 |
|
|||
|
|
|
|||
 |
|
Soil Washing for Remediation of Non
Volatile Hydrocarbon Polluted Soils This
paper illustrates the possibilities of applying what is essentially a physical
soil-washing technique for treatment of soil contaminated by semi-volatile hydrocarbons in
order to reduce the level of pollution to that permitted by Italian regulations. The
ground around a factory producing lubricating-oil additives consists of silty-sandy soils,
which have long been contaminated by heavy hydrocarbons, especially branched alkyl
benzenes and naphthalene derivatives. Pollution is particularly marked in some zones
(hot-spots) where Total Petroleum Hydrocarbon (TPH) values are as high as 7000ppm. The
hydrogeological characterization showed the presence of a gravely soil in a sandy/silty
matrix, with big stones making preferential paths to the water circulation. The
permeability is 10-5m/s and the water-table occurs at about 3m below ground level. After
laboratory and pilot-scale studies on representative samples of in-situ soils with TPH
between 2700 and 7000ppm a flow-sheet is proposed for reducing TPH values below the
acceptable limits in Italy, namely 700ppm for hydrocarbons with more than 12 carbon atoms
and less than 250ppm for those with fewer. Recovery of remediated soil to be returned to
the site is around 90%. |
|
