Petra Schneider

In-situ Treatment of Radioactive Mine Water using Reactive Materials - Results of Laboratory and Field Experiments in Uranium Ore Mines in Germany*

Flooding of uranium mines causes a release of considerable amounts of uranium, radium-226 and arsenic into rivers and aquifers. Thus treatment is necessary in some cases. In order to evaluate alternative water treatment methods for mine water a research project was carried out by means of both lab experiments and small scale fi eld tests in abundant mines of the Ore Mountains in East Germany. At two test sites columns fi lled with Fe 0 , Fe/Mn containing waste sludge and peat were installed for the duration of one year to investigate geochemical reactions and the fi xation processes of relevant radionuclides and arsenic. While Fe 0 is changing the geochemical conditions from oxidizing to reducing milieu, peat and Fe/Mn-sludge have a signifi cant sorption capacity. In addition iron hydroxides coprecipitate residual contaminants. The fi xation capacity of peat was found to be exhausted within half a year. The Fe/Mn-sludge adsorbed 60 % of radium and 70 % of arsenic. The best results for uranium elimination of about 96 % were obtained by means of Fe 0 . Bei der Flutung von Bergwerken sind die Metall- und Radionuklidgehalte der Wasser deutlich erhoht und mussen vielfach vor dem Eintritt in die Vorfl uter behandelt werden. Als Alternative zu konventionellen Wasserreinigungsverfahren wurden neben Laborversuchen in Bergwerken im sachsischen Erzgebirge uber ein Jahr Feldversuche mit reaktiven Materialien zur Eliminierung der Schadstoffe aus Flutungswassern durchgefuhrt. Als Materialien wurden Fe 0 , Fe/Mn haltiger Klarschlamm und Torf ausgewahlt. Wahrend die Fixierung des Urans mittels Fe 0 auf einer geochemischen Milieuwandlung und Aus- bzw. Mitfallung an Eisenhydroxiden basiert, wird bei den ubrigen Materialien die hohe Sorptionskapazitat ausgenutzt. Wie die Ergebnisse zeigen, ist Fe 0

Physico-chemical surface water conditions of catchments with metallogenic origin: A contribution to the establishment of the EC Water Framework Directive 2000/60/EG in Germany

For the realisation of the EC Framework Water Directive in Germany, the reference conditions of metals in surface waters have to be determined taking into consideration the so called surface water landscape. In catchments of metallogenic origin metals and radionuclides like uranium influence the quality of the surface waters. In this study, the quality status of metallogenic (Ore Mountains, Harz, Rhine Slate Mountains) and other surface water landscapes were compared in order to differentiate factors influencing the natural background in similar geological formations.

Contaminated Sediments in the Elbe Basin and its Tributary Mulde

Data from the Elbe River and its tributaries indicate, despite extensive improvement in water quality since reunification, that the sediment situation of many priority pollutants has not reached an acceptable level. The risks for downstream sites, especially the port of Hamburg, the lower part of the tidal river Elbe and the North Sea will persist in future. In practice, the catchment-wide assessment of contaminated soil and sediment should be identified and valued for acquiring a management plan for the EC Water Framework. The focus will be the on the tributary Mulde.

Strategy Concept Elbe

The pollution of the Elbe River and especially the catchment area of the tributary Mulde with rising groundwater-level in the mining areas and tailings of the old mines in the Ore Mountains is one of the great environmental problems of this catchment. In 1998 the strategy concept was installed to improve the Elbe water quality, reducing the impacts of uranium mining on the Elbe River. One main focus in the strategy concept was set on the use of passive water treatment methods: use of reactive materials and wetlands.

Integrated Climate Protection Program for the City of Chemnitz: Climate Diagnosis, Climate Change Prognosis, and Adaptation Measures in the Urban Area

The scope of this project was the evaluation of the regional needs caused by climate change in the city of Chemnitz (Saxony). A GIS-based method for regionalisation of the prognosis data at the city mesoscale was used. The simulations were elaborated for the diagnosis periods 1991–1990 and 2001–2010, as well as for the prognosis periods 2011–2020 and 2041–2050. The impact evaluation was carried out through a risk assessment of bioclimatic effects. The subject of the study was the evaluation of the expected impacts of climate change, and the development of protection and adaptation measures for the city. The proposed adaptation measures were evaluated in terms of efficiency, acceptance, practicability, feasibility and affordability.

