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Thompson KA, Ray H, Gerrity D, Quiñones O, Dano E, Prieur J, Vanderford B, Steinle-Darling E, Dickenson ERV. Sources of per- and polyfluoroalkyl substances in an arid, urban, wastewater-dominated watershed. Sci Total Environ 2024:173361. [PMID: 38777060 DOI: 10.1016/j.scitotenv.2024.173361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/30/2024] [Accepted: 05/17/2024] [Indexed: 05/25/2024]
Abstract
Per- and polyfluoroalkyl substances (PFAS) enter surface waters from various sources such as wastewater treatment plants, fire-fighting sites, and PFAS-producing and PFAS-using industries. The Las Vegas Wash in Southern Nevada of the United States (U.S.) conveys wastewater effluent from the Las Vegas metropolitan area to Lake Mead, a drinking water source for millions of people in the U.S. Southwest. PFAS have previously been detected in the Las Vegas Wash, but PFAS sources were not identified. In this study, upstream wash tributaries, wastewater treatment effluents, and shallow groundwater wells were sampled in multiple campaigns during dry-weather conditions to investigate possible PFAS sources. Out of 19 PFAS, two short-chain PFAS-perfluoropentanoic acid (48 % of the total molar concentration) and perfluorohexanoic acid (32 %)-comprised the majority of PFAS loading measured in the Las Vegas Wash, followed by perfluorooctanoic acid (9 %). On a mass loading basis, the majority of total measured PFAS (approximately 90 %) and at least 48 % of each specific PFAS in the Las Vegas Wash likely entered via municipal wastewater effluents, of which the main source was likely residential wastewater. One of the drainage areas with a major civilian airport was identified as a potential source of relatively enriched perfluorosulfonic acids to a small wash tributary and shallow groundwater samples. Nonetheless, that tributary contributed at most 15 % of any specific PFAS to the mainstem of the Las Vegas Wash. Total PFAS concentrations were relatively low for the small tributary associated with an urban smaller airport and the lack of flow in the tributary channel immediately downgradient of an Air Force Base indicates the smaller airport and base were unlikely significant PFAS sources to the Las Vegas Wash. Overall, this study demonstrated effective PFAS source investigation methodology and the importance of wastewater effluent as a PFAS environmental pathway.
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Affiliation(s)
- Kyle A Thompson
- Water Quality Research and Development, Southern Nevada Water Authority, Henderson, NV, USA; Carollo Engineers, Inc., Austin, TX, USA
| | - Hannah Ray
- Water Quality Research and Development, Southern Nevada Water Authority, Henderson, NV, USA
| | - Daniel Gerrity
- Water Quality Research and Development, Southern Nevada Water Authority, Henderson, NV, USA
| | - Oscar Quiñones
- Water Quality Research and Development, Southern Nevada Water Authority, Henderson, NV, USA
| | - Eric Dano
- Water Resources, Southern Nevada Water Authority, Henderson, Las Vegas, NV, USA
| | - James Prieur
- Water Resources, Southern Nevada Water Authority, Henderson, Las Vegas, NV, USA
| | - Brett Vanderford
- Water Quality Research and Development, Southern Nevada Water Authority, Henderson, NV, USA
| | | | - Eric R V Dickenson
- Water Quality Research and Development, Southern Nevada Water Authority, Henderson, NV, USA.
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2
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Morrison C, Hogard S, Pearce R, Mohan A, Pisarenko AN, Dickenson ERV, von Gunten U, Wert EC. Critical Review on Bromate Formation during Ozonation and Control Options for Its Minimization. Environ Sci Technol 2023; 57:18393-18409. [PMID: 37363871 PMCID: PMC10690720 DOI: 10.1021/acs.est.3c00538] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/28/2023]
Abstract
Ozone is a commonly applied disinfectant and oxidant in drinking water and has more recently been implemented for enhanced municipal wastewater treatment for potable reuse and ecosystem protection. One drawback is the potential formation of bromate, a possible human carcinogen with a strict drinking water standard of 10 μg/L. The formation of bromate from bromide during ozonation is complex and involves reactions with both ozone and secondary oxidants formed from ozone decomposition, i.e., hydroxyl radical. The underlying mechanism has been elucidated over the past several decades, and the extent of many parallel reactions occurring with either ozone or hydroxyl radicals depends strongly on the concentration, type of dissolved organic matter (DOM), and carbonate. On the basis of mechanistic considerations, several approaches minimizing bromate formation during ozonation can be applied. Removal of bromate after ozonation is less feasible. We recommend that bromate control strategies be prioritized in the following order: (1) control bromide discharge at the source and ensure optimal ozone mass-transfer design to minimize bromate formation, (2) minimize bromate formation during ozonation by chemical control strategies, such as ammonium with or without chlorine addition or hydrogen peroxide addition, which interfere with specific bromate formation steps and/or mask bromide, (3) implement a pretreatment strategy to reduce bromide and/or DOM prior to ozonation, and (4) assess the suitability of ozonation altogether or utilize a downstream treatment process that may already be in place, such as reverse osmosis, for post-ozone bromate abatement. A one-size-fits-all approach to bromate control does not exist, and treatment objectives, such as disinfection and micropollutant abatement, must also be considered.
