25.1 Introduction
Composting is a natural biological process carried out under controlled aerobic
conditions. In this process, various microorganisms including bacteria and fungi
break down organic matter into simpler substances. The effectiveness of the
composting process depends on the environmental conditions present within the
composting system, i.e., oxygen, temperature, moisture, material disturbance,
organic matter content, and the size and activity of microbial populations.
Composting has been proved to be efficient for remediation of soils contaminated
with PAHs. For remediation purposes, the composting substrate (based on an
agricultural-waste mixture of optimum nutrient ratio) is mixed with contaminated
soil. Due to a wide range of acting microorganisms, the process is quite robust and
the outcome appears to depend mainly on the bioavailability of the target pollutant,
which seems to be a crucial factor in biodegradability and ecotoxicity of PAHs in
environmental matrices (Cajthaml and Šašek 2005; Čvančarová et al. 2013).
This chapter describes two different approaches of PAH elimination using a
composting process tested under pilot-scale conditions:
1. PAH-contaminated soil matrices collected from four different long-term contaminated sites were co-composted with raw materials, such as straw, gypsum, and
chicken manure, used for cultivation of white button mushroom—Treatment 1.
2. Shaved creosote-treated railway crossties (CTW), which as PAH-contaminated
wood represent a bulking agent, were co-composted with two different additional
substrates, namely fresh grass cuttings (GC) and broiler litter straw-based substrate (BL)—Treatment 2.
Supercritical fluid extraction (SFE) was used as a rapid test to predict the
bioremediation results of composting for both treatments.
25.2 Materials and Methods
Soil Samples The PAH-contaminated soils for Treatment 1 were collected from the
following sites: former gasworks, Prague (sample A); former tar-processing plant,
Ostrava (sample B); former wood-treatment-plant, Soběslav (sample C); and former
gas-holder site, Prague (sample D). The soils were air-dried, sieved through a 5 mm
mesh screen and homogenized. The waste creosote-treated railway crossties (CTW)
for Treatment 2 were obtained from EKO-BIO VYSOČINA, spol. s r.o., Czech
Republic and shaved to fine debris (3 cm).
Preparation of Composting Experiments Treatment 1 was performed in a thermally insulated composting chamber using stabilized broiler litter (BL) that is
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P. Innemanová and T. Cajthaml
Composting is a natural biological process carried out under controlled aerobic
conditions. In this process, various microorganisms including bacteria and fungi
break down organic matter into simpler substances. The effectiveness of the
composting process depends on the environmental conditions present within the
composting system, i.e., oxygen, temperature, moisture, material disturbance,
organic matter content, and the size and activity of microbial populations.
Composting has been proved to be efficient for remediation of soils contaminated
with PAHs. For remediation purposes, the composting substrate (based on an
agricultural-waste mixture of optimum nutrient ratio) is mixed with contaminated
soil. Due to a wide range of acting microorganisms, the process is quite robust and
the outcome appears to depend mainly on the bioavailability of the target pollutant,
which seems to be a crucial factor in biodegradability and ecotoxicity of PAHs in
environmental matrices (Cajthaml and Šašek 2005; Čvančarová et al. 2013).
This chapter describes two different approaches of PAH elimination using a
composting process tested under pilot-scale conditions:
1. PAH-contaminated soil matrices collected from four different long-term contaminated sites were co-composted with raw materials, such as straw, gypsum, and
chicken manure, used for cultivation of white button mushroom—Treatment 1.
2. Shaved creosote-treated railway crossties (CTW), which as PAH-contaminated
wood represent a bulking agent, were co-composted with two different additional
substrates, namely fresh grass cuttings (GC) and broiler litter straw-based substrate (BL)—Treatment 2.
Supercritical fluid extraction (SFE) was used as a rapid test to predict the
bioremediation results of composting for both treatments.
25.2 Materials and Methods
Soil Samples The PAH-contaminated soils for Treatment 1 were collected from the
following sites: former gasworks, Prague (sample A); former tar-processing plant,
Ostrava (sample B); former wood-treatment-plant, Soběslav (sample C); and former
gas-holder site, Prague (sample D). The soils were air-dried, sieved through a 5 mm
mesh screen and homogenized. The waste creosote-treated railway crossties (CTW)
for Treatment 2 were obtained from EKO-BIO VYSOČINA, spol. s r.o., Czech
Republic and shaved to fine debris (3 cm).
Preparation of Composting Experiments Treatment 1 was performed in a thermally insulated composting chamber using stabilized broiler litter (BL) that is
528
P. Innemanová and T. Cajthaml