Das Projekt "Kopplung von Elektrokoagulation und Elektroflotation zur Behandlung Metall belasteter Abwässer - Eine Studie über Speziiestransformierung, Flockungsprozesse und Partikelcharakterisierung" wird vom Umweltbundesamt gefördert und von Technische Universität Hamburg-Harburg, Institut für Umwelttechnik und Energiewirtschaft V-9 durchgeführt. Traditional methods for the treatment of polluted waste water require a considerable and continual supply of chemicals. More cost-effective methods with minimal additives and with reuse of waste water are required for sustainable water management. Very promising techniques based on electrochemical technology are being developed and existing ones improved that do not require chemical additions. These include electrocoagulation and electroflotation. Although these processes have the potential to extensively eliminate the disadvantages of the classical treatment techniques, the mechanisms are yet not clearly understood. There has been little consideration of the factors that influence the effective removal of metal species. Typically, empirical studies are done, which provide little insights into fundamental chemical and physical mechanisms. These studies do not allow modeling of the process or the design of improved systems, process control, and optimization from fundamental physico-chemical principles. The main objectives of this project are to study on a practical level the formation of colloidal metal compounds during electrocoagulation, and to identify stable and short living metal species resulting from reactions occurring near the electrodes under varying hydrodynamic and electrochemical conditions, and to separate colloidal particles and formed flocs with a combined electroflotation process. In the first year the project work will concentrate on the construction and calibration of the electrocoagulation / electroflotation cell, the study of operational variables, and the characterization of the generated particles. In the second year, we will establish the optimum process conditions for a metal contaminated industrial waste water and experiments with different electrode arrangements and with different flow regime will be carried out. The third year will be used for scale-up studies and a comparison of the electrocoagulation / electroflotation with the electrocoagulation / ultrafiltration process in the respect of costs, operational, and environmental benefits will be assessed. Research will be carried out in cooperation with the Israelien partner who uses electrocoagulation as a pretreatment step to ultrafiltration. By optimizing the particle size distribution, better separation efficiencies can be obtained for both processes. The process of electrocoagulation has the potential to extensively eliminate the disadvantages of the classical treatment techniques, to reduce the volume of produces sludge, to avoid the additions of chemicals, and thus to achieve a sustainable and economic treatment of polluted waste water.