water Article
Removal of Natural Organic Matter and Organic Micropollutants during Riverbank Filtration in Krajkowo, Poland 2 Krzysztof Dragon 1, *, Józef Górski 1 , Roksana Kru´c 1 , Dariusz Dro˙zd˙zynski ´ 3 and Thomas Grischek 1
2 3
*
Department of Hydrogeology and Water Protection, Institute of Geology, Adam Mickiewicz University in Poznan, ´ ul. Bogumiła Krygowskiego 12, 61-680 Poznan, ´ Poland;
[email protected] (J.G.);
[email protected] (R.K.) Department of Pesticide Residue Research, Plant Protection Institute–National Research Institute, ul. Władysława W˛egorka 20, 60-318 Poznan, ´ Poland;
[email protected] Division of Water Sciences, University of Applied Sciences Dresden, Friedrich-List-Platz 1, 01069 Dresden, Germany;
[email protected] Correspondence:
[email protected]; Tel.: +48-618-296-058
Received: 19 September 2018; Accepted: 11 October 2018; Published: 16 October 2018
Abstract: The aim of this article is to evaluate the removal of natural organic matter and micropollutants at a riverbank filtration site in Krajkowo, Poland, and its dependence on the distance between the wells and the river and related travel times. A high reduction in dissolved organic carbon (40–42%), chemical oxygen demand (65–70%), and colour (42–47%) was found in the riverbank filtration wells at a distance of 60–80 m from the river. A lower reduction in dissolved organic carbon (26%), chemical oxygen demand (42%), and colour (33%) was observed in a horizontal well. At greater distances of the wells from the river, the removal of pharmaceutical residues and pesticides was in the range of 52–66% and 55–66%, respectively. The highest removal of pharmaceutical residues and pesticides was found in a well located 250 m from the river and no micropollutants were detected in a well located 680 m from the river. The results provide evidence of the high efficacy of riverbank filtration for contaminant removal. Keywords: riverbank filtration; removal efficacy; dissolved organic carbon (DOC); pesticides; pharmaceutical residues
1. Introduction Alluvial aquifers supply a significant amount of drinking water in many countries because they offer easy access to groundwater and usually have feasible hydraulic properties. One method used for increasing quantities of groundwater in alluvial aquifers is riverbank filtration (RBF). RBF is a good alternative to the direct supply of surface water because the passage of water through the aquifer improves water quality. First in the riverbed and then in the aquifer, the water undergoes combined physical, biological, and chemical processes such as dissolution, sorption, redox processes, and biodegradation [1]. Additionally, mixing with ambient groundwater usually occurs to some degree [2,3]. Among the multiple benefits of RBF, the removal of natural organic matter (NOM), which is usually present in surface waters at relatively high concentrations, is significant. During RBF, an effective removal of dissolved organic carbon (DOC) of more than 50% can be achieved [4,5]. The significant reduction in chemical oxygen demand (COD) is also important [6]. It has been documented that the effective reduction of high molecular weight organic fractions is achieved during RBF, but with a lower removal of low molecular weight fractions [7,8]. This finding is important for further water treatment due to the formation of by-products during water chlorination [9]. Water 2018, 10, 1457; doi:10.3390/w10101457
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during RBF, but with a lower removal of low molecular weight fractions [7,8]. This finding is important for further water treatment due to the formation of by-products during water chlorination [9]. The nature of the RBF system results in the quality of extracted water being dependent on surface The nature of the RBF system results in the quality of extracted water being dependent on surface water quality. Pollution of rivers is observed in many European countries due to agricultural activities water quality. Pollution of rivers is observed in many European countries due to agricultural in the catchment area [10,11], and wastewater effluents [12]. Water pollution by nitrates is common activities in the catchment area [10,11], and wastewater effluents [12]. Water pollution by nitrates is around the world [13,14], but in recent years, the pollution of surface water by pesticides has become common around the world [13,14], but in recent years, the pollution of surface water by pesticides increasingly problematic [15–17]. Other emerging contaminants in surface water are pharmaceutical has become increasingly problematic [15–17]. Other emerging contaminants in surface water are residues [18,19]. Due to the high vulnerability of RBF systems to contamination by source pharmaceutical residues [18,19]. Due to the high vulnerability of RBF systems to contaminationsurface by water, it is crucial determine organic removal rates to properly systems. source surfacetowater, it is crucial tomicropollutant determine organic micropollutant removalmanage rates toRBF properly The main goals of the present article are: (1) the determination of the changes in water chemistry manage RBF systems. The main goals ofthe the aquifer present article are: (1) of thewater changes in water chemistry during passage through in relation tothe thedetermination seasonal surface chemistry fluctuations; during passage through aquifer in and relation to the seasonal surface water chemistry fluctuations; (2) the investigation of thethe occurrence behaviour of selected pesticides and pharmaceuticals; of of theremoval occurrence and behaviour of selected pesticides and pharmaceuticals; and the and (2) (3) the theinvestigation investigation efficacy of RBF depending on the distance of the wells from (3) the investigation of removal efficacy of RBF depending on the distance of the wells from the river. river. For the present investigation, the Krajkowo site was selected, where an RBF system of vertical For the present investigation, the Krajkowo site was selected, where an RBF system of vertical wells wells exists as well as a horizontal well (HW), with drains located below the river bottom. exists as well as a horizontal well (HW), with drains located below the river bottom.
