This article was downloaded by: [University of Sherbrooke] On: 13 April 2015, At: 00:59 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Environmental Technology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tent20
Evaluation of single and multilayered reactive zones for heavy metals removal from stormwater a
Katarzyna Pawluk & Joanna Fronczyk
a
a
Department of Geotechnical Engineering, Warsaw University of Life Sciences – SGGW, Warsaw, Poland Accepted author version posted online: 13 Dec 2014.Published online: 06 Jan 2015.
Click for updates To cite this article: Katarzyna Pawluk & Joanna Fronczyk (2015) Evaluation of single and multilayered reactive zones for heavy metals removal from stormwater, Environmental Technology, 36:12, 1576-1583, DOI: 10.1080/09593330.2014.997299 To link to this article: http://dx.doi.org/10.1080/09593330.2014.997299
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Environmental Technology, 2015 Vol. 36, No. 12, 1576–1583, http://dx.doi.org/10.1080/09593330.2014.997299
Evaluation of single and multilayered reactive zones for heavy metals removal from stormwater Katarzyna Pawluk and Joanna Fronczyk ∗ Department of Geotechnical Engineering, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
(Received 30 July 2014; accepted 8 December 2014 ) In this paper, the ability of granular activated carbon (GAC), silica spongolite (SS) and zeolite (Z) to remove heavy metals from aqueous solutions has been investigated through column tests. The breakthrough times for a mobile tracer that does not sorb to the material for SS, GAC and layered SS, Z and GAC were as follows: 2.54 × 104 s, 2.38 × 104 s and 3.02 × 104 s. The breakthrough time (tbR ) for Ni was in the range from tbR = 1.70 × 106 s for SS, through tbR = 3.98 × 105 s for the layered bed, to tbR = 8.75 × 105 s for GAC. The breakthrough time for Cd was in the range from tbR = 1.83 × 105 s for GAC to tbR = 1.30 × 106 s for SS, Z, GAC. During the experiment, the concentration of Cd, Cu, Pb and Zn in the solution from a column filled with construction aggregate and the concentration of Pb, and Cu in a filtrate from the column filled with several materials was close to zero. The reduction in metal ions removal was due to high pH values of the solution (above 8.00). In addition, during the testing period, an increase in Cd and Zn concentrations in the filtrate from the column filled with the layered bed was observed, but at the end of the experiment the concentrations did not reach the maximum values. The test results suggest that the multilayered permeable reactive barrier is the most effective technology for long time effective removal of heavy metals. Keywords: permeable reactive barrier; reactive materials; heavy metals sorption; activated carbon; silica spongolite
Introduction Highway and bridge runoff may contain a number of constituents including salts, metals, organic compounds, and bacteria.[1–5] According to the best management practices, a wide variety of treatment facilities exists, including bioretention and bioslope, surface sand filter, gutter filter, infiltration trenches/strips, infiltration tanks, soakways, swales, natural or engineered wetlands, sustainable drainage systems, separators or separate sewer systems. [6–9] In these devices, the contaminants are removed only partially and insufficiently. Application of conventional water treatment methods such as chemical precipitation, reduction or osmosis may be very expensive and energyconsuming. In recent years, filter systems with specially selected sorption materials were presented as a relatively new method for treatment of first-flush stormwater,[10] parking lot runoff [11] and highly polluted urban road runoff.[8] An alternative to these treatment devices is the sorption of contaminants on mineral and organic sorbents in the technology of permeable reactive barriers (PRBs). In PRBs, the dissolved contaminants are removed by various processes (sorption, biodegradation, reduction, etc.) that take place during the flow of polluted runoff water through the reactive material filling the treatment zone. Kong et al. [12] and Kijjanapanich et al. [13] have conducted the laboratory tests on several organic materials as reactive
*Corresponding author. Email: [email protected] © 2015 Taylor & Francis
materials in multilayered PRB. Reddy et al. [14] have proposed the application of PRB technology in the treatment of urban stormwater runoff using calcite, zeolite, iron and sand fillings. Moreover, PRB composed of zero-valent iron (ZVI) and EHC© in the median of the Central Expressway in Sunnyvale, CA, USA, was designed to reduce total volatile organic compounds.[15] Proper design of a PRB requires the knowledge of the intensity and kinetics of processes occurring between the solution and the material, which are usually determined by equilibrium and kinetic batch tests.[16–18] Parameters calculated based on the batch test results are parameters of sorption isotherms (including the maximum amount of dissolved ions per unit mass of material) and parameters of kinetic models (including equilibrium rate constants). However, batch tests do not take into account the flow conditions (e.g. saturation of the reactive zone and flow velocity of the contaminated water), as well as physical properties of the reactive material (e.g. effective porosity and bulk density).[19,20] In column tests, the flow rates may be adjusted to imitate real rates in the aquifer, so as to reproduce the behaviour of the barrier and the pollutants in field conditions. Based on the column test results, different parameters, that is, velocity of flow, coefficient of hydrodynamic dispersion, retardation factor, and longitudinal dispersivity may be estimated. Therefore, it may
1577
Environmental Technology
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
be concluded that the column study provides information reflecting in situ conditions, which can be directly used in designing PRBs. The primary goals of the presented research are as follows: (1) to study the transport of heavy metals (Cd, Cu, Ni, Pb and Zn) through zeolite (Z), activated carbon and silica spongolite (SS); (2) to calculate the parameters of contaminant transport through porous materials using the STANMOD package CXTFIT [21] and (3) to determine the most favourable reactive material for road runoff treatment in PRBs. Experimental methodology Materials In this study, granular clinoptilolite-rich Slovak zeolite tuff (Zeocem, Slovakia), granular activated carbon (GAC, Active Carbon Research and Production Company, Poland) and SS (Wrzosówka Mine, Poland) were used as the reactive materials. A surface area and porosity analyser (ASAP 2020M Micromeritics, USA), a scanning electron microscope (SEM) images (FEG Quanta 250, USA) and Xray diffraction (Philips X’Pert APD, Netherlands) spectra were used for the detailed characterisation of the reactive materials. Characteristics of the particle size distribution, specific gravity and bulk density of the reactive materials are summarised in Table 1. Chemicals All chemicals used in the column tests were of reagent grade (CHEMPUR, Poland). The concentration of reagents (100 mg L−1 – chloride solution and 20 mg L−1 – multicomponent solution of Cd, Cu, Ni, Pb and Zn) were prepared using NaCl, CdCl2 ·2.5H2 O, CuCl2 ·2H2 O, NiSO4 ·7H2 O, Pb(NO3 )2 and ZnCl2 in distilled water (DI). The pH of the solutions was measured using a pH-meter (SCHOTT, Germany). In the tests, the pH of the chloride solution was in the range of 6.37–6.72 and the pH of the metal solution was between 7.02 and 7.21. Initial electrical conductivity values ranged within 205–389 and within 45–57 mS cm−1 for the chloride and metal solutions, respectively.
Table 2.
Column test parameters.
Column mark SS GAC SS Z GAC
Mass of dry material (g)
Porosity
Column PVF (mL)
14287.0 3532.5 4762.3 2757.9 1177.5
0.36 0.63 0.36 0.47 0.63
5497.8 9896.0 1832.4 2408.3 3298.34
through columns filled with the reactive materials. The laboratory set-up used in the experiment consists of three PVC columns 0.8 m long and of 0.1 m internal diameter. The main parameters of the column tests are listed in Table 2. Column experiments were used to simulate the groundwater conditions, therefore, the flow rates through the columns were adjusted to imitate real rates in the aquifer (4.16 × 10−8 m3 sec−1 ) in order to replicate the performance of the PRB and the pollutants in field conditions. The test was performed under constant upward flow of chemical solutions achieved by a multichannel peristaltic pump. Performance comparison tests were carried out using GAC alone, SS alone and duplicate layers of SS, Z and GAC combined (Figure 1). The column filled with zeolite alone was not performed due to its documented ability for the immobilisation of heavy metals.[22–25] The second material with a confirmed ability for heavy metal removal is activated carbon [26–28]; it was selected for result comparison in a test with SS. The selection of reactive materials and their order are driven by their removal properties. The SS is used as a pre-treatment layer to remove heavy metals by chemical precipitation. The second layer is zeolite which removes the precipitates and other contaminants by adsorption and ions exchange process. The last layer is activated carbon (the final cleansing layer), which exhibits high adsorption capacity due to its large surface area and
Column tests The efficiency of activated carbon, Z and SS was tested by passing chemical solutions (uni- and multicompounds) Table 1. Physical properties of the reactive materials. Material Zeolite Activated carbon Silica spongolite
Particle size (mm)
Specific gravity
Bulk density (cm3 g−1 )
0.5–1.0 0.5–2.0 0.5–2.0
2.40 1.96 2.71
1.054 0.450 1.820
Figure 1.
