Influence of a compost layer on the attenuation of 28 selected organic micropollutants under realistic soil aquifer treatment conditions: insights from a large scale column experiment.
Soil aquifer treatment is widely applied to improve the quality of treated wastewater in its reuse as alternative source of water. To gain a deeper understanding of the fate of thereby introduced organic micropollutants, the attenuation of 28 compounds was investigated in column experiments using two large scale column systems in duplicate. The influence of increasing proportions of solid organic matter (0.04% vs. 0.17%) and decreasing redox potentials (denitrification vs. iron reduction) was studied by introducing a layer of compost. Secondary effluent from a wastewater treatment plant was used as water matrix for simulating soil aquifer treatment. For neutral and anionic compounds, sorption generally increases with the compound hydrophobicity and the solid organic matter in the column system. Organic cations showed the highest attenuation. Among them, breakthroughs were only registered for the cationic beta-blockers atenolol and metoprolol. An enhanced degradation in the columns with organic infiltration layer was observed for the majority of the compounds, suggesting an improved degradation for higher levels of biodegradable dissolved organic carbon. Solely the degradation of sulfamethoxazole could clearly be attributed to redox effects (when reaching iron reducing conditions). The study provides valuable insights into the attenuation potential for a wide spectrum of organic micropollutants under realistic soil aquifer treatment conditions. Furthermore, the introduction of the compost layer generally showed positive effects on the removal of compounds preferentially degraded under reducing conditions and also increases the residence times in the soil aquifer treatment system via sorption.
Geoscience Center, Dept. Applied Geology, University of Göttingen, Goldschmidtstr. 3, 37077 Göttingen, Germany. Electronic address: Mario.Schaffer@geo.uni-goettingen.de.
Mario
M
Schaffer
Geoscience Center, Dept. Applied Geology, University of Göttingen, Goldschmidtstr. 3, 37077 Göttingen, Germany.
Kerrin Franziska
KF
Kröger
Geoscience Center, Dept. Applied Geology, University of Göttingen, Goldschmidtstr. 3, 37077 Göttingen, Germany.
Karsten
K
Nödler
GHS Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain.
Carlos
C
Ayora
GHS Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain.
Jesús
J
Carrera
CETaqua, Water Technology Center, Carretera d'Esplugues 75, 08940 Cornellà de Llobregat, Barcelona, Spain.
Marta
M
Hernández
Geoscience Center, Dept. Applied Geology, University of Göttingen, Goldschmidtstr. 3, 37077 Göttingen, Germany.
Tobias
T
Licha
D060587:Groundwater / Q000737:chemistry*; D009930:Organic Chemicals / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000737:chemistry*; D012987:Soil / Q000737:chemistry; D062065:Wastewater / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D009930:Organic Chemicals; D004364:Pharmaceutical Preparations; D012987:Soil; D062065:Wastewater; D014874:Water Pollutants, Chemical
Column experiments; Compost layer; Contaminant attenuation; Organic micropollutants; Redox conditions; Soil aquifer treatment