2. Materials and Methods
2. Materials and Methods
2.1. Site Description
2.1. Site Description
The Krajkowo well field supplies water to Poznan´ City and is located 30 km south of the city on The Krajkowo well field supplies water to Poznań City and is located 30 km south of the city on Krajkowo Island (52◦ 12’47”N 16◦ 56’49”E) in the Warta River valley (Figure 1). The wells are located in Krajkowo Island (52°12’47”N 16°56’49”E) in the Warta River valley (Figure 1). The wells are located the region wherewhere two main groundwater bodies Wielkopolska Burried Valley (WBV) in the region two main groundwater bodiesoverlap—The overlap—The Wielkopolska Burried Valley (WBV) aquifer and the Warszawa-Berlin Ice Marginal Valley (WBIMV) aquifer. The well field is located aquifer and the Warszawa-Berlin Ice Marginal Valley (WBIMV) aquifer. The well field is located in in the region where the sediments forming these aquifers overlap, thereby providing good conditions the region where the sediments forming these aquifers overlap, thereby providing good conditions for water (water-bearing sediments withwith a thickness of 30–40 m).m). forexploitation water exploitation (water-bearing sediments a thickness of 30–40
Figure 1. Map of the area.area. RBF:RBF: riverbank filtration; RBF-c: wells onon thethe flood terrace; RBF-f: wells Figure 1. Map of study the study riverbank filtration; RBF-c: wells flood terrace; RBF-f: wells on the higherHW: terrace; HW: horizontal on the higher terrace; horizontal well. well.
The The lithology of the upper aquifer byfine fineand and medium sands of fluvial lithology of the upper aquifer(WBIMV) (WBIMV) is is dominated dominated by medium sands of fluvial origin a depth m) by and by coarse and gravels of fluvio-glacial the deeper origin (to a(to depth of 10of m)10and coarse sandssands and gravels of fluvio-glacial originorigin in theindeeper portions (to a depth of 20 m) (Figure 2). The deepest aquifer (WBV) is also composed of fine and medium fluvial sands in the upper part (to a depth of 25–30 m) and by coarse fluvio-glacial sands and gravels in the deepest part of the aquifer. Unconfined aquifer conditions dominate the study area, whereas in small regions aquitard composed of glacial tills are present between the WBV and WBIMV aquifers. The static water level is approximately 3–5 m below the ground surface.
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Figure marked inin Figure 1).1) Figure2.2.Hydrogeological Hydrogeologicalcross-sections cross-sections(lines (linesofofcross-sections cross-sectionsare are marked Figure
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Two different well types are used for water extraction (Figure 1):
• •
a gallery of 29 vertical wells (RBF-c) on the left side of the Warta River located at a distance of 60–80 m from the river channel (Figure 3), a horizontal well (HW) with drains placed 5 m below the river bottom (Figure 3). The drains were installed by excavation (dredging) of the riverbed sediments.
