Fate and Transport of Micropollutants in the Drainfields of Onsite Wastewater Treatment Systems

Transcription

1 5 th University of Florida Water Institute Symposium, Fubruary 16, 2016, Gainesville, FL Fate and Transport of Micropollutants in the Drainfields of Onsite Wastewater Treatment Systems Yun-Ya Yang, Gurpal S Toor, P. Chris Wilson, and Clinton F. Williams Soil & Water Science Department University of Florida 1

2 What are Septic Systems? Septic systems are known as onsite wastewater treatment systems (OWTS) Used to treat and dispose of small amount of wastewater, usually from individual house or business Number of septic systems in US & Florida: USA: 25% households or 60 million people Annual discharge: 800 billion gallons Florida: 33% households or 6 million people Annual discharge: 156 billion gallons from ~2.5 million septic systems 40% of OWTS located in coastal areas Mound Septic System EPA 2011 Neptune Harbor Network

3 Why Worry About Micropollutants? Micropollutants originate from human activities: Pharmaceuticals: Over-the-counter, prescription, veterinary drugs Hormones Personal care products Endocrine disruptors mimic or block the action of the body s hormones Micropollutants can be present at very low levels (e.g., ng/l), but with potential to adversely impact humans and ecosystems Transport of micropollutants from septic systems can impact drinking water supplies

4 What Is the Fate of Micropollutants in the Environment? Animal Feeding Operations Land Application Micropollutants Biosolids Human Wastes, Treatment, Contraception Sewage/Septic Systems Agricultural Field Runoff Effluent Groundwater? River, Creek Drinking Water? Treatment Plant 4

5 Objectives Investigate the occurrence, behavior, and leaching of selected pharmaceuticals and personal care products (PPCPs) in septic drainfields Determine the mass balance of selected PPCPs in mounded drainfields of conventional septic systems Effluent Transport Septic tank PPCPs Septic drainfields 5

6 Methods: Construction of Small Drainfields 0.9 m 0.9 m 0.15 m Sand 0.3 m Sand Instruments: 10 multi-probe sensors Drip line 0.3 m Natural Soil 0.08 m Gravel + sand 1.5 m 6

7 Methods: Construction of Small Drainfields Effluent tank Drip line 9 L/day of effluent (3L/ft 2 ) 6 doses at 4 h intervals Leachate 7

8 Analysis Water samples were analyzed by solid-phase extraction and LC-MS/MS 17 selected PPCPs Markers 2 Pharmaceuticals 4 Hormones 3 PCPs 7 Plasticizer 1 Sucralose (sweetener) Acetaminophen (agalgesic) Estrone (reproductive hormone) Triclosan (antimicrobial agent) Bisphenol-A (plasticizer) Caffeine (stimulate) Carbamazepine (anticonvulsant) Estradiol (reproductive hormone) Triclocarban (antimicrobial agent) Ibuprofen (anti-inflammatory) Sulfamethoxazole (antibiotics) Ethinyl Estradiol (ovulation inhibitor) Butyl- Ethyl- Heptyl-Paraben Methyl- Propyl- (preservative) 8

9 PPCPs Detection Frequency (Jan-Aug 2013) N = 34 Sucralose Sucralose Caffeine Acetaminophen Carbamazepine Ibuprofen Sulfamethoxazole Estrone 17β-Estradiol Triclosan Triclocarben Triclocarban Butyl Paraben Ethyl Paraben Heptyl Paraben Methyl Paraben Propyl Paraben Bisphenol-A Acetaminophen Methyl Paraben Propyl Paraben Bisphenol-A Septic tank effluent PPCPs were detected in effluent The most frequency detected compounds: 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% 9

10 PPCPs Detection Frequency (Jan-Aug 2013) N = 120 Sucralose Sucralose Caffeine Acetaminophen Carbamazepine Ibuprofen Sulfamethoxazole Estrone 17β-Estradiol Triclosan Triclocarben Triclocarban Butyl Paraben Ethyl Paraben Heptyl Paraben Methyl Paraben Propyl Paraben Bisphenol-A Bisphenol-A Leachate PPCPs were detected in leachate The most frequency detected compounds: Markers: sucralose (83%) Pharmaceuticals: ibuprofen (65%) Hormones: <20% PCPs: triclocarban (68%) Bisphenol-A: 48% 10

11 Summary of Mean Concentrations of PPCPs in STE and Leachate N = 34 N = 120 Septic tank effluent Leachate Conc were <50 ng/l PPCPs are present in effluent and septic drainfields PPCPs concentrations decreased as effluent percolated in vadose zone 11

12 Mass Balance of Micropollutants in Drainfields <20% of applied PPCPs in STE recovered in leachate >80% either remained (stored) in soil, degraded in unsaturated soil zone <2% plant uptake Sucralose Caffeine Acetaminophen Carbamazepine Ibuprofen Sulfamethoxazole Estrone Estradiol Triclosan Triclocarban Butyl Paraben Ethyl Paraben Heptyl Paraben Methyl Paraben Propyl Paraben Bisphenol-A % Leachate STE Soil storage/ degradation 12

13 Where Are PPCPs in the Drainfields? Sand layer Soil layer Gravel layer 13

14 Spatial Distribution of PPCPs within Drainfield Acetaminophen pg/g on the bottom side Sand Sand Soil Soil 14

15 Spatial Distribution of PPCPs within Drainfield Acetaminophen pg/g on the bottom side Sand Soil 15

16 Spatial Distribution of PPCPs within Drainfield Acetaminophen Acetaminophen (Sand) Sterile Aerobic Anaerobic Acetaminophen (Soil) C t /C Microbial degradation C t /C Sterile Aerobic Anaerobic Microbial degradation Time (d) Time (d) 16

17 Spatial Distribution of PPCPs within Drainfield Carbamazepine pg/g on the top and side Sand Soil 17

18 Spatial Distribution of PPCPs within Drainfield Carbamazepine Carbamazepine relatively resistant to removal in the environment (Gomez et al. 2007) Carbamazepine (Sand) Sterile Aerobic Anaerobic Carbamazepine (Soil) Sterile Aerobic Anaerobic 1 1 C t /C C t /C Sand Time (d) 0 Soil Time (d) 18

19 Spatial Distribution of PPCPs within Drainfield Sulfamethoxazole pg/g in the middle Sand Soil 19

20 Spatial Distribution of PPCPs within Drainfield Sulfamethoxazole C t /C Sulfamethoxazole (Sand) Anaerobic Time (d) Sterile Aerobic C t /C Sulfamethoxazole (Soil) Sand Soil Time (d) Sterile Aerobic Anaerobic 20

21 Summary Micropollutants are present in effluent, drainfields, and leachate. Concentrations decreased as effluent percolated in vadose zone 21

22 Summary Mechanisms of micropollutants attenuation in the drainfield may include a combination of sorption and degradation in the vadose zone. 22

23 Thank You! Acknowledgements Many personnel Funding Agencies Mriganka De Melissa Francavilla Hui Wang Hazen and Sawyer Inc. Yun-Ya Yang 23

24 Questions? 24