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Affiliation(s)
- Christina
M. Morrison
- Southern
Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, Nevada 89193-9954, United
States
| | - Samantha Hogard
- Hampton
Roads Sanitation District, P.O. Box 5911, Virginia Beach, Virginia 23471-0911, United
States
- The
Charles Edward Via, Jr. Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Robert Pearce
- Hampton
Roads Sanitation District, P.O. Box 5911, Virginia Beach, Virginia 23471-0911, United
States
- The
Charles Edward Via, Jr. Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Aarthi Mohan
- Southern
Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, Nevada 89193-9954, United
States
| | - Aleksey N. Pisarenko
- Trussell
Technologies, Inc., 380
Stevens Avenue, Suite 212, Solana Beach, California 92075, United States
| | - Eric R. V. Dickenson
- Southern
Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, Nevada 89193-9954, United
States
| | - Urs von Gunten
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, CH-8600 Dubendorf, Switzerland
- School of
Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne
(EPFL), 1015 Lausanne, Switzerland
| | - Eric C. Wert
- Southern
Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, Nevada 89193-9954, United
States
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3
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Schaefer CE, Hooper JL, Strom LE, Abusallout I, Dickenson ERV, Thompson KA, Mohan GR, Drennan D, Wu K, Guelfo JL. Occurrence of quantifiable and semi-quantifiable poly- and perfluoroalkyl substances in united states wastewater treatment plants. Water Res 2023; 233:119724. [PMID: 36801573 DOI: 10.1016/j.watres.2023.119724] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Both quantifiable and semi-quantifiable poly- and perfluoroalkyl substances (PFAS) were evaluated in the influent, effluent, and biosolids of 38 wastewater treatment plants. PFAS were detected in all streams at all facilities. For the means of the sums of detected, quantifiable PFAS concentrations were 98 ± 28 ng/L, 80 ± 24 ng/L, and 160,000 ± 46,000 ng/kg (dry weight basis) in the influent, effluent, and biosolids (respectively). In the aqueous influent and effluent streams this quantifiable PFAS mass was typically associated with perfluoroalkyl acids (PFAAs). In contrast, quantifiable PFAS in the biosolids were primarily polyfluoroalkyl substances that potentially serve as precursors to the more recalcitrant PFAAs. Results of the total oxidizable precursor (TOP) assay on select influent and effluent samples showed that semi-quantified (or, unidentified) precursors accounted for a substantial portion (21 to 88%) of the fluorine mass compared to that associated with quantified PFAS, and that this fluorine precursor mass was not appreciably transformed to perfluoroalkyl acids within the WWTPs, as influent and effluent precursor concentrations via the TOP assay were statistically identical. Evaluation of semi-quantified PFAS, consistent with results of the TOP assay, showed the presence of several classes of precursors in the influent, effluent, and biosolids; perfluorophosphonic acids (PFPAs) and fluorotelomer phosphate diesters (di-PAPs) occurred in 100 and 92% of biosolid samples, respectively. Analysis of mass flows showed that, for both quantified (on a fluorine mass basis) and semi-quantified PFAS, the majority of PFAS exited WWTPs through the aqueous effluent compared to the biosolids stream. Overall, these results highlight the importance of semi-quantified PFAS precursors in WWTPs, and the need to further understand the impacts of their ultimate fate in the environment.
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Affiliation(s)
| | | | - Laurel E Strom
- CDM Smith, 14432 SE Eastgate Way Suite 100, Bellevue, WA 98007, USA
| | | | - Eric R V Dickenson
- Water Quality Research and Development, Southern Nevada Water Authority, 1299 Burkholder Blvd., Henderson, NV, 89015, USA
| | - Kyle A Thompson
- Water Quality Research and Development, Southern Nevada Water Authority, 1299 Burkholder Blvd., Henderson, NV, 89015, USA; Carollo Engineers, 8911N Capital of Texas Hwy, Austin, TX 78759, USA
| | - Gayathri Ram Mohan
- Gwinnett County Department of Water Resources, Lawrenceville, GA 30045, USA
| | - Dina Drennan
- CDM Smith, 14432 SE Eastgate Way Suite 100, Bellevue, WA 98007, USA
| | - Ke Wu
- Department of Civil, Environmental & Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Jennifer L Guelfo
- Department of Civil, Environmental & Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
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4
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Ersan MS, Dickenson ERV. Pretreatment strategies for ion exchange to control brominated disinfection byproducts in potable reuse. Chemosphere 2022; 296:134068. [PMID: 35202669 DOI: 10.1016/j.chemosphere.2022.134068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/17/2022] [Accepted: 02/19/2022] [Indexed: 06/14/2023]
Abstract
The application of ion exchange (IX) resins to remove disinfection byproduct (DBP) precursors in wastewater effluents is challenging due to relatively high concentrations of competing anions. This study examined various pretreatment strategies to target competing ions to improve IX removal of DBP precursors, bromide and dissolved organic matter (DOM), measured as trihalomethane and haloacetic acid formation potentials (THMFP and HAAFP). IX batch experiments were performed with four commercial anion exchange (AIX) resins selective for bromide (BrP), DOM (A860), sulfate (MTA) and PFOA/PFOS (PFA), and one cation exchange (CIX) resin selective for iodide (CT). For single AIX treatments the bromide removal ranking was the following: PFA (58%) > MTA (51%) > BrP (43%) > A860 (16%), which corresponded with decreasing brominated THMFP removals and increasing bromine incorporation factors. For dual AIX combinations (PFA and BrP, MTA and BrP), either