Article courtesy by Kien Thuc | February 4th 2014 | VietnamNet | Shared as educational material.
VietNamNet Bridge – The water filtration method with biotechnology found by the scientists of the Vietnam Science and Technology Academy has demonstrated the high ability of filtering organic matters and capable of cleansing nitrogen, a pollutant existing in water wells.
Bacteria help treat organic matters, filter water
According to Dr. Tran Van Nhi from the Biotechnology Institute, some kinds of bacteria have been well known to scientists as the substances that can help treat the water environment and cleanse food.
There are many ways to treat the water environment with bacteria or microorganisms.
The microorganisms suspended in water, for example, have the ability of converting dirt into a clean substance, toxins into non-toxic and can clean water. There are the bacteria and microorganisms living on the “carriers” – possibly the wood or plastic surface, nylon fiber or solid and rough surface, which create relatively thick layers.
When water goes through the carriers, the bacteria and microorganisms would work to convert dirty into clean water. This is the biological filtration method.
In principle, all kinds of creatures need organic matters and energy to exist. Taking full advantage of this, the biological filtration method has been used mostly to treat organic matters and filter nitrogen in water.
In order to treat organic matters, scientists use bacteria and microorganisms that eat organic matters, and when meeting oxygen in water, they will digest food and turn it into CO2.
During the process, more microorganisms would be generated, while the dead microorganisms would be oxidized to be decomposed into CO2. As such, the “filtration unit” is always renewed, while there is no waste left.
In order to cleanse nitrogen, scientists need to use the microorganisms reacting to nitrogen to release their energy. Through the filtration layers, microorganisms and bacteria would be used to convert NH4+ into NO2-, Nitrite into Nitrate (NO2) and then nitrate to nitrogen (N2), an inert gas, non-toxic, which then evaporates into the air.
The seed selection technology
Biofilter is believed to be the safest and most effective water filtration method. Especially, it requires low costs thanks to the popularity of domestic microorganisms existing in nature.
According to Dr. Nhi, bacteria and microorganisms need to be grown in a way which ensures that only useful bacteria and microorganisms can exist, while others cannot.
As for the “carriers,” Nhi said they need to be specifically created from burnt clay in order to be able to “carry” the amount of bacteria and microorganisms which can bring the highest efficiency.
Before Nhi and his colleagues could create the carriers, they had to use the ground up rocks from volcanoes. The rocks were very clean with no impurities. However, the use of the material required too much exertion. Sometimes the ground up rocks were useless because they were sticking.
Biofiltration is a pollution control technique using living material to capture and biologically degrade process pollutants. Thanks to its great advantages, the technology has been used in many works, including waste water treatment. It also allows to capture harmful chemicals or silt from surface, and microbiotic oxidization of contaminants in air.