developing tools to attenuate emerging contaminants in onsite wastewater treatment systems

Developing Tools to Attenuate Emerging Contaminants in Onsite Wastewater

Treatment Systems

Gurpal Toor and Chris Wilson

2015 USDA-NIFA NIWQP and AFRI Annual Project Directors’ Meeting, Greensboro, NC

Yun-Ya YangPost-doctoral Researcher

Used to treat and dispose relatively small amounts of wastewater-usually from houses and businesses (mostly in rural areas).

Evolution: French prototype (only septic tank). Introduced in 1883 in US. Drainfieldwas added in 1930-40s.

Today’s conventional septic system: Septic tank and drainfield or leachfield or soil treatment unit

Background: Septic Systems!

Florida:

~2.5 million septic systems. Used by 33% households or ~6 million people

Annual discharge: 156 billion gallons [40% located in coastal areas]

Population using septic systems to dispose household wastewater:

US: 25% of households

Europe: 26% of households

Australia: 20% of households

ObjectivesResearch: Investigate the occurrence, fate, and transport of selected emerging contaminants (EC) from septic systems to shallow groundwater.

Extension: Provide training, education, and outreach on the risk and ways to reduce groundwater contamination by EC.

3

Research Objective # 1:Fate of EC in Septic Drainfields

4Center of a DrainfieldEC

TransportEffluent

Septic tank

• Investigate occurrence of EC in effluent and drainfields.

• Determine the mass balance of selected EC in drainfields.

5

Methods: Construction of Drainfields

Drip line 9 L/day of effluent (3L/ft2)6 doses at 4 h intervals

Leachate

Effluent tank

Analysis• Samples were analyzed by solid-phase extraction and LC-MS/MS • Targeted 17 selected EC:

6

Markers/Tracers

(2 )

Pharmaceuticals(4)

Hormones(3)

PCPs(7)

Plasticizer(1)

Sucralose(sweetener)

Acetaminophen (analgesic)

Estrone(reproductive

hormone)

Triclosan(anti-microbial

agent)

Bisphenol-A (plasticizer)

Caffeine (stimulate)

Carbamazepine (anti-convulsant)

Estradiol (reproductive

hormone)

Triclocarban(antimicrobial agent)

Ibuprofen (anti-inflammatory)

Sulfamethoxazole(antibiotic)

Ethinyl Estradiol (ovulation inhibitor)

PARABENSButyl-Ethyl-Heptyl-Methyl-Propyl-(preservatives)

7

Detection Frequency (Jan-Aug)

• 14 EC were detected in the effluent • Most frequently detected compounds were:

• Markers: sucralose and caffeine (100%)• Pharmaceuticals: acetaminophen and ibuprofen (>90%) • Hormones: estrone (88%)• PCPs: triclosan, triclocarban, ethyl-, methyl-, and propyl paraben (>90%)• Bisphenol-A: 88%

0 20 40 60 80 100

SucraloseCaffeine

AcetaminophenCarbamazepine

IbuprofenSulfamethoxazole

Estrone17β-Estradiol

TriclosanTriclocarban

Butyl ParabenEthyl Paraben

Heptyl ParabenMethyl ParabenPropyl Paraben

Bisphenol-A

Septic tank effluent

SucraloseCaffeine

Acetaminophen

Ibuprofen

TriclosanTriclocarben

Ethyl Paraben

Methyl ParabenPropyl Paraben

Bisphenol‐A

N = 34

8

Detection Frequency (Jan-Aug)

• 12 EC were detected in leachate • The most frequency detected compounds:

• Markers: sucralose (83%)• Pharmaceuticals: ibuprofen (65%) • Hormones: <20%• PCPs: triclocarban (68%)• Bisphenol-A: 48%

0 20 40 60 80 100

SucraloseCaffeine



Estrone17β-Estradiol

TriclosanTriclocarban

Butyl ParabenEthyl Paraben


Bisphenol-A

Leachate

Sucralose

Triclocarben

Bisphenol‐A

Ibuprofen

N = 120

0100200300400

Jan-13 Feb-13 Mar-13 Apr-13 May-13 Jun-13 Jul-13 Aug-13

Rai

nfal

l (L)