simultaneous or sequential treatments had the highest bromide (PFA + BrP [69%], MTA + BrP [67%], (PFA→BrP [77%], MTA→BrP [74%]) and Br-THMFP (THMFP [∼80%]) and Br-HAAFP (HAAFP [∼77%]) removals, and therefore the lowest fractions of brominated DBPs (Br-DBPs). Despite ozone (O3), biological active carbon (BAC), and granular activated carbon (GAC) pretreatments reducing the overall DOM concentration (33%), these pretreatment steps did not improve the bromide removals of the resins, although it did increase the Br-THMFP and Br-HAAFP removals by 2-38% and 13-20%, respectively. Nanofiltration (NF) pretreatment significantly removed sulfate (97%) resulting in an increased bromide removal of 19% by the AIX resins, which led to increased removal of Br-THMFP and Br-HAAFP by 93% and 96%, respectively. Among all the IX resins the CT resin had the highest bromide removal (83%) and lowest fraction of Br-DBPs. The results reveal pretreatment with existing technologies including AIX, O3/BAC/GAC, or NF can potentially enhance the removal of brominated DBP precursors by IX resins during potable reuse applications.
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Affiliation(s)
- Mahmut S Ersan
- Water Quality Research and Development Division, Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA; School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, 85287-5306, USA.
| | - Eric R V Dickenson
- Water Quality Research and Development Division, Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA.
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5
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Thompson KA, Dickenson ERV. Using machine learning classification to detect simulated increases of de facto reuse and urban stormwater surges in surface water. Water Res 2021; 204:117556. [PMID: 34481284 DOI: 10.1016/j.watres.2021.117556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/28/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Water quality events such as increases in stormwater or wastewater effluent in drinking water sources pose hazards to drinking water consumers. Stormwater and wastewater effluent enter Lake Mead-an important drinking water source in the southwest USA-via the Las Vegas Wash. Previous studies have applied machine learning and online instruments to detect contamination in water distribution systems. However, alert systems at drinking water intakes would provide more time for corrective action. An array of online instruments measuring pH, conductivity, redox potential, turbidity, temperature, tryptophan-like fluorescence, UV absorbance (UVA254), TOC, and chlorophyll-a was fed raw water directly from Lake Mead. Wastewater effluent, dry weather Las Vegas Wash, and storm-impacted Las Vegas Wash samples were blended into the instrument inlets at known ratios to simulate three types of adverse water quality events. Data preprocessing was conducted to correct for diurnal patterns or instrument drift. Supervised machine learning was conducted using previously published models in R. Ninety-nine models were screened on the raw data. Eight high-performing models were evaluated in-depth and optimized. Weighted k-Nearest Neighbors, Single C5.0 Ruleset, Mixture Discriminant Analysis, and an ensemble of these three models had accuracy over 97% when assigning test set data among three classes (Normal, Event, or Maintenance). The ensemble detected all event types at the earliest timepoint and had one false positive that was not a lag error (i.e., consecutively following a true positive). Omitting Maintenance, the Adaboost model had over 99% test set accuracy and zero false positives that were not lag errors. Data preprocessing was beneficial, but the optimal methods were model-specific. All nine water quality variables were useful for most models, but UVA254 and turbidity were most important.
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Affiliation(s)
- Kyle A Thompson
- Water Quality Research and Development, Southern Nevada Water Authority, 1299 Burkholder Blvd., Henderson, United States; Carollo Engineers, Inc., 8911 N Capital of Texas Hwy, Austin, TX 78759, United States.
| | - Eric R V Dickenson
- Water Quality Research and Development, Southern Nevada Water Authority, 1299 Burkholder Blvd., Henderson, United States.
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6
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Vatankhah H, Riley SM, Murray C, Quiñones O, Steirer KX, Dickenson ERV, Bellona C. Simultaneous ozone and granular activated carbon for advanced treatment of micropollutants in municipal wastewater effluent. Chemosphere 2019; 234:845-854. [PMID: 31247495 DOI: 10.1016/j.chemosphere.2019.06.082] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 05/13/2019] [Accepted: 06/07/2019] [Indexed: 06/09/2023]
Abstract
The main objective of this study was to compare the efficacy of ozone (O3) and O3 with granular activated carbon (GAC) (O3/GAC) at pilot-scale for the enhanced removal of micropollutants (MPs) from wastewater effluent. The results revealed enhanced removal of tris (2-carboxylethyl) phosphine (TCEP), sucralose, and meprobamate during the O3/GAC treatment experiments compared to the sum of their removal during isolated ozonation and GAC adsorption experiments. The long-term O3/GAC experiment showed the promotive effect of GAC substantially decreased after 20 h of O3 exposure. This decreased performance correlates with changes to GAC surface properties caused by O3. After 6 h of operation, O3 initially led to an increase in Brunauer-Emmett-Teller (BET) surface area on the GAC improving the elimination level of investigated MPs (except N-nitrosomorpholine (NMOR)). However, after 20 h of exposure, O3 ultimately caused structural damages to the GAC surface, decreased the BET surface area in the final stages of the experiment, and a 4-fold increase in O1s:C1s ratio on the GAC surface was observed due to an increase in surface acidic functional groups caused by O3 treatment.
