An Innovative Method for the On-Site Remediation of Polluted Soil under existing Infrastructures
INCO Project in the 6th EU framework programme
01.05.2005 – 30.04.2008
Barbara De Mena
The CLEANSOIL project will develop and promote the on-site in-situ treatment of hazardous substances at local point source by means of adsorption mechanisms. Based on its simplicity it is specially targeted for large areas of polluted land, and when removal is not practicable i.e. under existing infrastructures.
Soil is a vital and largely non-renewable (in the 50-100 years timescale) resource increasingly under pressure, which performs a number of key environmental, social and economic functions vital for life, but increasingly threatened by a range of human activities, causing its degradation. Unfortunately this problem is aggravated due to diffuse contamination, which in most cases result in damage or loss of several functions of soil, groundwater contamination and possible transfer of pollutants to humans.
In the EU 1.5 M polluted sites have been estimated, and in Russia and the New Independent States (NIS) the number is at least comparable, due to former military sites, machinery repair, fuel stations, and industrial production sites. Heavy metals, PCB, chlorinated hydrocarbons, pesticides and nitrates lead to severe consequences on the environment, the agricultural production system and human health (gastrointestinal, respiratory diseases, blood exchange disorders, oncological diseases).
Soil clean-up is a difficult operation with very high costs, varying from 59 to 109 billion €/ha, irrespective of the degree of contamination and technology applied. The most generally used method to address land pollutants is to excavate and remove the polluted land, which is then treated or transported to a landfill at another location. Apart from being costly, this method results in a heavy environmental load and many times not financial or technically feasible. The development of new technologies for the removal of poisons from the soil has thus become a priority. Further research has been carried out in the field of bioremediation, phytoremediation and sorption based methods as alternative method to excavation.
CLEANSOIL aims to develop an economically friendly sound alternative to enable the on-site/in-situ treatment of hazardous substances, by means of adsorption mechanisms. Based on its simplicity, it is specially targeted for large areas of polluted land, and highly recommended when the removal is not applicable (under buildings, roads, railroads, etc), as it causes minimum disturbance.
The method consists of several inserted cords connecting a multitude of sorbent material-containing sockets inside the same number of parallel horizontal holes drilled in the ground. After a sufficient period of time the sorbents absorb the pollutants to the desired remediation effect, the system is removed and the sorbent regenerated for further application.
The proposed project will investigate and clearly define the potential applications of the CLEANSOIL system. By making the necessary adaptations, selective systems for each kind of contaminant will be established, which will allow to offer solutions for large contaminated areas at moderate costs. Still further applied research is required in order to adapt the method to different soil conditions and contamination problems. With these aim, tests will be conducted for selection of the most suitable sorbents and reactive agents for the removal of a wide range of pollutant compounds in conjunction with studies of soil geological properties and the hydraulic characteristics.