Endocrine disrupting chemicals (EDCs) and pathogens removal in an hybrid CW system for a tourist facility wastewater treatment and reuse

Tags: wastewater treatment, Florence, Escherichia Coli, faecal coliforms, Naphthalene, constructed wetlands, European Community, removal rates, organic compounds, Endocrine Disrupting Chemicals, Checchini L., Lepri L., VF outlet, Endocrine Disrupters, Polprasert C., Giovannelli L., Water Research, Horizontal Subsurface Flow, Del Bubba M., European Commission, Water Pollution, Sesto Fiorentino, endocrine system, constructed wetland, Del Bubba, Fluoranthene, University of Florence, natural organic compounds, reed beds, Wastewater reuse, reed bed, treatment system
Content: Endocrine Disrupting Chemicals (EDCs) and Pathogens removal in an hybrid CW system for a tourist facility wastewater treatment and reuse F. Masi*, G. Conte*, L. Lepri**, T. Martellini** and M. Del Bubba** * IRIDRA S.r.l., Via Lorenzo il Magnifico 70, 50129, Florence, IT (E-mail: [email protected]; [email protected]) ** Dept. of Chemistry, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, IT (E-mail: [email protected]; [email protected]) Abstract Within the frame of the "SWAMP" project (a demonstration project co-financed by the European Community) an hybrid constructed wetland (CW) system was realized for the treatment of wastewater produced by a medium-size hotel located in Florence, Italy. The system consisted of a 70 m3 primary treatment by Imhoff tanks, a 160 m2 HF and a 180 m2 VF. The results obtained in the first year of operation regarding to the hygienic indicator bacteria (total coliforms, faecal coliforms, faecal streptococci and Escherichia coli) and some selected organic compounds (Phthalates, PAHs and Estrogens) were reported. In terms of overall performances the following mean removal rates were obtained: COD 94%, BOD5 95%, TSS 90%. The CW system showed a satisfactory functioning of the treatment process, especially related to the sedimentation and filtration processes and to organic matter trapping and degradation inside the reed beds. As regard the EDCs a clear water quality increase during the purification process was observd. PAHs were found below 0.5 µg/l in the inlet and at significantly lower amounts in the outlet of the system. Total inlet phthalates concentration was included in the range 100 to 300 µg/l and this class of compounds showed a certain persistence even in the outlet (10-200 µg/l) due to HDPE liner release. Among the other compounds, 17--estradiol and ethynyl-estradiol were revealed in the inlet at concentration below 10 µg/l, while were absent in the outlet. Keywords Hybrid systems, Endocrine disruptors, Sustainable water management, Constructed wetlands, Reed beds, Wastewater reuse INTRODUCTION Chemical substances that can interfere with the normal functioning of the endocrine system have been termed Endocrine Disrupting Chemicals (EDCs) (Keith et al., 1997). The full list of EDCs includes a large range of anthropogenic and natural organic compounds, such as phthalates, pesticides, polychlorinated biphenyls (PCBs), dioxins, polyciclic aromatic hydrocarbons (PAHs), alkylphenols, bisphenols and steroid estrogens (Birkett and Lester, 2003). Several of these substances have been released in increasing amounts in the environment since decades, and, due to their low degradation rate, a significant increase of their background concentrations have been observed in the different environmental compartments (Skakkebaeck et al, 2000, Tyler et al 1998). In wastewater, EDCs, have a variety of source. A number of EDC classes (phthalates, pesticides, PCBs and bisphenols) are industrial products, worldwide used for several applications and are therefore ubiquitous pollutants (Staples et al, 1997, Kupfer, 1975, Safe S.H., 1994, Chen et al, 2002). Other kinds of EDCs compounds (dioxins and PAHs) are not commercial products, but are formed as by-products of various industrial and combustion processes; they are transported from atmosphere to soil and water bodies by the atmospheric runoff or deposited on the soil during the dry period and then go through the water cycle by land runoff (Birkett and Lester, 2003). Alkylphenols are metabolites of their ethoxylate precursors, which are non-ionic surfactants used in
many industrial, commercial and household functions (Del Bubba and Lepri, 2002). The presence of steroid estrogens in wastewater mainly arises from direct women excretion, in particular from pregnant females and women using oral contraception or hormone replacement therapies (ArcandHoy et al, 1998; Andrews, 1995). Several studies have shown that EDCs are present in the effluents from domestic and industrial conventional sewage treatment plants (Birkett and Lester, 2003) and this evidence is of potential concern about their reuse for non industrial applications, such as irrigation of crops and aquaculture, since EDCs could represent a contamination source of food chain. The behaviour of some EDCs has been studied in pilot constructed wetlands pointing out that reed beds are effective in the removal of phthalates and alkylphenol ethoxylates (Del Bubba et al., 1998; Del Bubba and Lepri, 