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Affiliation(s)
- Hooman Vatankhah
- Department of Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO, 80401, USA; National Science Foundation Engineering Research Center for Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt), USA; Montrose Environmental Group, Inc., 1 Park Plaza, Irvine, CA, 92614, USA
| | - Stephanie M Riley
- Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV, 89015, USA
| | - Conner Murray
- Department of Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO, 80401, USA
| | - Oscar Quiñones
- Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV, 89015, USA
| | - K Xerxes Steirer
- Department of Physics, Colorado School of Mines, 1500 Illinois Street, Golden, CO, 80401, USA
| | - Eric R V Dickenson
- Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV, 89015, USA
| | - Christopher Bellona
- Department of Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO, 80401, USA; National Science Foundation Engineering Research Center for Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt), USA.
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7
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Glover CM, Verdugo EM, Trenholm RA, Dickenson ERV. N-nitrosomorpholine in potable reuse. Water Res 2019; 148:306-313. [PMID: 30390511 DOI: 10.1016/j.watres.2018.10.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 09/30/2018] [Accepted: 10/04/2018] [Indexed: 06/08/2023]
Abstract
As potable reuse guidelines and regulations continue to develop, the presence of N-nitrosamines is a primary concern because of their associated health concerns. In this study, bench-, pilot-, and full-scale tests were conducted to focus on the occurrence and treatment of N-nitrosomorpholine (NMOR) in United States (U.S.) potable reuse systems. Out of twelve U.S. wastewater effluents collected, ambient NMOR was detected in eleven (average = 20 ± 18 ng/L); in contrast, only two of the thirteen surface water and stormwater samples had NMOR. Across all of these samples maximum formation potential by chloramination produced an average increase of 3.6 ± 1.8 ng/L. This result underscores the need to understand the sources of NMOR as it is not likely a disinfection byproduct and it is not known to be commercially produced within the U.S. At the pilot-scale, three potable reuse systems were evaluated for ambient NMOR with oxidation (i.e., chlorination and ozonation), biofiltration, and granular activated carbon (GAC). Both pre-oxidation and biofiltration were ineffective at mitigating NMOR during long-term pilot plant operation (at least eight-months). GAC adsorbers were the only pilot-scale treatment to remove NMOR; however, complete breakthrough occurred rapidly from <2000 to 10,000 bed volumes. For comparison, a full-scale reverse osmosis (RO) potable reuse system was monitored for a year and confirmed that RO effectively removes NMOR. Systematic bench-scale UV-advanced oxidation experiments were undertaken to assess the mitigation potential for NMOR. At a fluence dose of 325 ± 10 mJ/cm2, UV alone degraded 90% of the NMOR present. The addition of 5 mg/L hydrogen peroxide did not significantly decrease the UV dose required for one-log removal. These data illustrate that efficient NMOR removal from potable reuse systems is limited to RO or UV treatment.
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Affiliation(s)
- Caitlin M Glover
- Water Quality Research and Development Division, Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA.
| | - Edgard M Verdugo
- Water Quality Research and Development Division, Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA
| | - Rebecca A Trenholm
- Water Quality Research and Development Division, Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA
| | - Eric R V Dickenson
- Water Quality Research and Development Division, Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA.
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8
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Glover CM, Quiñones O, Dickenson ERV. Removal of perfluoroalkyl and polyfluoroalkyl substances in potable reuse systems. Water Res 2018; 144:454-461. [PMID: 30071400 DOI: 10.1016/j.watres.2018.07.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/05/2018] [Accepted: 07/07/2018] [Indexed: 06/08/2023]
Abstract
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a group of persistent contaminants that have been identified throughout the aquatic environment. In this study, ten targeted perfluoroalkyl acids (PFAAs), three targeted PFAA precursors, and non-targeted PFAA precursors were monitored in four full- and pilot-scale potable reuse plants at each stage of advanced treatment. Non-targeted PFAA precursors were quantified by applying a total oxidizable precursor assay in which PFAA precursors are oxidized by hydroxyl radicals to targeted PFAAs. Two of the potable reuse systems had membrane-based treatments with reverse osmosis and UV-advanced oxidation (RO-UV/AOP) and two used ozone, biological activated carbon filtration and granular activated carbon adsorption (O3-BAC-GAC). The total targeted PFAAs in the four tertiary effluents, the influent sources for the potable reuse systems, ranged from 52 to 227 ng/L with non-targeted PFAA precursors accounting for 30-67% of total PFASs on a molar basis. The RO-UV/AOP treatment trains reduced PFAAs and PFAA precursors to below their method reporting limits through the barrier provided by RO. The O3-BAC-GAC based treatment trains reduced, but did not completely remove PFAAs or PFAA precursors and the PFASs present in the product water were primarily shorter-chain PFAAs, some of which lack human health guidance values for drinking water. The relative fraction of targeted shorter-chain PFAAs increased after each treatment step indicating that there was preferential removal of the PFAA precursors and longer-chain PFAAs. This study provides new insight on the concentrations and treatment of PFAA precursors through potable reuse treatment systems.