At longer distances from the river (between 400 and 1000 m), the second well group is located on a higher terrace. This group includes 56 vertical wells. This part of the well field is not continuously exploited. For this study, only the portion of the well group shown in Figure 1 (RBF-f) was continuously pumped for of two years. Water 2018, 10,axperiod FOR PEER REVIEW 5 of 18
Figure the location of of thethe horizontal drains of the collector wellwell andand positions of Figure3.3.AAscheme schemepresenting presenting the location horizontal drains of the collector positions the RBF-c wells [20]. Legend: 1—the embankment; 2—sands; 3—gravels; 4—silts; 5—clays; 6—the static of the RBF-c wells [20]. Legend: 1—the embankment; 2—sands; 3—gravels; 4—silts; 5—clays; 6—the and dynamic water level; flow directions; 8—the position of the RBF wellRBF screen; static and dynamic water7—groundwater level; 7—groundwater flow directions; 8—the position of the well 9—the position the HW drains; observation wells; 11—Quaternary; 12—Neogene. 12— screen; 9—theofposition of the 10—other HW drains; 10—other observation wells; 11—Quaternary;
Neogene.
2.2. Methods
investigate groundwater chemistry changes in the RBF system, wells along two transects were 2.2. To Methods selected for sampling. Transect I (shorter) was located between the river and the RBF-c production To investigate groundwater chemistry changes in the RBF system, wells along two transects well and transect II (longer) was located between the river and the RBF-f well (Figure 1). The sampling were selected for sampling. Transect I (shorter) was located between the river and the RBF-c points along transects were located along the flow paths, permitting the investigation of hydrochemical production well and transect II (longer) was located between the river and the RBF-f well (Figure 1). transformations associated with bank filtration at different distances from the source (river) water. The sampling points along transects were located along the flow paths, permitting the investigation The monitoring programme included a one-year sampling campaign in two selected wells of hydrochemical transformations associated with bank filtration at different distances from the located on the transects (1AL and 19L) and an 18-month sampling campaign at sampling point source (river) water. H, which received mixed water from 15 wells located on the eastern side of the well gallery (Figure 1). The monitoring programme included a one-year sampling campaign in two selected wells Sampling was performed monthly between October 2016 and May 2018. Warta River water was located on the transects (1AL and 19L) and an 18-month sampling campaign at sampling point H, which received mixed water from 15 wells located on the eastern side of the well gallery (Figure 1). Sampling was performed monthly between October 2016 and May 2018. Warta River water was also sampled during the investigation period. For pesticides and pharmaceuticals, 6 sampling series were planned at all sampling points located on the transects. In this article, the preliminary results from
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also sampled during the investigation period. For pesticides and pharmaceuticals, 6 sampling series were planned at all sampling points located on the transects. In this article, the preliminary results from the first three series are presented along with the results of the first pilot sampling series for pharmaceutical residues. Additionally, Aquanet (waterworks operator) operational monitoring data were used, including the analyses of HW from January 2015 to May 2018. The production wells were continuously pumped during sampling, while the observation wells were pumped using a portable pump (MP-1, Grundfos, Bjerringbro, Denmark). The