0

20

40

60

80

100

120

140

160

180

200

0

10000

20000

30000

40000

50000

60000


Cl c

once

ntra

tion

(mg/

L)

Con

cent

ratio

n (n

g/L)

Sucralose

Caffeine

Acetaminophen

Carbamazepine

Ibuprofen

Sulfamethoxazole

Estrone

Triclosan

Triclocarban

Butyl Paraben

Ethyl Paraben

Methyl Paraben

Propyl Paraben

Bisphenol-A

Cl

Septic tank effluent25-54,000 ng/L

N = 34

9

Temporal Variability (Individual) in Effluent

10

Temporal Variability of Tracers in Leachate

0

200

400


Rai

nfal

l (L)

0

20

40

60

80

100

120

140

160

180

200

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000


Cl c

once

ntra

tion

(mg/

L)

Con

cent

ratio

n (n

g/L)

Sucralose

Cl

Leachate290-8,900 ng/L

N = 120

Temporal Variability (Individual) in Leachate

0

200

400


Rai

nfal

l (L)

N = 120

0

20

40

60

80

100

120

140

160

180

200

0

20

40

60

80

100

120

140


Cl c

once

ntra

tion

(mg/

L)

Con

cent

ratio

n (n

g/L)

Acetaminophen

Carbamazepine

Ibuprofen

Sulfamethoxazole

Estrone

Estradiol

Triclocarban

Heptyl Paraben

Methyl Paraben

Propyl Paraben

Bisphenol-A

Cl

Leachate6-130 ng/L

11

12

Summary: Mean Concentrations in Effluent & Leachate

• EC are present in effluent and septic drainfields• Conc. decreased as effluent percolated in vadose zone

N = 34 N = 120Septic tank effluent Leachate

Conc. were <50 ng/L

13

Mass Balance of EC in Drainfields• <14% of applied EC in STE recovered in leachate• >84% either remained (stored) in soil, degraded in unsaturated soil zone• <2% plant uptake (based on literature)

0 20 40 60 80 100

SucraloseCaffeine



EstroneEstradiolTriclosan

TriclocarbanButyl ParabenEthyl Paraben


Bisphenol-A

Leachate

STE

%Sucralose

CaffeineAcetaminophenCarbamazepine


EstroneEstradiolTriclosan

TriclocarbanButyl ParabenEthyl Paraben


Bisphenol-A

Leachate

Soil storage

14

Methods: Sorption and Biodegradation of EC

Sand

Soil

Soil collected from drainfields

IncubationStudy

60 d incubation study • 5 g sterilized (autoclaved) or

unsterilized soil/sand• Spiked 25 ng/g of EC• ~10% of moisture content• Anaerobic: N2 for 5 min• Aerobic: kept aerated• 3 replicates for each treatment• at 22°C in the dark

EC

Extraction

• What are the mechanisms of EC attenuation in the drainfields?

• Do microorganisms in the drainfields break down EC?

?

Sorption and Biodegradation?

Carbamazepine

cm

cm

Drip line

Sand

Sand

Soil

00.20.40.60.81

1.21.41.6

0 5 10 15 20 25

C t/C

0

Time (d)

Sand

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15 20 25

C t/C

0

Time (d)

Soil

Sorption (sterile)AerobicAnaerobic

• 77- 594 pg/g on the top and side 15

Leaching: 13%

Sorption and Biodegradation?

• 250- 2024 pg/g at the bottom

Acetaminophen

Sand

Sand

Soil

0

0.2

0.40.6

0.8

1

1.21.4

1.6

0 5 10 15 20 25

C t/C

0

Time (d)

Sand

00.20.40.60.81

1.21.41.6

0 5 10 15 20 25

C t/C

0

Time (d)

Soil


16

Leaching: 6%

Sorption or Biodegradation?

• 134-5109 pg/g in the middle

Sulfamethoxazole

Sand

Sand

Soil

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15 20 25

C t/C

0

Time (d)

Sand

00.20.40.60.81

1.21.41.6

0 5 10 15 20 25

C t/C

0

Time (d)

Soil


17

• Mechanisms of EC attenuation in the drainfield may include a combination of sorption and degradation in the vadose zone

Leaching: 3%

18

Septic drainfieldsEC

TransportEffluent

Septic tank

• Are EC applied with effluent are attenuated in septic drainfields before effluent reaches shallow groundwater?

