examining the influence of operating characteristics on ... the influence of operating...
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Examining the influence ofoperating characteristics onpharmaceutical and personal careproduct (PPCP) removal inwastewater treatment plants
Jim T. Yu,1 Kevin Bisceglia,1Mehmet Coelhan,2 A. Lynn Roberts,1 andEdward J. Bouwer1
1Johns Hopkins University2Technical University of Munich, Germany
Pharmaceuticals and Personal CareProducts (PPCPs) as “Emerging”Contaminants Certain PPCPs (e.g., caffeine and aspirin) have been
found in the environment for over 20 years
Recent (1990s) occurrence monitoring of PPCPs haselucidated the prevalence and persistence of numerousPPCPs in the environment
Despite the increases in occurrence studies, the fate andramifications of PPCPs in the environment are stilllargely unknown
Sewage treatment plants (STPs) have been found to bethe major sources of PPCP contamination
Human Health Impacts
Human health risks for PPCPs are largelyUNKNOWN
However;Approximately 36% of “Class A” carcinogensand 22% of “Class B” carcinogens are (or were)used as drugsApproximately 63 drugs in common use areclassified as “Class X” (use is contraindicated inpregnancy), and an additional 107 are rated as“Class D” (positive evidence of fetal risk) by USFDA
Ecological Impact
Aquatic species are atmost risk.
Selective serotoninreuptake inhibitors(SSRIs) affect spawningand other behavior inshellfish.
Estrogens and otherEDCs have causedfeminization of male fish.
Motivation-Sampling plan
4 STPs on Northeastern seaboard with collectiveinfluent flow ~ 1 BGD
Different treatmentprocesses arerepresented
Each STP hasunique HRT andSRT
Washington, DCBaltimore, MD
Philadelphia,PA
Yonkers,NY
Water Sample(500 ml) Solid Phase Extraction
SPE Cartridges
GC/MS AnalysisGC/MS Results
Elution
Derivatization
Solid Phase Extraction-Procedure Acidified the 500 ml of the water sample to pH 2
by adding 1 M HClCondition the cartridge by first applying 5 ml of
ethylacetate, then 5 ml of methanol, and finally 5ml of Milli-Q water (adjusted to pH 2)
After conditioning the cartridge, vacuum wasapplied, and samples were passed through thecartridge at a flow rate of approximately 6 ml/min
After all 500 ml of water has been extracted ontoSPE cartridge, the target analytes were elutedfrom the cartridge with 7 ml acetonitrile withoutvacuum
Derivatization Procedure Add 7mL of the water into a 20 mL test tube
150 µl of 2M K2CO3 adjusted to pH 10.5 is added to theacetonitrile/water mixture
80 µl of PFBBr is added and the sample is vortexed for 30seconds
heat the sample at 100 °C for one hour
After heating, 200 µl of cyclohexane (contain internal standard)is added and vortexed for one minute.
5% NaCl water is added to the sample for phase separation
Take the cyclohexane phase and analyze it by GC/MS
20480PCMX (chloro-xylenol)
130380Phenytoin
030Phenobarbital
6085Diclofenac
50990Ketoprofen
120830Triclosan
NDNDSecobarbital
1202300Naproxen
0310Chlorophene
NDND5-Fluorouracil
0220Gemfibrozil
0480Acetaminophen
070Gabapentin
1503200Ibuprofen
50490Biphenylol
50320Biosol
0604-Chloro-m-cresol
0210Valproic Acid
Effluent Concentration(ng/L)
Influent Concentration(ng/L)Target Aanlytes
Removal Efficiencies for Pharmaceuticals
0%
20%
40%
60%
80%
100%
120%
Valpro
icAcid
Ibupro
fen
Gabap
entin
Aceta
min
ophen
Gemfib
rozil
Napro
xen
Ketopr
ofen
Diclofe
nac
Pheno
barbita
l
Phenyt
oin
Rem
oval
Eff
icie
ncy
NYPhiladelphiaDCBaltimore
Removal Efficiency for Antiseptics
0%
20%
40%
60%
80%
100%
120%
p-Chlo
ro-m
-cre
sol
Biosol
PCMX(c
hloro
-xyle
nol)
Biphenylol
Chloro
phene
Triclo
san
Rem
ova
lEff
icie
ncy
NY
Philadelphia
DCBaltimore
Research Questions:
What governs variability in removalefficiencies from plant to plant? (SRT? seeClara et al., Water Research, 2005)
What governs variability in removalefficiencies from one PPCP to another?(Biodegradability? Log Kow? Degree ofionization?)