2002). Another crucial parameter in order to assess the suitability of effluent wastewater to be reused is the occurrence of pathogens, which presence is usually evaluated by the analysis of the indicators total coliforms (TC), faecal coliforms (FC) and faecal streptococci (FS). Such microorganisms are commonly removed at high percentages in conventional sewage treatment plants and in constructed wetlands (Karpiscak et al., 2001; Arias et al., 2003), but the evaluation of residual concentrations is of strong importance for establishing the performances of the treatment plant and the final destination of the effluent wastewater. For these reasons, the understanding of removal processes and fate of EDCs and pathogens during wastewater treatment, may facilitate controlling or limiting exposure of both humans and environment to these compounds and create more solid basis for the choose of different Sustainable Water Management approaches. This paper presents the removal data of some EDCs and of TC, FC, FS and Escherichia Coli (which is required by the Italian national law about water reuse, D.Lgs. 185/2003) for an hybrid reed bed system located at an Hotel in Florence (Italy). This research was realized under the EC FP5 project SWAMP (for more details about the project see the website www.swamp-eu.org). MATERIAL AND METHODS Description of the CW system The reed bed is composed by a first stage horizontal submerged flow (HF) and a second stage vertical flow (VF) (see Fig. 1). In Table 1 are reported the main features of the reed bed system, including the measured hydraulic loading rate (HLR) and organic loading rate (OLR) during the monitoring period. In fact, an important characteristic of this treatment plant is the tourist fluctuation, which involves a high variability of the daily flow and, consequently, of the loading rate. A pump station located after the Imhoff tanks regulates the loading inside the HF bed by a floating valve and so proportionally to the raw wastewater production.. The effluent from the HF bed is divided by a partition well into two independent siphons which feed the VF filter in an alternate way. The waterproofing of the bed has been realized by an HDPE geo-membrane. Fig. 1 - Schematic representation of the hybrid constructed wetland at the Relais Certosa Hotel.
Table 1 ­ Main features of the Relais Certosa Hotel wastewater treatment facility
Parameter
Value
Load (p.e.) Inflow (m3 d-1) Surface Area HF (m2) Surface area VF (m2) HF depth (m)
140 17-33 160 180 0.7
HF Gravel size (mm)
5-10
VF filling media (sand+gravel) VF depth (m) HRT ­ HF (theoretical) (d) HLR (m3 m-2 d-1)
Top 10 cm 6-12mm Middle 60 cm sand 0/4 Bottom 20 cm 30-40 mm 0.9 3 HF: mean 0.17 min 0.11 max 0.23
OLR (g COD m-2 d-1) Primary treatment
VF: mean 0.15 min 0.10 max 0.21 HF: mean 23.5 min 6.8 max 38.1 VF: mean 2.0 min 0.9 max 5.7 Imhoff ­ Total volume 70 m3
Operating since
January 2003
Sampling and analyses As regards the ECDs analyses, grab samples were collected in glass bottles previously washed with hot chromic mixture and repeatedly rinsed with ultra pure water; collection of samples for sanitary indicators was carried out in glass bottles previously sterilized by autoclave treatment. The sampling took place monthly from September 2003 to February 2004 (six samples), at the inlet of the HF stage (after the Imhoff tank) and at the outlet of both the HF and VF stages. Inlet grab samples were collected three days before the outlet ones, according to the estimated hydraulic retention time (HRT) of the HF bed. Sampling campaigns were carried out when rain did not occur within three days before the collection of the inlet and the sampling of the outlet samples, so as to avoid dilution effects and HRT shortening, even if the rainwater is managed by a separated sewage system. Analyses of ECDs were performed, separately for dissolved and particulate phases, after filtration of the samples. In order to determine the concentration of particulate matter, filtration of each sample was carried out on two aliquots of wastewater. One of the two filters was used for the extraction of EDCs, while the other was dried in oven at 105°C for one hour and finally weighed. Water phase, previously modified for pH and polarity by adding hydrochloric acid, sodium chloride and methanol, was extracted by a triple liquid/liquid treatment with methylene chloride, evaporated to 200 µl and analysed by a GC/MS Varian, model Saturn 4D in "micro selected ion storage (micro SIS)" way. For phenols and estrogens a derivatization with N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) needed, in order to enhance the GC/MS response (Del Bubba et al., 2004). Particulate samples were extracted according to the method of Desideri et al. (1987), significantly modified in order to obtain satisfactory recovery percentages (60-97%) for all the investigated compounds (Del Bubba et al., 2004). Instrumental analysis of the extracted compounds was performed as described above. The bacteriological indicators TC, FC, FS and Escherichia Coli were evaluated according to the protocols for membrane filter procedures of Standard Methods for the Examination of Water and Wastewater (1995).