water was stored in polyethylene bottles that were flushed three times before sampling. On the same day, watersamples were transported to the laboratory in a refrigerated container. Chemical analyses (Table 1) were performed at the Aquanet Laboratory (Poznan, ´ Poland) with use of a Dionex ionic chromatograph (Thermo Fisher Scientific, Waltham, MA, USA) (NO3 − and NO2 − ), a Varian Cary 50 spectrometer (Varian, Inc, Palo Alto, CA, USA) (NH4 + ), and a Shimadzu TOC-L-CSN IR spectrometer (Shimadzu Corporation, Kyoto, Japan), and filtered through a 0.45-µm membrane filter (DOC). Coliform bacteria were analysed with use of Quantitray Model 2X (IDEXX Laboratories, Westbrook, ME, USA). Pharmaceutical residues were measured in the laboratory of the Institute for Water Chemistry, TU Dresden (Germany), with an HPLC system (Agilent 1100, Agilent Technologies, Waldbronn, Germany) coupled with MS/MS detection (Sciex Q3200, AB Sciex Pte. Ltd, Woodlands, Singapore) after enrichment via solid-phase extraction. Pesticide measurements were performed at the laboratory of Plant Protection Institute, National Research Institute in Poznan´ (Department of Pesticide Residue Research) with use of liquid chromatograph (ACQUITY® UPLC, Waters, Milford, MA, USA). Table 1. Statistical characteristics of the data set. Parameters
Colour (mg Pt/L)
EC (µS/cm)
NO3 (mg/L)
NO2 (mg/L)
Average Median Minimum Maximum Standard deviation
25 25 20 40 4
624 619 542 703 49
18.6 14.0 0.5 48.0 13.0
Average Median Minimum Maximum Standard deviation Reduction/Increase (average)
17 17 10 30 5
626 614 539 695 56
18.4 16.0 3.6 44.0 12.0
0.02 0.01 0.00 0.11 0.03
32.5%
−0.4%
0.9%
74.8%
13 15 7.5 15 2
650 662 581 695 33
7.8 6.4 0.0 18.0 6.8
0.09 0.11 0.02 0.16 0.04
49.8%
−4.3%
58.1%
−6.9%
NH4 (mg/L)
COD (mg O2 /L)
DOC (mg/L)
Coliform Bacteria MPN/100 mL
28.2 28.0 17.0 44.0 6.6
8.4 8.0 5.0 13.0 1.8
6154 5475 308 24,200 5432
0.02 0.02 0.00 0.06 0.02
16.5 17.5 4.0 29.0 6.2
6.2 5.9 3.8 9.0 1.5
1 1 0 2 1
80.5%
41.5%
26.01%
99.98%
0.19 0.18 0.12 0.25 0.04
13.8 13.0 3.0 29.0 5.2
5.0 5.0 3.9 6.6 0.7
0 0 0 0 0
−91.5%
51.1%
40.3%
100%
Warta river (n = 37) 0.09 0.09 0.03 0.18 0.04
0.10 0.06 0.02 0.58 0.13
Horizontal well (HW) (n = 32)
RBF barrier (Point H) (n = 21) Average Median Minimum Maximum Standard deviation Reduction/Increase (average)
Well 19L (n = 10) Average Median Minimum Maximum Standard deviation Reduction/Increase (average)
15 15 10 20 4
614 622 580 652 29
0.58 0.23 0.00 1.91 0.68
0.03 0.02 0.01 0.09 0.03
0.19 0.21 0.10 0.27 0.07
9.8 9.0 3.0 20.0 6.83
5.0 5.1 4.3 5.8 0.6
0 0 0 0 0
42.1%
1.5%
96.9%
64.2%
−99.9%
65.3%
40.4%
100%
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Table 1. Cont. Parameters
Colour (mg Pt/L)
EC (µS/cm)
NO2 (mg/L)
NH4 (mg/L)
COD (mg O2 /L)
DOC (mg/L)
Well 1AL (n = 12)
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Average Median Average Minimum Median Maximum Standard deviation Minimum Reduction/Increase Maximum (average)
NO3 (mg/L)
Coliform Bacteria MPN/100 mL 7 of 18
13.75 1013.75 10 25 10 5 10
598 612 598 563 612 618 24 563
1.55 1.23 1.55 0.91 1.23 2.83 0.80 0.91
0.04 0.03 0.04 0.01 0.03 0.12 0.04 0.01
0.61 0.42 0.61 0.14 0.42 1.18 0.45 0.14
8.6 8.5 8.6 3.7 8.5 15.0 4.7 3.7
4.9 4.9 4.9 4.1 4.9 5.4 0.6 4.1
46.9% 25
4.1% 618
91.7% 2.83
54.0% 0.12
−529% 1.18
69.6% 15.0
42.4% 5.4
0 0 0 0 0 0 0 0
0100%
Standard deviation 24 conductivity; 0.80 0.04 0.45 oxygen demand; 4.7 0.6 0organic TDS—total dissolved solids;5 EC—electrical COD—chemical DOC—dissolved carbon; n—number of analyses; (−)—increase. Reduction/Increase 46.9% 4.1% 91.7% 54.0% -529% 69.6% 42.4% 100% (average)
3. Results
TDS—total dissolved solids; EC—electrical conductivity; COD—chemical oxygen demand; DOC— dissolved organic carbon; n—number of analyses; (-)—increase.
