Transcript Presentation for environmental session CEST 2013

Alexandros G. Asimakopoulos1,2,
Kurunthachalam Kannan2, Nikolaos S. Thomaidis1
1Laboratory
of Analytical Chemistry, Department of Chemistry,
University of Athens, Panepistimioupolis Zografou, Athens,
Greece.
2Wadsworth Center, New York State, Department of Health,
and Department of Environmental Health Sciences, School
of Public Health, State University of New York at Albany,
Albany, NY, USA.
Benzotriazoles (BTRs) – Benzothiazoles (BTHs):
Uses & Applications
 BTRs contain the 1,2,3-benzotriazole skeleton in their structure.
Flame and corrosion inhibitors.
Ultraviolet (UV) light stabilizers in plastics &
antifogging agents.
Found in pigments, dishwasher detergents,
de-icing fluids.
R: chemical group or atom
 BTHs contain the 1,3-benzothiazole skeleton in their structure.
Corrosion inhibitors, are used as herbicides,
slimicides, fungicides, photosensitizers.
Constituents of azo dyes, de-icing fluids, drugs,
food flavors, rubber.
Some occur naturally in the environment, i.e.,
tobacco smoke and tea leaves.
R: chemical group or atom
Target chemicals assessed in the WWTP
BTRs
:
BTRs:
BTHs:
BTHs:
1.
1H-benzotriazole
1.
(1H-BTR)
2.
(BTH)
1-hydroxy-benzotriazole
2.
(1-OH-BTR)
3.
2-hydroxy-benzothiazole
(2-OH-BTH)
Tolyltriazole
3.
(TTR, a mixture of isomers of
4-methyl-1H-benzotriazole [4-Me-1H-BTR]
and 5-methyl-1H-benzotriazole [5-Me-1H-BTR])
4.
benzothiazole
2-methylthio-benzothiazole
(2-Me-S-BTH)
4.
2-amino-benzothiazole
(2-amino-BTH)
Xylyltriazole
(XTR, or 5,6-dimethyl-1H-benzotriazole
[5,6-diMe-1H-BTR])
 Polar compounds.
 BTRs are weak bases.
 BTHs present both acidic and basic properties.
Schematic diagram of Treatment Process
Sample collection
 Wastewater and sludge samples were collected from a WWTP that serves
a population of 3.700.000, in Athens.
 Samples were collected in April 2012; the average flow rate of sewage was
approx. 743.000 m3/day, and the average production of dewatered sludge
was approx. 112.000 kg/day.
 Influent and effluent samples (50 mL), primary sludge (5 mL),
secondary sludge (20 mL), and mixed liquor samples from the
bioreactors (20 mL) were immediately filtered after collection.
 The filtered wastewater samples were acidified to pH 2.50±0.10, and stored
in the dark at 4 °C until analysis.
 All solid samples were stored at −20 °C until analysis.
Schematic diagram of the analytical method
Dried Sludge:
100 mg
Liquid samples: 50/20/5 mL
Filtration: pre-ashed GF/F filter
Filtrate
Adjustment pH to 3.0±0.1
SPE: Strata-X RP (200mg, 6cc)
Conditioning: 10 mL CH3OH
Equilibration: 10 mL acidified H2O
Washing: 2×5 mL acidified H2O
Filter
SLE: Vortex mixing for 1 min
with 5 mL MeOH/Milli-Q water
(1:1 v/v) (adjusted to pH
3.00±0.10). Sonication for 45
min (37 oC).
Centrifugation: 4000 rpm/10 min
(×1,×2,×3)
Elution: 10 mL CH3OH/ACN (1:1 v/v)
Supernatant dilution to 50 mL
Evaporation to near-dryness with N2
gas, reconstituted in 1 mL
CH3OH/ACN (1:1 v/v)
LC-ESI(+)MS/MS
Occurrence in 24-h composite flow proportional Influent
and Effluent samples
.
