ApplicationApplication ofof DifferentDifferent TracersTracers toto EvaluateEvaluate thethe FlowFlow RegimeRegime atat RiverbankRiverbank FiltrationFiltration SitesSites inin BerlinBerlin (Germany)(Germany)
G. Massmann, D. Richter, J. Rümmler & A. Pekdeger Free University of Berlin A. Knappe Alfred Wegener Institute Potsdam
Free University of Berlin Hydrogeology Group Talk outline Introduction
• Introduction - Nasri - Berlin situation • Methods/Tracer • Results - Surface water - Bank filtrate - Microcystin Experiments (Gesche Grützmacher, UBA Berlin) • Summary/Conclusions
Free University of Berlin Hydrogeology Group Research program in Berlin to study the fate of pathogens and organics, geochemical processes and hydraulics in bankfiltration and artificial recharge systems at laboratory, semi-technical and field scale.
May 2002 – May 2005 atural and
rtificial
ystems for
echarge and
nfiltration
Free University of Berlin Hydrogeology Group Nasri: 7 Teams Introduction
Algae: Retention and elimination of cyanobacterial toxins (microcystins) (Dr. Chorus/Dr. Bartel, German Environmental Acency). Bacteria: Using bacteriophages, indicator bacteria and viral pathogens for assessing the health risk (Dr. Lopez-Pila, Dr. Szewzyk, German Environmental Acency). Drugs: Occurrence and fate of drug residues and related polar contaminants (Dr. Heberer, Technical University, Dr. Dünnbier, Berlin Water Company). Hydrogeo: Hydrogeological-hydrogeochemical processes using a multi tracer approach (Prof. Pekdeger, Free University) Models: Integrated modelling concepts: coupled groundwater transport and biochemical reactions (Prof. Nuetzmann,Institute for Freshwater Ecology) Organics: Organic substances– process studies (Prof. Jekel, Technical University) BWB: Data management, water sampling, analyses
Free University of Berlin Hydrogeology Group Objectives of Nasri Introduction
• To ensure the long term sustainability of the groundwater resource and drinking water quality through the bankfiltration and the groundwater recharge process • To expand the Know-How and quantify the relevant processes • To obtain quantitative and qualitative guidelines for proper design and optimised operation of existing sites and for transfer of the integrated knowledge to other locations (use of models etc..)
Free University of Berlin Hydrogeology Group Berlin characteristics Introduction
• ~ 3.4 million inhabitants • semi-closed water cycle • drinking water derived from Berlin groundwater • ~ 70 % originates from bank filtration • production well galleries adjacent to surface water system
Free University of Berlin Hydrogeology Group Factors influencing the raw water quality Introduction
Temporal and spatial variation of surface Well design water quality (location, length & depth of filter screens)
presence, permeability Processes occurring & thickness of clogging during infiltration Quality of layer background Hydraulic regime Groundwater (mainly a result of pumping (inland and performances) deeper aquifers)
Lithology, permeability and geochemistry of aquifer sediments
Free University of Berlin Hydrogeology Group Objectives Objectives
to use a variety of tracers at several field-sites in order to: • estimate the proportion of treated wastewater in the surface water system • estimate the proportion of bank-filtrate (and likewise deeper and landside groundwater) in the production wells • derive travel times from the surface water to the production wells • understand flow regime