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Affiliation(s)
- Caitlin M Glover
- Water Quality Research and Development Division, Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA.
| | - Oscar Quiñones
- Water Quality Research and Development Division, Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA
| | - Eric R V Dickenson
- Water Quality Research and Development Division, Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA.
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9
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Greenstein KE, Lew J, Dickenson ERV, Wert EC. Investigation of biotransformation, sorption, and desorption of multiple chemical contaminants in pilot-scale drinking water biofilters. Chemosphere 2018; 200:248-256. [PMID: 29494905 DOI: 10.1016/j.chemosphere.2018.02.107] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/15/2018] [Accepted: 02/17/2018] [Indexed: 06/08/2023]
Abstract
The evolving demands of drinking water treatment necessitate processes capable of removing a diverse suite of contaminants. Biofiltration can employ biotransformation and sorption to remove various classes of chemicals from water. Here, pilot-scale virgin anthracite-sand and previously used biological activated carbon (BAC)-sand dual media filters were operated for ∼250 days to assess removals of 0.4 mg/L ammonia as nitrogen, 50-140 μg/L manganese, and ∼100 ng/L each of trace organic compounds (TOrCs) spiked into pre-ozonated Colorado River water. Anthracite achieved complete nitrification within 200 days and started removing ibuprofen at 85 days. Limited manganese (10%) removal occurred. In contrast, BAC completely nitrified ammonia within 113 days, removed all manganese at 43 days, and exhibited steady state removal of most TOrCs by 140 days. However, during the first 140 days, removal of caffeine, DEET, gemfibrozil, naproxen, and trimethoprim decreased, suggesting a shift from sorption to biotransformation. Acetaminophen and sulfamethoxazole were removed at consistent levels, with complete removal of acetaminophen achieved throughout the study; ibuprofen removal increased with time. When subjected to elevated (1 μg/L) concentrations of TOrCs, BAC removed larger masses of chemicals; with a subsequent decrease and ultimate cease in the TOrCs spike, caffeine, DEET, gemfibrozil, and trimethoprim notably desorbed. By the end of operation, anthracite and BAC exhibited equivalent quantities of biomass measured as adenosine triphosphate, but BAC harbored greater microbial diversity (examined with 16S rRNA sequencing). Improved insight was gained regarding concurrent biotransformation, sorption, and desorption of multiple organic and inorganic contaminants in pilot-scale drinking water biofilters.
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Affiliation(s)
- Katherine E Greenstein
- Southern Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, NV 89193-9954, United States
| | - Julia Lew
- Southern Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, NV 89193-9954, United States
| | - Eric R V Dickenson
- Southern Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, NV 89193-9954, United States
| | - Eric C Wert
- Southern Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, NV 89193-9954, United States.
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10
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Inyang M, Dickenson ERV. The use of carbon adsorbents for the removal of perfluoroalkyl acids from potable reuse systems. Chemosphere 2017; 184:168-175. [PMID: 28586657 DOI: 10.1016/j.chemosphere.2017.05.161] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/08/2017] [Accepted: 05/28/2017] [Indexed: 06/07/2023]
Abstract
Bench- and pilot-scale sorption tests were used to probe the performance of several biochars at removing perfluoroalkyl acids (PFAA) from field waters, compared to granular activated carbon (GAC). Screening tests using organic matter-free water resulted in hardwood (HWC) (Kd = 41 L g-1) and pinewood (PWC) (Kd = 49 L g-1) biochars having the highest perfluorooctanoic acid (PFOA) removal performance that was comparable to bituminous coal GAC (Kd = 41 L g-1). PWC and HWC had a stronger affinity for PFOA sorbed in Lake Mead surface water (KF = 11 mg(1-n) Ln g-1) containing a lower (2 mg L-1) dissolved organic carbon (DOC) concentration than in a tertiary-filtered wastewater (KF = 8 mg(1-n) Ln g-1) with DOC of 4.9 mg L-1. A pilot-scale study was performed using three parallel adsorbers (GAC, anthracite, and HWC biochar) treating the same tertiary-filtered wastewater. Compared to HWC, and anthracite, GAC was the most effective in mitigating perfluoropentanoic acid (PFPnA), perfluorohexanoic acid (PHxA), PFOA, perfluorooctane sulfonic acid (PFOS), and DOC (45-67% removed at 4354 bed volumes) followed by HWC, and then anthracite. Based on bench- and pilot-scale results, shorter-chain PFAA [perfluorobutanoic acid (PFBA), PFPnA, or PFHxA] were more difficult to remove with both biochar and GAC than the longer-chain, PFOS and PFOA.
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Affiliation(s)
- Mandu Inyang
- Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA.
| | - Eric R V Dickenson
- Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA.
