KEMIKALIEFRI VATTENDESINFICERING / Non-chemical water disinfection
The purpose of this project was to develop non-chemical and energy efficient alternatives to chlorination and traditional boiling as drinking-water disinfection methods in emergency situations.
The project was started with an investigation of methods in use today and possible alternatives. Two alternative methods that seemed to be promising were chosen – the first method is to kill bacteria with pulsing high voltage, and the second is boiling with high efficient heat exchanging.
Experimental apparatus were made for testing both methods. Experiments were performed to verify the performance of the methods. Coliform bacteria in sewage water were used as test agents. A licensed commercial laboratory performed all bacterial analysis.
The method with pulsing high voltage has given some very good results (about 99 % reduction of coliform bacteria) and some not very good results (50 % reduction of coliform bacteria), but the time has not permitted to investigate the causes of the problems.
The heat exchanger has performed very well. Tests have shown that the heat exchanging efficiency of the experimental apparatus is 80-90%, but can easily be improved with good isolation.
These two methods are still at the developing stage, but the experiments have shown that both methods should be possible to develop into useful products.