Bioremediation Technology for Soil Polution
1. What is bioremediation technology?
Bioremediation is a natural process based remediation technology for contaminated land. Microorganisms in soil or groundwater can "eat" certain harmful chemicals. For example, microbes found in oil fields could be used to treat oil-contaminated soil. When microbes "eat" chemicals, they convert them into harmless substances such as water and carbon dioxide.
2. What are the characteristics of bioremediation technology?
●Microbial treatment of pollutants requires suitable soil or groundwater conditions, such as temperature, nutrients and oxygen. Microbes grow and multiply under the right conditions and "eat" contaminants. If the growth conditions are not suitable, the microorganisms will grow slowly or even die. Bioremediation technology can improve soil environmental conditions, such as increasing soil nutrients.
●Optimum conditions for bioremediation are difficult to achieve underground. For the plots with low temperature and tight soil, the contaminated soil can be dug out, heated and mixed with other soils, appropriate nutrients are added, and the soil conditions are improved by stirring to increase the oxygen content in the soil to improve the efficiency of bioremediation. When the temperature, oxygen content and nutrient conditions are suitable for microbial reproduction, the microorganisms will "eat" the pollutants and complete the restoration of the contaminated land. But there are also microbes that thrive without oxygen.
●Sometimes, mixing soil causes organic matter to evaporate before it can be "eaten" by microorganisms. In order to prevent air pollution, soil can be mixed in a special container to facilitate the collection and treatment of volatile organic matter.
●To treat groundwater with microorganisms, the groundwater can be pumped out first, and then nutrients are added to the water and aerated to create conditions suitable for microbial reproduction to repair the polluted groundwater. It is also possible to add nutrients directly to the well, aerate it, and then pump out the groundwater for treatment.
When the pollutants are "eaten up" and the nutrients are used up, the microbes die.
3. Is bioremediation safe?
The microorganisms used in the restoration are from the soil and do not pose a threat to the plot or surrounding population. No harmful chemicals are used in bioremediation, and the added nutrients are fertilizers. Bioremediation can completely destroy the structure of pollutants and convert them into water and harmless gases, so it is very safe. To ensure the effectiveness of bioremediation, soil and groundwater samples should be analyzed prior to bioremediation.
4. How long does bioremediation take?
Bioremediation can take months to years, depending on the site. It may take longer if:
(1) the concentration of pollutants is very high, or the area where the pollutants are located is deep and difficult to reach, such as the rock structure layer;
(2) The area of the contaminated area is large and the depth is long;
(3) The physical properties of contaminated soil need to be improved, such as temperature, nutrient composition and indigenous microbiome;
(4) The pollutants need to be transported to off-site treatment.
5. Why use bioremediation?
Bioremediation is a natural process in which contaminated soil and groundwater can be repaired in situ if underground conditions are suitable for microbial growth. Bioremediation can prevent workers from coming into contact with contaminated soil or groundwater, and prevent volatile harmful gases from entering the atmosphere. Microorganisms can convert pollutants into water and harmless substances with almost no secondary pollution.