Ex situ remediation

The adsorbent can be used in several ways for field applications. In one method, the material can be placed into a trench installed in the path of a contaminant plume. The material wiU form an in situ permeable barrier, removing contaminants as they pass through the Humasorb. Another method involves injecting or angering the adsorbent into the soil to accomplish the same task. The technology can also be applied as part of an ex situ remediation system. 

BioGEE HC is a bioremediation product for the in situ or ex situ remediation of soil or groundwater. It consists of a blend of several strains of aerobic microorganisms selected for their ability to degrade hydrocarbon contaminants. The BioGEE HC technology has been used in multiple full-scale apphcations and is commercially available. 

The Biotrol methanotrophic bioreactor system is an ex situ remedial technology that uses methanotrophic bacteria to degrade contaminants in groundwater. Methanotrophs use methane... 

Reduces the risks, costs, aud effort associated with excavatiou aud ex situ remediation technologies. 

The thermal recycling system (TRS) is a thermal desorption unit designed for the on-site, ex situ remediation of mercury from contaminated soils. The system volatilizes and then condenses mercury for recovery. The TRS processes contaminants in a nonreactive atmosphere. It uses indirect heat sources to desorb contaminants and recovers 90% of the contaminants. 

TPS Technologies operates several stationary site thermal desorption units exclusively for the ex situ remediation of petroleum-contaminated soil. After processing, the soil is tested by an independent laboratory and reused in commercial construction projects. According to the vendor, over 6000 projects have been completed. TPS has eight soil remediation facilities across the United States. 

Versar, Inc., has developed a method for the ex situ remediation of soils contaminated with hexavalent chromium. In this process, soil is mixed with a sodium bisulfite solution to chemically reduce the chromium to the less toxic trivalent form. 

Ellis, B. (1994). Reclaiming contaminated land in situ/ex situ remediation of creosote- and petroleum hydrocarbons-contaminated sites. In Bioremediation Field Experience, ed. P. Flathman et al., pp. 107-43. Boca Raton, FL CRC Press. 

The studies with sediment cultures indicate natural degradation potential for aquatic sediments exposed to anthropogenic CP pollution. However, in situ remediation rates for CP-contaminated sediments may be difficult to enhance. Possibilities involve nutrient and electron donor/acceptor amendments. Ex situ remediation could involve sediment dredging and application of methods developed for soil decontamination, such as slurry reactors and composting. 

Ex situ remediation Refers to the treatment of contaminants either by excavating contaminated soils and sediments or pumping contaminated groundwater to the surface for on- or off-site treatment and disposal (compare with in situ remediation). 

Phytoremediation can be placed in the bioremediation category as either an in situ or ex situ remediation technology, depending on the approach used. It uses plants and associated micro-organisms to extract, degrade, and stabilize PAHs. If the plants are used in place, the method is in situ. If the soil is excavated and taken to a greenhouse, then the method is classified as ex situ. 

Ex situ remediation techniques require the excavation of polluted soil for subsequent treatment or disposal. Ex situ treatments can be broadly classified into extraction versus stabilization treatments that will render the polluted soil less harmful and suitable for deposition in a landfill or backfill. Soil washing is an example of an ex situ extraction technique in which the treated soil can either be returned to its original site (backfill) or be land filled, depending on the success of the cleanup stage. Asphalt incorporation, thermal treatment, and encapsulation are ex situ stabilization techniques in which the metal(loid)-contaminated soil is either incorporated (e.g., asphalt) or contained (encapsulation) by secondary materials that are subsequently land filled. Thermal treatments involve the incineration of the metal(loid)-polluted soil and the conversion of the pollutants into their metallic (zero-valent) states. In the following section we present an overview of the various technologies based on their mechanism of action. 

For remediation of contaminated groundwater, biological processes can be applied in both in situ as well as ex situ remediation techniques. In both cases, the microorganisms demand control of various parameters in order to degrade MTBE/TBA. Most importantly, pH, dissolved oxygen and temperature dictate bacterial growth and thus bioremediation success, beside the presence and survival of MTBE-acclimated MTBE/TBA-degraders. 

Literature investigations were used in order to address the six listed challenges these are considered to be some of the most important aspects related to the bioremoval of MTBE in reactors. The focus is on the use of aerobic bioreactors for aqueous phase MTBE removal by direct metabolism. The discussions on cometabolism are confined to its own section. The concepts and information provided are mainly applicable to the ex situ remediation of MTBE contaminated groundwater. The ideas presented, however, can also be applied to MTBE removal in drinking water treatment or industrial applications. Most of the discussions are equally valuable to TBA and other ethers used as fuel oxygenates. These are for example, ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME) and diisopropyl ether (DIPE). 

In situ versus ex situ remediation refers to the location of the remediation technology. In this context, an important distinction arises relative to the location of the application of the technology versus the location of the treatment. For example, in the pump-and-treat approach to remediation, the pumping occurs in situ, but the treatment of the pumped, contaminated water occurs ex situ. 

Gary Owens (environmental contaminants environmental risk assessment and remediation engineered nanoparticles remediation environmental chemistry and toxicology metal bioavailability cost effective in-situ and ex-situ remediation techniques). Division of Information Technology, Engineering and the Environment, Future Industries Institute, University of South Australia (UniSA), Adelaide, SA... 

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