RESULTS AND DISCUSSION Removal of indicator bacteria The average removals of the four analysed hygienic indicators were in the range 99.93-99.99%, showing a very high efficiency of the system to remove pathogens (Tables 2-5). During the passage through the HF Reed Bed the bacteria were reduced 2.9-3.2 log units, whereas the reduction in the second stage VF bed was 0.7-1.2 log units. Table 2 - Changes in Total Coliform density (cfu/100ml) through the CW system May03 Jun03 Jul03 Aug03 Sep03 Oct03 Nov03 Dec03 Jan04 Feb04 Mar04 HF IN 1x107 3x107 2x107 1x107 4x106 7x106 7x105 4x106 2x106 8 x105 3x106 HF OUT 19000 31000 42000 18000 16000 4700 2300 320 1900 6600 550 VF OUT 2700 29000 300 12000 20000 770 1600 77 130 330 60
Table 3 - Changes in Fecal Coliform density (cfu/100ml) through the CW system May03 Jun03 Jul03 Aug03 Sep03 Oct03 Nov03 Dec03 Jan04 Feb04 Mar04 HF IN 8x106 3x107 7x106 8x106 2x106 3x106 5x105 7x105 1x106 4x105 9x105 HF OUT 11200 14000 15000 11000 14000 3900 90 49 1300 2900 110 VF OUT 290 1200 420 270 19000 70 30 12 100 170 20
Table 4 - Changes in Faecal Streptococci density (cfu/100ml) through the CW system May03 Jun03 Jul03 Aug03 Sep03 Oct03 Nov03 Dec03 Jan04 Feb04 Mar04
HF IN 1x106 HF OUT 1200 VF OUT 70
1x106 3800 150
4x106 1x106 2x105 4x105 4x105 3x105 4x105 4x105 3x105
1200 1100 180 330 270 47 1400 2700 40
350 62 68 30 170 2
50 70 10
Table 5 ­ Changes in Escherichia Coli density (cfu/100ml) through the CW system May03 Jun03 Jul03 Aug03 Sep03 Oct03 Nov03 Dec03 Jan04 Feb04 Mar04
HF IN 6x106 3x107 7x106 6x106 2x106 2x106 4x105 6x105 1x106 4 x105 5x105
HF OUT 3900 11000 13000 4500 490 3900 70 33 1300 2600 90
VF OUT 210 1000 380 240 530 20 20 2
70 90 10
From such data, the following considerations can be highlighted:
- the reed population establishment inside HF and VF beds during July-August 2003 seems to have increased the pathogens removal in comparison to the first operating months; since October 2003 the removal rates increased, despite the different loading rates and the strong temperature changes during the seasons (water temp. range: 7-25 °C); - from the same month the treated wastewater fulfilled the Italian regulation limits for reuse as regard the pathogens indicator E. Coli (80 percentile equal to 50 cfu/100ml and maximum admitted value equal to 200 cfu/100ml).
Removal of EDCs The investigated organic compounds and their endocrine disrupting potencies (EDP), expressed as 17-Я-estradiol equivalent, are reported in Table 6.