The statistical characteristics of the water samples are presented in Table 1. Figure 4 presents fluctuations in some parameter concentrations of RBF water relative to the source water in the Warta 3. Results River. The most apparent difference is seen in the case of coliform bacteria. Despite the high The statistical characteristics of the water samples are presented in Table 1. Figure 4 presents concentration of bacteria in river concentrations water, almost weretofound in water bank in filtrate. This is a fluctuations in some parameter of no RBFbacteria water relative the source the Warta commonRiver. effectThe observed at RBF sites and a result of filtration and adsorption and inactivation or most apparent difference is seen in the case of coliform bacteria. Despite the high die-off concentration of bacteria in river water, almost no bacteria found inreflecting bank filtrate. is a with time. A high removal efficiency was also observed for were parameters theThis occurrence of RBF sitesdemand and a result of filtration and adsorption and inactivation die- source NOM incommon water. effect The observed chemicalatoxygen (COD) reflected good removal of NOMorfrom off with time. A high removal efficiency was also observed for parameters reflecting the occurrence water. In the Warta River, the maximum concentration occasionally reached levels higher than 50 mg of NOM in water. The chemical oxygen demand (COD) reflected good removal of NOM from source O2 /L (median 24.5 mg O /L) whereas in the bank filtrate the level of COD was much lower (maximum water. In the Warta 2River, the maximum concentration occasionally reached levels higher than 50 mg 27.0 mgOO2/L /L, median O2 /L). in The DOC 8.2lower mg/L and was quite 2 (median 24.5 13.0 mg Omg 2/L) whereas themedian bank filtrate theconcentration level of COD waswas much (maximum high compared to2/L, other rivers. DOC concentration large was fluctuation source water from 27.0 mg O median 13.0 The mg O 2/L). The median DOCshowed concentration 8.2 mg/Lin and was quite compared other rivers. The DOC showed large fluctuation in source from lower 5.0 to 10high mg/L, whiletothe concentration of concentration DOC in bank filtrate was relatively stablewater and much 5.0 toconcentration 10 mg/L, while of the6.0 concentration of DOC bank filtrate relatively stablelevel and much lower (maximum mg/L, median 5.0inmg/L). Thewas relatively stable of DOC achieved (maximum concentration of 6.0 mg/L, median 5.0 mg/L). The relatively stable level of DOC achieved by RBF is important for post-treatment. In contrast to COD, the DOC concentration did not follow by RBF is important for post-treatment. In contrast to COD, the DOC concentration did not follow seasonalseasonal fluctuations in source water. The ofNOM NOMcaused caused a significant decrease fluctuations in source water. Thereduction reduction of a significant decrease in waterin water colour. A 30–40 Pt/L decrease in in colour than1515mg mg Pt/L observed RBF wells. colour. A mg 30–40 mg Pt/L decrease colourto to less less than Pt/L waswas observed in RBFin wells. Colour
a 45
b 60
40
50
35
40 mg O2/L
mg Pt/L
30 25 20 15
10
5 Jan-17
c
0 Oct-16
Apr-17 Aug-17 Nov-17 Feb-18 May-18
d
DOC
10 9
12
20000 MPN/100mL
10 8 6
8 7
15000
6 5
10000
4 3
4 5000 2 0 Oct-16
Jan-17 Apr-17 Aug-17 Nov-17 Feb-18 May-18
Coliform bacteria 25000
14
mg/L
30 20
10
0 Oct-16
COD
2 1
Jan-17
Apr-17 Aug-17 Nov-17 Feb-18 May-18
0 0 Oct-16 Jan-17 Apr-17 Aug-17 Nov-17 Feb-18 May-18
Figure 4. Cont.