Free University of Berlin Hydrogeology Group T/He age dating Methods
3 12.32y 3 H oder T He in water : 1TU 1T / 1018 H0.118Bq/kg Groundwater „age“:
t1/2 . 3He* τ = / ln 2 ln (1 + /T ) 10000 Tritium in precipitation t1/2 = 12.32y Ottawa annual mean ³He* = tritiogenic He Valentia annual mean Hof annual mean Hof winter mean 1000 Hof summer mean Berlin annual mean Oder annual mean ation in TU ation r
100 itium concent itium r T
10
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 year data: IAEA,Data BfG : IAEA, BfG Free University of Berlin Hydrogeology Group Overview on applicable tracers in Berlin Methods Tracer: Origin: Useful for the interpretation of: Difficulties:
δD, δ18O surface water with seasonal water movement none, conservative tracer variations
Temperature surface water with seasonal water movement retarding variations
Cl- surface water with seasonal water movement only if influence of saline variations groundwater can be excluded Cl-, Na+, B saline deeper groundwater proportion of deeper saline may vary strongly locally groundwater 2- SO4 dissolution of gypsum derived proportion of shallow “native” may vary strongly locally from building rubble in the groundwater shallow aquifer B surface water, effluent water movement, proportion of bank only if influence of saline filtrate in raw water groundwater can be excluded Gd surface water, effluent water movement, proportion of bank possibly degradable filtrate in raw water
EDTA surface water, effluent water movement, proportion of bank sometimes the background filtrate in raw water groundwater has also got very high concentrations Sr surface water, very few proportion of bank filtrate in raw not always applicable seasonal variations water
T/He Surface water, through groundwater “age” minimum age required is 2 atmospheric input months
Free University of Berlin Hydrogeology Group Mixing calculation Methods
X = [Cw-CGW)/(CSW-CGW)]*100 [%]
X = Percentage of bank-filtrate in the production well
Cw= Tracer concentration in the production well
CSW= Tracer concentration in the surface water
Cgw= Tracer concentration in the groundwater
Free University of Berlin Hydrogeology Group Surface water Results Spatial variations of B and percentage of treated wastewater in the surface water Depending on location in space & time, the proportion of treated wastewater in the surface water can be high.
Free University of Berlin Hydrogeology Group Location of field sites Results
Transect Lake Tegel Transect GWA Tegel
Transect Lake Wannsee 1 & 2
Free University of Berlin Hydrogeology Group Surface water Results Percentage of treated wastewater in Lake Tegel near the transect
Since operation of pumping device started, the proportion of treated wastewater in SW near Surface water pumping transect declined to an device starts operation average of 12 % 50
45 Cl
40 B
35
30
25
20 15
10 % treated wastewater treated % 5
0
1 1 1 2 2 2 1 0 2 i 01 0 01 0 01 0 02 0 02 0 02 0 02 a n g 01 t b r n p kt z Jul u e p Jul 02 e M Ju A Sep Ok Nov 0 Dez Jan 02 F Mrz 02 A Mai 02 Ju Aug S O Nov De month
Free University of Berlin Hydrogeology Group Field-site Lake Wannsee Results
Free University of Berlin Hydrogeology Group Transect Lake Wannsee 1, hydrochemistry Results
1397.666.7 2- EDTAClSO [mg/l]4 [mg/l][µg/l] 1356.967.1 1367.966.3 1357.567.4 1356.866.2
133*7.7*64.5* 418*<25.0* 2*
23.51.3143 <54.33.6 1
<27373 1 2.7<19.8 1
Data: Ilat average 10/2000 –11/2001 *BWB 01/2003 – 04/2003 Free University of Berlin Hydrogeology Group Transect Lake Wannsee 1, age dating Results