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11
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Woods-Chabane GC, Glover CM, Marti EJ, Dickenson ERV. A novel assay to measure tertiary and quaternary amines in wastewater: An indicator for NDMA wastewater precursors. Chemosphere 2017; 179:298-305. [PMID: 28376393 DOI: 10.1016/j.chemosphere.2017.03.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 06/07/2023]
Abstract
This study examined the potential of using a novel bulk amine assay as an approximation for the tertiary and quaternary amine load in wastewaters and surface water samples, and this approximation was compared to N-nitrosodimethylamine (NDMA) formation potential using chloramines. An existing colorimetric method was examined and optimized for the detection of amines in environmental water samples. The method consists of liquid-liquid extraction followed by a catalyzed reaction to form a yet-undefined product that is known to be both a strong chromophore and fluorophore. Previous work verified that this reaction was effectively catalyzed by a number of compounds containing tertiary and quaternary amine moieties. Many tertiary and quaternary compounds are also efficient producers of NDMA under chloramination conditions, and a linear correlation was consequently derived from the bulk amine signals vs. NDMA formation potential in various wastewater samples (R2 = 0.74; n = 24; p-value < 0.05). The results provide evidence that approximately 2% of the tertiary and quaternary amines measured can form NDMA and an estimated 0.01-1.3% of nitrogen in dissolved organic nitrogen originates from these bulk amines. The normalization of NDMA concentration by the amine measurement revealed that ozone effectively destroyed those tertiary and quaternary amine structures more likely to form NDMA in treated wastewater samples. This bulk amine assay illustrates that proxy measurements of tertiary and quaternary amines can be linked to the NDMA formation potential of a given sample, and this approach may prove useful as a characterizing tool for NDMA precursors in wastewater.
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Affiliation(s)
- Gwen C Woods-Chabane
- Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA.
| | - Caitlin M Glover
- Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA
| | - Erica J Marti
- Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA
| | - Eric R V Dickenson
- Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV, 89193-9954, USA.
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12
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Stratton GR, Dai F, Bellona CL, Holsen TM, Dickenson ERV, Mededovic Thagard S. Plasma-Based Water Treatment: Efficient Transformation of Perfluoroalkyl Substances in Prepared Solutions and Contaminated Groundwater. Environ Sci Technol 2017; 51:1643-1648. [PMID: 28080043 DOI: 10.1021/acs.est.6b04215] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A process based on electrical discharge plasma was tested for the transformation of perfluorooctanoic acid (PFOA). The plasma-based process was adapted for two cases, high removal rate and high removal efficiency. During a 30 min treatment, the PFOA concentration in 1.4 L of aqueous solutions was reduced by 90% with the high rate process (76.5 W input power) and 25% with the high efficiency process (4.1 W input power). Both achieved remarkably high PFOA removal and defluorination efficiencies compared to leading alternative technologies. The high efficiency process was also used to treat groundwater containing PFOA and several cocontaminants including perfluorooctanesulfonate (PFOS), demonstrating that the process was not significantly affected by cocontaminants and that the process was capable of rapidly degrading PFOS. Preliminary investigation into the byproducts showed that only about 10% of PFOA and PFOS is converted into shorter-chain perfluoroalkyl acids (PFAAs). Investigation into the types of reactive species involved in primary reactions with PFOA showed that hydroxyl and superoxide radicals, which are typically the primary plasma-derived reactive species, play no significant role. Instead, scavenger experiments indicated that aqueous electrons account for a sizable fraction of the transformation, with free electrons and/or argon ions proposed to account for the remainder.
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Affiliation(s)
| | | | - Christopher L Bellona
- Department of Civil and Environmental Engineering, Colorado School of Mines , Golden, Colorado 80401, United States
| | | | - Eric R V Dickenson
- Southern Nevada Water Authority, Water Quality Research and Development Division, Henderson, Nevada 89015, United States
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13
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Zeng T, Glover CM, Marti EJ, Woods-Chabane GC, Karanfil T, Mitch WA, Dickenson ERV. Relative Importance of Different Water Categories as Sources of N-Nitrosamine Precursors. Environ Sci Technol 2016; 50:13239-13248. [PMID: 27993049 DOI: 10.1021/acs.est.6b04650] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A comparison of loadings of N-nitrosamines and their precursors from different source water categories is needed to design effective source water blending strategies. Previous research using Formation Potential (FP) chloramination protocols (high dose and prolonged contact times) raised concerns about precursor loadings from various source water categories, but differences in the protocols employed rendered comparisons difficult. In this study, we applied Uniform Formation Condition (UFC) chloramination and ozonation protocols mimicking typical disinfection practice to compare loadings of ambient specific and total N-nitrosamines as well as chloramine-reactive and ozone-reactive precursors in 47 samples, including 6 pristine headwaters, 16 eutrophic waters, 4 agricultural runoff samples, 9 stormwater runoff samples, and 12 municipal wastewater effluents. N-Nitrosodimethylamine (NDMA) formation from UFC and FP chloramination protocols did not correlate, with NDMA FP often being significant in samples where no NDMA formed under UFC conditions. N-Nitrosamines and their precursors were negligible in pristine headwaters. Conventional, and to a lesser degree, nutrient removal wastewater effluents were the dominant source of NDMA and its chloramine- and ozone-reactive precursors. While wastewater effluents were dominant sources of TONO and their precursors, algal blooms, and to a lesser degree agricultural or stormwater runoff, could be important where they affect a major fraction of the water supply.
