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May 21-23, 2015 Athens
TREATING MICROPOLLUTANTS OF EMERGING CONCERN:
A CASE OF TRICLOSAN
Filiz B. Dilek Middle East Technical University
Dept. of Environmental EngineeringAnkara, Turkey
Industrial Waste & Wastewater Treatment & Valorization
May 21-23, 2015 Athens
Biocide!to preserve materials including food, to decontaminate
surfaces, for personal hygiene...
• CAS Number: 3380-34-5• Partition coefficient (Octanol/Water); log KOW = 4.76• Molecular weight = 289.54 g/mol• Density = 1.55 ± 0.04 g/cm3
• Solubility in water = 1 mg/L @ 20°C• Vapor Pressure = 4 x 10-6 mmHg at 20°C
Triclosan (TCS) …
May 21-23, 2015 Athens
• Produced since 1965
• Production of 10-1000 tones per year only in Europe
• Consumption changes from country to country with a total 450tones/yr
Production and use around the world …
May 21-23, 2015 Athens
Not hazardous to humans, but skin, eye and respiratory irritations, allergy susceptibility and inhalation toxicityMight be harmful to the immune system Alters hormone regulation in animals-Endocrine distruptioneffects! Toxicity on biota
Bioaccumulation due to its hydrophobic nature –
BCF: 3700-8400 for fish speciesMight contribute to the development of antibiotic-resistant germs
http://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/triclosan/faq-20057861http://www.fda.gov/forconsumers/consumerupdates/ucm205999.htm
Adverse Effects?
May 21-23, 2015 Athens
• Exposure to low levels of TCS disrupts thyroid hormoneassociated gene expression and can alter the rate of thyroid hormone-mediated postembryonic anuran development.
May 21-23, 2015 Athens
Not hazardous to humans, but skin, eye and respiratory irritations, allergy susceptibility and inhalation toxicityMight be harmful to the immune systemAlters hormone regulation in animals-Endocrine distruptioneffects!Toxicity on biota
Bioaccumulation due to its hydrophobic nature –
BCF: 3700-8400 for fish speciesMight contribute to the development of antibiotic-resistant germs
http://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/triclosan/faq-20057861http://www.fda.gov/forconsumers/consumerupdates/ucm205999.htm
Adverse Effects?
May 21-23, 2015 Athens
TCS affected both bacterial and algal communities within the biofilm, although TCS toxicity was higher for bacteria than algae (NEC: 0.21 µg/L for bacteria; 0.42 µg/L for algae).
The potential environmental risk of TCS is high especially in rivers where water scarcity results in low dilution capacity, like in Mediterranean areas.
May 21-23, 2015 Athens
Not hazardous to humans, but skin, eye and respiratory irritations, allergy susceptibility and inhalation toxicityMight be harmful to the immune system Alters hormone regulation in animals-Endocrine distruptioneffects! Toxicity on biota
Bioaccumulation due to its hydrophobic nature –
BCF: 3700-8400 for fish speciesMight contribute to the development of antibiotic-resistant germs
http://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/triclosan/faq-20057861http://www.fda.gov/forconsumers/consumerupdates/ucm205999.htm
Adverse Effects?
May 21-23, 2015 Athens
TCS could exert a selective pressure able to drive the spread of a resistance determinant in a human pathogen – Biocide resistance
However,
No statistical correlation between reduced susceptibility to TCS and any antibiotic resistance!
EC project KBBE-227258 BIOHYPO (2013), which is a research project aimed at evaluating the impact of biocide use on the generation of antibiotic resistance
May 21-23, 2015 Athens
Legislative Acts
• Directive 76/768/EEC (Annex VI)
Maximum authorized concentration: 0.3% in cosmetic products !
• Directives 98/8/EC (528/2012), 95/2/EC and Regulation (EC)1831/2003
Not allowed to be used as disinfectant and preservative in foodand feed production !
Country Level Acts
• Germany introduced a ban on the use of TCS within the plasticproducts having a direct contact with foods since September 2009.
Restriction on use …
May 21-23, 2015 Athens
TCS(ng/L) (µg/kg)*
Surface waters 0.16-2300 BIOHYPO, 2012
Kolpin et al., 2002 Mezcua et al., 2004
Svensson, 2002 Ying -Kookana, 2007
etc.
