Soils and sediments may become contaminated by diesel, petroleum, BTEX, polycyclic aromatic hydrocarbons (PAHs) and other volatile and semi volatile organic compounds. Sediment remediation is the process of neutralizing contaminants and restoring environments to their pre-contamination condition. There is a variety of treatment options available and the choice of which one to use depends on the nature of the contaminant and on the time and money that are available for the procedure.
Remediation of sediments is basically an aquatic problem. Once the soils and sediments underlying the nations harbors and inland waterways become compromised by contamination, their use for navigational or recreational purposes is seriously impaired. As at 2004, the Environmental Protection Agency (EPA) had identified approximately twelve dozen sites that needed to be remediated. Of these, 60 were thought to require attention at the national level, while others were deemed suitable for management by local or state authorities, by volunteers or by other federal authorities.
The three basic approaches to the control of contaminated sediments and soils are: in situ capping, dredging and monitored natural recovery. The main sources of sedimentary contamination are industrial accidents and mining incidents. Additional contaminants to those specified above include phthalate esters, metals and organometals (mercury, lead, etc.), cyanide, chlorinated hydrocarbons (PCBs) and mononuclear aromatic hydrocarbons (MAHs).
Some of these chemicals either do not dissolve or they only partially dissolve in water and end up sinking into the sediments of aquatic environments. This results in large amounts of contaminants that cannot be detected in the water column. The size and shape of particles, the ecology of benthic organisms and their organic content all contribute to the accumulation of contaminated sediments over time.
When a government agency such as a land remediation agency identifies an area to be decontaminated, or remediated, imminent action is arequired to protect the environment, not to mention human health. This process is subject to regulatory oversight. In the USA, this is the purview of the EPA, Region Nine.
Nanotechnology, the process of using particles between 1 and 100 nanometers, is becoming more and more important in aquatic soil remediation. Their high surface area per unit mass makes them extremely reactive; their miniscule size makes it easy for them to infiltrate micropores in the sediments, which gives them ready access to the target materials. A nanometer is one billionth of a meter.
When a nanoparticle-sized decontaminant collides with a target contaminant, the result is a neutralizing chemical reaction. So far, the global NanoRem project has targeted as many as 70 sites all over the world that need to be treated. Most of these are groundwater projects, although wastewater treatment methods are being investigated.
What makes nanoremediation is the minute scale of the contaminants being removed. Any idiot can filter out junk the size of coffee grounds. Nanoparticles are too small to filter using available technology, and so that is why neutralizing chemical reactions are necessary. Once those are under control, maybe we can start tackling pico particles, which are one thousandth of a billionth of a meter.
Remediation of sediments is basically an aquatic problem. Once the soils and sediments underlying the nations harbors and inland waterways become compromised by contamination, their use for navigational or recreational purposes is seriously impaired. As at 2004, the Environmental Protection Agency (EPA) had identified approximately twelve dozen sites that needed to be remediated. Of these, 60 were thought to require attention at the national level, while others were deemed suitable for management by local or state authorities, by volunteers or by other federal authorities.
The three basic approaches to the control of contaminated sediments and soils are: in situ capping, dredging and monitored natural recovery. The main sources of sedimentary contamination are industrial accidents and mining incidents. Additional contaminants to those specified above include phthalate esters, metals and organometals (mercury, lead, etc.), cyanide, chlorinated hydrocarbons (PCBs) and mononuclear aromatic hydrocarbons (MAHs).
Some of these chemicals either do not dissolve or they only partially dissolve in water and end up sinking into the sediments of aquatic environments. This results in large amounts of contaminants that cannot be detected in the water column. The size and shape of particles, the ecology of benthic organisms and their organic content all contribute to the accumulation of contaminated sediments over time.
When a government agency such as a land remediation agency identifies an area to be decontaminated, or remediated, imminent action is arequired to protect the environment, not to mention human health. This process is subject to regulatory oversight. In the USA, this is the purview of the EPA, Region Nine.
Nanotechnology, the process of using particles between 1 and 100 nanometers, is becoming more and more important in aquatic soil remediation. Their high surface area per unit mass makes them extremely reactive; their miniscule size makes it easy for them to infiltrate micropores in the sediments, which gives them ready access to the target materials. A nanometer is one billionth of a meter.
When a nanoparticle-sized decontaminant collides with a target contaminant, the result is a neutralizing chemical reaction. So far, the global NanoRem project has targeted as many as 70 sites all over the world that need to be treated. Most of these are groundwater projects, although wastewater treatment methods are being investigated.
What makes nanoremediation is the minute scale of the contaminants being removed. Any idiot can filter out junk the size of coffee grounds. Nanoparticles are too small to filter using available technology, and so that is why neutralizing chemical reactions are necessary. Once those are under control, maybe we can start tackling pico particles, which are one thousandth of a billionth of a meter.
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