Weitergehende Untersuchungen zur Entwicklung und Erprobung eines Verfahrens zur Behandlung saurer Bergbauwaesser. Teilprojekt 1: Mikrobiologische ex-situ Sulfatreduktion. Teilprojekt 2: Feststoffabtrennung und -entsorgung bei der mikrobiologischen ex-situ Sulfatreduktion Abschlussbericht

The aim of the project was to prove at pilot scale the long-term stability of the biological sulphate reduction - even for wintertime. The target was to collect data to enable an advanced optimisation of the biological and technical processes. We had to decrease the residence time in the bioreactor and to optimise the substrate concentration. Simultaneous we had to realise a long-term stable process. The most important factors were the temperature in the bioreactor at operating plant and decreasing outside temperatures as well as the efficiency of the microbial processes at high, low or extreme varying temperatures. An additional target was the minimisation of the consumption of chemicals and energy for all technological processes. The targets of the project have been fulfilled. A residence time of less than 2 hours has been realised. The realised specific Methanol demand has been measured with about 200 mg/g sulphate. A maximum sulphate reduction rate of > 800 mg/l"*h has been reached. The finally effluent concentration for sulphate depends on controlled process conditions. We were able to realise effluent concentrations down to <10 mg/l sulphate. The operating costs depend on the throughput of a water treatment plant. Costs of 0,028 Euro are generated for the reduction of 0,1 kg SO_4 per m"3 at a throughput rate of 100-1000 m"3/h. The pilot plant was working during 16 month at several weather conditions. High stability of the microbial process was demonstrated. No fault, breakdown or interruption of electricity and supply of chemical or nutrients lead to a collapse of the microbial process. No re-inoculation was needed. The finished work serves as a base for the scale up of the process to the 10... 100 m"3/h scale. The results given by the pilot plant are better than the German state-of-the-art and there are no experiences to scale up such processes. So the further work must include further optimisation of the process and measuring devices. (orig.)Available from TIB Hannover: F03B647+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung, Berlin (Germany); Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Projekttraegerschaft Wassertechnologie und EntsorgungDEGerman