Knowledge Network Community Blog
9 Methods of Environmental Remediation
14 September 2016 |
There are multiple ways to confront environmental clean-up when disaster strikes or when authorities need to make contaminated ground and buildings safe for learning, work, play, or simple, day-to-day life.
Here are 9 methods that may be used, depending on the circumstances.
One of the most common ways to contain an ocean-born oil spill is by laying down large barriers called booms around the oil slick. These float on the water and contain or block the oil’s spread. Skimmers are then used to suck or scoop the oil off the surface, where it is sent to storage tanks on nearby ships.
Oil from spills that wash up on shore can be exposed to biological agents, such as bacteria and other microorganisms. These natural organisms digest the oil, leaving only non-toxic products, like fatty acids and carbon dioxide, behind. This process is called biodegradation.
Leaking home heating oil from underground tanks in older residences can contaminate surrounding soil and drinking water, putting families, children, and pets in danger. Even small leaks can be emergencies that need to be handled immediately. Underground spills like these are dealt with by soaking up the oil with absorbent materials and removing contaminated dirt, venting basements when there is a buildup of toxic gases, and filtering oil from well water. Tests in surrounding soil and water determine when the property is clear of contaminants.
Land that has been used for mining, manufacturing, or other industrial processes can be contaminated with heavy metals such as mercury, zinc, cadmium, lead, and arsenic. These elements exist in low levels in nature, but when concentrated, they are toxic to humans and other animals. Remediation of heavy metals is both time-consuming and costly, due to the amount of soil that needs to be processed. Clean-up usually involves one of three methods: heating the soil to produce granular glass-like compounds that do not leach toxins; adding solidifying agents that yield a solid, cement-like material; or washing the soil to leach out and store or neutralize the contaminants.
PCBs (polychlorinated biphenyls) are chemicals that were widely used as electrical insulators and are found in caulk in older schools and historic buildings. They are a major cause of pollution in our nation’s streams and waterways, which were once legally used as repositories for industrial waste. It was shown only later that these synthetic chemicals are toxic to the immune, reproductive, and neurological systems of humans and animals, and they are known to cause cancer. Removal of PCBs in river sludge is one of the key functions of the clean-up efforts at Superfund sites. This is often done through suction removal and storage of the contaminated waste. So as not to stir up the surrounding soil, this kind of dredging must be done by technologically advanced machines, such as the Eddy Pump.
Even though trains are normally a safe means of travel and transportation, devastating derailments can happen from time to time. These often cause environmental hazards, from leaking oil to spillage of toxic freight. In this case environmental remediation and site restoration involves clearing tracks, testing for toxic chemicals and leaks, sealing leaking train cars, vacuuming up and removing harmful pollutants, and scraping and removing damaged train cars. When derailments happen near rivers and streams, booming can help prevent chemicals from running into and contaminating the waterways.
Buildings constructed before 1978, including schools, homes, and offices, are almost sure to contain lead paint, which is harmful, especially to children. Exposure happens when children or other individuals ingest paint chips (or paint dust) or breathe in tiny, aerosolized paint dust particles. Because lead is dangerous, it’s important to use qualified, trained contractors when doing a renovation project or repainting older buildings. These personnel are knowledgeable about effective methods for containing dust and paint chips in the work area as well as disposing of all tools, containment materials, and cleaning items at the end of the project. It is important to cover the work area in plastic sheeting, use spray water bottles to contain dust, and clean up with wet mops and specially ionized cleaning cloths, which soak up and attract lead dust particles. In cases where the building’s lead contaminant is exposed to outdoor elements, fabric buildings can be used to cover large areas while cleanup continues.
Brownfield sites are areas designated for redevelopment. They are generally not highly contaminated, so they don’t rise to the level of national or state priorities for remediation. The clean-up needed in these cases varies tremendously, depending on the nature of the contaminant. Some brownfield sites have previously been used as hospitals, waste treatment plants, bus depots, battery manufacturers, paper processing plants, or printers. Depending on the contaminant found on the site, multiple methods can be used in cleanup efforts, from electrokinetics (using a low-voltage charge to collect contaminants at an electrode, where they can then be neutralized) to phytoremediation (where plants are used to absorb contaminants into their root systems) to soil vapor extraction (where sending a slight flow of air through soil enables volatile chemicals to be removed).
Remediation of pesticides from agricultural areas is critical when the land is slated for development or when the chemicals begin to harm urban areas or waterways. A new, cost-effective method for this kind of vast undertaking has recently been successfully piloted in Denmark, and it may soon be destined for broader use. The method involves pumping a diluted form of a highly corrosive alkaline solution into contaminated soil. The chemical reaction between this solution and certain pesticides yields non-toxic products. Remnants of the alkaline solution can then be easily neutralized, leaving only non-toxic land behind. This technique ensures that affected soil can be treated on site and does not require costly removal and treatment procedures.
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