Sediment treatment with a nitrate-storing compound to reduce phosphorus release.
The application of Fe(III), in combination with sediment oxidation by NO(3)(-), is an accepted procedure to manage stratified eutrophic lakes by controlling the phosphorus release from sediments into overlying water. Depox(R), a newly developed compound, consisting of Fe(III) and NO(3)(-), has a storage effect for NO(3)(-). NO(3)(-) is released slowly, hence the disadvantageous high solubility of NO(3)(-) in water can be retarded. The compound was added to water as a suspension which quickly flocculated and precipitated. Within 3 weeks, NO(3)(-) was desorbed from the Depox(R) compound in deionized water. After application in lakes, the NO(3)(-) availability on the sediment surface was prolonged for 2 months. After treatment, P release from the sediment and microbial metabolism were investigated under laboratory conditions as well as in the mesocosm. P release was almost stopped in both cases during the experiment. SO(4)(2-) consumption was significantly lower after Depox(R) addition, and CH(4) production was completely suppressed by Depox(R) treatment in the laboratory, whereas in the enclosures SO(4)(2-) and also CH(4) concentrations at the sediment water interface did not change significantly between treated enclosures and controls.
Wauer
Gerlinde
G
Department of Limnology of Stratified Lakes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, D-16775 Stechlin-Neuglobsow, Germany. gerlinde@igb-berlin.de
Gonsiorczyk
Thomas
T
Kretschmer
Klaus
K
Casper
Peter
P
Koschel
Rainer
R
D002412:Cations; D004784:Environmental Monitoring; D005290:Ferric Compounds / Q000737:chemistry; D005618:Fresh Water; D019015:Geologic Sediments / Q000032:analysis / Q000737:chemistry*; D008697:Methane / Q000737:chemistry / Q000494:pharmacology; D009566:Nitrates / Q000737:chemistry*; D010758:Phosphorus / Q000032:analysis*; D013431:Sulfates / Q000737:chemistry / Q000494:pharmacology; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis*
D002412:Cations; D005290:Ferric Compounds; D009566:Nitrates; D013431:Sulfates; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D008697:Methane