摘要：Sewage sludge is certainly a waste because of its contents of inorganic and organic contaminants. Recent investigations have shown that sewage sludge contains considerable amounts of pathogenic germs, drugs, hormones, carcinogenic and mutagenic substances.

Incineration of sewage sludge in the fluidized bed is able to establish a sink in the food chain by thermally destroying these latter contaminants.

Sewage sludge on the other hand can in the future become a valuable resource. This is particularly valid for phosphorus as a fertilizer material. Presently available mineral fertilizers rely on phosphate production from phosphate rock which is a finite resource. The European Union has just in 2016 put phosphorus on their list of 20 raw materials considered critical for the EU.

At present, several processes are under development to recover P from sewage water, sludge or ash. However, costs of recycling products exceed prices of mineral fertilizers based on phosphate rock.

At the Waste Water Treatment Plant Ulm the strategy is to produce a "clean" sewage sludge which after incineration leads to an ash which satisfies the quality requirements of the German Fertilizer ordinance. This strategy implies a strict quality control of the incoming effluent. An additional cleaning step i.e. a contact reactor with activated carbon followed by a filter enhances the P recovery and its transfer into the sludge. The optimization of the Waste Water Treatment Plant and the incineration leads to a high efficiency of the total P recovery from the waste water to the ash product of 97.8 %.

The plant availability of phosphorus in recycling products is still under discussion among experts. It is the neutral-ammonium-citrate solubility which is considered to describe that part of the total P which is 100 % plant available during one growing season. In the Ulm case this amounts to 43.7 % of the total P in the incoming waste water.

报告人介绍：As one of most famous experts in Chemical Engineering science and energy utilization, Prof. Dr.-Ing. Joachim Werther, was born on December 24, 1942, and got the Diploma (Dipl.-Ing.) in Mechanical Engineering, University of Karlsruhe in 1967, got the Dr.-Ing. of Chemical Engineering, University Erlangen-Nuremberg in 1972. since 1980, Professor, Chair of Chemical Engineering I, Technical University Hamburg-Harburg, 1988 – 1999, as Chairman, DFG-Sonderforschungsbereich 238 “In-situ Measuring Techniques and Dynamic Modeling for Multiphase Flow Systems”, 1999–2001, as Vice President Research, Technical University Hamburg-Harburg,2006 – 2008, as Head, Institute of Solids Process Engineering and Particle Technology, Technical University Hamburg-Harburg. since 2008, retired as head of SPE Institute, ongoing research on CCS technologies and biorefineries.