Implication of two in-stream processes in the fate of nutrients discharged by sewage system into a temporary river.
The aim of this study was to better understand the fate of nutrients discharged by sewage treatment plants into an intermittent Mediterranean river, during a low-flow period. Many pollutants stored in the riverbed during the low-flow period can be transferred to the downstream environments during flood events. The study focused on two processes that affect the fate and the transport of nutrients, a physical process (retention in the riverbed sediments) and a biological process (denitrification). A spatial campaign was carried out during a low-flow period to characterize the nutrient contents of both water and sediments in the Vène River. The results showed high nutrient concentrations in the water column downstream of the treated wastewater disposal (up to 13,315 μg N/L for ammonium and 2,901 μg P/L for total phosphorus). Nutrient concentrations decreased rapidly downstream of the disposal whereas nutrient contents in the sediments increased (up to 1,898 and 784 μg/g for total phosphorus and Kjeldahl nitrogen, respectively). According to an in situ experiment using sediment boxes placed in the riverbed for 85 days, we estimated that the proportion of nutrients trapped in the sediments represents 25% (respectively 10%) of phosphorus (respectively nitrogen) loads lost from the water column. In parallel, laboratory tests indicated that denitrification occurred in the Vène River, and we estimated that denitrification likely coupled to nitrification processes during the 85 days of the experiment was significantly involved in the removal of nitrogen loads (up to 38%) from the water column and was greater than accumulation processes.
Université Montpellier 2, Hydrosciences Montpellier, UMR 5569, 34095, Montpellier Cedex 5, France. art61@haotmail.com
Arthur
A
David
Jean-Louis
JL
Perrin
David
D
Rosain
Claire
C
Rodier
Bernadette
B
Picot
Marie-George
MG
Tournoud
D058440:Denitrification; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D012621:Seasons; D012722:Sewage / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000706:statistics & numerical data*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D012722:Sewage; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D009584:Nitrogen
Chemosphere. 2003 Feb;50(7):919-28
12504130
Sci Total Environ. 2003 Sep 1;313(1-3):199-212
12922071
Sci Total Environ. 2008 Aug 1;400(1-3):379-95
18804845
Science. 2001 Apr 6;292(5514):86-90
11292868
J Environ Qual. 2004 Jan-Feb;33(1):285-93
14964383
Environ Monit Assess. 2007 Jun;129(1-3):461-70
17057967
Sci Total Environ. 2005 Jan 5;336(1-3):225-41
15589261
Sci Total Environ. 2002 Jan 23;282-283:175-203
11846070
Sci Total Environ. 2002 Jan 23;282-283:341-51
11846078
Sci Total Environ. 2005 Jul 15;347(1-3):217-29
15878611
Science. 1971 Mar 12;171(3975):1008-13
4993386
Sci Total Environ. 1997 Oct 7;205(1):25-49
9352669
Water Res. 2001 Oct;35(14):3478-82
11547871
J Environ Qual. 2010 Feb 19;39(2):449-59
20176818