Schematic diagram of the test columns.
1578
K. Pawluk and J. Fronczyk The columns were fed with distilled water from the right to the left using a ZALIMP (Poland) peristaltic pump. After reaching a steady flow rate, a slug input of a mobile tracer (chloride) was added to evaluate the hydrodynamic characteristics of the reactive materials in each column. To estimate the sorption parameters of the materials, the tests were performed for a multicomponent model
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
presence of several different types of surface functional groups. A few laboratory studies on sequenced PRB remediation for wastewater have been carried out using ZVI, zeolites, ORC and organic carbon (e.g. wood chips and compost).[12,29,30] However, to our knowledge, the layers of SS, Z and GAC have never been carried out on the column test.
Figure 2. SEM images, SEM spectra and XRD spectra of activated carbon, zeolite and spongolite.
1579
Environmental Technology
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
solution (20 mg Cd2+ L−1 , 20 mg Cu2+ L−1 , 20 mg Ni2+ L−1 , 20 mg Pb2+ L−1 and 20 mg Zn2+ L−1 ). Migration parameters of the mixtures, that is, dispersivity, retardation factor and partitioning coefficients were estimated from these tests. The samples were taken from the column effluent at appropriate intervals and analysed for the contents of chloride and heavy metals. The metals were analysed using atomic absorption spectrometry – AAS method (iCE 3000, ThermoLab USA), while the chloride content in the solutions was analysed using the Mohr method. Electrical conductivities and pH values were also measured. The column tests were carried out at room temperature (20–22 °C).
where C (mg L−1 ) is the concentration of the contaminant at depth z at time t, t (hr) is the time, t1 (hr) is the tracer injection start time and t2 (hr) is the tracer injection ending time. The zero concentration gradient at the outflow end of the sample (x = L) was assumed as ∂C (∞, t) = 0. ∂x
(4)
Using the CXTFIT package, the following parameters characterising the contaminant migration conditions were calculated: ratio of flow velocity vR , ratio of dispersion DR , longitudinal dispersivity α L , Péclet number P e and breakthrough time tR , after which the tracer concentration in the effluent solution was 0.5 C0 .
Hydrodynamic and sorption parameters Sorption capacity studies (column tests) were performed in order to select a system suitable for PRBs in the vicinity of road infrastructure. The tested chemical compounds were selected based on the results of chemical composition analyses of road runoff and snowmelt from several reports.[31–36] In most cases, concentrations of heavy metals exceeded acceptable limits in the runoff and snowmelt samples. Accordingly, the following chemical compounds were applied in the studies: cadmium, copper, nickel, lead and zinc. The parameters of the advection–dispersion equation of contaminant transport in groundwater were calculated using the STANMOD package CXTFIT.[21] This software uses a non-linear, least-square parameter optimisation method from the observed concentration data. During numerical modelling, the homogeneity of the sample, zero diffusion coefficient DM and zero initial concentration in the sample were assumed as the initial boundaries: C(x, 0) = 0 for
x ≥ 0,
(1)
where C (mg L−1 ) is the concentration of the contaminant at depth z at time t and x (m) is the distance. For the influent solution, the first-type (Dirichlet) boundary conditions, constant concentration of selected ions, described by the following formula were assumed: for the jump function 0 for t < t1 , (2) C(t) = 1 for t ≥ t1 , for the impulse function ⎧ ⎪ ⎨0 C(t) = C0 ⎪ ⎩ 0
for t < t1 , for t1 ≤ t ≤ t2 , for t > t2 ,
(3)
Figure 3. Observed (circles) and fitted values (solid lines) of the non-decaying indicator for spongolite, activated carbon and layers of SS, Z and GAC.
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
1580
K. Pawluk and J. Fronczyk the solution outlet concentrations versus the time or number of pore volume of flow (PVF). The PVF represents the volume of the solutions equal to the volume of the reactive material pores. During these tests, the outlet concentrations are expressed as absolute concentrations of chemicals C/C0 . In the backward analysis of the advection–dispersion equation, the value of the retardation coefficient R was 1. In consequence, no interaction between the indicator and the samples was observed. The parameters of transport equation estimated on the basis of the tests are shown in Table 3. The equilibrium model was applied in all analyses of the indicator breakthrough curves for spongolite, activated carbon and layers of SS, Z and GAC. In Figure 3, the fitted breakthrough curves are symmetrical, which confirms the homogeneity of the samples. In the column with SS, the breakthrough began earlier than in other columns and the outflow curve had a long tail. The velocity and hydrodynamic dispersion coefficient values were estimated with determination coefficients at 0.71–0.99.
Results and discussion Characteristics of the adsorbent Figure 2 shows the XRD pattern and scanning electron images of the activated carbon, zeolite and spongolite samples. The pattern and increased values of the background (15–35 (2)) on XRD spectra of the GAC sample show that the dominant mineral component is an amorphous substance characteristic of activated carbons. The characteristic interplanar spacing (4.255, 3.344, 2.456, 2.283, 2.237, 2.128 and 1.981 Å) has been attributed to quartz as an additional mineral component of the sample. Observations of the microstructure lead to the conclusion that the surface of the reactive material is highly porous and rough. The pores are circular in shape and of variable size (from 10 to 300 μm). The reactive material is characterised by extraordinary specific surface area, which is determined at 856 m2 g−1 . The total pore volume of GAC is 0.00016 m3 kg−1 . Pattern of SEM spectra of the zeolite sample indicates that the dominant components include silica, gold, aluminium, sodium and potassium. SEM observations showed the microstructure of the zeolite surface. The pores are irregular in shape and have sizes from 0.1 to 10 μm. The specific surface area is 32.44 m2 g−1 and the total pore volume is 5.0 × 10−6 m3 kg−1 . The diffractogram of the spongolite sample showed the characteristic peaks for calcite and quartz. The structure of the material is rough without pores. The SBET of the sample is 2.82 m2 g−1 and the total pore volume is 2.0 × 10−7 m3 kg−1 .
