Hazardous wastes remediation methods

However several POPs, particularly the OCPs and dioxins, remain at low levels in the Australian environment and several remain persistent at low levels in body fats and fluids of Australians. The levels reflect the past use and persistence of OCPs in the Australian environment, contamination of the food chain and the capacity of the body to metabolise and store in body fats. The dioxins remain due to the ubiquitous nature of their sources with combustion as a major source and their persistence. Future trends are likely to mean very low-level residues in human fats of DDE, cyclodienes, HCB, HCHs and dioxins in the long term. Their rate of decline will probably depend on removing HCB from chlorinated industrial chemicals and OCPs from the environment (e.g. remediation of contaminated soils) by hazardous waste treatment methods (e.g. physical, chemical and biological degradation or fixation) or secure landfill. 

There are currently thousands of sites in the U.S.A. containing soil contaminated with volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides, mercury, and mixed waste (radioactive and hazardous waste). One method used frequently to remediate these sites is thermal desorption. 

The use of a drain system permits the quick construction of a collection/removal system which also serves as a barrier for leachate from large, shallow sites. At the Sylvester hazardous waste site in Nashua, New Hampshire, a groundwater interception and recirculation system was installed as a method to retard further spread of the leachate plume until a remedial cleanup action could be implemented. The system was operated for 1 year until a containment wall and cap were constructed over the 20-acre site (McAneny, 1985). 

With the recent Increase In activity at hazardous waste sites where cleanup and remedial action are underway, there has emerged a need for rapid analytical methods for assessing contamination in water, sediment, and soil. Of special Interest, because of widespread use and disposal. Is the group of materials known as PCB s (polychlorinated biphenyls). 

The SW-846 methods are used in the RCRA compliance and monitoring programs for hazardous waste and stack gas characterization, groundwater monitoring, soil, surface water, and groundwater analysis during site investigation and remediation. Many laboratories adopted the SW-846 technical provisions as standards for routine operations. The fact that many of the SW-846 methods do not specify the acceptance criteria for analytical accuracy and precision and allow laboratories to use their own makes these methods even more attractive to the laboratories. 

Fermentation is also used to treat industrial chemical or organic waste. The principle is very similar to the described anaerobic sludge treatment. That means that the organic material is converted to methane. Examples include waste containing cotton, rubber, plastics, fats, explosives, and detergents. The waste can be transferred to special treatment plants or be treated in situ in the open field where the waste was buried. Open-field microbiological treatment of spills or deposits of hazardous chemicals is a potentially attractive and inexpensive remediation method and has attracted a lot of research attention. So far, however, only a few examples have been successful. 

One potential application is the use of neural networks to facilitate decisions about hazardous waste sites. These sites generate a great deal of data, in which patterns are inherent. Sites that once produced batteries, for example, will typically show a great deal of cadmium in the soil this finding usually leads to a decision about a particular form of remediation. A network s input layer could represent characteristics of hazardous sites (such as type of site, volume of contamination, type of contaminants, contaminated media, etc.), and its output units could correspond to possible decisions regarding methods of cleanup. Such a network could be trained and tested on RODS (Records of Decision) to establish the appropriate relationships and assess the network s accuracy. 

The EPA initiated this program to promote and evaluate newly developed techniques that had not been fully demonstrated. The goal of this effort was to find new ways to remediate uncontrolled hazardous waste sites. The technologies accepted for field-scale evaluation represented a wide array of innovative methods, from thermal treatment and bioremediation to soil washing, solvent extraction, and in situ stripping. 

In many countries starter batteries are almost 100 percent recycled PVC separators can cause some problems here [67]. A prior separation of PVC from other battery components, which is quite tedious, would be desirable, because a PVC content decreases the recycling purity of the container polypropylene and makes further processing of this plastic more difficult. Also, any chlorine compounds liberated can form environmentally hazardous products with other substances the usual remedy is to install costly filter stations, with the residues representing possibly toxic wastes requiring special disposal methods. 

Fisk JF. 1986. Semi-volatile organic analytical methods - general description and quality control considerations. In Perket CL, ed. Quality control in remedial site investigation Hazardous and industrial solid waste testing, ASTM Spec Tech Publ 925. Vol. 5, American Society for Testing and Materials, 143-156. 

The composting system effectively remediates soils that are heavily contaminated and cannot be treated by in situ methods as well as wastes containing hazardous volatile constituents untreatable by land farming methods. 

The primary remediation activity should be control of atmospheric releases or spills or run-off within the defined containment area, and to make certain that hazardous materials do not enter the sewer system, porous soil, or surface or ground water. This section of the plan should address not only the initial containment activity, but also post-incident clean-up, waste disposal, and environmental restoration. Safe clean-up methods should be outlined in the plan. 

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