Pilot Plant Wienenergie

The aim of the Wienenergie project was the remediation of two former gas plant sites. Leopoldau and Simmering were the biggest gas plants in Vienna, working until the 1970s. The production of town gas by dry distillation of coal sets free a number of by products that got into soil and groundwater. The site specific pollutants polycyclic aromatic hydrocarbons, benzene, toluene, ethylbenzene, xoluene and cyanides (PAHs, BTEX, CN) are considered as highly toxic. The aim of the project was on one hand to protect the surroundings and inhibit the diffusion of the contamination and on the other hand develop a concept for groundwater purification. It should be investigated, which remediation goals can be achieved by which means, and where to dispose the different flows. It was shown, that each site had to be treated differently, according to geological circumstances and the different contaminations. In Leopoldau the hot spot was encapsulated by a cut off wall, and in addition, the groundwater was extracted downstream, purified and drained away upstream. The most efficient setup was a flotation, a biological activated carbon filter and an activated carbon filter. In Simmering a sedimentation step, a biofilter, a multi layer filtration and an active carbon filter as most successful during the pilot scale experiments. A line of extraction wells and drain wells supplied the hydraulic security. The legal limits for water bodies (AAEV) could be achieved for all parameters.