Test with reactive indicator The effect of adsorbate heavy metal ions concentration on the column performance was studied using an inlet concentration of 20 mg L−1 and a unit feed flow rate of 2.6 mL min−1 . The breakthrough curve is illustrated in Figure 4. As can be observed on the plots (Figure 4), the activated carbon beds were exhausted faster than other materials. In the column with GAC, an earlier breakthrough point was reached for the Ni, Cd and Zn ions, which competed for free place on the material structure by reducing the intensity of Cu and Pb ions removal. Comparison of the shape of the breakthrough curves for Ni, Cd and Zn (Figure 4) indicates similar changes of ion concentrations in the effluent
Test with non-decaying adsorbing chemicals The results of the experiment are shown in Figure 3 as breakthrough curves that illustrate relationships between
Table 3. Hydrodynamic and sorption parameters of SS, GAC and layers of SS, Z and GAC obtained from column tests for the model solutions. Column
PVF
v (m sec−1 )
SS Cl− SS Ni2+ GAC Cl− GAC Cd2+ GAC Ni2+ GAC Pb2+ GAC Zn2+ SSZGAC Cl− SSZGAC Cd2+ SSZGAC Ni2+ SSZGAC Zn2+
0.04 2.72 0.02 1.46 1.46 1.46 1.46 0.07
3.94 3.94 4.21 4.21 4.21 4.21 4.21 3.31
0.92
3.31 × 10−5
7.670 × 10−7
9.93 × 10−6
0.92
3.31 × 10−5
2.520 × 10−7
0.92
3.31 × 10−5
1.738 × 10−8
× × × × × × × ×
10−5 10−5 10−5 10−5 10−5 10−5 10−5 10−5
vR (m sec−1 ) 5.888 5.461 1.140 9.190 2.528
1 × 1 × × × × 1
10−7 10−6 10−6 10−7 10−6
D (m2 sec−1 )
DR (m2 sec−1 )
R
α L (m)
Pe
R2
1.00 67.06 1 7.71 36.84 45.83 16.67 1
0.14 0.14 0.18 1.14 0.82 0,14 3.30 0.24
7.30 7.05 5.58 0.88 1.22 7.22 0.30 4.19
0.94 0.98 0.98 0.91 0.71 0.86 0.89 0.95
2.30 × 10−7
43.14
0.30
3.33
0.98
3.07 × 10−5
2.33 × 10−6
13.16
0.93
1.07
0.94
1.66 × 10−5
8.71 × 10−9
1905
0.50
1.99
0.97
5.40 5.59 7.54 4.80 3.46 5.83 1.39 7.90
× × × × × × × ×
10−5 10−6 10−6 10−5 10−5 10−6 10−4 10−6
1 8.34 × 1 6.23 × 9.39 × 1.27 × 8.36 × 1
10−8 10−6 10−7 10−7 10−6
Notes: PVF is the pore volume of flow, v is the velocity of flow, vR is the ratio of flow velocity decrease, D is the coefficient of hydrodynamic dispersion, DR is the ratio of dispersion decrease, R is the retardation factor, α L is the longitudinal dispersivity and P e is the Péclet number.
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
Environmental Technology
Figure 4. Observed (points) and fitted values (lines) of the reactive indicators for spongolite, activated carbon and layers of SS, Z and GAC.
solution. These breakthrough curves evidence a faster flow of Cd, Ni and Zn through the pore channels by diffusion processes.[37] Lead ions were also immobilised during contact with activated carbon, however without achieving the equilibrium stage. However, the most intensive retention on GAC was noted for copper ions as confirmed by the breakthrough curve shape. The test performed on the column with SS indicated intensive removal of heavy metals from the aqueous solution. The final concentrations of Cd, Cu, Pb and Zn in the filtrate from the column were close to zero. Figure 4 shows that the nickel ions were also immobilised, however less intensively than the other heavy metals in the solution. Similar results were noted for the column with the layers of GAC, Z and SS. As previously, heavy metals were
1581
removed from the aqueous solution with different intensities. The most intensive reduction was observed for Cu, Pb and Zn. In contrast, increased concentrations of Cd and Ni were detected in the outflow at the end of the experiment. Summarising, the removal of nickel ions in the three columns was the lowest of all reactive indicators in the aqueous solution. Using the characteristic points of the breakthrough curves, the dynamic sorption capacities of the materials tested were calculated: S m and S mR for the breakthrough point and the point, at which the relative concentration of the tracer in the effluent solution is 0.95, respectively. The results of the calculations are presented in Table 4. For all materials, the obtained maximum sorption capacity for heavy metals was at the same level, with one exception – Zn on GAC. On the other hand, based on the values of the retardation factor, the sorption processes were unlimited for Zn on SS, Z, and GAC, high for Ni on all beds, for Cd on GAC and the layered bed, as well as for Pb on GAC and the layered bed. In comparison to the breakthrough capacity, significant similarities have been observed: S mR = 8.459 mg Zn2+ · g−1 for GAC, S mR = 1.797 mg Cd2+ · g−1 for GAC, S mR = 1.528 mg Ni2+ · g−1 for GAC, S mR = 1.334 mg Ni2+ · g−1 for SS, Z and GAC, and S mR = 0.661 mg Ni2+ g−1 for SS. By feeding the calculated values of this parameter for several reactive materials, it was recognised that nickel has a higher affinity to activated carbon. On the other hand, cadmium affinity to activated carbon was much higher than in the case of nickel. The obtained retardation factors are presented in Table 3. The Péclet number P e may be used to characterise the nature of the transport processes of contaminates during flow through the columns. For the column with SS, P e indicated an advantage of advection over dispersion, whereas dispersion had the same role in the transport of heavy metals through the columns with GAC and layers of SS, Z and GAC. The pH profile of the exit solution for the sorption of heavy metals onto GAC, SS, and layers of SS, Z, GAC in the column is shown in Figure 5. The pH value of the outflow solutions during the column experiments indicated that the heavy metal ions were removed from the solution by both sorption and precipitation processes. The heavy metal concentration in the solutions is a function of pH. Precipitation of Cu, Zn, Ni, and Pb in the insoluble forms occurs at pH values in the range of 6.50–9.00. The pH of the aqueous solution affects both the solubility and speciation of the metal ions, and the dissociation degree of the functional groups from the sorbent surface; thus, it is one of the most important parameters controlling the uptake of heavy metals from aqueous solutions.[38] The pH profiles have demonstrated that at the beginning of the test, initial pH increased from 6.80 to 9.00–10.00, which points to precipitation of heavy metals. Subsequently, the reduction in the values of the pH
1582
K. Pawluk and J. Fronczyk Table 4. Hydraulic and sorption parameters of SS, GAC and layers of SS, Z and GAC obtained from column tests.
Material
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
SS Ni2+ GAC Cd2+ GAC Ni2+ GAC Pb2+ GAC Zn2+ SSZGAC Cd2+ SSZGAC Ni2+ SSZGAC Zn2+
tbR (sec)
Sm (mg g−1 )
S mR (mg g−1 )
Range of pH
Range of electrical conductivity (mS cm−1 )
× × × × × ×
106 105 105 106 105 106
0.047 0.150 0.183 1.245 0.102 0.730
0.661 1.797 1.528 – 8.459 –
6.89–10.58 6.80–9.14 6.80–9.14 6.80–9.14 6.80–9.14 6.99–9.68
57–667 45–355 45–355 45–355 45–355 59–375
3.02 × 104
3.98 × 105
0.159
1.334
6.99–9.68
59–375
3.02 × 104
5.76 × 107
0.175
–
6.99–9.68
59–375
tb (sec) 2.54 2.38 2.38 2.38 2.38 3.02
× × × × × ×
104 104 104 104 104 104
1.70 1.83 8.75 1.09 3.96 1.30
Notes: PVF is the pore volume of flow, tb (sec) is the breakthrough time for the mobile chemical that does not sorb to the material tb = L/v, tbR (sec) is the breakthrough time for a tracer with retardation factor R tbR = Rtb, S m and S mR (mg g−1 ) is the dynamic sorption capacities of the breakthrough point and of the point, at which the relative concentration of the tracer in the effluent solution is 0.95, respectively, and – indicated undetermined values.
(3) (4)
(5) (6) Figure 5. The pH profile at the exit of the column with GAC, SS, and layers of SS, Z, GAC.
in the range of 6.45–6.84 for GAC and the layered beds, as well as the value of about 7.75 for SS was observed. This suggests that adsorption processes of heavy metals by activated carbon and zeolite were initiated by ion exchange and surface complexation of heavy metals on the surfaces of the reaction materials. In turn, heavy metal removal during the contact with SS was achieved mainly by precipitation.
(7)
which competed for free place in the material structure by reducing the intensity of removal of Cu and Pb ions. The most intensive retention on GAC was noted for copper ions. The test performed on the column with SS indicated intense removal of heavy metals from the aqueous solution – the final concentrations of Cd, Cu, Pb and Zn in the filtrate from the column were close to zero. Nickel removal from the solution was least efficient in comparison to the other heavy metals. On the layered bed, the heavy metals were immobilised with different intensities. The most intensive reduction was observed for Cu, Pb and Zn. In contrast, increased concentrations of Cd and Ni were detected in the outflow at the end of the experiment. The pH value of the outflow solutions during column experiments indicated that the heavy metal ions were removed from the solution by both sorption and precipitation processes.
