Investigation of an in-situ technology for efficient recovery of acidified waters

摘要

Despite initial success in the global reduction of acid sulfur and nitrogen emissions, a rapid and complete recovery of anthropogenically acidified waters cannot be expected. The liming of lakes is often not efficient, difficult to control chemically, and linked with undesirable effects. Therefore a new buffering substance of mineral compounds was tested in enclosure experiments realized in an acidified reservoir. The whole experimental water body was neutralized within a few minutes without transitional alkaline overshooting. The buffering capacity increased considerably and was lasting. Within two hours after the treatment, dissolved Al and Fe were transformed into particles settling with phosphorus and organic matter (e.g. phytoplanktonic cells). With a delay of several weeks, dissolved Mn slowly oxidized and settled together with other heavy metals (Co, Ni, Zn, Cd). None of these effects were observed in the untreated reference enclosure. In spite of an increased water transparency in the experimental enclosure, the development of phyto- and zooplankton was hampered temporarily, but new species of diatoms, chlorophyta, and cladocera appeared.