Adsorption contamination remediation

Remediation. Many companies specialize in hazardous-waste remediation by providing a variety of disposal services and equipment, not limited to catalytic oxidizers and carbon adsorption systems. Remediation includes reduction and cleanup of hazardous wastewater by using oil-water separators to separate oil and solids from wastewater effluents of petroleum-based industries. Other hazardous-vwiste remediation services include demolition and removal of hazardous materials such as asbestos, removal of leaky fuel tanks, cleanup of contaminated sods, and the construction of slurry walls to aid in the remediation of groundwater that is polluted with hazardous waste. Bioremediation is also a growing field that involves disposal of medical and laboratory wastes often by using microorganisms to break down the hazardous materials. 

The application of adsorption to contaminated groundwater remediation is not only an important subject, but one we could expand upon into several volumes unto itself. At best, all we can do is try to provide a concise overview in this volume. 

The most commonly used remediation technique for the recovery of organic contaminants from ground water has been pump- and-treat, which recovers contaminants dissolved in the aqueous phase. In this regard, the application of carbon adsorption has found extensive, but not exclusive use. Vacuum extraction (also called soil venting) has also become popular for removal of volatile organic contaminants from the unsaturated zone in the gaseous phase. Both of these techniques can, in the initial remediation phase, rapidly recover contaminants at concentrations approximately equal to the solubility limit (pump-and-treat), or the maximum gas phase concentration of the contaminant (vacuum extraction). The... 

Description of granular activated carbon (GAC) adsorption (liquid phase) remediation technology used to clean up pumped ground water contaminated with volatile/semi-volatile organics and PCBs. http //erb. nfesc. navy. mil/restoration/te. 

Phenanthrene dissolved in Triton X-100 solution was separated by sorption with three GACs with different particle size (4 12,12 20, and 20 40 mesh). The highest adsorption selectivity was obtained with the 20 40 mesh over a wide concentration range of phenanthrene and Triton X-100. The results demonstrate that the selective adsorption is potentially effective to reuse surfactants in a soil-washing process for the remediation of contaminated soils. 

Pure Ti02 was recently reported to be active in the disinfection of water contaminated by spores of the type Fusarium solani [142], Bacillus anthracis [143], or Cryptosporidium parvum oocysts [144], or when supported as nanocomposites on zeolite H(i for E. coli deactivation [145], and it found applications in water treatment as a replacement for chlorine. Ag-Ti02 immobilized systems were used for inactivation of bacteria, coupling the visible light response of the system and the strong bactericidal effect of Ag [146]. Silver was deposited on hydroxyapatite to form nanocomposites with a high capacity for bacterial adsorption and inactivation [147], or used for airborne bacterial remediation in indoor air [148],... 

Liquid-phase adsorption using GAC is one of the most widely used remediation technologies. The major disadvantage of this approach is that it simply transfers contaminants from one phase to another, and further treatment or disposal of the receiving phase is typically required. Biological treatment has the potential to completely destroy contaminants, and it is generally... 

Imbiber Beads are spherical plastic particles that can absorb certain liquid organic contaminants. Absorption is a process where the material taken up is distributed throughout the solid body of the absorbing material. This is different than adsorption, another common remediation technology in which the target substance attaches only to the surface of the adsorbent material. 

The Thermatrix, Inc., PADRE process is a commercial, off-gas treatment technology that purifies airstreams contaminated with volatile organic compounds (VOCs). The PADRE vapor treatment process traps VOCs using filter beds that contain a proprietary resin. This regenerative adsorption method involves an on-line treatment bed for infiuent air, while another bed undergoes a desorption cycle. PADRE often works in conjunction with soil vapor extraction or air stripping systems. The PADRE process can be applied at site remediation projects, industrial wastewater facilities, and industrial air processing sites. 

The most important water treatment technologies are summarized in Fig. 5-6. Depending on the source and on the water quahty, either mechanical, biological, physical, thermal, or chemical processes or their combinations may be applied. Photochemical AOPs and AOTs are subordinated to chemical processes, mainly because the current technological versions of photochemical wastewater remediation are dependent on the addition of auxihary oxidants, such as hydrogen peroxide, ozone or special catalysts such as titanium dioxide. Photochemical AOPs are attractive alternatives to non-destructive physical water treatment processes, for example adsorption, air stripping or desorption and membrane processes. The last merely transport contaminants from one phase to another, whereas the former are able to minerahze organic water contaminants (cf. Chapter 1). 

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