Ex situ biological treatment

The advantage of ex situ biological treatment is the ability to control the effluent quality. The use of air for aerobic treatment is easier to control and costs less. Nutrient can be added more effectively and the temperature can be controlled. 

The disadvantages of ex situ biological treatment in comparison to in situ biological treatment are as follows ... 

Ex Situ Biological Treatment on Excavated Soil by Slurry Biodegradation... 

Alleman, B. C. and Leeson, A. (editors), 1999b, Bioreactor and Ex Situ Biological Treatment Technologies. Battelle Press, Columbus, OH, Vol. 5, No. 5, 221 pp. 

In cases where in situ biological treatment cannot be applied, the contaminated soil is excavated and transferred to specially prepared areas where bioremediation can be carried out under well-controlled conditions. Some common ex situ biological methods are the landfarming technique and the biopile or biopit treatment options.32... 

SafeSoil is an ex situ, biostimulation treatment technology that is specifically designed to remediate soil contaminated with organic compounds. The SafeSoil process biologically oxidizes... 

The treatment methods for remediation of energetic materials from soils are divided on in situ and ex situ biological (bioremediation, phytoremediation, composting), in situ and ex situ physico-chemical (adsorption, oxidation, electrokinetic separation, extraction, solidification, reduction, soil washing), in situ and ex situ thermal (pyrolysis, desorption) [1]. Among the above described... 

They may be favored over in situ treatment where they will reduce cleanup times, their operation and capabiHties are considered more reHable or better understood, or they can achieve lower cleanup levels. Both in situ and ex situ treatment for soil and ground water rely on a combination of unit processes, which often include biological degradation of organics. 

Ex situ bioremediation may use various biological wastewater treatment processes, soil piles, or land appHcation. With in situ bioremediation, the basic process is the same microbes, soil, and water working together as a bioreactor. Where the in situ techniques differ are in how contaminants and microbes are brought in contact and how oxygen, nutrients, and other chemical supplements ate distributed in the soil—water—air matrix. Typical in situ bioremediation techniques include natural or intrinsic attenuation, air sparging, and bioventing. 

Because they can be chemically oxidized or biologically degraded, chemical oxidation and biodegradation technologies (both in situ and ex situ) can be effective in the treatment of oxygenates. 

The Biocube aerobic biofilter is an ex situ off-gas filtration system that is commercially available. The technology utilizes microbes to biologically oxidize volatile organic compounds (VOCs) and complex odors. It can be used in conjunction with vapor-vacuum-extraction (VVE), a process that draws gases from subsurface soil. These gases often require further treatment before being released into the atmosphere. Biocube has been field tested and has been implemented at over 100 sites for the treatment of hydrocarbon vapors. The technology has also been successfully used for odor control at a variety of sites. In addition, the Biocube system can treat odor and VOC emissions simultaneously. The units are modular, so additional stacks can be added as needed for increased flow and/or removal rates. 

The BIOX biotreater is a commercially available, ex situ technology for the treatment of wastewater, groundwater, and surface water containing organic contaminants. The BIOX biotreater is a biological submerged, fixed-film reactor capable of aerobic, anoxic, or anaerobic operation. 

Constructed wetlands are engineered systems designed to mimic the physical, chemical, and biological mechanisms of a natural wetland. Wetlands may be constructed above ground to resemble natural wetlands such as swamps, bogs, and marshes or they may treat contaminated water below the surface. Constructed wetlands have been used for the ex situ treatment of groundwater contaminated with explosives. 

Advanced Fluidized Composting (AFC ) is an ex situ technology that combines aerobic and anaerobic biological treatment with a chemical treatment such as oxidation and hydrolysis. 

The Simplot Anaerobic Biological Remediation (SABRE ) process is a patented, ex situ technology used to treat soils contaminated with nitroaromatic compounds. Researchers isolated a selection of anaerobic bacteria based on their ability to degrade nitroaromatic compounds with the total destruction of intermediate compounds by the completion of treatment. These bacteria are the basis of the SABRE process. 

According to treatment mechanisms, however, treatment technologies are classified as biological, physicochemical, and thermal processes. In terms of the place where the actual treatment takes place, the issue of in situ vs. ex situ comes into play as far as selecting the most cost-effective remediation processes. For example, most bioremediation processes are in situ, while physicochemical processes may be implemented both in situ and ex situ, according to the following ... 

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