Disposal options for polluted plants grown on heavy metal contaminated brownfield lands - A review

Reducing or preventing damage caused by environmental pollution is a significant goal nowadays. Phytoextraction, as remediation technique is widely used, but during the process, the heavy metal content of the biomass grown on these sites special treatment and disposal techniques are required, for example liquid extraction, direct disposal, composting, and combustion. These processes are discussed in this review in economical and environmental aspects. The following main properties are analyzed: form and harmful element content of remains, utilization of the main and byproducts, affect to the environment during the treatment and disposal. The thermal treatment (combustion, gasification) of contaminated biomass provides a promising alternative disposal option, because the energy production affects the rate of return, and the harmful elements are riched in a small amount of solid remains depending on the ash content of the plant (1-2%). The biomass combustion technology is a wildely used energy production process in residential and industrial scale, but the ordinary biomass firing systems are not suited to burn this type of fuel without environmental risk.