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Phytotechnology with Biomass Production
(Capuana, 2020). Phytoremediation reduces soil erosion and the spread of
contaminants because of wind and water.
The social value of phytoremediation with biomass includes employment
to carry out the remediation and to harvest the biomass. There would also
be employment associated with the conversion of the biomass into products.
The quality of life and safety near the site should be improved.
The economic costs and benefits include the costs associated with the phytoremediation with biomass production project. There are costs for site characterization, development of the remediation plan, and implementation of
the plan. There are annual costs of caring for the site, harvesting the biomass,
and selling the product. The annual income includes the net receipts for the
biomass. There is economic value associated with the improved soil quality
and the carbon sequestration, also.
The estimated value of the avoided social cost of carbon is $42.00/metric ton
of carbon dioxide (Mikhailova et al., 2019; U.S. EPA, 2016). This is the estimated
global value of reducing GHG emissions in the form of carbon dioxide by
1 metric ton. This is an appropriate value to use when the social benefit of adding soil organic carbon to a remediation project is to be included in the analysis.
The concept of reducing GHG emissions by adding organic carbon to soil
has received significant attention, and the idea has strong support (Lal, 2016;
Mikhailova et al., 2019; NASEM, 2019).
There is value in improving soil quality at contaminated sites. Many of these
sites have little or no economic value in their present state; however, if the soil
can be improved by establishing vegetation and producing a biomass product
such as Miscanthus or wood that can be harvested and sold, the value of the
site increases. Since productive land sells for more than $10,000/ha in many
locations, one of the ecosystem benefits of phytoremediation with biomass
production is the improvement in soil quality associated with the project.
If one can remediate a contaminated site so that it can be used productively
with products of the same quality as nearby farms, this is beneficial for society.
One way to improve the global carbon balance is to use phytoremediation
with biomass production to establish trees on contaminated sites. Growing
trees will increase soil carbon below ground and plant carbon above ground.
At $42.00/ton of carbon dioxide avoided, it may be beneficial to do this at
many sites. The soil carbon below Miscanthus after 8–10 years is about
90 MgC ha −1 (Cattaneo et al., 2014; Dondini et al., 2009; Hansen et al., 2004),
which adds about $13,860 ha to the value of the project. Trees also have
significant amounts of carbon in the soil and associated with their roots
(Mikhailova et al., 2019). The amount of carbon added assumes that the site
has very low soil carbon prior to the start of the remediation project.
The improvement in soil quality and the carbon added to the site are important ecosystem and economic reasons to go forward with phytoremediation
projects. If one can move from the state of an abandoned site to one where a
product is being produced, this has social value because of the employment
that is created.