examining the influence of operating characteristics on ... the influence of operating...

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

AntisepticsTriclosan

Biphenylol

Chlorophene

Biosol

PCMX

P-chloro-m-cresol

Anticonvulsant DrugsValproic Acid Phenytoin

Gabapentin Phenobarbital

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




Gemfibrozil



Phenobarbital



Biphenylol

Chlorophene

Co

nce

ntra

tion

(µg

/L)

0

0.2

0.8

1

0 10 20 30 40

Days




Gemfibrozil



Phenobarbital



Biphenylol

Chlorophene

Co

nce

ntra

tion

(µg

/L)

0.4

0.6

1.2

50

Days




Gemfibrozil



Phenobarbital



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

General Cases onLoss Mechanisms

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 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




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




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


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%


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

examining the influence of operating characteristics on ... the influence of operating...

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