In-lake Neutralization of East German Lignite Pit Lakes: Technical History and New Approaches from LMBV

Abstract

The Lausitzer und Mitteldeutsche Bergbau Verwaltungsgesellschaft (LMBV), a state-owned company, is the responsible partner for remediation of East Germany’s lignite mining areas. This includes the obligation to create ecological and economically sustainable pit lakes. LMBV currently opts for in-lake treatment as the more reasonable alternative to classical discharge treatment in terms of environment and economics. LMBV has neutralized more than 20 highly acidic pit lakes and keep them in neutral conditions by regular follow up neutralization. Techniques especially adapted for the needs of East German pit lakes were developed. Of note has been the development and construction of the mobile treatment vessel “Klara”, which combines a high daily neutralization agent input with a high efficiency factor. Some whole lake experiments with in-lake treatment plants for buffering pit lakes with CO2 were also carried out. These techniques are quite costly, but under long term conditions, the buffering can be necessary to prevent re-acidification when the continuous addition of a neutralization agent is not possible, for instance under an ice cover.