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Systems and processes for soil treatment

Systems and processes for air and soil treatment

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Chemico-physical treatment of contaminated materials

Process description: TERRALAVAR® is a soil washing procedure for the chemico-physical remediation of soils and soil-like materials that are contaminated by organic and/or inorganic hazardous substances, such as mineral oils and tar oils, PAH, PCB, TNT and heavy metals. The process is based on the migration of contaminating agents to the finest soil fraction under the influence of kinetic energy and water. The contaminated agents, which are contained in the finest soil fraction, will then be evacuated of the system as filter cakes. The thus decontaminated soil may then be used as filling or road construction material. In combination with the TERRAFERM treatment process and with thermal soil treatment processes, TERRALAVAR® covers the treatment of the entire contaminating agents’ scope. This treatment method stands out for its short process duration. Compared to thermal treatment processes, the TERRALAVAR®-treatment process offers price and approval advantages.

Material supply: The soil is delivered, weighted and subjected to an entry sampling by lots.

Soil washing process: Once the coarse fraction has been separated (>40-240 mm), the contaminating agents’ containing soil is subjected to a wet mechanical and chemical disassociation process. This process takes place in special disassociation drums, mixers, and/or logwashers. In order to separate contaminating agents, the suspended soil material passes through different traditional treatment units, which are specifically adapted to soil characteristics.

Sorting according to grain size: This classification procedure is required to secure the separation of the fine grain particles, and to allow further treatment. To do so, screens as well as centrifugal separators will be used.

Sorting according to density: This classification procedure is indispensable as soon as highly contaminated and adsorbent substances, such as coke, carbon slag, wood or humus have to be separated. To do so, sedimentation units and spiral separators will be used.

Emission protection/prevention: Not only the material feed-in process, but also the dissociation process, are executed as capsulated processes for being potential sources of emissions. Controlled evacuation and treatment will be provided for volatile contaminants. The required process water will be continuously recycled in order not to generate any wastewater.

Flexibility: Due to its modular configuration, TERRALAVAR® is a highly flexible process. The system will be adjusted to individual soil and contaminating agents’ characteristics.

Control: Electronic safety devices and process programmability provide for an almost automatic operation. Control functions are carried out from the central switchboard gallery.

Process parameter: Retention time, energy consumption and the use of adjuvants can be freely adjusted.

Residues: Residues are considered to be soil particles that may not further be treated, such as digestion sludge generated in the process water treatment. These residues will be dewatered and the obtained filter cake will be subjected either to a secondary treatment or recycled.

Secondary treatment: Fractions of residues, which contain biologically degradable hazardous substances, may be further treated by means of the TERRAFERM®-treatment process. If the recycling process in a company-owned facility does not appear to be reasonable, the substances will be externally used in cement plants or they will be disposed off.

Soil re-use: Depending on the origin, the structure and the material composition, there are manifold re-use options for decontaminated soils due to its very good quality features, e.g. in the field of landscaping (as filling material or for the construction of noise barriers), in the field of sanitary landfill construction as drainage material and in the field of road construction. Decontaminated ballast is transformed into recycled gravel and high-quality chippings.

Experience: ZECH UMWELT GmbH has developed the TERRALAVAR®-soil washing process in order to broaden the biological remediation techniques, which have been successfully used for more than one decade. In cooperation with its affiliated companies, ZECH UMWELT GmbH is presently operating four stationary soil washing plants. Mobile plant technique is being used for on-site remediation measures both in Germany and abroad. The in-house production secures the rapid availability of very specific equipment. Modified frame conditions can be handled within short notice.

Our large experience potential is backed by the remediation of more than 2.5 million tons of soil, building waste and ballast generated in the scope of the most various and international remediation projects.

TERRALAVAR®-Process Scheme


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