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Nitrates
e 60
8 of 18
f 0.6
50
0.5 mg/L
mg/L
40 30 20
0.4 0.3 0.2
10 0 Oct-16
Ammonia 0.7
0.1
Jan-17
Apr-17 Aug-17 Nov-17 Feb-18 May-18
0.0 Oct-16
Jan-17
Apr-17 Aug-17 Nov-17 Feb-18 May-18
Figure 4.Figure Temporal changes of selected parameters inbank bankfiltrate filtrate Warta (a) Colour, 4. Temporal changes of selected parameters in andand Warta RiverRiver water.water. (a) Colour, (b)(c) COD, (c) DOC, (d) coliform bacteria, nitrates, (f) ammonia. (b) COD, DOC, (d) coliform bacteria, (e)(e)nitrates, ammonia. high of level of nitrogen reduction wasobserved observed during filtration. ThereThere were very A highAlevel nitrogen reduction was duringbank bank filtration. werehigh very high fluctuations of nitrate, nitrite, and ammonia in river water (Figure 4e,f). The seasonal variations in fluctuations of nitrate, nitrite, and ammonia in river water (Figure 4e,f). The seasonal variations in nitrogen concentrations are related to the growth periods of flora and fauna in the river, which result nitrogen concentrations are related to the growth periods of flora and fauna in the river, which result from seasonal temperature changes and are a major factor in regulating the biological processes that from seasonal temperature changes are fluctuations, a major factor in regulating theextreme biological processes determine N-cycling [21]. During and seasonal the changes related to weather that determine N-cycling [21]. During fluctuations, the related extreme Itweather conditions overlap (mainly long-termseasonal drought and the influence of changes the wet season aftertodroughts). was overlap observed (mainly [11] that high concentrations of nitrate up toinfluence 80 mg/L occurred drought conditions long-term drought and the of the after wet long-term season after droughts). as a result of flushing the accumulated contaminants in the environment. Bank filtrate displayed It was observed [11] that high concentrations of nitrate up to 80 mg/L occurred after long-term drought significantly lower nitrogen concentrations. The variability is related to nitrate, which was reduced as a result of flushing the accumulated contaminants in the environment. Bank filtrate displayed from the maximum level of 50 mg/L (median 17.5 mg/L) in source water to a maximum level of 18.0 significantly lower nitrogen concentrations. The variability is related to nitrate, which was reduced mg/L (median 6.4 mg/L) in bank filtrate during winter. In summer months, denitrification causes a from thestrong maximum of 50 concentration mg/L (median 17.5 filtrate. mg/L)The in source water peaks to a maximum decreaselevel in nitrate in bank concentration of ammonialevel of 18.0 mg/L (median 6.4 water mg/L) in bankconcentration filtrate during In summer months, denitrification observed in river (maximum 0.58 winter. mg/L) were buffered by RBF (maximum concentration 0.25 mg/L). However, the average ammonia level was higher in bank filtrate in causes a strong decrease in nitrate concentration in bank filtrate. The concentration peaksthan of ammonia river water (median in bank filtrate 0.18 mg/L compared to 0.09 mg/L in source water), indicating a observed in river water (maximum concentration 0.58 mg/L) were buffered by RBF (maximum portion of ammonia coming from mixing with ambient groundwater. concentration 0.25 mg/L). However, the average ammonia level was higher in bank filtrate than in Figure 5 presents the fluctuations of some parameter concentrations from the HW in relation to river water (median in bank 0.18 mg/L to 0.09 mg/Lwater in source water), indicating a the source water in the filtrate Warta River. In the compared case of coliform bacteria, treatment is usually portion effective, of ammonia coming from mixing with ambient groundwater. but during some periods, coliform bacteria were present in HW water. A distinct decrease in COD was observed in HW water. of In some the Warta River, periodic peaks were from observed, Figure 5 presents the fluctuations parameter concentrations the mainly HW ininrelation summer because activityIn in the the case river of (maximum mg O2/L).water The COD in the HW to the source water in of thebiological Warta River. coliform60bacteria, treatment is usually low fluctuation, usually significantly less than 20 mg O2/L, with an increase to 30 mg O2/L in effective,showed but during some periods, coliform bacteria were present in HW water. A distinct decrease in spring 2018. The DOC behaviour in the HW followed the concentration peaks observed in the river, COD was observed in HW water. In the Warta River, periodic peaks were observed, mainly in summer but the concentration level was significantly lower (maxima significantly lower than 6 mg/L with an becauseincrease of biological activity the river (maximum 60 mginOwater The COD in the HW low 2 /L). colour in spring 2018 toin a value of 9 mg/L). The decrease was evident in theshowed HW, fluctuation, significantly less than mg Othe with increase to 30 mg O2 /L in spring but inusually some periods, the high colour peak 20 followed colour of an water in the river. 2 /L, Low behaviour ammonia concentrations were foundthe in the HW. In general, the observed high concentration peaks but the 2018. The DOC in the HW followed concentration peaks in the river, followed the behaviour of ammonia in the(maxima source river water, but thelower concentration ammonia theincrease concentration level was significantly lower significantly than 6 of mg/L withinan HW was significantly lower (maximum of 0.5–0.6 mg/L in the river compared to less than 0.2 mg/L in the in spring 2018 to a value of 9 mg/L). The decrease in water colour was evident in the HW, but in some HW). There was no removal of nitrate between the river and the HW. The behaviour of nitrate in HW periods,strictly the high colour peak followed colour of water in the river. follows fluctuations observed inthe surface water. The minima and maxima observed in river water Low ammonia concentrations were found in the HW. In general, the high concentration peaks and the HW were almost identical with respect to time and range of concentration. followed the behaviour of ammonia in the source river water, but the concentration of ammonia in the HW was significantly lower (maximum of 0.5–0.6 mg/L in the river compared to less than 0.2 mg/L in the HW). There was no removal of nitrate between the river and the HW. The behaviour of nitrate in HW strictly follows fluctuations observed in surface water. The minima and maxima observed in river water and the HW were almost identical with respect to time and range of concentration.