Marine waters 16.2-99.3
WWTP influent <0.87-562000
WWTP effluent 100-269000
WWTP sludge 28-37189 *
TCS accumulates in sludge !
Environmental Occurence …
May 21-23, 2015 Athens
Adsorption to ozonation system
TCS decrease in identical reactors after 5 h – But, adsorption on glass reactor surface was negligable
0
1
2
3
4
5
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0 1 2 3 4 5 6TC
S C
once
ntra
tion
(mg/
L)
Time (h)
Glass tubing
Plastic tubing
TCS concentration in glass reactors aerated with plastic or glass tubing (TCS spiked at 5 mg/L)
(without ozone gas, but air)
For ozonation tests, it is definitely advised to use glass reactors with glass tubing if possible
May 21-23, 2015 Athens
Adsorption to membrane filtration system
0100200300400500600700800
0 20 40 60 80 100 120 140TCS
conc
entra
tion
(µg/
L)
Time (h)
0
200
400
600
800
1000
0 20 40 60 80 100 120 140TCS
conc
entra
tion
(µg/
L)
Time (h)
0
200
400
600
800
1000
1200
1400
0 20 40 60 80 100 120 140TCS
conc
netra
tion
(µg/
L)
Time (h)
(NF system - without membrane)
It is essential firstly to saturate the system with TCS without membrane and then to carry out actual runs.
747 µg/L TCS
898 µg/L TCS
1268 µg/L TCS
May 21-23, 2015 Athens
REMOVAL OF TCS FROM WASTEWATER
BIOLOGICAL TREATMENT
Effect of Culture Acclimation on the Fate of Triclosan During Biological Wastewater Treatment
May 21-23, 2015 Athens
Acclimated cultureInfluent TCS
Concentration COD Removal (%)
0 94.0
100 ng/L 93.0
100 µg/L 92.6
500 µg/L 91.0
1 mg/L 84.4
10 mg/L 81.2
20 mg/L 67.6
50 mg/L 57.8
100 mg/L 47.4 TCS > 100 mg/L toxic effects! Positive effect of acclimation !
Influent TCS
Concentration (mg/L)
COD Removal
(%)
0 94.0
1 66.0
10 62.8
20 58.4
50 57.2
100 42.2
Non- acclimated culture
Pulse-fed sequencing batch reactor
May 21-23, 2015 Athens
Acclimated culture Non-acclimated culture
Main TCS removal mechanism: Biodegradation for acclimated Adsorption becomes more prominent for non-acclimated
0.00.10.20.30.40.50.60.70.80.91.0
2 20 40 100 200
Dis
trib
utio
n
Influent TCS as Mass (mg)
TCS Biodegraded
TCS in Effluent
TCS in Sludge
Pulse-fed sequencing batch reactor
May 21-23, 2015 Athens
By-product formation
Parent compound: TCS
BP2: 2,4-DCABP1: 2,4-DCP
Pulse-fed sequencing batch reactor
May 21-23, 2015 Athens
By-product formation
e.g. Non-acclimated culture-10 mg/L TCS (effluent water)
2,4-DCA has not been reported before.Me-TCS was not detected in both culture cases (owing to TCS stock solution prepared in NaOH)
So, one should be very careful in reporting Me-TCS as a by-product of TCS degradation without considering this fact
Acclimation resulted in lower by-product levels
Pulse-fed sequencing batch reactor
May 21-23, 2015 Athens
In the presence of biodegradable COD
Acclimated culture Non-acclimated culture
Reduced COD removal efficiency with higher TCS input ! TCS did not interfere with biodegradable COD use as long as < 20 mg/L !
0.0
0.2
0.4
0.6
0.8
1.0
0 5 10 15 20 25
CO
D/C
OD
o
Time (h)
1 mg/L TCS 10 mg/L TCS
20 mg/L TCS 50 mg/L TCS
100 mg/L TCS
0.0
0.2
0.4
0.6
0.8
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0 5 10 15 20 25
CO
D/C
OD
oTime (h)
1 mg/L TCS 10 mg/L TCS
20 mg/L TCS 50 mg/L TCS
100 mg/L TCS
Kinetics
May 21-23, 2015 Athens
Acclimated culture Non-acclimated culture
Substrate inhibition for non-acclim. culture Reduced inhibition for acclim. culture and substrate inhibition was in approach to the
Monod Model !