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Affiliation(s)
- Teng Zeng
- Department of Civil and Environmental Engineering, Stanford University , 473 Via Ortega, Stanford, California 94305, United States
- National Science Foundation Engineering Research Center for Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt), 473 Via Ortega, Stanford, California 94305, United States
- Department of Civil and Environmental Engineering, Syracuse University , 151 Link Hall, Syracuse, New York 13244, United States
| | - Caitlin M Glover
- Water Quality Research and Development Division, Southern Nevada Water Authority , Henderson, Nevada 89015, United States
| | - Erica J Marti
- Water Quality Research and Development Division, Southern Nevada Water Authority , Henderson, Nevada 89015, United States
| | - Gwen C Woods-Chabane
- Water Quality Research and Development Division, Southern Nevada Water Authority , Henderson, Nevada 89015, United States
- HDR, Inc., 431 W Baseline Road, Claremont, California 91711, United States
| | - Tanju Karanfil
- Department of Environmental Engineering and Earth Sciences, Clemson University , 342 Computer Court, Anderson, South Carolina 29625, United States
| | - William A Mitch
- Department of Civil and Environmental Engineering, Stanford University , 473 Via Ortega, Stanford, California 94305, United States
- National Science Foundation Engineering Research Center for Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt), 473 Via Ortega, Stanford, California 94305, United States
| | - Eric R V Dickenson
- Water Quality Research and Development Division, Southern Nevada Water Authority , Henderson, Nevada 89015, United States
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14
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Brouillard BM, Dickenson ERV, Mikkelson KM, Sharp JO. Water quality following extensive beetle-induced tree mortality: Interplay of aromatic carbon loading, disinfection byproducts, and hydrologic drivers. Sci Total Environ 2016; 572:649-659. [PMID: 27515013 DOI: 10.1016/j.scitotenv.2016.06.106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/14/2016] [Accepted: 06/14/2016] [Indexed: 06/06/2023]
Abstract
The recent bark beetle epidemic across western North America may impact water quality as a result of elevated organic carbon release and hydrologic shifts associated with extensive tree dieback. Analysis of quarterly municipal monitoring data from 2004 to 2014 with discretization of six water treatment facilities in the Rocky Mountains by extent of beetle impact revealed a significant increasing trend in total organic carbon (TOC) and total trihalomethane (TTHM) production within high (≳50% areal infestation) beetle-impacted watersheds while no or insignificant trends were found in watersheds with lower impact levels. Alarmingly, the TTHM concentration trend in the high impact sites exceeded regulatory maximum contaminant levels during the most recent two years of analysis (2013-14). To evaluate seasonal differences, explore the interplay of water quality and hydrologic processes, and eliminate variability associated with municipal reporting, these treatment facilities were targeted for more detailed surface water sampling and characterization. Surface water samples collected from high impact watersheds exhibited significantly higher TOC, aromatic signatures, and disinfection byproduct (DBP) formation potential than watersheds with lower infestation levels. Spectroscopic analyses of surface water samples indicated that these heightened DBP precursor levels are a function of both elevated TOC loading and increased aromatic character. This association was heightened during precipitation and runoff events in high impact sites, supporting the hypothesis that altered hydrologic flow paths resulting from tree mortality mobilize organic carbon and elevate DBP formation potential for several months after runoff ceases. The historical trends found here likely underestimate the full extent of TTHM shifts due to monitoring biases with the extended seasonal release of DBP precursors increasing the potential for human exposure. Collectively, our analysis suggests that while water quality impacts continue to rise nearly one decade after infestation, significant increases in TOC mobilization and DBP precursors are limited to watersheds that experience extensive tree mortality.
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Affiliation(s)
- Brent M Brouillard
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA; Hydrologic Science and Engineering Program, Colorado School of Mines, Golden, CO 80401, USA
| | - Eric R V Dickenson
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA; Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA
| | - Kristin M Mikkelson
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA; Hydrologic Science and Engineering Program, Colorado School of Mines, Golden, CO 80401, USA
| | - Jonathan O Sharp
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA; Hydrologic Science and Engineering Program, Colorado School of Mines, Golden, CO 80401, USA.
