from the theoretical and practical viewpoints including steam-enhanced extraction,
thermal conductive heating, and electrical resistance heating. The advantages and
limitations of these technologies, as well as innovative techniques such as radio
frequency heating are also debated in this chapter.
Keywords In situ thermal treatment · In situ thermal enhancements · Steamenhanced extraction · Thermal conductive heating · In situ thermal desorption ·
Electrical resistance heating · Radio frequency heating · Free product thermal
enhancement recovery
3.1 Introduction
Combined thermal and chemical treatment enhancements for Dense Non-Aqueous
Phase Liquid (DNAPL) remediation mainly stem from research studies on enhanced
oil recovery (EOR). The goal of EOR is to develop efficient methods to recover
residual oil from geological formations for secondary oil production (Holm and
Csaszar 1962; Lake 1989; Taber 1981). While many lessons can be learned from
EOR studies conducted with experiments ranging from lab- to pilot-scale treatability
tests, there are numerous substantial differences between EOR and soil remediation,
such as porous media structure (unconsolidated media), the physical and chemical
conditions (low temperature and low pressure), the physicochemical properties of
the recovered organic compounds, as well as recovery and remediation goals (e.g.,
obtaining a low soil pollutant saturation) (Pennell et al. 1996).
Most in situ thermal treatments improve organic pollutant recovery. Deciding
which temperature to apply to treated soils should consider the physical and chemical properties of the pollutants as well as the soils’ properties (i.e., porosity,
permeability, heterogeneity, water content, and thermophysical properties). Thermal
treatments have been applied to highly concentrated pollution sources. Table 3.1
shows the potential applicability of thermal treatment techniques compared to other
techniques in two generic hydro-geological situations.
The main In Situ Thermal Treatments (ISTT) are the following: (1) SteamEnhanced Extraction (SEE); (2) Thermal Conductive Heating (TCH) or In Situ
Thermal Desorption (ISTD); (3) Electrical Resistance Heating (ERH), (4) Radio
Frequency Heating (RFH), and (5) Free product thermal enhancement recovery.
It is shown that increasing the temperature reduces viscosity (and to a lesser
extent NAPL–water interfacial tension), increases reaction rates, aqueous solubility,
volatility (by increasing vapor pressure and partitioning to the gas phase), and
pollutant desorption from a solid matrix (Hiester et al. 2013; Johnson et al. 2009;
Kingston et al. 2014; Smith and Hinchee 1993). Temperature ranges of subsurface
heating remediation techniques are plotted in Fig. 3.1. The processes with the most
significant results operate within a temperature range of 50–100
C at atmospheric
pressure. Temperatures above 120
C can generate chemical transformations such as
gasification and hydrolysis of organic pollutants (from 120
C), steam cracking for
150
S. Colombano et al.
thermal conductive heating, and electrical resistance heating. The advantages and
limitations of these technologies, as well as innovative techniques such as radio
frequency heating are also debated in this chapter.
Keywords In situ thermal treatment · In situ thermal enhancements · Steamenhanced extraction · Thermal conductive heating · In situ thermal desorption ·
Electrical resistance heating · Radio frequency heating · Free product thermal
enhancement recovery
3.1 Introduction
Combined thermal and chemical treatment enhancements for Dense Non-Aqueous
Phase Liquid (DNAPL) remediation mainly stem from research studies on enhanced
oil recovery (EOR). The goal of EOR is to develop efficient methods to recover
residual oil from geological formations for secondary oil production (Holm and
Csaszar 1962; Lake 1989; Taber 1981). While many lessons can be learned from
EOR studies conducted with experiments ranging from lab- to pilot-scale treatability
tests, there are numerous substantial differences between EOR and soil remediation,
such as porous media structure (unconsolidated media), the physical and chemical
conditions (low temperature and low pressure), the physicochemical properties of
the recovered organic compounds, as well as recovery and remediation goals (e.g.,
obtaining a low soil pollutant saturation) (Pennell et al. 1996).
Most in situ thermal treatments improve organic pollutant recovery. Deciding
which temperature to apply to treated soils should consider the physical and chemical properties of the pollutants as well as the soils’ properties (i.e., porosity,
permeability, heterogeneity, water content, and thermophysical properties). Thermal
treatments have been applied to highly concentrated pollution sources. Table 3.1
shows the potential applicability of thermal treatment techniques compared to other
techniques in two generic hydro-geological situations.
The main In Situ Thermal Treatments (ISTT) are the following: (1) SteamEnhanced Extraction (SEE); (2) Thermal Conductive Heating (TCH) or In Situ
Thermal Desorption (ISTD); (3) Electrical Resistance Heating (ERH), (4) Radio
Frequency Heating (RFH), and (5) Free product thermal enhancement recovery.
It is shown that increasing the temperature reduces viscosity (and to a lesser
extent NAPL–water interfacial tension), increases reaction rates, aqueous solubility,
volatility (by increasing vapor pressure and partitioning to the gas phase), and
pollutant desorption from a solid matrix (Hiester et al. 2013; Johnson et al. 2009;
Kingston et al. 2014; Smith and Hinchee 1993). Temperature ranges of subsurface
heating remediation techniques are plotted in Fig. 3.1. The processes with the most
significant results operate within a temperature range of 50–100
C at atmospheric
pressure. Temperatures above 120
C can generate chemical transformations such as
gasification and hydrolysis of organic pollutants (from 120
C), steam cracking for
150
S. Colombano et al.