Disclosure statement No potential conflict of interest was reported by the authors.
Conclusions The experimental results of this research allow us to draw the following conclusions:
(1) Activated carbon beds were exhausted faster than other materials. (2) In the column with GAC, an earlier breakthrough point (tbR ) was reached for Ni, Cd and Zn ions,
Funding This work was supported by the National Science Centre, Poland [under grant number N N523 561638] and the European Union funds by the European Social Fund.
References [1] Novotny EV, Murphy D, Stefan HG. Increase of urban lake salinity by road deicing salt. Sci Total Environ. 2008;406:131–144.
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
Environmental Technology [2] Davis B, Birch G. Comparison of heavy metal loads in stormwater runoff from major and minor urban roads using pollutant yield rating. Environ Pollut. 2010;158(8):2541– 2545. [3] Fronczyk J, Pawluk K, Garbulewski K. Multilayer PRBs – effective technology for protection of groundwater environment in traffic infrastructure. Chem Eng Trans. 2012;28: 67–72. [4] Kaczala F, Marques M, Vinrot E, Hoglan W. Stormwater run-off from an industrial log yard: characterization, contaminant correlation and first-flush phenomenon. Environ Technol. 2012;33(14):1615–1628. [5] El-Mufleh A, Husseini A, Béchet B, Gaudin A, Ruban V. Trace metal fractionation as a mean to improve on the management of contaminated sediments from runoff water in infiltration basins. Environ Technol. 2013;34(10):1255– 1266. [6] Terzakis S, Fountoulakis MS, Georgaki I, Albantakis D, Sabathianakis I, Karathanasis AD, Kalogerakis N, Manios T. Constructed wetlands treating highway runoff in the central Mediterranean region. Chemosphere. 2008;72: 141–149. [7] Fu DF, Singh RP, Juan H, Ojha CSP, Surapalli RY, Zhang TC. Highway runoff treatment by lab-scale horizontal subsurface flow constructed wetlands. Ecol Eng. 2014;64: 193–201. [8] Hilliges R, Schriewer A, Helmreich B. A three-stage treatment system for highly polluted urban road runoff. J Environ Manage. 2013;128:306–312. [9] Imran HM, Akib S, Karim MR. Permeable pavement and stormwater management systems: a review. Environ Technol. 2013;34(18):2649–2656. [10] Kus B, Kandasamy J. Low-cost filtration system to treat first-flush stormwater. Water Air Soil Pollut. 2009;9: 347–355. [11] Fuerhacker M, Haile TM, Monai B, Mentler A. Performance of a filtration system equipped with filter media for parking lot runoff treatment. Desalination. 2011;275: 118–125. [12] Kong X, Bi E, Liu F, Huang G, Ma J. Laboratory column study for evaluating a multi-media permeable reactive barrier for the remediation of ammonium contaminated groundwater. Environ Technol. 2014. doi:10.1080/09593330.2014.992482 [13] Kijjanapanich P, Pakdeerattanamint K, Lens PNL, Annachhatre AP. Organic substrates as electron donors in permeable reactive barriers for removal of heavy metals from acid mine drainage. Environ Technol. 2012;33(23):2635–2644. [14] Reddy KR, Xie T, Dastgheibi S. Removal of heavy metals from urban stormwater runoff using different filter materials. J Environ Chem Eng. 2014;2:282–292. [15] ITRC (Interstate Technology & Regulatory Council). Permeable reactive barrier: technology update. PRB-5. Washington, DC: Interstate Technology & Regulatory Council, PRB: Technology Update Team; 2011. Available from: http://www.itrcweb.org [16] Fronczyk J, Garbulewski K. Selection of material suitable for permeable reactive barriers in the vicinity of landfills. Ann Warsaw Univ Life Sci SGGW Land Reclam. 2009;41:3–9. [17] Ho YS, McKay G. Pseudo-second order model for sorption processes. Process Biochem. 1999;34:451–465. [18] Ho YS, Chiu WT, Wang CC. Regression analysis for the sorption isotherm of basic dyes on sugarcane dust. Bioresource Technol. 2002;96:1285–1291. [19] Burt TA, Li Z, Bowman RS. Evaluation of granular surfactant-modified/zeolite zero valent iron pellets as a
[20] [21]
[22]
[23] [24]
[25] [26]
[27] [28]
[29]
[30] [31] [32]
[33] [34]
[35] [36]
[37] [38]
1583
reactive material for perchloroethylene reduction. J Environ Eng. 2005;131(6):934–942. Li Z. Chromate transport through surfactant-modified zeolite columns. Ground Water Monit R. 2006;26(3):117–124. Toride N, Leij FJ, van Genuchten M.Th. The CXTFIT code for estimating transport parameters from laboratory or field tracer experiments. Version 2.1. Research Report No. 137. Riverside, CA: USDA-ARS U.S. Salinity Laboratory; 1999. Zamzow MJ, Eichbaum BR, Sandgren KR, Shanks DE. Removal of heavy metals and other cations from waste water using Zeolites. Separ Sci Technol. 1990;25(13– 15):1555–1569. Ouki SK, Kavannadg M. Performance of natural zeolites for the treatment of mixed metal-contaminated effluents. Waste Manage Res. 1997;15(4):383–394. Derkowski A, Franus W, Beran E, Czímerová A. Properties and potential applications of zeolitic materials produced from fly ash using simple method of synthesis. Powder Technol. 2006;166(1):47–5. Wang S, Peng Y. Natural zeolites as effective adsorbents in water and wastewater treatment. J Chem Eng. 2010;156: 11–24. Mohan D, Singh KP. Single- and multi-component adsorption of cadmium and zinc using activated carbon derived from BagasseFan agricultural waste. Water Res. 2002;36:2304–2318. Zayat ME, Smith E. Removal of heavy metals by using activated carbon produced from cotton stalks. Can J Environ Constr Civil Eng. 2010;1(4):71–79. del Mar Gómez-Tamayo M, Macías-García A, Díaz Díez MA, Cuerda-Correa EM. Adsorption of Zn(II) in aqueous solution by activated carbons prepared from evergreen aak (Quercus rotundifolia L.). J Hazard Mater. 2008;153:28–36. Barrett M, Kearfott P, Malina J. Stormwater quality benefits of a porous friction course and its effect on pollutant removal by roadside shoulders. Water Environ Res. 2006;78(11):2177–2185. Barrett M, Irish L, Malina J, Charbeneau R. Characterisation of highway runoff in Austin Texas. Area J Environ Eng. 1998;124:131–137. Scholz M, Yazdi SK. Treatment of road runoff by a combined storm water treatment. Detention and infiltration system. Water Air Soil Pollut. 2009;198:55–64. Jun D, Yongsheng Z, Weihong Z, Mei H. Laboratory study on sequenced permeable reactive barrier remediation for landfill lechate – contaminated groundwater. J Hazard Mater. 2009;161:224–230. Han YH, Lau SL, Kayhanian M, Stenstrom MK. Correlation analysis among highway stormwater pollutants and characteristics. Water Sci Technol. 2006;53(2):235–243. Kayhanian M, Singh A, Suverkropp C, Borroum S. Impact of annual average daily traffic on highway runoff pollutant concentrations. J Environ Eng ASCE. 2003;129(11): 975–990. Kayhanian M, Stransky C, Bay S, Lau SL, Stenstrom MK. Toxicity of urban highway runoff with respect to storm duration. Sci Total Environ. 2007;389(2–3):386–406. Lau S-L, Han Y, Kang JH, Kayhanian M, Strenstrom M. Characteristics of highway stormwater runoff in Los Angeles – Part 2: metals and polycyclic aromatic hydrocarbons. Water Environ Res. 2009;81(3):308–18. Jury WA, Horton R. Soil physics. 6th ed. Hoboken, NJ: Wiley; 2004. Meena AK, Kadirvelu K, Mishraa GK, Rajagopal C, Nagar PN. Adsorption of Pb(II) and Cd(II) metal ions from aqueous solutions by mustard husk. J Hazard Mater. 2008;150:619–625.