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a
9 of 18
b
Colour
COD 60
45 40
50
35 40 mg O2/L
mg/L
30 25 20
20
15 10
10
5 0 Dec-14
c
30
Sep-15
May-16
Jan-17
DOC
Sep-17
May-18
0 Dec-14
d
14
Sep-15
May-16
Jan-17
Sep-17
Coliform bacteria
May-18
25000
250
20000
200
15000
150
10000
100
5000
50
12
NPL/100mL
mg/L
10 8 6 4 2 0 27-Dec
e
3-Sep
10-May
15-Jan
22-Sep
0 Dec-14
30-May
f
Nitrates
0.7
50
0.6
Jan-17
Sep-17
0 May-18
0.5 mg/L
40 mg/L
May-16
Ammonia
60
30 20
0.4 0.3 0.2
10 0 Dec-14
Sep-15
0.1
Sep-15
May-16
Jan-17
Sep-17
May-18
0.0 Dec-14
Sep-15
May-16
Jan-17
Sep-17
May-18
Figure 5. Temporal changes of selected parameters in the horizontal well (HW) and the Warta River. Figure 5. Temporal changes of selected parameters in the horizontal well (HW) and the Warta River. (a) Colour, (b) COD, (c) DOC, (d) coliform bacteria, nitrates,(f)(f) ammonia. (a) Colour, (b) COD, (c) DOC, (d) coliform bacteria, (e) (e) nitrates, ammonia.
Preliminary results show thethepresence pharmaceutical compounds and other Preliminary results show presence of of some some pharmaceutical compounds and other micropollutants in both source water andbank bank filtrate filtrate (Table In In total, 30 micropollutants were were micropollutants in both source water and (Table2).2). total, 30 micropollutants analysed. The following pharmaceuticalresidues residues were in the Warta river,river, but not in bank analysed. The following pharmaceutical weredetected detected in the Warta but not in bank filtrate: diclofenac (15 ng/L), iohexol (20 ng/L), iomeprol (20 ng/L), iopamidol (20 ng/L), metoprolol filtrate: diclofenac (15 ng/L), iohexol (20 ng/L), iomeprol (20 ng/L), iopamidol (20 ng/L), metoprolol (10 ng/L), and theophylline (40 ng/L). The pharmaceutical residues that were not found in river water (10 ng/L), theophylline (40asng/L). The pharmaceutical residues thatatenolol, were not found in river nor and in bank filtrate were follows: 4-DMA-antipyrin, 4-IP-antipyrine, bezafibrate, water nor in bankloratidin, filtrate were as follows: 4-DMA-antipyrin, 4-IP-antipyrine, atenolol, bezafibrate, diazepam, naproxen, paracetamol, phenazone, primidone, sulfadiazine, theophylline, aspartam, chloramphenicol, and phenobarbital. diazepam, loratidin, naproxen,gemfibrozil, paracetamol, phenazone, primidone, sulfadiazine, theophylline, aspartam, chloramphenicol, gemfibrozil, and phenobarbital.
Water 2018, 10, 1457
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Table 2. Concentration of relevant pharmaceuticals and other micropollutants in ng/L (Limit of Quantification (LOQ) < 5). Sampling Point
1H-Benzotriazole
Carbamazepine
Caffeine
Sulfamethoxazole
Tolytriazole
Warta River Horizontal well 168b/2 177b/1 19L 1AL 78b/1s 50A
120 180 180 110 50 80
