(e.g. Kon-tiki flame curtain kilns [205, 206]) accessible to small-scale rural
farming. A detailed step-by-step description of LCA is beyond the scope of this
chapter but can be found in the handbook by Hauschild et al. [207], and several
reviews [202, 208] in which cases study are discussed.
8 Conclusions
Crops need healthy soils, but their fertility is under permanent threat of degradation
by multiple environmental stressors (e.g. high agrochemical input, nutrient
imbalance, loss of soil biodiversity, salinisation and decrease of organic matter).
Additionally, water consumption for crop irrigation is a serious challenge in the
coming years because of the global climate change, particularly in areas of arid and
semiarid climates. The use of by-products derived from wastewater treatment plants
such as biosolids and treated wastewater seems an affordable solution to alleviate the
water and organic matter demands in the agriculture. However, both biosolids and
treated wastewater contain significant amounts of APIs that pose a serious threat to
soil functioning and human health.
One of the strategies for removal APIs at the source or in agricultural soils is the
vermiremediation (i.e. use of earthworms to remove environmental pollutants).
Earthworms provide multiple ecosystem benefits, from improve soil quality and
fertility up to be used in the recycling of solid organic waste (vermicomposting). All
these ecosystem services require the intervention of microorganisms. Indeed,
microbes, earthworms and their interactions are proposed as a vermiremediation
strategy to remove APIs. Many ecotoxicological studies with earthworms indicate
that these organisms may contribute to contaminant degradation by stimulating
microbial degraders, or may reduce contaminant mobility and bioavailability by
facilitating sorption of contaminants to soil organic-mineral complexes. Likewise,
certain earthworm species (epigeic earthworms) are commonly used in the aerobic
composting of solid organic residues to produce organic fertilisers (vermicompost).
Data in the literature reveal that vermicomposting may be also a viable strategy for
removing organic contaminants occurring in raw materials such as biosolids and
manure. Based on this knowledge, we propose two bioremediation strategies to
reduce the risk of API uptake by plants and the potential adverse effects on soil
microorganisms. The first system consists of vermicomposting of API-contaminated
biosolids and manure (ex situ vermiremediation), whereas the second one involves
the inoculation of agricultural soils with earthworms (in situ vermiremediation). In
the last decade, biochar has emerged as an eco-friendly strategy for fighting against
soil pollution. Because recent studies indicate that the co-application of earthworms
and biochar improve soil quality in terms of microbial proliferation and soil detoxification, the in situ vermiremediation system considers also the synergistic effects of
soil-dwelling earthworms and biochar in the removal or immobilisation of APIs.
Main advantages, drawbacks and uncertainties in the use of earthworms in API
364
J. C. Sanchez-Hernandez
farming. A detailed step-by-step description of LCA is beyond the scope of this
chapter but can be found in the handbook by Hauschild et al. [207], and several
reviews [202, 208] in which cases study are discussed.
8 Conclusions
Crops need healthy soils, but their fertility is under permanent threat of degradation
by multiple environmental stressors (e.g. high agrochemical input, nutrient
imbalance, loss of soil biodiversity, salinisation and decrease of organic matter).
Additionally, water consumption for crop irrigation is a serious challenge in the
coming years because of the global climate change, particularly in areas of arid and
semiarid climates. The use of by-products derived from wastewater treatment plants
such as biosolids and treated wastewater seems an affordable solution to alleviate the
water and organic matter demands in the agriculture. However, both biosolids and
treated wastewater contain significant amounts of APIs that pose a serious threat to
soil functioning and human health.
One of the strategies for removal APIs at the source or in agricultural soils is the
vermiremediation (i.e. use of earthworms to remove environmental pollutants).
Earthworms provide multiple ecosystem benefits, from improve soil quality and
fertility up to be used in the recycling of solid organic waste (vermicomposting). All
these ecosystem services require the intervention of microorganisms. Indeed,
microbes, earthworms and their interactions are proposed as a vermiremediation
strategy to remove APIs. Many ecotoxicological studies with earthworms indicate
that these organisms may contribute to contaminant degradation by stimulating
microbial degraders, or may reduce contaminant mobility and bioavailability by
facilitating sorption of contaminants to soil organic-mineral complexes. Likewise,
certain earthworm species (epigeic earthworms) are commonly used in the aerobic
composting of solid organic residues to produce organic fertilisers (vermicompost).
Data in the literature reveal that vermicomposting may be also a viable strategy for
removing organic contaminants occurring in raw materials such as biosolids and
manure. Based on this knowledge, we propose two bioremediation strategies to
reduce the risk of API uptake by plants and the potential adverse effects on soil
microorganisms. The first system consists of vermicomposting of API-contaminated
biosolids and manure (ex situ vermiremediation), whereas the second one involves
the inoculation of agricultural soils with earthworms (in situ vermiremediation). In
the last decade, biochar has emerged as an eco-friendly strategy for fighting against
soil pollution. Because recent studies indicate that the co-application of earthworms
and biochar improve soil quality in terms of microbial proliferation and soil detoxification, the in situ vermiremediation system considers also the synergistic effects of
soil-dwelling earthworms and biochar in the removal or immobilisation of APIs.
Main advantages, drawbacks and uncertainties in the use of earthworms in API
364
J. C. Sanchez-Hernandez