Environmental Technology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tent20
Evaluation of single and multilayered reactive zones for heavy metals removal from stormwater a
Katarzyna Pawluk & Joanna Fronczyk
a
a
Department of Geotechnical Engineering, Warsaw University of Life Sciences – SGGW, Warsaw, Poland Accepted author version posted online: 13 Dec 2014.Published online: 06 Jan 2015.
Click for updates To cite this article: Katarzyna Pawluk & Joanna Fronczyk (2015) Evaluation of single and multilayered reactive zones for heavy metals removal from stormwater, Environmental Technology, 36:12, 1576-1583, DOI: 10.1080/09593330.2014.997299 To link to this article: http://dx.doi.org/10.1080/09593330.2014.997299
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Environmental Technology, 2015 Vol. 36, No. 12, 1576–1583, http://dx.doi.org/10.1080/09593330.2014.997299
Evaluation of single and multilayered reactive zones for heavy metals removal from stormwater Katarzyna Pawluk and Joanna Fronczyk ∗ Department of Geotechnical Engineering, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
(Received 30 July 2014; accepted 8 December 2014 ) In this paper, the ability of granular activated carbon (GAC), silica spongolite (SS) and zeolite (Z) to remove heavy metals from aqueous solutions has been investigated through column tests. The breakthrough times for a mobile tracer that does not sorb to the material for SS, GAC and layered SS, Z and GAC were as follows: 2.54 × 104 s, 2.38 × 104 s and 3.02 × 104 s. The breakthrough time (tbR ) for Ni was in the range from tbR = 1.70 × 106 s for SS, through tbR = 3.98 × 105 s for the layered bed, to tbR = 8.75 × 105 s for GAC. The breakthrough time for Cd was in the range from tbR = 1.83 × 105 s for GAC to tbR = 1.30 × 106 s for SS, Z, GAC. During the experiment, the concentration of Cd, Cu, Pb and Zn in the solution from a column filled with construction aggregate and the concentration of Pb, and Cu in a filtrate from the column filled with several materials was close to zero. The reduction in metal ions removal was due to high pH values of the solution (above 8.00). In addition, during the testing period, an increase in Cd and Zn concentrations in the filtrate from the column filled with the layered bed was observed, but at the end of the experiment the concentrations did not reach the maximum values. The test results suggest that the multilayered permeable reactive barrier is the most effective technology for long time effective removal of heavy metals. Keywords: permeable reactive barrier; reactive materials; heavy metals sorption; activated carbon; silica spongolite
Introduction Highway and bridge runoff may contain a number of constituents including salts, metals, organic compounds, and bacteria.[1–5] According to the best management practices, a wide variety of treatment facilities exists, including bioretention and bioslope, surface sand filter, gutter filter, infiltration trenches/strips, infiltration tanks, soakways, swales, natural or engineered wetlands, sustainable drainage systems, separators or separate sewer systems. [6–9] In these devices, the contaminants are removed only partially and insufficiently. Application of conventional water treatment methods such as chemical precipitation, reduction or osmosis may be very expensive and energyconsuming. In recent years, filter systems with specially selected sorption materials were presented as a relatively new method for treatment of first-flush stormwater,[10] parking lot runoff [11] and highly polluted urban road runoff.[8] An alternative to these treatment devices is the sorption of contaminants on mineral and organic sorbents in the technology of permeable reactive barriers (PRBs). In PRBs, the dissolved contaminants are removed by various processes (sorption, biodegradation, reduction, etc.) that take place during the flow of polluted runoff water through the reactive material filling the treatment zone. Kong et al. [12] and Kijjanapanich et al. [13] have conducted the laboratory tests on several organic materials as reactive
*Corresponding author. Email: [email protected] © 2015 Taylor & Francis
materials in multilayered PRB. Reddy et al. [14] have proposed the application of PRB technology in the treatment of urban stormwater runoff using calcite, zeolite, iron and sand fillings. Moreover, PRB composed of zero-valent iron (ZVI) and EHC© in the median of the Central Expressway in Sunnyvale, CA, USA, was designed to reduce total volatile organic compounds.[15] Proper design of a PRB requires the knowledge of the intensity and kinetics of processes occurring between the solution and the material, which are usually determined by equilibrium and kinetic batch tests.[16–18] Parameters calculated based on the batch test results are parameters of sorption isotherms (including the maximum amount of dissolved ions per unit mass of material) and parameters of kinetic models (including equilibrium rate constants). However, batch tests do not take into account the flow conditions (e.g. saturation of the reactive zone and flow velocity of the contaminated water), as well as physical properties of the reactive material (e.g. effective porosity and bulk density).[19,20] In column tests, the flow rates may be adjusted to imitate real rates in the aquifer, so as to reproduce the behaviour of the barrier and the pollutants in field conditions. Based on the column test results, different parameters, that is, velocity of flow, coefficient of hydrodynamic dispersion, retardation factor, and longitudinal dispersivity may be estimated. Therefore, it may
1577
Environmental Technology
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
be concluded that the column study provides information reflecting in situ conditions, which can be directly used in designing PRBs. The primary goals of the presented research are as follows: (1) to study the transport of heavy metals (Cd, Cu, Ni, Pb and Zn) through zeolite (Z), activated carbon and silica spongolite (SS); (2) to calculate the parameters of contaminant transport through porous materials using the STANMOD package CXTFIT [21] and (3) to determine the most favourable reactive material for road runoff treatment in PRBs. Experimental methodology Materials In this study, granular clinoptilolite-rich Slovak zeolite tuff (Zeocem, Slovakia), granular activated carbon (GAC, Active Carbon Research and Production Company, Poland) and SS (Wrzosówka Mine, Poland) were used as the reactive materials. A surface area and porosity analyser (ASAP 2020M Micromeritics, USA), a scanning electron microscope (SEM) images (FEG Quanta 250, USA) and Xray diffraction (Philips X’Pert APD, Netherlands) spectra were used for the detailed characterisation of the reactive materials. Characteristics of the particle size distribution, specific gravity and bulk density of the reactive materials are summarised in Table 1. Chemicals All chemicals used in the column tests were of reagent grade (CHEMPUR, Poland). The concentration of reagents (100 mg L−1 – chloride solution and 20 mg L−1 – multicomponent solution of Cd, Cu, Ni, Pb and Zn) were prepared using NaCl, CdCl2 ·2.5H2 O, CuCl2 ·2H2 O, NiSO4 ·7H2 O, Pb(NO3 )2 and ZnCl2 in distilled water (DI). The pH of the solutions was measured using a pH-meter (SCHOTT, Germany). In the tests, the pH of the chloride solution was in the range of 6.37–6.72 and the pH of the metal solution was between 7.02 and 7.21. Initial electrical conductivity values ranged within 205–389 and within 45–57 mS cm−1 for the chloride and metal solutions, respectively.
Table 2.
Column test parameters.
Column mark SS GAC SS Z GAC
Mass of dry material (g)
Porosity
Column PVF (mL)
14287.0 3532.5 4762.3 2757.9 1177.5
0.36 0.63 0.36 0.47 0.63
5497.8 9896.0 1832.4 2408.3 3298.34
through columns filled with the reactive materials. The laboratory set-up used in the experiment consists of three PVC columns 0.8 m long and of 0.1 m internal diameter. The main parameters of the column tests are listed in Table 2. Column experiments were used to simulate the groundwater conditions, therefore, the flow rates through the columns were adjusted to imitate real rates in the aquifer (4.16 × 10−8 m3 sec−1 ) in order to replicate the performance of the PRB and the pollutants in field conditions. The test was performed under constant upward flow of chemical solutions achieved by a multichannel peristaltic pump. Performance comparison tests were carried out using GAC alone, SS alone and duplicate layers of SS, Z and GAC combined (Figure 1). The column filled with zeolite alone was not performed due to its documented ability for the immobilisation of heavy metals.[22–25] The second material with a confirmed ability for heavy metal removal is activated carbon [26–28]; it was selected for result comparison in a test with SS. The selection of reactive materials and their order are driven by their removal properties. The SS is used as a pre-treatment layer to remove heavy metals by chemical precipitation. The second layer is zeolite which removes the precipitates and other contaminants by adsorption and ions exchange process. The last layer is activated carbon (the final cleansing layer), which exhibits high adsorption capacity due to its large surface area and
Column tests The efficiency of activated carbon, Z and SS was tested by passing chemical solutions (uni- and multicompounds) Table 1. Physical properties of the reactive materials. Material Zeolite Activated carbon Silica spongolite
Particle size (mm)
Specific gravity
Bulk density (cm3 g−1 )
0.5–1.0 0.5–2.0 0.5–2.0
2.40 1.96 2.71
1.054 0.450 1.820
Figure 1.
