title: Quantifying, assessing and removing the extreme gas load from meromictic Guadiana pit lake, Southwest Spain.
abstract: High gas charges in deep waters of lakes can represent a hazard to the lives of human beings and animals in the surrounding. As this danger was feared, we quantified the amount of dissolved gas in Guadiana pit lake (Las Herrerías, Huelva; southwest Spain) and documented the temporal evolution over a period of two years. Gas pressure due to dissolved gases, such as carbon dioxide, methane and nitrogen was measured. Based on these data, we assessed the risk and the associated danger of limnic eruptions from the lake and concluded that the present situation cannot be considered safe. By deploying a vertical pipe, the updraft of degassing water was tested and demonstrated: the pilot plant provided enough energy to drive a self-sustained flow. Such a system could be implemented to remove the extreme gas pressure from the deep water. Measurements of discharges could be extrapolated to indicate the size for an efficient plant for the gas removal. The construction of such a system would be technically and economically viable. A reintroduction of degassed water into the monimolimnion would be advisable.
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Brueckstrasse 3a, D-39114 Magdeburg, Germany. Electronic address: Bertram.Boehrer@ufz.de.
authors.forename: Bertram
authors.initials: B
authors.lastname: Boehrer
authors.affiliation: Department of Mineralogy and Petrology, University of the Basque Country (UPV/EHU), Apdo. 644, 48080 Bilbao, Biscay, Spain.
authors.forename: Iñaki
authors.initials: I
authors.lastname: Yusta
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Brueckstrasse 3a, D-39114 Magdeburg, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Magin
authors.affiliation: Geological Survey of Spain (IGME), c/Calera, 1, 28760 Tres Cantos, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Sanchez-España
keywords: Dissolved gas; Limnic eruption; Limnology; Mine pit lake; Remediation; Water density