Objectives:Develop a mass balance model to explore
the dominant removal mechanisms forPPCPs during wastewater treatment
Examine the influence of operatingcharacteristics on PPCP removal inwastewater
Focus: 10 pharmaceuticals and 6antiseptics with ionizable functional groupsfor which we have occurrence data
Non-Steroidal Anti-InflammatoryDrugs (NSAIDs)
Naproxen Diclofenac
Ketoprofen Ibuprofen
Acetaminophen
Other Drugs
Gemfibrozil(Antilipid)
5-Fluorouracil(Antineoplastic)
Secobarbital(Barbiturates)
(Not Detected)
(Not Detected)
Biodegradation/Sorption Biodegradation/Volatilization/Sorption
Sludge Wasting(sorption) Sludge Wasting
(sorption)
Generic Schematic of a Treatment Plant
Biodegradation (assume secondary substrate utilization) Sorption (loss to sludge wasting) Volatilization (loss in bubble aeration)
Possible Removal Mechanisms:
PrimaryClarifier Aeration Basin
SecondaryClarifier
Schematic of Chemical Fate:
Assumptions:
• Chemical speciation/partitioning is at equilibrium with respect totransport/transformation
• Only uncharged, dissolved phase chemicals partition to biosolids
• Only uncharged, dissolved phase chemicals volatilize
• Both anionic and neutral dissolved chemicals biodegrade, and do so at identicalrates. Sorbed chemicals do not biodegrade
Volatilization (KLa, KH)
Settling (KD)Biodegradation (Xa, kb,)
Advection
(Q, CT)Caq,ionic Caq,neutral Caq,neutral
Loss ProcessesVolatilizationRvol = -GHC Caq,neutral [1-exp (- KLabubZ/KHU)] (Matter- Muller, 1981)
SorptionRsorption = (XTVKDCaq,neutral )/SRT where
Log KD = 0.58 log Kow + 1.14 (Dobbs et al., 1989) Solids residence time (SRT) is the average time the activated sludge
solids are in the system
BiodegradationRbio = kbXaV(Caq,anionic + Caq,neutral) where
Xa = (SRT/ θ) { [Yww(Sinf,ww-Seff,ww)]/ [ 1+ b SRT)]} (Metcalf & Eddy,2003)
-5.82
-5.75
-4.73
-5.69
-4.58
-4.31
-9.38
-9.72
-9.17
-9.06
-7.86
-6.31
-10.58
-9.13
-5.21
-3.91
Log KH
0.4
0.02
0.03
0.02
0.06
0.02
0.0035
0.0004
0.04
0.02
0.02
0.06
0.1
0.02
0.03
0.2
kb (d-1)Fitted
100
90
100
86
96
84
29
66
100
95
95
100
100
100
95
100
RemovalEfficiency (%)
9.814.18Chlorophene
9.993.09Biphenylol
9.633.1p-Chloro-m-cresol
7.84.76Triclosan
9.963.27PCMX (chloro-xylenol)
10.353.52Biosol
8.332.16Phenytoin
4.184.02Diclofenac
7.631.47Phenobarbital
4.233.12Ketoprofen
4.843.18Naproxen
4.754.77Gemfibrozil
9.50.46Acetaminophen
4.6-1.73Gabapentin
4.413.97Ibuprofen
4.822.75Valproic Acid
pKaLog Kow
Pha
rmac
euti
cal
An
tise
pti
cs
Laboratory Biodegradation DataC
on
cent
rati
on(µ
g/L
)
0
0.2
0.8
1
0 10 20 30 40
Days
Naproxen ControlExperiments
Valproic Acid ControlExperiments Valproic Acid
IbuprofenGabapentinAcetaminophen
Gemfibrozil
5-FluorouracilNaproxen
SecobarbitalKetoprofen
Phenobarbital
DiclofenacPhenytoinBiosol
PCMX ( chloro -xylenol )Triclosan5-Chloro -m-cresol
Biphenylol
Chlorophene
Co
nce
ntra
tion
(µg
/L)
0.4
0.6
1.2
50
Days
Naproxen ControlExperiments
Valproic Acid ControlExperiments Valproic Acid
IbuprofenGabapentinAcetaminophen
Gemfibrozil
5-FluorouracilNaproxen
SecobarbitalKetoprofen
Phenobarbital
DiclofenacPhenytoinBiosol
PCMX ( chloro -xylenol )Triclosan5-Chloro -m-cresol
Biphenylol
Chlorophene
Co
nce
ntra
tion
(µg
/L)
0
0.2
0.8
1
0 10 20 30 40
Days
Naproxen ControlExperiments
Valproic Acid ControlExperiments Valproic Acid
IbuprofenGabapentinAcetaminophen
Gemfibrozil
5-FluorouracilNaproxen
SecobarbitalKetoprofen
Phenobarbital
DiclofenacPhenytoinBiosol
PCMX ( chloro -xylenol )Triclosan5-Chloro -m-cresol
Biphenylol
Chlorophene
Co
nce
ntra
tion
(µg
/L)
0.4
0.6
1.2
50
Days
Naproxen ControlExperiments
Valproic Acid ControlExperiments Valproic Acid
IbuprofenGabapentinAcetaminophen
Gemfibrozil
5-FluorouracilNaproxen
SecobarbitalKetoprofen
Phenobarbital
DiclofenacPhenytoinBiosol
PCMX ( chloro -xylenol )Triclosan5-Chloro -m-cresol
Biphenylol
Chlorophene
0
0.2
0.4
0.6
0.8
1
1.2
0 10 20 30 40 50 60
Days
Co
ncen
trat
ion
(µg
/L) Valproic Acid