24-h composite flow
proportional influent
wastewater
Target
analytes
Dissolved
phase
(ng/L)
D1/D2
1H-BTR
587/580
1-OH-BTR
217/243
TTR
15841/7735
XTR
ND/ND
BTH
1119/1160
2-OH-BTH
481/640
2-Me-S-BTH
346/331
2-Amino-BTH
<13/ND
24-h composite flow
proportional effluent
wastewater
Removal
efficiency
(%)
Particulate
matter
(ng/L)
D1/D2
Dissolved
phase
(ng/L)
D1/D2
Particulate
matter
(ng/L)
D1/D2
D1/D2
154/146
ND/ND
131/106
ND/ND
108/210
54/80
39/51
ND/ND
325/385
ND/ND
5156/5737
ND/ ND
<55/<55
151/172
50/46
ND/ND
143/162
ND/ND
19/37
ND/<1.1
132/89
16/86
18/20
ND/ND
37/25
100/100
68/26
-/87/91
69/64
82/83
-/-
Occurrence in primary and secondary sludge & influent
bioreactor samples
.
Primary sludge
(grab samples)
Target
analytes
Influent bioreactor
(grab samples)
Secondary sludge
(grab samples)
Dissolved
phase
(ng/L)
D1/ D2
Particulate
matter
(ng/g)
D1/ D2
Dissolved
phase
(ng/L)
D1/ D2
Particulate
matter
(ng/g)
D1/ D2
Dissolved
phase
(ng/L)
D1/ D2
Particulate
matter
(ng/g)
D1/ D2
1H-BTR
2621/4514
17/10
141/125
38/39
531/665
27/26
1-OH-BTR
173/ND
ND/ND
ND/ND
ND/ND
ND/ND
31/35
TTR
27109/210883
16/71
6123/4639
22/71
4964/6383
23/32
XTR
ND/ND
1/ND
ND/ND
1/1
ND/ND
ND/ND
BTH
10543/14010
<41/<41
ND/172
ND/<41
288/ND
<41.3/ND
2-OH-BTH
11545/30224
102/93
207/102
35/44
175/216
21/29
2-Me-S-BTH
1250/1887
26/33
ND/ND
29/21
ND/ND
25/28
2-Amino-BTH
108/248
ND/ND
<34/<34
ND/ND
<34/ND
ND/ND
• A major portion is biotransformed during the activated sludge treatment
process.
Occurrence in Sewage sludge
Target
analytes
1H-BTR
1-OH-BTR
TTR
XTR
BTH
2-OH-BTH
2-Me-S-BTH
2-Amino-BTH
Sewage
Sludge
(ng/g)
D1/D2
81/84
ND/ND
116/107
ND/ND
174/88
74/33
61/61
ND/ND
 Removal by sorption onto
sludge seems insignificant.
.
Distribution of BTRs and BTHs between aqueous
phase and suspended solids in influent
and effluent wastewater
 The presence of exocellular biopolymers on the surfaces of biosolids
following secondary treatment creates favorable conditions for higher
sorption onto particulates present in bioreactors and secondary sludge.
Solid-Liquid Distribution Coefficients,
Log Kd of BTRs & BTHs
Target
Analytes
1H-BTR
TTR
Primary
sludge
0.58
0.35
Influent
bioreactor
1.65
0.68
Secondary
sludge
2.46
0.86
BTH
2-OH-BTH
0.32
0.72
1.99
2.11
2.17
2.43
2-Me-S-BTH
2-Amino-BTH
1.28
0.41
-*
-*
-*
-*
*Concentrations were not detectable
 Both BTRs & BTHs have low affinity
for primary sludge and this changed
gradually in biosolids from the
bioreactor and the secondary sludge.
However, log Kd values were lower
than 2.5.
Average Daily Loadings & Discharges
Summary (1/2)
 Biotransformation of some BTHs had been reported, and
this contributes significantly to their removal during wastewater
treatment. A similar mechanism is expected for BTRs.
 The removal efficiencies for BTHs calculated agree with the
results from previous studies.
 The concentrations of 1H-BTR and TTR in sludge from Athens
were similar to those reported previously. Only one study had
reported BTH concentrations in sludge, where BTH, 2-Me-S-BTH
and 2-OH-BTH were found approximately three times higher
than the values reported here.
Summary (2/2)
 Based on the results of the influent and effluent wastewater
samples, most of the target analytes were determined in all
samples at concentrations similar to or lower than those
reported for other WWTP samples.
This is the first environmental study that analyzed the
particulate matter of wastewater for these compounds.
 Distribution between aqueous phase and suspended
solids in influent and effluent wastewater, and calculation of
solid-liquid distribution coefficients were reported for the
first time for these compounds.
Acknowledgements
This project was implemented under the
Operational Program “Education and
Lifelong Learning” and funded by the
European Union (European Social Fund)
and National Resources — THALIS.
Reference