
high power consumption, a high-efficiency solar panel on top of the device would provide
enough power for UV purification and charging the battery for a timely backup.
In conclusion, despite some complexity of the UV disinfection system, the presented solution
is feasible, could be manufactured at an affordable cost, and is ideal for deployment in
deprived locations.
References:
[1] Yagi, N., et al., “Sterilization Using 365 nm UV-LED”, EMBS 2007, 22-26 Aug. 2007, pp. 5841-
5844.
170 3 rd meeting of young researchers at UP