Transcript Document

Pyrethroid Fate & Behavior in
Publicly Owned Wastewater
Treatment Works
Daniel M. Tessier
Environmental Safety Assessment
DuPont Crop Protection
On behalf of the Pyrethroid Working Group member companies:
AMVAC, Bayer, Cheminova, DuPont, FMC, Syngenta, Valent
© 2013 by Pyrethroid Working Group. All rights reserved.
Key questions regarding pyrethroids as
wastewater microcontaminants








urban sources ?
influent concentrations ?
degradation / partitioning during wastewater processing ?
is known efate behavior (determined for agricultural
settings) relevant in wastewater / POTWs ?
are current analytical methods sufficient?
effect of various wastewater treatment processes?
effluent concentrations?
PWG sought to answer these questions via
laboratory, pilot and plant-scale studies as well as
monitoring of selected California POTWs
Generalized POTW Processes
8 pyrethroids included in the studies
Pyrethroid
log Kow
Water
Solubility
(µg/L)
Bifenthrin
6.4
0.014
237,000
Cyfluthrin
6.0
2.3
124,000
Cypermethrin
6.5
4.0
310,000
Deltamethrin
4.5
0.2
704,000
Esfenvalerate
5.6
6.0
375,000
Fenpropathrin
6.0
10.3
42,500
-Cyhalothrin
7.0
5
326,000
Permethrin
6.1
5.5
277,000
Koc
Bench-scale treatability study
Post-screen influent
fortified at nominal
5 mg/L (50 mg/L
permethrin)
aerobic system
anaerobic digester
Results – Primary Settling
Pyrethroid
Calculated
Primary
Influent
(µg/L)
Measured
Primary
Influent (µg/L)
Measured
Primary
Effluent (µg/L)
Measured
Sludge (µg/L)a
Bifenthrin
4.5
3.35
3.38
59.09
Fenpropathrin
4.4
3.67
3.47
132
l-Cyhalothrin
4.8
3.79
3.72
88.1
Permethrin
37.7
29.0
29.6
704
Cyfluthrin
3.3
2.44
2.42
66.3
Cypermethrin
5.2
3.85
3.85
101
Esfenvalerate
5.2
3.89
3.83
86.1
Deltamethrin
4.7
3.72
3.89
90.3
a. Ca 0.85 gal / 200 gal influent
‡ No sorption to solids during primary settling
Pyrethroid Removal in Anaerobic Reactor
Pyrethroid Distribution in the Aerobic System
Conclusions: Bench-scale experiment

No sorption of pyrethroids to solids in primary settling
(attributed to high DOC as alternate sorption
compartment; short detention time)

Anaerobic digestion (biodegradation)
ca. 32 – 79% removal of pyrethroid input.

Aerobic treatment - biodegradation + low sorption of
pyrethroids to solids (13 – 51% remain in effluent)

>90% removal of effluent residual pyrethroids via ultrafiltration

Overall >90% removal in final filtered effluent
Plant-scale process modeling
o
o
Water & biosolids (sludge) phases collected
over 1 week period & analyzed for
pyrethroid concentrations
Data modeled via TOXCHEM+ (Hydromantis,
Ontario, Canada)
Plant-scale process modeling:
POTW schematic and sampling locations
TOXCHEM Representation of SRCSD POTW
Pyrethroid concentrations following aerobic
treatment and ultrafiltration
Model Predicted vs Measured Concentrations
Modeling Results- Pyrethroid Fate
NB: Measured concentrations of deltamethrin, fenpropathrin and esfenvalerate were too low for comparison against predicted
concentrations
Conclusions: Full Scale Sampling / Process Modeling

Predicted concentrations in good agreement with measured
values.

Log Kow used in the model (4.8 to 5.9) were generally lower
than literature values (Laskowski, 2002) Attributable to high
aqueous DOC.

