Adsorption Plants For the removal of non-biodegradable COD and halogenated hydrocarbon (AOX) look no further than activated carbon. For example, wastewater from medicine production can be treated with a combination of biological and activated carbon processes, thereby ensuring the complete removal of endocrine mimicking compounds. At a chemical plant, activated carbon can be employed to remove non-biodegradable COD. Another application is the treatment of leachate from landfill sites.
The adsorption of organic contaminants is based on physical process that take place on the surface of the activated carbon. Due to a highly developed pore system, activated carbon has an extremely large inner surface area. The concentration gradient of the material that is adsorbed is the driving force behind adsorption. Once the activated carbon is completely loaded it can be removed and replaced with fresh activated carbon.
WEHRLE Umwelt GmbH uses activated carbon both as a primary treatment process and a secondary one after biological pretreatment.
Biological pretreatment, preferably where the biomass is separated by membrane filtration (Membrane Bioreactors) results in a higher loading onto the activated carbon and therefore a more economic operation.
Used activated carbon can be returned to the supplier and reactivated. The carbon is thus made available again for the customer. The disposal of problematic substances is included in this procedure.
A number of vessels are used in series to ensure that the consumption of activated carbon is in accordance with any process guarantees and to provide the necessary contact time. This allows the complete loading of the first chamber without exceeding the discharge consent for COD and AOX in the effluent of the final chamber.
After being completely loaded the activated carbon in the first chamber is removed. From then on the flow through the plant is redirected so that the chamber with the fresh carbon is always last in the series. This ensures low rates of carbon usage whilst maintaining excellent effluent quality.
In order to size an activated carbon plant we produce adsorption isotherms in our laboratory. This allows us to ascertain the feasibility of meeting the discharge requirements. Trials with activated carbon vessels can be conducted on site to confirm these results and to establish the rate of carbon consumption.