Table 6 ­ Organic compounds investigated in the present work and their endocrine disrupting potencies (EDP); n.a. = quantitative data or magnitude order not available
Compound Naphthalene Acenaphtylene
EDA n.a., weak n.a., weak
Reference Santodonato, 1997 Santodonato, 1997
Acenaphtene Fluorene Phenathrene Anthracene
n.a., weak n.a., weak n.a., weak n.a., weak
Santodonato, 1997 Santodonato, 1997 Santodonato, 1997 Santodonato, 1997
Fluoranthene Pyrene Benzo(a)anthracene Crisene
n.a., weak n.a., weak n.a., weak n.a., weak
Santodonato, 1997 Santodonato, 1997 Santodonato, 1997 Santodonato, 1997
Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(a)pyrene Indeno(1,2,3-c,d)pyrene
n.a., weak n.a., weak n.a., weak n.a., weak
Santodonato, 1997 Santodonato, 1997 Santodonato, 1997 Santodonato, 1997
Dibenzo(a,h)anthracene Benzo(g,h,i)perylene Diethylphthalate Di-n-butylphthalate Butylbenzylphthalate Bis-2-ethylhexylphthalate n-octylphenol nonylphenol Bisphenol F Bisphenol A Estrone 17-a -estradiol
n.a., weak n.a., weak ~10-7 ~10-6 ~10-6 n.a. ~10-5 ~10-5 n.a. ~10-4 0.19 n.a., high
Santodonato, 1997 Santodonato, 1997 Harris et al., 1997 Harris et al., 1997 Harris et al., 1997 White et al., 1994; Tabira et al., 1999 White et al., 1994; Tabira et al., 1999 Shafer et al., 1999 Svenson et al., 2003 Birkett and Lester, 2003
Mestranol 17-Я-estradiol Ethinylestradiol Estriol
n.a., high 1 2.4 0.0037
Birkett and Lester, 2003 - Svenson et al., 2003 Svenson et al., 2003
Among these compounds, estriol, butylbenzylphthalate, phenols and the most part of PAHs were never detected in the analysed samples. As regards PAHs, the compounds found in the inlet samples of the CW system were only Naphthalene, Phenanthrene, Fluoranthene and Pyrene, which concentrations for water and particulate phase ranged from 15 to 180 ng/L and from 2 to 7 mg/Kg, respectively. This clearly indicated a strong enrichment of PAHs in the particulate phase, according to their high value of log KO/W (Naphthalene 3.45; Phenanthrene 4.46; Fluoranthene 6,12; Pyrene 6.04). These compounds were below the detection limits (7-9 ng/L) in the outlet particulate matter, while the outlet concentrations for the dissolved phase ranged from 13 to 22 ng/L, giving rise to a removal efficiencies of about 60-70%. Steroid estrogens were detected in two inlet samples in the range 164 - 259 ng/L and 2.3 - 2.9 mg/Kg for water and suspended matter, respectively. These data pointed out that also for estrogenic compounds the adsorption onto particulate material is high, according to the log KO/W values, included in the range 3.43 (estrone) ­ 4.67 (mestranol). All the estrogens were below detection
limits (15 ng/L) in dissolved and particulate phase of outlet samples of the HF stage, pointing out the high efficiency of this plant in the estrogen removal. Phthalates, with the exception of the butylbenzyl ester, were determined in all the inlet samples and were, generally, the most abundant compounds. For the dissolved phase concentrations changed in the ranges 151-3788, 43-6134 and 40-2480 ng/L, for diethyl, di-n-butyl and bis-2ethylhexylphthalate, respectively. The concentrations found in the particulate phase were affected by a less variation and were in the ranges 33-152, 49-194 and 209-4566 ng/L. According to the different values of log KO/W for the above-mentioned phthalates (ranging from 1,46 for diethyl to 13,1 for bis-2-ethylhexyl), the enrichment factors increased, going from diethylphthalate to bis-2ethylhexylphthalate. The trend of phthalate along the CW system was different from those of the other classes of EDCs as shown in Figure 2 and 3 for dissolved and particulate phase, respectively. As shown by figures, diethyl and di-n-butyl-phthalate were highly removed during the treatment, while for bis-2-ethylhexylphthalate an opposite trend was observed. This trend was found in all the analysed samples suggesting that a source of this compound could be present inside the plant. In order to explain this unexpected behavior a little portion of the HDPE geo-membrane (50 cm2) was placed in water (HPLC grade) under stirring for three days (the design HRT). The results of this test pointed out that the membrane released all the three phthalates. However the compound released at highest concentration was bis-2-ethylhexylphthalate, which accounted for more than 70% of the total phthalate release. These findings explain the different observed trend among phthalates.
