Technology is regarded as the birthplace of environmental pollution and subsequent degradation. But only technology can revive our dying mother earth. One such system is the Geospatial Measurement of Air Pollution (GMAP). It acts as a digital sniffer and detects possible contamination by pulling air into the system and reading levels of pollution. It assesses facilities like refineries, shipping, oil and gas production facilities.
Remediation scientists have come up with exciting tech and methods to undo the extent of the damage. While there are various aggressive methods like incineration, which can instantly remove the contamination from site but they destroy the natural properties, as well. The process of remediation services should aim to save our Earth. Here are some natural ways in which the environment is cleaned, naturally.
Different Types of Environmental Remediation
1 – Bioremediation
It uses either naturally occurring or specially bred microbes to eliminate organic contaminants from soil and groundwater. It can also be achieved by using special plants, using phytoremediation feature, and also integrating with systems like Pump and Treat.
The basic principle is to grow certain types of microbes, which use contaminants as a food source. These microbes eat and digest contaminants, decomposing them into natural harmless gases such as Carbon Dioxide and Ethene. Proper growth of bacteria requires correct temperature, nutrients, and moisture. If these conditions are not met, microbes grow very slowly or die completely. Amendments can be added to assist their growth with household items like molasses and vegetable oil. It can be used to treat groundwater, as well as soil by pumping amendments (or catalysts) underground, through wells and pits.
2 – Encapsulation
It is a technique for separating the contaminants rather than filtering them out by treatment. It physically isolates the contaminated soil from the rest of the neighborhood. In this technique, the impacted soil is insulated by low permeability caps, slurry walls, grout curtains, or cutoff walls. The most common practice is to mix the contaminated soil with a mixer, typically lime, cement or concrete. The hardened contaminated soil is not miscible with the clean one. Encapsulation is designed to limit the infiltration of precipitation and hence prevents leaching and migration into the groundwater or away from the site.
3 – Electokinetic Remediation
It relies upon the application of current to infuse motion among metals and charged ions. A low-intensity DC current is run through the soil between ceramic electrodes, divided into cathode and anode array. The resulting potential difference mobilizes atoms and charged ions including water molecule to move toward the electrodes.
Metal ions, Ammonia, and other positively charged organic compounds move towards the electrode, whereas chlorides, cyanide, fluoride and other negatively charged organic compounds move towards the anode.
Once segregated, the removal of contaminants is very easy. It can be undertaken by several means including electroplating, precipitation, redox reactions with ion exchange resins or even physical processes like thermal desorption. The two primary mechanisms of transportation of contaminants are electromigration and electroosmosis.
4 – Bioreactor Landfill
A bioreactor landfill transforms and degrades organic waste and creates it into useful substitutes. Liquid and Oxidizing elements are added to enhance microbial processes to increase waste degradation and stabilize the process. The concept of bioreactor differs from the traditional dry tomb approach used by municipal landfills. The different types of bioreactor configuration include:
Aerobic – Leachate is removed from the bottom-most layer and recirculated into the landfill to promote aerobic activity and accelerate waste stabilization.
Anaerobic – Moisture is added to the waste mass in form of leachate, where degradation occurs in the absence of oxygen (anaerobically). It produces landfill gas which can be used for energy projects.
Hybrid – A sequential aerobic-anaerobic treatment is applied for accelerated waste degradation in the upper section of landfills, whereas the gas is collected from lower sections.
5 – Monitored Natural Attenuation
Nature has a way to replenish itself. At most polluted sites, some level of natural attenuation occurs, which relies on natural processes to clean up pollution from soil and groundwater. However, to clean sites properly, proper conditions need to be met. Scientists monitor and add artificial elements in this natural process to accelerate the operation. This is called Monitored Natural Attenuation (MNA).
MNA is useful at places where the source of pollution has been cut off. For instance, if a buried oil tank is spilling organic waste, digging it up and then undertaking MNA is a better and more useful approach. After the removal of the source and assisting natural processes with catalysts, the contamination is disposed off, gradually. The soil and groundwater must be monitored regularly to make sure that the level of pollution is within safe limits. Some MNA methods are biodegradation, sorption, dilution, evaporation and chemical reactions with natural substances.
6 – Pump and Treat
It is a very common method of cleaning up groundwater from dissolved chemicals, industrial solvents, metals, and fuel oil. The water is pumped, ex-situ to surface level and treated, to remove the contamination. It is also used to contain the Plume from spreading to other sources like drinking water and other natural resources.
It includes a well to extract groundwater which is transferred to the treatment plant directly or held in a storage tank. The treatment system may include a single method, such as using activated carbon or air stripping. Activated carbon captures organic contaminants and gives way to cleaner water. If the groundwater is contaminated with different types of contaminants, several multiple methods are employed.
Once the treated water comes to a safe limit, it is discharged into natural resources or used for special purposes. However, it is wiser to use it for daily activities like sprinkler systems, or irrigation, because the water has already been pumped out, using electric pumps. Other waste byproducts of treatment such as sludge or used filters should be disposed off, properly. The range of treatment and methods used after pumping may vary according to the level and source of contamination.
The remediation process is followed by a proper site assessment and preparation of Phase 1 Environmental site assessment. It must incorporate the historical use of the site and the operations, undertaken on the land. It is highly recommended to keep away from sites which are being remediated because it poses a threat of incremental health risk.