Schematic diagram of the test columns.
1578
K. Pawluk and J. Fronczyk The columns were fed with distilled water from the right to the left using a ZALIMP (Poland) peristaltic pump. After reaching a steady flow rate, a slug input of a mobile tracer (chloride) was added to evaluate the hydrodynamic characteristics of the reactive materials in each column. To estimate the sorption parameters of the materials, the tests were performed for a multicomponent model
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
presence of several different types of surface functional groups. A few laboratory studies on sequenced PRB remediation for wastewater have been carried out using ZVI, zeolites, ORC and organic carbon (e.g. wood chips and compost).[12,29,30] However, to our knowledge, the layers of SS, Z and GAC have never been carried out on the column test.
Figure 2. SEM images, SEM spectra and XRD spectra of activated carbon, zeolite and spongolite.
1579
Environmental Technology
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
solution (20 mg Cd2+ L−1 , 20 mg Cu2+ L−1 , 20 mg Ni2+ L−1 , 20 mg Pb2+ L−1 and 20 mg Zn2+ L−1 ). Migration parameters of the mixtures, that is, dispersivity, retardation factor and partitioning coefficients were estimated from these tests. The samples were taken from the column effluent at appropriate intervals and analysed for the contents of chloride and heavy metals. The metals were analysed using atomic absorption spectrometry – AAS method (iCE 3000, ThermoLab USA), while the chloride content in the solutions was analysed using the Mohr method. Electrical conductivities and pH values were also measured. The column tests were carried out at room temperature (20–22 °C).
where C (mg L−1 ) is the concentration of the contaminant at depth z at time t, t (hr) is the time, t1 (hr) is the tracer injection start time and t2 (hr) is the tracer injection ending time. The zero concentration gradient at the outflow end of the sample (x = L) was assumed as ∂C (∞, t) = 0. ∂x
(4)
Using the CXTFIT package, the following parameters characterising the contaminant migration conditions were calculated: ratio of flow velocity vR , ratio of dispersion DR , longitudinal dispersivity α L , Péclet number P e and breakthrough time tR , after which the tracer concentration in the effluent solution was 0.5 C0 .
Hydrodynamic and sorption parameters Sorption capacity studies (column tests) were performed in order to select a system suitable for PRBs in the vicinity of road infrastructure. The tested chemical compounds were selected based on the results of chemical composition analyses of road runoff and snowmelt from several reports.[31–36] In most cases, concentrations of heavy metals exceeded acceptable limits in the runoff and snowmelt samples. Accordingly, the following chemical compounds were applied in the studies: cadmium, copper, nickel, lead and zinc. The parameters of the advection–dispersion equation of contaminant transport in groundwater were calculated using the STANMOD package CXTFIT.[21] This software uses a non-linear, least-square parameter optimisation method from the observed concentration data. During numerical modelling, the homogeneity of the sample, zero diffusion coefficient DM and zero initial concentration in the sample were assumed as the initial boundaries: C(x, 0) = 0 for
x ≥ 0,
(1)
where C (mg L−1 ) is the concentration of the contaminant at depth z at time t and x (m) is the distance. For the influent solution, the first-type (Dirichlet) boundary conditions, constant concentration of selected ions, described by the following formula were assumed: for the jump function 0 for t < t1 , (2) C(t) = 1 for t ≥ t1 , for the impulse function ⎧ ⎪ ⎨0 C(t) = C0 ⎪ ⎩ 0
for t < t1 , for t1 ≤ t ≤ t2 , for t > t2 ,
(3)
Figure 3. Observed (circles) and fitted values (solid lines) of the non-decaying indicator for spongolite, activated carbon and layers of SS, Z and GAC.
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
1580
K. Pawluk and J. Fronczyk the solution outlet concentrations versus the time or number of pore volume of flow (PVF). The PVF represents the volume of the solutions equal to the volume of the reactive material pores. During these tests, the outlet concentrations are expressed as absolute concentrations of chemicals C/C0 . In the backward analysis of the advection–dispersion equation, the value of the retardation coefficient R was 1. In consequence, no interaction between the indicator and the samples was observed. The parameters of transport equation estimated on the basis of the tests are shown in Table 3. The equilibrium model was applied in all analyses of the indicator breakthrough curves for spongolite, activated carbon and layers of SS, Z and GAC. In Figure 3, the fitted breakthrough curves are symmetrical, which confirms the homogeneity of the samples. In the column with SS, the breakthrough began earlier than in other columns and the outflow curve had a long tail. The velocity and hydrodynamic dispersion coefficient values were estimated with determination coefficients at 0.71–0.99.
Results and discussion Characteristics of the adsorbent Figure 2 shows the XRD pattern and scanning electron images of the activated carbon, zeolite and spongolite samples. The pattern and increased values of the background (15–35 (2)) on XRD spectra of the GAC sample show that the dominant mineral component is an amorphous substance characteristic of activated carbons. The characteristic interplanar spacing (4.255, 3.344, 2.456, 2.283, 2.237, 2.128 and 1.981 Å) has been attributed to quartz as an additional mineral component of the sample. Observations of the microstructure lead to the conclusion that the surface of the reactive material is highly porous and rough. The pores are circular in shape and of variable size (from 10 to 300 μm). The reactive material is characterised by extraordinary specific surface area, which is determined at 856 m2 g−1 . The total pore volume of GAC is 0.00016 m3 kg−1 . Pattern of SEM spectra of the zeolite sample indicates that the dominant components include silica, gold, aluminium, sodium and potassium. SEM observations showed the microstructure of the zeolite surface. The pores are irregular in shape and have sizes from 0.1 to 10 μm. The specific surface area is 32.44 m2 g−1 and the total pore volume is 5.0 × 10−6 m3 kg−1 . The diffractogram of the spongolite sample showed the characteristic peaks for calcite and quartz. The structure of the material is rough without pores. The SBET of the sample is 2.82 m2 g−1 and the total pore volume is 2.0 × 10−7 m3 kg−1 .