Pyrethroid emissions to the atmosphere were predicted to be
< 2.4% for all tested compounds

Median removal for biodegradation ranged from 44% to 65%

Median removal for sorption ranged from 30% to 42%

Pyrethroid discharge to effluent ranged from 2.9 to 11.9%
Pyrethroid Monitoring at California POTWs


PWG and Tri-TAC developed a partnership beginning in
August 2007
Revised DPR requirement – July 15, 2011
 Monitor for group III pyrethroids in influent,
effluent, biosolids
 Monitor at least 20 POTWs in California
o Submit analytical
methods for
influent, effluent
and biosolids for
eight pyrethroids
Study Design

32 California POTWs
Varying size (volume of treated wastewater)
 Location (urban to rural)
 Treatment processes used (primary, secondary, tertiary)
 Customer base (residential, industrial, commercial)
 Population served
Facilities divided into 3 groups for sampling (north to south)
Samples
 Influent (31)-consecutive grabs
 Effluent (31)-consecutive grabs
 Biosolids (24)-grabs, composited in laboratory



Study Design (cont.)

Samples analyzed for pyrethroids by two
laboratories



Group III pyrethroids (permethrin, cypermethrin,
bifenthrin, cyfluthrin, esfenvalerate, l-cyhalothrin,
deltamethrin, fenpropathrin)
TSS, TOC and TS determined by one laboratory
Extensive QA program (SWAMP comparable)
Results: Influent - All Sites
Bifenthrin
Cyfluthrin
Cypermethrin
Permethrin
# of samples
67
67
67
67
# of detects
64
59
54
67
% detected
96
88
81
100
Maximum
74 ng/L
55
200
3800
Minimum
ND
ND
ND
30
Average
15 ng/L
11 ng/L
35 ng/L
330 ng/L
Median
9.7 ng/L
7.4 ng/L
21 ng/L
230 ng/L
# of detects = number of results that are above the limit of detection
Results: Biosolids - All Sites
Bifenthrin
Cyfluthrin
Cypermethrin
Permethrin
# of samples
52
52
52
52
# of detects
50
45
47
48
% detected
96
87
90
92
Maximum
1100 ng/g
190 ng/g
1000 ng/g
11000 ng/g
Minimum
ND
ND
ND
ND
Average
150 ng/g
34 ng/g
110 ng/g
1500 ng/g
Median
120 ng/g
29 ng/g
28 ng/g
1200 ng/g
# of detects = number of results that are above the limit of detection
All results reported on a dry weight basis
Results: Effluent - All Sites
Bifenthrin
Cyfluthrin
Cypermethrin
Permethrin
# of samples
62
62
62
62
# of detects
51
37
50
40
% detected
82
60
81
65
Maximum
3.9 ng/L
4 ng/L
13 ng/L
170 ng/L
Minimum
ND
ND
ND
ND
Average
0.89 ng/L
0.60 ng/L
2.11 ng/L
20 ng/L
Median
0.6 ng/L
0.3 ng/L
1.3 ng/L
9.4 ng/L
# of detects = number of results that are above the limit of detection
3 sites contained no detectable residues of the 8 pyrethroid pesticides
Effect of Treatment Level on Effluent Concentration
Bifenthrin-Effluent
Bifenthrin Residues, ng/L
4.5
4
3.5
3
2.5
Primary
Secondary
2
Tertiary
1.5
1
0.5
0
Sites
Conclusions: POTW Monitoring


Pyrethroids are likely to be found in influents, effluents and
biosolids from California POTWs
Effluent (31 sites)
 Pyrethroids were detected in 28 of the 31 sites
examined
 Bifenthrin (82%) was the most frequently detected
pyrethroid followed by cypermethrin (81%) and
permethrin (65%)
 Total pyrethroid residues ranged from non-detectable
to a maximum residue of 190 ng/L
Overall Conclusions




Pyrethroids are likely to be present in wastewater influent,
effluent & biosolids.
Bench-scale and plant scale studies indicate ca. 90%
removal of pyrethroids from influent streams via sorption &
biodegradation; this benchmark is reflected in real-world
monitoring.
POTW process parameters (e.g detention time, 1o vs 2o vs 3o
treatment) anticipated to influence % removal; effective
modeling procedures are available to predict pyrethroid
fate in POTW matrices.
Baseline data and assumptions from e-fate studies must be
applied judiciously to POTW investigations (e.g, Kow; Koc).
Key Personnel

PWG /DuPont Crop Protection



HDR Engineering




Jim Markle
Van Buuren Consulting, LLC


Kevin Clark
Coalition for Urban/Rural Environmental Stewardship


Heather Ramil
Kurt Ohlinger
ABC / Morse Laboratories


Joe Cleary
Joy McGrath
Sacramento Regional Sanitation District


Al Barefoot
Dan Tessier
Beverly van Buuren
Hydromantis

Hugh Monteith