Dear Karthika Natarajan, 

A soil washing is a water-based process for mechanically scrubbing. Its removal efficiencies depend on the type of contaminant as well as the type of soil. The water used in the soil washing process is treated by conventional wastewater treatment (WWTP); secondary or tertiary treatments.

http://www.wmsym.org/archives/1993/V1/160.pdf

http://nepis.epa.gov/Exe/ZyNET.exe/200085GV.txt?ZyActionD=ZyDocument&Client=EPA&Index=1986%20Thru%201990&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5CZYFILES%5CINDEX%20DATA%5C86THRU90%5CTXT%5C00000005%5C200085GV.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h%7C-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r65g4/r65g4/x150y150g16/i360&Display=p%7Cf&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1

Hoping this will be helpful,

Rafik

For the treatment of soil washing solutions, the goal is to remove target pollutants and to recover extracting agents for further soil washing steps, in order to improve the cost-efficiency of the whole soil remediation process (extracting agents are expensive). It can be used solvent extraction for HOC, air stripping for VOC, selective adsorption onto activated carbon, selective oxidation ... But it is not very easy to achieve selective removal of target pollutants. Therefore, it can be also decided to remove the organic load of the soil washing solution in the most cost effective way (without any consideration about extracting agents recycling) by using for example biological processes or combined processes. In this case, the use of low-cost extracting agents would be better. Please have a look on this review about the treatment of soil washing solution if you are interested in.

Best regards,

Clément

Article Removal of hydrophobic organic pollutants from soil washing/...

thank you all