Test with reactive indicator The effect of adsorbate heavy metal ions concentration on the column performance was studied using an inlet concentration of 20 mg L−1 and a unit feed flow rate of 2.6 mL min−1 . The breakthrough curve is illustrated in Figure 4. As can be observed on the plots (Figure 4), the activated carbon beds were exhausted faster than other materials. In the column with GAC, an earlier breakthrough point was reached for the Ni, Cd and Zn ions, which competed for free place on the material structure by reducing the intensity of Cu and Pb ions removal. Comparison of the shape of the breakthrough curves for Ni, Cd and Zn (Figure 4) indicates similar changes of ion concentrations in the effluent
Test with non-decaying adsorbing chemicals The results of the experiment are shown in Figure 3 as breakthrough curves that illustrate relationships between
Table 3. Hydrodynamic and sorption parameters of SS, GAC and layers of SS, Z and GAC obtained from column tests for the model solutions. Column
PVF
v (m sec−1 )
SS Cl− SS Ni2+ GAC Cl− GAC Cd2+ GAC Ni2+ GAC Pb2+ GAC Zn2+ SSZGAC Cl− SSZGAC Cd2+ SSZGAC Ni2+ SSZGAC Zn2+
0.04 2.72 0.02 1.46 1.46 1.46 1.46 0.07
3.94 3.94 4.21 4.21 4.21 4.21 4.21 3.31
0.92
3.31 × 10−5
7.670 × 10−7
9.93 × 10−6
0.92
3.31 × 10−5
2.520 × 10−7
0.92
3.31 × 10−5
1.738 × 10−8
× × × × × × × ×
10−5 10−5 10−5 10−5 10−5 10−5 10−5 10−5
vR (m sec−1 ) 5.888 5.461 1.140 9.190 2.528
1 × 1 × × × × 1
10−7 10−6 10−6 10−7 10−6
D (m2 sec−1 )
DR (m2 sec−1 )
R
α L (m)
Pe
R2
1.00 67.06 1 7.71 36.84 45.83 16.67 1
0.14 0.14 0.18 1.14 0.82 0,14 3.30 0.24
7.30 7.05 5.58 0.88 1.22 7.22 0.30 4.19
0.94 0.98 0.98 0.91 0.71 0.86 0.89 0.95
2.30 × 10−7
43.14
0.30
3.33
0.98
3.07 × 10−5
2.33 × 10−6
13.16
0.93
1.07
0.94
1.66 × 10−5
8.71 × 10−9
1905
0.50
1.99
0.97
5.40 5.59 7.54 4.80 3.46 5.83 1.39 7.90
× × × × × × × ×
10−5 10−6 10−6 10−5 10−5 10−6 10−4 10−6
1 8.34 × 1 6.23 × 9.39 × 1.27 × 8.36 × 1
10−8 10−6 10−7 10−7 10−6
Notes: PVF is the pore volume of flow, v is the velocity of flow, vR is the ratio of flow velocity decrease, D is the coefficient of hydrodynamic dispersion, DR is the ratio of dispersion decrease, R is the retardation factor, α L is the longitudinal dispersivity and P e is the Péclet number.
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
Environmental Technology
Figure 4. Observed (points) and fitted values (lines) of the reactive indicators for spongolite, activated carbon and layers of SS, Z and GAC.
solution. These breakthrough curves evidence a faster flow of Cd, Ni and Zn through the pore channels by diffusion processes.[37] Lead ions were also immobilised during contact with activated carbon, however without achieving the equilibrium stage. However, the most intensive retention on GAC was noted for copper ions as confirmed by the breakthrough curve shape. The test performed on the column with SS indicated intensive removal of heavy metals from the aqueous solution. The final concentrations of Cd, Cu, Pb and Zn in the filtrate from the column were close to zero. Figure 4 shows that the nickel ions were also immobilised, however less intensively than the other heavy metals in the solution. Similar results were noted for the column with the layers of GAC, Z and SS. As previously, heavy metals were
1581
removed from the aqueous solution with different intensities. The most intensive reduction was observed for Cu, Pb and Zn. In contrast, increased concentrations of Cd and Ni were detected in the outflow at the end of the experiment. Summarising, the removal of nickel ions in the three columns was the lowest of all reactive indicators in the aqueous solution. Using the characteristic points of the breakthrough curves, the dynamic sorption capacities of the materials tested were calculated: S m and S mR for the breakthrough point and the point, at which the relative concentration of the tracer in the effluent solution is 0.95, respectively. The results of the calculations are presented in Table 4. For all materials, the obtained maximum sorption capacity for heavy metals was at the same level, with one exception – Zn on GAC. On the other hand, based on the values of the retardation factor, the sorption processes were unlimited for Zn on SS, Z, and GAC, high for Ni on all beds, for Cd on GAC and the layered bed, as well as for Pb on GAC and the layered bed. In comparison to the breakthrough capacity, significant similarities have been observed: S mR = 8.459 mg Zn2+ · g−1 for GAC, S mR = 1.797 mg Cd2+ · g−1 for GAC, S mR = 1.528 mg Ni2+ · g−1 for GAC, S mR = 1.334 mg Ni2+ · g−1 for SS, Z and GAC, and S mR = 0.661 mg Ni2+ g−1 for SS. By feeding the calculated values of this parameter for several reactive materials, it was recognised that nickel has a higher affinity to activated carbon. On the other hand, cadmium affinity to activated carbon was much higher than in the case of nickel. The obtained retardation factors are presented in Table 3. The Péclet number P e may be used to characterise the nature of the transport processes of contaminates during flow through the columns. For the column with SS, P e indicated an advantage of advection over dispersion, whereas dispersion had the same role in the transport of heavy metals through the columns with GAC and layers of SS, Z and GAC. The pH profile of the exit solution for the sorption of heavy metals onto GAC, SS, and layers of SS, Z, GAC in the column is shown in Figure 5. The pH value of the outflow solutions during the column experiments indicated that the heavy metal ions were removed from the solution by both sorption and precipitation processes. The heavy metal concentration in the solutions is a function of pH. Precipitation of Cu, Zn, Ni, and Pb in the insoluble forms occurs at pH values in the range of 6.50–9.00. The pH of the aqueous solution affects both the solubility and speciation of the metal ions, and the dissociation degree of the functional groups from the sorbent surface; thus, it is one of the most important parameters controlling the uptake of heavy metals from aqueous solutions.[38] The pH profiles have demonstrated that at the beginning of the test, initial pH increased from 6.80 to 9.00–10.00, which points to precipitation of heavy metals. Subsequently, the reduction in the values of the pH
1582
K. Pawluk and J. Fronczyk Table 4. Hydraulic and sorption parameters of SS, GAC and layers of SS, Z and GAC obtained from column tests.
Material
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
SS Ni2+ GAC Cd2+ GAC Ni2+ GAC Pb2+ GAC Zn2+ SSZGAC Cd2+ SSZGAC Ni2+ SSZGAC Zn2+
tbR (sec)
Sm (mg g−1 )
S mR (mg g−1 )
Range of pH
Range of electrical conductivity (mS cm−1 )
× × × × × ×
106 105 105 106 105 106
0.047 0.150 0.183 1.245 0.102 0.730
0.661 1.797 1.528 – 8.459 –
6.89–10.58 6.80–9.14 6.80–9.14 6.80–9.14 6.80–9.14 6.99–9.68
57–667 45–355 45–355 45–355 45–355 59–375
3.02 × 104
3.98 × 105
0.159
1.334
6.99–9.68
59–375
3.02 × 104
5.76 × 107
0.175
–
6.99–9.68
59–375
tb (sec) 2.54 2.38 2.38 2.38 2.38 3.02
× × × × × ×
104 104 104 104 104 104
1.70 1.83 8.75 1.09 3.96 1.30
Notes: PVF is the pore volume of flow, tb (sec) is the breakthrough time for the mobile chemical that does not sorb to the material tb = L/v, tbR (sec) is the breakthrough time for a tracer with retardation factor R tbR = Rtb, S m and S mR (mg g−1 ) is the dynamic sorption capacities of the breakthrough point and of the point, at which the relative concentration of the tracer in the effluent solution is 0.95, respectively, and – indicated undetermined values.
(3) (4)
(5) (6) Figure 5. The pH profile at the exit of the column with GAC, SS, and layers of SS, Z, GAC.
in the range of 6.45–6.84 for GAC and the layered beds, as well as the value of about 7.75 for SS was observed. This suggests that adsorption processes of heavy metals by activated carbon and zeolite were initiated by ion exchange and surface complexation of heavy metals on the surfaces of the reaction materials. In turn, heavy metal removal during the contact with SS was achieved mainly by precipitation.
(7)
which competed for free place in the material structure by reducing the intensity of removal of Cu and Pb ions. The most intensive retention on GAC was noted for copper ions. The test performed on the column with SS indicated intense removal of heavy metals from the aqueous solution – the final concentrations of Cd, Cu, Pb and Zn in the filtrate from the column were close to zero. Nickel removal from the solution was least efficient in comparison to the other heavy metals. On the layered bed, the heavy metals were immobilised with different intensities. The most intensive reduction was observed for Cu, Pb and Zn. In contrast, increased concentrations of Cd and Ni were detected in the outflow at the end of the experiment. The pH value of the outflow solutions during column experiments indicated that the heavy metal ions were removed from the solution by both sorption and precipitation processes.
Disclosure statement No potential conflict of interest was reported by the authors.