11.150-0.50 10.750-0.500 0-0.5011.120 4 -1 Heterr~Age [NmlT [years] [TU] kg ]
1.63E-42.41mixed26
7.07E-5>650.02 50
2.84E-4>>1000.03 50 >3.97E-51000.02 50 Data: Helis Laboratory, University of Bremen
Free University of Berlin Hydrogeology Group Transect Lake Wannsee 1, dD versus d18O Results
lake Wannsee & most obs. wells well 3 (new transect) has a much higher well 3 proportion of bank- filtrate! well 5
well 4
deeper aquifers Data: Alfred-Wegener Institute Potsdam
Free University of Berlin Hydrogeology Group Field-site Lake Wannsee Results Time-series of EDTA in production wells
Proportion of bank-filtrate calc. with EDTA: Well3 = 61-97 % Well4 = 10-47 % Well5 = 88-96 %
Data: Berlin Water Company
Free University of Berlin Hydrogeology Group Transect Lake Wannsee 1 Results Time-series of d18O in shallow observation wells o o o
Travel time Lake-well4 1-2 months in shallow aquifer All production wells show no seasonal variation
Data: Alfred-Wegener Institute Potsdam
Free University of Berlin Hydrogeology Group Flow model Lake Tegel Results
4583000 4584000 4585000 4586000 4587000 4588000 4589000 4590000 5830000 N
HASSELWERDER 5830000 Tegelort # # Nord # # 5829000 # # # GÄNSEWERDER 5829000 # ## LINDWERDER # Tegelort # # Galerie # #
Süd # Ost 5828000 # Legend # # #S # WW Tegel # well # 5828000 # # # ### well gallery # Tegelort # Scharfenberg 5827000 Süd name of well gallery # # # # # 5827000 # transect Tegel # Baumwerder # model region # Galerie
# West 5826000 # # # # # # # 5826000 # Saatwinkel # # # #
# # 5825000 # #
5825000 Hohenzollern- kanal Kartengrund: TK 50 Blatt L3544 Berlin-Spandau, 1998 4583000 4584000 4585000 4586000 4587000 4588000 4589000 4590000 Koordinaten: Gauß-Krüger Potsdam-Datum (Zentralpunkt Rauenberg) 020004000MeterBesselellipsoid Erstellungsdatum: 12/2002 Bearbeiter: Jeannette Rümmler
Free University of Berlin Hydrogeology Group Transect Lake Tegel Results W E P P O U 1 1 2 7 7 0 9 8 1 7 2 3 6 5 4 11 1 0 0 0 G3 G37 0 0 G 0 3 0 0 3 3 3 3 3 E 3 3 E 3 30 3 3 3 3 3 3 3 TE T 3 3 T 3 3 3 3
m below m above ground sea-level 3307neu3302 33063303 33053304neu TEG372 3301neu3308 TEG371OPTEG371UP 3309 0.0 1.0 33.034.0 3311 3310 2.0 32.0 3.0 31.0 4.0 30.0 5.0 29.0 6.0 28.0 7.0 27.0 8.0 26.0 9.0 25.0 10.0 24.0 11.0 23.0 12.0 22.0 13.0 21.0 14.0 20.0 Lithology 15.0 19.0 16.0 18.0 17.0 rocks 17.0 18.0 16.0 gravel 19.0 15.0 20.0 14.0 coarse sand 21.0 13.0 22.0 12.0 medium sand 23.0 11.0 24.0 10.0 fine sand 25.0 9.0 26.0 8.0 silt 27.0 7.0 28.0 6.0 clay 29.0 5.0 30.0 4.0 glacial till 31.0 3.0 32.0 2.0 brown coal 33.0 1.0 34.0 0.0 35.0 -1.0 36.0 -2.0 37.0 -3.0 38.0 -4.0 39.0 -5.0 40.0 0 10 20 30 40 m -6.0 41.0
Free University of Berlin Hydrogeology Group Flow model Lake Tegel Results steady state model
N Shortest travel time Well 10 between single wells and position shoreline* in weeks/days well 10 = 31/217 well 11 = 32/224 well 12 = 29/203 well 13 = 26/182 well 14 = 34/238 well 15 = 32/224 well 16 = 28/196
*Flow field after 190 days
Leakage aquifer 1 Leakage lake sediment Boulder clay above aquifer 2 Well
0 200 Meter
Well 16 Bearbeiter: J. Rümmler, 7/2003
Free University of Berlin Hydrogeology Group Flow model Lake Tegel Results
N Scenario 3 Well 10 Pumping regime is very Shortest travel time complicated – between single wells and position shoreline in weeks Flow models help to Br 10 = 23 Br 11 = 29/30 understand the influence Br 12 = 29 Br 13 = - of different pumping Br 14 = 30/31 Br 15 = 32 scenarios on Br 16 = 22/23 groundwater flow paths!
