Microbial Waste Water Purification in the Explosives Industry

The company Dynamit Nobel Wien GmbH, St. Lambrecht, produces waste water as a result of the production of explosives, which is highly contaminated with nitroglycoles and nitrate. The aim of this project is the biological purification of the waste water in a technical plant, which should be achieved by screening in the laboratory scale, optimization tests in a larger scaled pilot plant and investigation of the degradation processes. The purification process consists of three stages: In the first stage the organic compounds are biodegraded aerobically, the second stage is a denitrification unit for the removal of nitrate, and in the third stage residual carbon is eliminated. After the addition of growth factors, the processed waste water is pumped into the 400 cubic meter plant, where input concentrations of nitrate up to 25 g nitrate/L can be reduced by the factor of 0.9. This is enabled by the use of large trickling filters (submerged biofilters) with special carriers. The investigation of the kinetics and the optimization of the process in collaboration with Prof. Schappacher/Mag. Gollner from the Institute of Mathematics of the University Graz lead to a mathematical model of the denitrification. The project is supported by the Austrian "Forschungsförderungsfonds für die gewerbliche Wirtschaft (FFF)" and was awarded with the Environmental Prize of the Austrian Industry 1996.