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
0 20 40 60 80 100
µ (1
/h)
TCS (mg/L)
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0 20 40 60 80 100
µ (1
/h)
TCS (mg/L)
In the absence of biodegradable COD
Kinetics
May 21-23, 2015 Athens
REMOVAL OF TRICLOSAN FROM SURFACE WATERS
OZONATIONNANOFILTRATION
Ankara
Kesikköprü Dam
May 21-23, 2015 Athens
TCS levels in surface waters: 0.65–48.96 ng/LTCS levels in the distribution network: below LOQ
May 21-23, 2015 Athens
0102030405060708090100
0
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5 10 15 24 70
TC
S re
mov
al (%
)
App
lied
ozon
e (m
g)
Ozone dose (mg/L)
10 min 5 min 1 min 10 min 5 min 1 minOzonation time (for mg) Ozonation time (for %)
about 99% TCS removal in 10 min5 min ozone : almost complete abatement (except 5 mg/L)
Effect of Ozone Dose
May 21-23, 2015 Athens
initial TCS: 1 mg/L, ozone dose: 5 mg/L
t=0
t=10
t=5
t=20 t=30
OH
OH
Cl
Cl
Cl
OH
Undefined t=1
2,4-DCP & 4-CC comply with Chen et al. ( 2012)
Ozonation by-products of TCS
May 21-23, 2015 Athens
Therefore, in ozonation studies being worked with any methyl containingsolutions or solvents, this issue should be considered cautiously.
with methanol
with NaOH
2,4-DCA is formed in the presence of methanol in water.
May 21-23, 2015 Athens
• Although almost complete TCS depletion in 10 min, ozoneconsumption continued due to the presence of its ozonationby-products (i.e. 2,4-DCP, 4-CC, 2,4-DCA)
Time (min)
O3 consumed/TCS (mg/mg)
Removal
(%)1 2.311 96.05 4.036 98.5
10 6.390 10020 9.841 10030 13.036 100
For complete removal!
Ozone Demand of TCS
May 21-23, 2015 Athens
Membrane used
Membrane Name Polymer Structure pH Range Rejection Size Typical Flux/psi GFD@PSI
DL-NF Thin Film 2-11 96 -MgSO4 31/100
Nanofiltration
May 21-23, 2015 Athens
TCS removal from surface water spiked with 5000 ppb TCS
PhaseSystem Sorption Nanofiltration
TCS Concentration (ppb)Initial feed 4626 1862Steady-state feed 1862 1160Steady-state permeate NA 798
TCS Removal (%)Total 60.1 57.1By membrane sorption NA 37.7 (66)By surface rejection NA 19.4 (34)
May 21-23, 2015 Athens
TCS= 2000 ppb, HA: 10 mg C/L;
TCS= 5000 ppb, HA: 10 mg C/L;
TCS= 5000 ppb, HA: 26 mg C/L)
TMP:6.9 bar; CFV: 1.2 m/sec
Effect of HumicAcid (HA) as NOM
HA injected
May 21-23, 2015 Athens
Schematic of processes controlling the permeation of small organics
E. Steinle-Darlinga, M. Zeddab, M. H. Plumleea, H.F. Ridgwaya, M. Reinharda, Evaluating the impacts of membrane type, coating, fouling, chemical properties and water chemistry on reverse osmosis rejection of seven nitrosoalklyamines, including NDMA, Water Res. 41 (2007) 3959 – 3967
May 21-23, 2015 Athens
Effect of HA concentration on TCS retention (TCS:5000 ppb)
NOM had a positive effect on TCS removal (due to TCS-HA complex formation)NOM leads to an increase in TCS removal mainly by sorption into the membrane
May 21-23, 2015 Athens
Effect of HA concentration on flux and flux decline (TCS:5000 ppb)
Positive effect of HA on membrane fouling!Concentration polarization disappeared with anincrease in HA
May 21-23, 2015 Athens
• Significant TCS removal in ASP• Acclimation has a positive effect• By-products of 2,4-DCP and 2,4-DCA, but with lower levels with
acclimation
Remarks- wastewater
May 21-23, 2015 Athens
Ozonation:
• Very effective
• By-products of 4-CC, 2,4-DCP and 2,4-DCA
NF:
• NOM content is a factor in TCS removal from surface water by NF
• TCS removal increases with NOM
Remarks – surface water