Research Objective #2:Transport to Shallow Groundwater

19

Drip Dispersal

Gravel Trench

0.3 m gravel layer

Methods: Construction of Large Drainfields

P

L

Tensiometer

Lysimeter

Piezometer

Lysimeter

PiezometerTensiometer

• 120 L/day/drainfield (~3 L/ft2/day) in 6-doses at 4-hr intervals

T

Drip Dispersal System

30 cm Sand

15 cm Sand

Natural Soil

Drip line with emitters

Instruments• Tensiometers: 0.3, 0.6, 1.1 m• Suction lysimeters: 0.3, 0.6, 1.1 m• Piezometers: upto 3.7 m

Gravel Trench System

30 cm Sand

30 cm Gravel15 cm Sand

Natural Soil

Drip line with emitters

Instruments• Tensiometers: 0.3, 0.6, 1.1 m• Suction lysimeters: 0.3, 0.6, 1.1 m• Piezometers: upto 3.7 m

22

Transport from Effluent to Groundwater

Sulfamethoxazole

Mean = 4,242 ng/L

61.544.5 9.0

Bisphenol‐A327.9

42.3 30.4

ND

Acetaminophen

12.814

61.6

316.8

n = 30

Carbamazepine

57.3

14.7 15.8

1.5

• Do emerging contaminants persist in the watersheds that drain areas served by septic systems?

River SedimentsECWastewater

23

Research Objective # 3:Persistence in Stream Sediments

37 32

12

24

1439

6671

2535 23 24

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Buckho

rm Creek

Bell Creek

English Creek

Turkey

Creek

North Prong

Fishha

wk Creek

South Pron

g

Forest Agricultural Pasture Mined Urban

Land Use

12‐37% 1‐24% 2‐23% 0‐66% 4‐71%

24

270, 000 acre

Alafia River watershed, FLWWTP: No No No One One No NoSeptic: 0.37 0.12 0.10 0.11 0.57 0.007 0.034

Methods: Sampling Locations

Summary: EC in the Sediments

Concentrations (ng/g)

South Prong

North Prong 1

English Creek

Turkey Creek

North Prong 2

Buckhorn Creek

Bell Creek

FishhawkCreek 1

FishhawkCreek 2

Total (ng/g) 61.9 41.2 4.2 1.2 1.2 18.8 1.5 0.7 0.5

AcetaminophenCaffeine

CarbamazepineDiphenhydramine

LidocaineNicotine

Pseudoephedrine

Trimethoprim

25

Yang, Y. Y.; Toor, G. S.; Williams, C. F. 2015. Pharmaceuticals and organochlorine pesticides in sediments of an urban river in Florida, USA. Journal of Soils and Sediments. 15 (4): 993‐1004.

39

6671

24

0%10%20%30%40%50%60%70%80%90%

100%

Buckho

rm Creek

Bell Creek

English Creek

Turkey

Creek

North Prong

Fishha

wk Creek

South Pron

g

Forest Agricultural Pasture Mined Urban

Land useWWTP: No No No One One No NoSeptic: 0.37 0.12 0.10 0.11 0.57 0.007 0.034

Summary: EC in the Sediments

• Septic systems and the WWTP are the main sources.

26

27

Summary

• EC are present in effluent and septic drainfields

• Conc. decreased as effluent percolated in vadose zone

• Mechanisms of EC attenuation in the drainfielddepend on the compound and include sorption and/or degradation

• Septic systems contribute EC in rural and urbanizing watersheds

28

Extension Education (Continuing…)

• Presentations: “Managing EC in the Environment” in 2015 Tri-Country Water Summit and at other extension events

• Extension factsheets: :Pharmaceuticals and Personal Care Products”. “Trace Organics in Septic Systems”. Available at http://edis.ifas.ufl.edu

• Training: In-service training at the Extension Professional Association of Florida Annual Conference in Sept. 2015

• Citizens Education: Local magazines: “In the Field”