Soil pollution prevention and remediation using physicochemical and biological technologies

Runoff from agricultural and urban areas can represent a nonpoint source of nitrogen pollution. Such runoffs can affect both terrestrial and aquatic ecosystems. For example, in many cases, the inputs of nitrogen in soil in the form of fertilizers may exceed the outputs. Additionally, nutrients in manure can be recycled by applying the manure to cropland. Still, the amount of manure generated can exceed the capacity of croplands to use and retain the nutrients. In urban areas, nonpoint source nitrogen pollution can be due to septic tanks, urban runoff from areas lacking sewers, etc. In all these cases the excess nitrogen builds up in the soil, runs off to surface water, or leaches toward groundwater. Urban best management practice (BMP), that is, flood control measures and surface water quantity and quality management training, can be introduced into sewage systems. Prevention technologies are crucial and have already been implemented in many circumstances to deal with this issue, and new solutions are also under study. On the contrary, when the soil is already polluted, it is still possible to reverse course through remediation interventions, although more effort is usually needed. Consequently, this chapter focuses on prevention and remediation technologies to deal with nonpoint source nitrogen pollution.