Flood Risk Protection Concept for the Urban Region Geising/Altenberg in the Flood Formation Area of the Eastern Ore Mountains, Germany

Due to the results of the climate change prognosis for Saxony County, and especially the Ore Mountains, the number of heavy rain events will have a higher recurrence interval in the near future. There were more prognosticated heavy rain events with destructive capacity for the urban areas. The urban areas are densely located especially in the valleys of the East Ore Mountains, which form natural run-off channels for heavy rain events in flood generation areas. Straightforward climate change measures must be taken into account such as sustainable land use technologies. Additionally, in flood generation areas appropriate flood protection concepts, for example, engineered protection methods, should be implemented. The key activities in terms of flood protection in the Geising/Altenberg area include a potential analysis of retention effects as well as the discussion on the effectivity of compensation measures on agricultural lands, settlements and forestry areas. The main scope was an assessment of the efficiency of possible compensatory measures to support the effect of the natural water infiltration and water retention in the flood generation areas. The required flood protection measures in the flood generation area of Geising and Altenberg must not affect the natural character of the area. The inclusion of mining facilities for flood retention or discharge was evaluated to be critical.

Assessment of Uranium Waste Dump Closure Systems: Results of Long Term Test Fields at the Former Uranium Mining Site in Schlema-Alberoda, Germany

Within the frame of the environmental monitoring of the former uranium mining sites in Schlema-Alberoda have been established in 1999 soil hydrological test fields on covered and revegetated waste heap dumps. The objectives of the long term investigations on the test fields are the quantification of infiltration rates as well as the evaluation of the dynamics of the soil water balance. The data, obtained from more than one decade of observation, provide the time development of the water balance in the system soil – vegetation – atmosphere. The data were used to optimize the covering and revegetation concept for the mine dumps. At the Schlema-Alberoda mine dumps the rehabilitation has been successfully carried out using of a 2-cover-layer which contains a humus surface layer.

Uranium – a Problem in the Elbe Catchment Area?

Data from the Elbe River and its tributaries indicate that the river water quality has been improved since reunification due to the closure of mining and industrial sites. Despite those actions uranium concentrations which exceed the environmental quality norms are still measured in some parts of the Elbe catchment. Former mining areas are still the main uranium sources. The contributing loads from Zwickauer Mulde and Saale tributaries are still relevant for the total uranium concentrations in the Elbe catchment. Further, there is a relevant amount of heavy metals still available from the sediments, which acted as metal sinks. As in the Hamburg Harbor uranium values were analyzed in the sediment in the range of the natural background, the relevant geochemical sink for uranium is situated between Magdeburg and Hamburg harbor and should be subjected to further investigations.

Radionuclide Data for Geothermal Prospection — A Contribution to the Geothermal Resources Map of Saxony

Geothermal energy is one of the long term perspectives in the field of renewable energy. A research and development project was started to evaluate the deep geothermal potential in Saxony, East Germany. The investigation is a contribution to the geothermal resources map of Saxony. The geological setting of Saxony is characterised by a variety of solid rocks. A lot of them are containing remarkable radionuclide concentrations, so they are source of radioactive heat generation due to radioactive decay. This source was investigated quantitativly.

Concept of a Surface Water Monitoring at the Former Uranium Mining Site Schlema-Alberoda

After the remediation works at the Schlema-Alberoda Mining Site the existing water monitoring has to be modified. The monitoring has to focus on the main contaminated streams. The separation of contaminated and not contaminated streams an their distribution in surface respectively underground portions allows the determination of the real transported load of radioactive and toxic compounds. The principle of load determination is the more suitable concept in the assessment of discharges like in industry and waste water treatment (EU).