stated in his review that the pesticide analyses of finished composts from various
farms in the USA revealed the presence of only a few pesticides, usually chlorinated
pesticides, including substances that were already banned in the USA years ago.
Other pesticides of the organophosphate and carbamate types were detected only
rarely. The comparison of pesticide concentrations before and after the composting
showed that chlorinated substances were mostly resistant to biological degradation
during the composting. Pesticides of other kinds were degraded relatively well, with
certain exceptions. The studies examining the degradation mechanisms showed that
mineralization was responsible only for partial removal of the pesticides. Other
important mechanisms were adsorption and volatilization.
23.3.3.6 Micropollutants
Less attention was paid to the removal of newly emerging pollutants, for instance,
pharmaceuticals and personal care products. Although the subject is rather wide
owing to numerous substances that are nowadays present in the environment, many
of typical micropollutants are trapped in wastewater treatment sludge that is
composted for hygienization purposes. Nevertheless, the subject has been reviewed,
e.g., in the paper by Semblante et al. (2015). The composting process represents an
ideal method for elimination of micropollutants transfer into the environment. Many
of the newly emerging micropollutants are not as recalcitrant as typically persistent
organic pollutants and the process is probably able to substantially reduce the
concentrations of the micropollutants only with moderate condition adjustment.
An overview of studies dealing with this subject is shown in Table 23.2.
23.4 Conclusions
Composting and compost addition are sustainable and effective bioremediation
option, especially for the treatment of soil contaminated with mixtures of hydrocarbons (fuels, lubricating oils, creosote, etc.), explosives, phenols, some pesticides,
and emerging pollutants. In order to design full-scale bioremediation technology
based on composting processes, preliminary investigations on the process variables,
i.e., co-substrate composition, bulking agents, aeration or turning, ideal ratio of
non-contaminated to contaminated waste as well as physical, chemical, and microbiological characteristics of the matrix to be remediated are necessary.
Beside the degradation of contaminants initially present in the polluted waste that
is chiefly used to check whether remedial goals were met, a set of toxicological
analyses will help assessing the effectiveness of the process and evaluate the residual
eco- and genotoxicity associated to the final product. Unfortunately, it is not always
clear what the potential reuse of the soil that has undergone such treatment is,
especially considering the relatively high content of organic matter still present
that prevents its use.
23 Composting Practices for the Remediation of Matrices Contaminated by. . .
487
farms in the USA revealed the presence of only a few pesticides, usually chlorinated
pesticides, including substances that were already banned in the USA years ago.
Other pesticides of the organophosphate and carbamate types were detected only
rarely. The comparison of pesticide concentrations before and after the composting
showed that chlorinated substances were mostly resistant to biological degradation
during the composting. Pesticides of other kinds were degraded relatively well, with
certain exceptions. The studies examining the degradation mechanisms showed that
mineralization was responsible only for partial removal of the pesticides. Other
important mechanisms were adsorption and volatilization.
23.3.3.6 Micropollutants
Less attention was paid to the removal of newly emerging pollutants, for instance,
pharmaceuticals and personal care products. Although the subject is rather wide
owing to numerous substances that are nowadays present in the environment, many
of typical micropollutants are trapped in wastewater treatment sludge that is
composted for hygienization purposes. Nevertheless, the subject has been reviewed,
e.g., in the paper by Semblante et al. (2015). The composting process represents an
ideal method for elimination of micropollutants transfer into the environment. Many
of the newly emerging micropollutants are not as recalcitrant as typically persistent
organic pollutants and the process is probably able to substantially reduce the
concentrations of the micropollutants only with moderate condition adjustment.
An overview of studies dealing with this subject is shown in Table 23.2.
23.4 Conclusions
Composting and compost addition are sustainable and effective bioremediation
option, especially for the treatment of soil contaminated with mixtures of hydrocarbons (fuels, lubricating oils, creosote, etc.), explosives, phenols, some pesticides,
and emerging pollutants. In order to design full-scale bioremediation technology
based on composting processes, preliminary investigations on the process variables,
i.e., co-substrate composition, bulking agents, aeration or turning, ideal ratio of
non-contaminated to contaminated waste as well as physical, chemical, and microbiological characteristics of the matrix to be remediated are necessary.
Beside the degradation of contaminants initially present in the polluted waste that
is chiefly used to check whether remedial goals were met, a set of toxicological
analyses will help assessing the effectiveness of the process and evaluate the residual
eco- and genotoxicity associated to the final product. Unfortunately, it is not always
clear what the potential reuse of the soil that has undergone such treatment is,
especially considering the relatively high content of organic matter still present
that prevents its use.
23 Composting Practices for the Remediation of Matrices Contaminated by. . .
487