Regenerating ground polluted by any hydrocarbon, on site and at ambient temperature, where the pollutant and transfer matrix form a high-grade fuel

摘要

A plastic matrix of any plastic excluding PVC, powdered to around 1.5mm, is used to clean up ground polluted by hydrocarbons, operating at up to 35 tonnes/hour and at ambient temperature. The cleaned soil contains less than 150ppm pollutants so the ecosystem can be re-established and the matrix, including pollutants, forms a high-grade fuel for industrial use with a PCI of 10,000kcal/kg : Process using a plastic matrix of high and low density or other plastic, excluding PVC, produced from recycling waste plastic such as telephone, computer or other plastic casings from domestic electrical equipment at the end of its life, powdered to around 1.5mm. This is used to clean up ground polluted by aromatic, paraffinic or olefinic hydrocarbons with the intention of using this matrix, including pollutants, as a high quality fuel with a PCI of 10000kcal.kg which can be used by industry as a replacement for conventional fuels. The process returns a soil containing less than 150ppm pollutants, with an ecosystem which can be returned to place. The process is carried out on site at ambient temperature without any emissions during the treatment. Independent claims are made for the plastic matrix, before and after it contains pollutants. The process involves excavating the soil and then sieving it to remove large bodies or those which will disturb the operation such as wood, metal, unpowdered plastic, textiles, electrical wires and large stones. The soil is then broken up in a grinder (2) to produce a granulometry of 100mm and transferred to a mixer (5) with a capacity of 10m3. The plastic matrix (7) is also introduced into the mixer, together with a soil conditioner (6). After a mixing time of about 10min, the mixture is evacuated by a hydraulic emptying guillotine at the bottom of the mixer to an agitated tank (8) containing about 12m3 of water, provided with nozzles through which air jets are blown by a compressor (10). The tank also has a surface skimmer (11). The separation of the soil and the matrix is achieved by the blowing air, so the soil sinks and the matrix floats. The matrix containing the pollutant is removed to a hopper (13) by the skimmer and stored in a secure area (17) with the intention of selling it to industry as a fuel. The clean soil at the bottom of the tank is evacuted to another hopper (14) by an endless screw or bucket wheel (12) to be returned to its excavation site. The separating water is recycled (16) through a little press filter (9) which allows fine particles to be removed and added to the fuel. A control system (18) prevents deflagration. The treatment unit is mobile.