Soil remediation treatment

In the early years of ground water and soil remediation, pump and treat was the conventional technology. Contaminated ground water is pumped to the surface where it is treated and reinjected or discharged to surface waters or wastewater treatment plants. Reinjection maybe used to stimulate in situ... 

Soil remediation technologies can be classified according to the type of treatment processes taking place5-7 ... 

In situ soil remediation with physical methods includes the in situ heating (in situ thermal treatment), ground-freezing, hydraulic fracturing, immobilization/stabilization, flushing, chemical detoxification, vapor extraction, steam extraction, biodegradation/bioremediation, electroosmosis/ electrokinetic processes, etc. 

All ex situ soil treatment methods involve a two-step approach soil excavation and aboveground treatment of the excavated soil. The differences in the various ex situ excavation/treatment methods for soil remediation lie only in the methods of soil treatment aboveground, such as soil washing plus extraction, and slurry biodegradation. 

Various soil remediation techniques such as incineration, soil washing, or biological soil treatment were applied in the past, but the microbiological degradation of TNT-contaminated soils is considered to be the most favorable technique as far as costs are concerned [414]. The following is a summary of these TNT remediation technologies ... 

T0458 Kenox Technology Corporation, Wet Air Oxidation T0461 Kinit Enterprises, Trozone Soil Remediation System T0465 Klohn-Crippen Consultants, Ltd., ChemTech Soil Treatment Process T0468 KVA, C-Sparger System... 

Based on data from the Sandia National Laboratory demonstration, the cost of operating this technology was estimated for treating 4600 m of soil at a single site. The total cost of treatment is estimated to be 160 m of soil remediated. This cost is based on treating the soil in three equal batches of approximately 1500 m. Each batch can be treated in a period of 2 months using a 200-kw-amp RF power source. This cost includes the following parameters ... 

The Oil Snapper soil remediator is a nutrient formulation designed to enhance the activity of soil microbes, leading to faster bioremediation of petroleum hydrocarbons. It can be used with either indigenous soil microbes or added commercial microbes and is absorbent to prevent runoff and control odors when applied to spills. Oil Snapper may be used to improve bioremediation processes in treatment cells, biopiles, landfarms, or for in situ bioremediation. 

A site in northern New Jersey was to be remediated by Sybron using the ABR Hydrocarbon blend in 1995/1996. This application was an in situ soil remediation described in Case Study 1 (see D14650J, p. 21). The projected cost for the soil clean-up was approximately 11 per ton or 14.50/yd for the 35 -acre treatment area. 

According to the vendor, the Thermatek thermal desorption system is no longer being used for soil remediation. The Thermatek thermal desorption system is commercially available for use in recovering oil product from wastewater treatment sludges in petroleum refineries. 

The vendor estimates that treatment costs for a Bio-Raptor soil remediation would range from 15 to 100 per ton of treated soil compared with treatment costs of 100 to 400 per ton for other applicable technologies such as landfill disposal, mobile incineration, and stabilization. The vendor states that typical treatment costs using Bio-Raptor system are 3 per ton for the treatment of manure and 2.70 per ton to reduce odor, pathogens, and waste volume in yard waste (D204637, pp. 16, 28). 

Hodson, M. E., Valsami-Jones, E. Cotter-Howells, J. D. 2000. Bonemeal additions as a remediation treatment for metal contaminated soil. Environmental Science Technology, 34, 3501-3507. 

From a practical point of view, reduction of NACs is of great interest for two reasons. First, the amino compounds formed may exhibit a considerable (eco)toxi-city, and therefore may be of even greater concern as compared to the parent compounds. Additionally, the reduced products may react further with natural matrices, in particular with natural organic matter, thus leading to bound residues (see sections on oxidations below). One prominent example involves the reduction products of the explosive, 2,4,6-trinitrotoluene (TNT see Fig. 14.6), particularly the two isomeric diaminonitrotoluenes (2,4-DA-6-NT and 2,6-DA-4-NT) and the completely reduced triaminotoluene (TAT). These have been found to bind irreversibly to organic matter constituents present in soils (Achtnich et al., 2000) and sediments (Elovitz and Weber, 1999). This process offers interesting perspectives for the treatment of NAC contaminated sites. In fact, a dual step anaerobic/aerobic soil slurry treatment process has been developed for remediation of TNT contaminated soils (Lenke et al., 2000). 

The chemist reviews analytical results as they are received from the laboratory. It is particularly important for remediation projects with field decisions pending results of analysis. Laboratory data often guide remedial activities, such as soil removal, treatment plant operations, and compliance monitoring. For these projects, reliable data with expedited turnaround time of analysis may be necessary. To avoid making decisions on data of completely unknown quality, the chemist reviews such data in a cursory manner to verify that the basic laboratory QC requirements have been met, whereas a complete evaluation of data packages will be conducted later. 

A multidisciplinary approach, including chemical, physical and mineralogical characterisation of contaminants and soils, has been shown to be fundamental to understand comprehensively the history of industrial soil contamination, to assess the potential and the actual risk associated with elevated levels of PTMs in soil (i.e. the relation of PTMs with soil matrix and their chemical accessibility and mobility) and to define the feasibility of potential remediation treatments (Adriano et al., 2004 Banat et al., 2005 Gasser and Dahlgren, 1994 Sahuquillo et al., 2003 Venditti et al., 2000a,b). 

Hanna, K., Chiron, S. and Oturan, M. A. (2005) Coupling enhanced water solubilization with cyclodextrin to indirect electrochemical treatment for pentachlorophenol contaminated soil remediation. Water Res. 39, 2763-2773. 

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