Common Treatment Technologies for Nonhalogenated SVOCs in Ground Water, Surface Water, and Leachate
It may be necessary to know other subsurface information to remediate nonhalogenated semivolatile organics in water. Treatability studies may be required to determine the contaminant biodegradability for any biodegradation technologies. Treatability studies are also necessary to ensure that the contaminated ground water can be treated effectively at the design flow. A subsurface geologic characterization would be particularly useful to any isolation or stabilization technologies. Ground water models are also often needed to predict flow characteristics, changes in contaminant mixes and concentrations, capture zones, and times to reach clean up levels.
The most commonly used ex situ treatment technologies for nonhalogenated SVOCs in ground water and surface water include carbon adsorption and UV oxidation. In situ treatment technologies are not widely used. Ground water and surface water concentrations are usually not sufficiently high to support biological processes, however, biological process may be applicable to leachate.
Liquid phase carbon adsorption is a full-scale technology in which ground water is pumped through a series of vessels containing activated carbon to which dissolved contaminants are adsorbed. When the concentration of contaminants in the effluent from the bed exceeds a certain level, the carbon can be regenerated in place; removed and regenerated at an off-site facility; or removed and disposed of. Carbon used for explosives- or metals-contaminated ground water must be removed and properly disposed of. Adsorption by activated carbon has a long history of use in treating municipal, industrial, and hazardous wastes.
UV oxidation is a destruction process that oxidizes organic and explosive constituents in wastewaters by the addition of strong oxidizers and irradiation with intense UV light. The oxidation reactions are catalyzed by UV light, while ozone (O3) and/or hydrogen peroxide (H2O2) are commonly used as oxidizing agents. The final products of oxidation are carbon dioxide, water, and salts. The main advantage of UV oxidation is that organic contaminants can be converted to relatively harmless carbon dioxide and water by hydroxyl radicals generated during the process. UV oxidation processes can be configured in batch or continuous flow modes. Catalyst addition may enhance the performance of the system.