Patent DE-102008008031-A1 (DE)
Title: Combined in-situ and on-site cleaning of water containing harmful substances e.g. phenol and alkylphenols, comprises in-situ cleaning of contaminated groundwater in subsurface oxidation and on-site removing substances in the groundwater
Inventor: OVIEDO ISIDRO
IPC: C02F1/78
Filed: 2008-02-06
Abstract: The method comprises in-situ cleaning of contaminated groundwater in a subsurface oxidation and on-site removing substances in the groundwater. The in-situ and on-site procedures are independently linked with one another. The process of on-site removing substances includes one or multi-level biological treatment by cultured microorganisms, one or multi-level oxidation and final treatment by filtration and adsorption in a complex cleaning operation by a procedure combination of pretreatment and conditioning. During in-situ cleaning, the groundwater is saturated with an ozone oxygen mixture. The method comprises in-situ cleaning of contaminated groundwater in a subsurface oxidation and on-site removing substances in the groundwater. The in-situ and on-site procedures are independently linked with one another. The process of on-site removing substances includes one or multi-level biological treatment by cultured microorganisms, one or multi-level oxidation and final treatment by filtration and adsorption in a complex cleaning operation by a procedure combination of pretreatment and conditioning. During in-situ cleaning, the groundwater is saturated with an ozone oxygen mixture using an ozone injection unit. The ozone spreads in the direction of flow of the groundwater while an oxidative degradation of the pollutants takes place, is controlled over the monitoring levels of the ozone oxygen dosage and takes place between first and second monitoring level of the pure filtration of cleaned groundwater. A hydrological and biological barrier is formed, by which the chemically oxidative and biological pollutant degradation is positively stimulated. The ozone oxygen mixture has an ozone content of 5-8% and is infiltrated in such a way that ozone separates completely in the aqueous phase. The ozone in-situ process step is produced from dried air by an ozone generator, is dosed into the groundwater so that further a micro-biological degradation of the pollutants takes place, and is continuously or discontinuously introduced. The ozone supply is controlled over the monitoring level to reach an optimization of the chemical oxidation. The micro-biological degradation of the pollutants is promoted by a nutrient addition according to carbon:nitrogen:phosphorus ratio of 100:10:1. The nutrients are supplied above the monitoring level by an infiltration unit. The pH value adjustment during the entire procedure takes place by the buffer effect of the ground and no further pH adjustment is needed. The ozone-oxygen mixture is infiltrated in such a way that the surplus oxygen guides when discharging from the saturated phase to a stripping of volatile pollutants and so that contributes to an additional cleaning of the groundwater. The microorganisms are located on carriers. A nutrient salt dosage according to carbon:nitrogen:phosphorus ratio of 100:10:1 takes place in the biological process. All process steps are carried out in reactors under normal pressure with ambient temperature without separate heating. The oxidation is carried out in the oxidation reactors by the ozone and an additional catalyst or additive of hydrogen peroxide. The entry of ozone is carried out by in the oxidation reactors with normal pressure or with small positive pressure. No elimination of surplus ozone is needed in or after the oxidation reactors. The pollutant concentrations of different species up to 500 mg/l are eliminated by the method. An independent claim is included for a device for combined in-situ and on-site cleaning water containing harmful substances.