IbuprofenGabapentinAcetaminophenGemfibrozil5-FluorouracilNaproxenSecobarbitalKetoprofenPhenobarbitalDiclofenacPhenytoin
Laboratory Biodegradation Data
Effect of KH on PPCP RemovalSlow Biodegradation Rate and Low Sorption
SRT=10 dpKa=10pH=7
kb=0.00001/dayLog Kow=1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.0E-06 1.0E-02 2.0E-02 3.0E-02 4.0E-02 5.0E-02 6.0E-02 7.0E-02 8.0E-02 9.0E-02
KH
Fra
ctio
nof
PP
CP
Fraction of PPCP remainingFraction lost due to sorptionFraction lost due to biodegradation
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Log Kow
Fra
ctio
no
fP
PC
P
Fraction of PPCP remaining
Fraction lost due to sorption
Fraction lost due to biodegradation
Effect of Log Kow on PPCP RemovalSlow Biodegradation Rate
pH=7SRT=10 d
pKa=10kb=0.0001/dayKH=0.00001
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Log Kow
Fra
ctio
nof
PP
CP
Fraction of PPCP remaining
Fraction lost due to sorptionFraction lost due to biodegradation
Effect of Log Kow on PPCP RemovalMedium Biodegradation Rate
pH=7SRT=10 d
pKa=10kb=0.001/dayKH=0.00001
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Log Kow
Fra
ctio
no
fP
PC
P
Fraction of PPCP remaining
Fraction lost due to sorption
Fraction lost due to biodegradation
Effect of Log Kow on PPCP RemovalHigh Biodegradation Rate
pH=7SRT=10 d
pKa=10kb=0.1/dayKH=0.0001
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09
kb (per day)
Frac
tion
ofP
PC
P
Fraction of PPCP remaining
Fraction lost due to sorption
Fraction lost due to biodegradation
Effect of Biodegradation Rate on PPCP RemovalHigh Sorption Case
SRT=10 dpKa=10pH=7
Log Kow=5KH=0.00001
Solids Residence Time (SRT)
500
1000
1500
2000
2500
3000
3500
4000
1 6 11 16
SRT (days)
Co
nce
ntr
ati
on
of
Xa
(mg
/L)
Solids (Biomass) Wasted ONLY ~1-5% INFLUENT FLOW
Aeration BasinSecondaryClarifier
Recycled Solids (Biomass)
Effluent
Xa=Active biomass
Rbio = kbXaVCAs SRT, Xa
Mass of Solids(Biomass)SRT=Mass of Solids(Biomass) Wasted Per Day
As SRT, Rsorption
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0 2 4 6 8 10 12 14 16 18 20
Solid Residence Time (Days)
Eff
luen
tC
onc
entr
atio
n(m
g/L
)
Diclofenac
Phenytoin
Gabapentin
Naproxen
Ketoprofen
Ibuprofen
Phenobarbital
Gemfibrozil
Acetaminophen
Valproic Acid
Effect of Solids Residence Time
Effect of Solids Residence Time
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0 2 4 6 8 10 12 14 16 18 20
Solid Residence Time (Days)
Eff
luen
tC
once
ntr
atio
n(m
g/L
)
Biosol
PCMX (chloro-xylenol)
Biphenylol
p-chloro-m-cresol
Triclosan
Chlorophene
Valproic Acid
2%
1%
97%
SRT= 1 day
96%
2%
2%
SRT= 6 days SRT= 20 days
Fast biodegradation rateand low sorption
pKa=4.82
Log Kow=2.75
kb= 0.2/dayo
o-
98%
2%
0%
Fraction lost due to biodegradation Fraction lost due to sorption Fraction of PPCP remaining
Phenytoin
Fraction lost due to biodegradation Fraction lost due to sorption Fraction of PPCP remaining
36%
2%
62%
SRT= 1 day SRT= 6 days SRT= 20 days
Medium biodegradation rateand low sorption
pKa=8.33
Log Kow=2.16
kb=0.003/day
67%2%
31%
76%
2%
22%
Diclofenac
7%
3%
90%
21%
2%
77%
SRT= 1 day SRT= 6 days SRT= 20 days
Slow biodegradation rateand low sorption
pKa=4.18
Log Kow=4.02
kb=0.0004/day
29%
2%
69%
Fraction lost due to biodegradation Fraction lost due to sorption Fraction of PPCP remaining
Summary of the Findings Volatilization has little effect on the removal of these
pharmaceuticals and antiseptics Biodegradation loss was the most sensitive loss mechanism;
it typically dominates removal efficiency. Low biodegradability results in high effluent concentrations
(e.g.,diclofenac) Although sorption may influence PPCP concentrations in
sludge, it has a limited effect on effluent concentrations in atypical STP
Sorption can even enhance biodegradation losses byproviding a “reservoir”
Increasing SRT would increase PPCP removal forbiodegradable chemicals, but will decrease PPCP removalfor those few cases of PPCPs that sorb but are recalcitrant tobiodegradation