Schaltung und Fördermenge Szene 1 bis 3 Well operation and pumping rate scenario 3
s 0,0095 /
s ³
/
³ 0,00945 m
m
n n
i i
0,0094
e e
g t
n
a 0,00935
e
r
m g
r 0,0093 n
e i
d p r 0,00925
ö m
F
u 0,0092 P 12345678 StressStressperioden period Br 10 Br 11 Br 12 Br 13 Br 14 Br 15 Br 16
Leakage aquifer 1 Leakage lake sediment Boulder clay above aquifer 2 Well Well 16 Intervall < < = 1 Week
0 100 Meter Bearbeiter: J. Rümmler, 7/2003
Free University of Berlin Hydrogeology Group Lake Tegel, age dating and hydrochemistry Results
Lake to 3303: 3 - 4 months x Lake to 3301: 2 - 3 months
x x x
Production well water shows no seasonal variation Travel time Lake- well 13: 6-9 months (Fritz 2002)
Data: Alfred-Wegener Institute Potsdam
Free University of Berlin Hydrogeology Group Transect Lake Tegel, dD versus d18O
-46
-48 lake tegel, shallow & deep obs. wells
-50
-52
production wells -54 Production well
vs. SMOW] vs. water is a mixture ‰ -56 [ of background D obs. wells inland δ -58 groundwater and 3301-3302-3303 bank-filtrate -60 below lake, 3310, 3311 Proportion of inland, 3305 lake Tegel bank-filtrate: -62 medium depth, TEG371-372 ~ 80 % production wells 12-14 -64 shallow, 3306-3309 Data: Alfred-Wegener Institute Potsdam -8 -7 -6 -5 δ18Ο [‰ vs SMOW]
Free University of Berlin Hydrogeology Group Lake Tegel, age dating Results
0-0.6
4.3 11.9 1.7 12.7
~Age [years]
Free University of Berlin Hydrogeology Group Lake Tegel, age dating Results
30 lake Tegel obs. wells, TS Tegel inland TS Tegel, 3304, 3305 prod. wells 13, 14, 15
20 Specific water groundwater constituents confirm that production wells may contain a EDTA [ g/l] considerable amount of older bank-filtrate! 10 surface water (at present)
production wells
< 2 0 0.4 0.8 1.2 1.6 amdoph [µg/l] Data: Berlin Water Company
Free University of Berlin Hydrogeology Group Summary & Conclusions • Combining a number of tracer may help to understand the hydrogeology and hydraulics at a very complex bank-filtration system in Berlin.
• With the help of T/He, ages of groundwater from different aquifers can be estimated. • Combining discharge measurements with the concentrations of wastewater indicators, proportions of wastewater in the surface water can be calculated. (Wannsee: ∅ 8.5 % in winter, 20.1 % in summer; Lake Tegel ∅ 12 % near respective transects). • With tracers showing strong seasonal variations in the surface water, travel times can be estimated (Lake to wells: Wannsee: 1-2 months, Tegel: 5-8 months).
• Relatively “young” water constituents like EDTA are only present in the bank-filtrate and can be used to calculate proportions of bank-filtrate in the wells at Lake Wannsee. Large differences exist in the different wells (~ 10 % BF in well 4, ~ 90 % BF in well 5).
• At Lake Tegel, proportions of bank-filtrate in the wells are generally high (~ 80 % in average).
• Age dating, lack of seasonal variations in the wells as well as substances formerly present in the surface water in higher concentrations (e.g. amdoph) indicate that a proportion of the bank-filtrate is much older that predicated from observation wells.
Free University of Berlin Hydrogeology Group Free University of Berlin HydrogeologyUBA`s GroupExperimental Field in Berlin Results Grützmacher et al. Slow Sand Filter Experiments
samples of water body live cyanobacteria (Planktothrix agardhii)
50 to 8 µg/L MC samples from 10 cm depth 1 cm/h
samples of effluent
Free University of Berlin Hydrogeology Group Results Grützmacher et al. Cellbound / Extracellular Cyanotoxins (Microcystins)
2 biovolume in water body 1,8 end of dosing of cyanobacteria total MC in water body 1,6 total MC 10 cm below filter 1,4 surface 1,2 1 0,8 0,6 0,4 0,2 0 50 55 60 65 70 75 80 days aber beginning of experiment
FreeÎ UniversityCells of Berlin can act as long-term source for microcystins Hydrogeology Group