Concentration (ng/L)
900 800 700 600 500 400 300 200 100 0 HF Inlet
HF outlet VF outlet
Dissolved Phase Diethylphthalate Di-n-butylphthalate Bis-2-ethylhexylphthalate
Fig. 2 ­ Concentration of diethyl, di-n-butyl and bis-2-ethylhexylphthalate in the dissolved phase of the sample collected on December 2004.
Concentration (ng/L)
3000 2500 2000 1500 1000 500 0
HF Inlet
HF outlet
VF outlet
Particulate Phase Diethylphthalate Di-n-butylphthalate Bis-2-ethylhexylphthalate
Fig. 3 - Concentration of diethyl, di-n-butyl and bis-2-ethylhexylphthalate in the particulate phase of the sample collected on December 2004.
CONCLUSIONS The hybrid CW system, realized for the treatment of wastewater produced by a medium-size hotel, was suitable for the removal of pathogens and of ECDs since eight months from its conctruction, and the outlet water was able to be reused according to Italian regulations. Among ECDs trace amounts of estrogens (17--estradiol and ethynyl-estradiol), PAHs (Naphthalene, Phenanthrene, Fluoranthene and Pyrene) and phthalates (diethyl, di-n-butyl and bis-2-ethylhexylphthalate) were found in inlet wastewater. All of these compounds were removed at high percentages (up to 100% for estrogens), with the only exception of bis-2-ethylhexylphthalate, which was released by the HDPE liner. Therefore the use of geo-membrane with no ECDs release it is of paramount importance, especially for the reuse of the final effluent. ACKNOWLEDGEMENTS This study was partially funded by the European Commission under the Fifth Framework Programme and contributing to the implementation of the Key Action "sustainable management and Quality of Water" within the Energy, Environment ans sustainable development Programme, project "SWAMP" n° EVK1-CT-2000-00071. The authors are solely responsible for the content of this paper that does not represent the opinion of the Community. The European Community isn't responsible for any use that might be made of data appearing therein. REFERENCES Andrews W.C. (1995). Continuous combined estrogen/progestin hormone replacement therapy, Clin. Ther., 17, 812-820. Arcand-Hoy L.D., Nimrod A.C., Bensen W.H. (1998). Endocrine-modulating substances in the environment: estrogenic effects of pharmaceutical products, Int. J. Toxicol., 17, 139-145. Arias C.A., Cabello A., Brix H. and Johansen N.H. (2003). Removal of indicator bacteria from municipal wastewater in an experimental two-stage vertical flow constructed wetland system. Wat. Sci. Tech., 48 (5), 35-41. Birkett J.W. and lester J.N. (2003). Endocrine Disrupters in Wastewater and Sludge Treatment Processes. IWA Publishing and Lewis Publishers, Washington D.C. Chen M.Y., Ike M., Fujita M. (2002). Acute toxicity, mutagenicity and extrogenicity of bisphenolA and other bisphenols, Environ. Toxicol., 17, 80-88. Conte G., Martinuzzi N., Giovannelli L., Pucci B. and Masi F. (2001). Constructed wetlands for wastewater treatment in central Italy. Wat. Sci. Tech., 44 (11-12), 339-343. Del Bubba M., Lepri L. (2002). Surfactant removal by Horizontal Subsurface Flow (SFS-h) pilotscale constructed wetland. In: Res. Adv. in Water Research, 3, 89-109. Del Bubba M., Checchini L., Lepri L., Ducceschi L., Griffini O. and Tabani F. (1998). Use of subsurface horizontal wetlands as tertiary treatment system. Proceedings of 6th Int. Conf. On Wetlands System for Water Pollution Control, Aguas de Sao Pedro, SP, Brasil, 688-696. Del Bubba M., Masi F., Checchini L., Martellini T., Lepri L. (2004). Identification and quantitative determination of selected carcinogenic and endocrine disrupting organic micropollutants in a
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