Conclusions The experimental results of this research allow us to draw the following conclusions:
(1) Activated carbon beds were exhausted faster than other materials. (2) In the column with GAC, an earlier breakthrough point (tbR ) was reached for Ni, Cd and Zn ions,
Funding This work was supported by the National Science Centre, Poland [under grant number N N523 561638] and the European Union funds by the European Social Fund.
References [1] Novotny EV, Murphy D, Stefan HG. Increase of urban lake salinity by road deicing salt. Sci Total Environ. 2008;406:131–144.
Downloaded by [University of Sherbrooke] at 00:59 13 April 2015
Environmental Technology [2] Davis B, Birch G. Comparison of heavy metal loads in stormwater runoff from major and minor urban roads using pollutant yield rating. Environ Pollut. 2010;158(8):2541– 2545. [3] Fronczyk J, Pawluk K, Garbulewski K. Multilayer PRBs – effective technology for protection of groundwater environment in traffic infrastructure. Chem Eng Trans. 2012;28: 67–72. [4] Kaczala F, Marques M, Vinrot E, Hoglan W. Stormwater run-off from an industrial log yard: characterization, contaminant correlation and first-flush phenomenon. Environ Technol. 2012;33(14):1615–1628. [5] El-Mufleh A, Husseini A, Béchet B, Gaudin A, Ruban V. Trace metal fractionation as a mean to improve on the management of contaminated sediments from runoff water in infiltration basins. Environ Technol. 2013;34(10):1255– 1266. [6] Terzakis S, Fountoulakis MS, Georgaki I, Albantakis D, Sabathianakis I, Karathanasis AD, Kalogerakis N, Manios T. Constructed wetlands treating highway runoff in the central Mediterranean region. Chemosphere. 2008;72: 141–149. [7] Fu DF, Singh RP, Juan H, Ojha CSP, Surapalli RY, Zhang TC. Highway runoff treatment by lab-scale horizontal subsurface flow constructed wetlands. Ecol Eng. 2014;64: 193–201. [8] Hilliges R, Schriewer A, Helmreich B. A three-stage treatment system for highly polluted urban road runoff. J Environ Manage. 2013;128:306–312. [9] Imran HM, Akib S, Karim MR. Permeable pavement and stormwater management systems: a review. Environ Technol. 2013;34(18):2649–2656. [10] Kus B, Kandasamy J. Low-cost filtration system to treat first-flush stormwater. Water Air Soil Pollut. 2009;9: 347–355. [11] Fuerhacker M, Haile TM, Monai B, Mentler A. Performance of a filtration system equipped with filter media for parking lot runoff treatment. Desalination. 2011;275: 118–125. [12] Kong X, Bi E, Liu F, Huang G, Ma J. Laboratory column study for evaluating a multi-media permeable reactive barrier for the remediation of ammonium contaminated groundwater. Environ Technol. 2014. doi:10.1080/09593330.2014.992482 [13] Kijjanapanich P, Pakdeerattanamint K, Lens PNL, Annachhatre AP. Organic substrates as electron donors in permeable reactive barriers for removal of heavy metals from acid mine drainage. Environ Technol. 2012;33(23):2635–2644. [14] Reddy KR, Xie T, Dastgheibi S. Removal of heavy metals from urban stormwater runoff using different filter materials. J Environ Chem Eng. 2014;2:282–292. [15] ITRC (Interstate Technology & Regulatory Council). Permeable reactive barrier: technology update. PRB-5. Washington, DC: Interstate Technology & Regulatory Council, PRB: Technology Update Team; 2011. Available from: http://www.itrcweb.org [16] Fronczyk J, Garbulewski K. Selection of material suitable for permeable reactive barriers in the vicinity of landfills. Ann Warsaw Univ Life Sci SGGW Land Reclam. 2009;41:3–9. [17] Ho YS, McKay G. Pseudo-second order model for sorption processes. Process Biochem. 1999;34:451–465. [18] Ho YS, Chiu WT, Wang CC. Regression analysis for the sorption isotherm of basic dyes on sugarcane dust. Bioresource Technol. 2002;96:1285–1291. [19] Burt TA, Li Z, Bowman RS. Evaluation of granular surfactant-modified/zeolite zero valent iron pellets as a
[20] [21]
[22]
[23] [24]
[25] [26]
[27] [28]
[29]
[30] [31] [32]
[33] [34]
[35] [36]
[37] [38]
1583
reactive material for perchloroethylene reduction. J Environ Eng. 2005;131(6):934–942. Li Z. Chromate transport through surfactant-modified zeolite columns. Ground Water Monit R. 2006;26(3):117–124. Toride N, Leij FJ, van Genuchten M.Th. The CXTFIT code for estimating transport parameters from laboratory or field tracer experiments. Version 2.1. Research Report No. 137. Riverside, CA: USDA-ARS U.S. Salinity Laboratory; 1999. Zamzow MJ, Eichbaum BR, Sandgren KR, Shanks DE. Removal of heavy metals and other cations from waste water using Zeolites. Separ Sci Technol. 1990;25(13– 15):1555–1569. Ouki SK, Kavannadg M. Performance of natural zeolites for the treatment of mixed metal-contaminated effluents. Waste Manage Res. 1997;15(4):383–394. Derkowski A, Franus W, Beran E, Czímerová A. Properties and potential applications of zeolitic materials produced from fly ash using simple method of synthesis. Powder Technol. 2006;166(1):47–5. Wang S, Peng Y. Natural zeolites as effective adsorbents in water and wastewater treatment. J Chem Eng. 2010;156: 11–24. Mohan D, Singh KP. Single- and multi-component adsorption of cadmium and zinc using activated carbon derived from BagasseFan agricultural waste. Water Res. 2002;36:2304–2318. Zayat ME, Smith E. Removal of heavy metals by using activated carbon produced from cotton stalks. Can J Environ Constr Civil Eng. 2010;1(4):71–79. del Mar Gómez-Tamayo M, Macías-García A, Díaz Díez MA, Cuerda-Correa EM. Adsorption of Zn(II) in aqueous solution by activated carbons prepared from evergreen aak (Quercus rotundifolia L.). J Hazard Mater. 2008;153:28–36. Barrett M, Kearfott P, Malina J. Stormwater quality benefits of a porous friction course and its effect on pollutant removal by roadside shoulders. Water Environ Res. 2006;78(11):2177–2185. Barrett M, Irish L, Malina J, Charbeneau R. Characterisation of highway runoff in Austin Texas. Area J Environ Eng. 1998;124:131–137. Scholz M, Yazdi SK. Treatment of road runoff by a combined storm water treatment. Detention and infiltration system. Water Air Soil Pollut. 2009;198:55–64. Jun D, Yongsheng Z, Weihong Z, Mei H. Laboratory study on sequenced permeable reactive barrier remediation for landfill lechate – contaminated groundwater. J Hazard Mater. 2009;161:224–230. Han YH, Lau SL, Kayhanian M, Stenstrom MK. Correlation analysis among highway stormwater pollutants and characteristics. Water Sci Technol. 2006;53(2):235–243. Kayhanian M, Singh A, Suverkropp C, Borroum S. Impact of annual average daily traffic on highway runoff pollutant concentrations. J Environ Eng ASCE. 2003;129(11): 975–990. Kayhanian M, Stransky C, Bay S, Lau SL, Stenstrom MK. Toxicity of urban highway runoff with respect to storm duration. Sci Total Environ. 2007;389(2–3):386–406. Lau S-L, Han Y, Kang JH, Kayhanian M, Strenstrom M. Characteristics of highway stormwater runoff in Los Angeles – Part 2: metals and polycyclic aromatic hydrocarbons. Water Environ Res. 2009;81(3):308–18. Jury WA, Horton R. Soil physics. 6th ed. Hoboken, NJ: Wiley; 2004. Meena AK, Kadirvelu K, Mishraa GK, Rajagopal C, Nagar PN. Adsorption of Pb(II) and Cd(II) metal ions from aqueous solutions by mustard husk. J Hazard Mater. 2008;150:619–625.