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15
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Woods GC, Dickenson ERV. Natural attenuation of NDMA precursors in an urban, wastewater-dominated wash. Water Res 2016; 89:293-300. [PMID: 26706247 DOI: 10.1016/j.watres.2015.11.058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 11/07/2015] [Accepted: 11/25/2015] [Indexed: 06/05/2023]
Abstract
N-Nitrosodimethylamine (NDMA) is a disinfection by-product (DBP) that is potentially carcinogenic and has been found to occur in drinking water treatment systems impacted with treated wastewater. A major gap in NDMA research is an understanding of the persistence of wastewater-derived precursors within the natural environment. This research sought to fill this knowledge gap by surveying NDMA precursors across the length of a wastewater effluent-dominated wash. Significant precursor reduction (17%) was found to occur from introduction into the wash to a point 9 h downstream. This reduction translates into a half-life of roughly 32 h for bulk NDMA precursors. Further laboratory experiments examining rates of photolysis, biodegradation and loss to sediments, illustrated that both photolytic and biological degradation were effective removal mechanisms for NDMA precursors. Loss to sediments that were acquired from the wash did not appear to reduce NDMA precursors in the water column, although a control conducted with DI water provided evidence that significant NDMA precursors could be released from autoclaved sediments (suggesting that sorption does occur). Microbial experiments revealed that microbes associated with sediments were much more effective at degrading precursors than microbes within the water column. Overall, this study demonstrated that natural processes are capable of attenuating NDMA precursors relatively quickly within the environment, and that utilities might benefit from maximizing source water residency time in the environment, prior to introduction into treatment plants.
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Affiliation(s)
- Gwen C Woods
- Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA.
| | - Eric R V Dickenson
- Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA.
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16
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Hyland KC, Blaine AC, Dickenson ERV, Higgins CP. Accumulation of contaminants of emerging concern in food crops-part 1: Edible strawberries and lettuce grown in reclaimed water. Environ Toxicol Chem 2015; 34:2213-21. [PMID: 25988333 DOI: 10.1002/etc.3066] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 02/09/2015] [Accepted: 05/12/2015] [Indexed: 06/04/2023]
Abstract
Contaminants of emerging concern present in domestic waste streams include a highly diverse group of potentially biologically active compounds that can be detected at trace levels in wastewater. Concerns about potential uptake into crops arise when reclaimed water is used in food crop production. The present study investigated how 9 contaminants of emerging concern in reclaimed water are taken up into edible portions of two food crops. Two flame retardant chemicals, tris(1-chloro-2-propyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) and several polar pharmaceuticals (carbamazepine, diphenhydramine, sulfamethoxazole, and trimethoprim) accumulated in a linear, concentration-dependent manner in lettuce (Lactuca sativa) irrigated with reclaimed water, suggesting passive uptake of both neutral and ionizable chemical contaminants in lettuce. Furthermore, concentration-dependent accumulation of TCEP and TCPP from reclaimed water was also observed in strawberry fruits (Fragaria ananassa). Collectively, these data suggest that highly polar or charged contaminants can be taken up by crops from water bearing contaminants of emerging concern and can be accumulated in the edible portions. Using these data, however, estimates of human exposure to these contaminants from reclaimed water food crop accumulation suggest that exposure to the contaminants of emerging concern examined in the present study is likely substantially lower than current exposure guidelines.
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Affiliation(s)
- Katherine C Hyland
- Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado, USA
| | - Andrea C Blaine
- Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado, USA
| | - Eric R V Dickenson
- Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado, USA
- Southern Nevada Water Authority, Las Vegas, Nevada, USA
| | - Christopher P Higgins
- Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado, USA
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17
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Woods GC, Trenholm RA, Hale B, Campbell Z, Dickenson ERV. Seasonal and spatial variability of nitrosamines and their precursor sources at a large-scale urban drinking water system. Sci Total Environ 2015; 520:120-126. [PMID: 25804879 DOI: 10.1016/j.scitotenv.2015.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/02/2015] [Accepted: 03/03/2015] [Indexed: 06/04/2023]
Abstract
Nitrosamines are considered to pose greater health risks than currently regulated DBPs and are subsequently listed as a priority pollutant by the EPA, with potential for future regulation. Denver Water, as part of the EPA's Unregulated Contaminant Monitoring Rule 2 (UCMR2) monitoring campaign, found detectable levels of N-nitrosodimethylamine (NDMA) at all sites of maximum residency within the distribution system. To better understand the occurrence of nitrosamines and nitrosamine precursors, Denver Water undertook a comprehensive year-long monitoring campaign. Samples were taken every two weeks to monitor for NDMA in the distribution system, and quarterly sampling events further examined 9 nitrosamines and nitrosamine precursors throughout the treatment and distribution systems. NDMA levels within the distribution system were typically low (>1.3 to 7.2 ng/L) with a remote distribution site (frequently >200 h of residency) experiencing the highest concentrations found. Eight other nitrosamines (N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitroso-di-n-propylamine, N-nitroso-di-n-butylamine, N-nitroso-di-phenylamine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosomorpholine) were also monitored but none of these 8, or precursors of these 8 [as estimated with formation potential (FP) tests], were detected anywhere in raw, partially-treated or distribution samples. Throughout the year, there was evidence that seasonality may impact NDMA formation, such that lower temperatures (~5-10°C) produced greater NDMA than during warmer months. The year of sampling further provided evidence that water quality and weather events may impact NDMA precursor loads. Precursor loading estimates demonstrated that NDMA precursors increased during treatment (potentially from cationic polymer coagulant aids). The precursor analysis also provided evidence that precursors may have increased further within the distribution system itself. This comprehensive study of a large-scale drinking water system provides insight into the variability of NDMA occurrence in a chloraminated system, which may be impacted by seasonality, water quality changes and/or the varied origins of NDMA precursors within a given system.
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Affiliation(s)
- Gwen C Woods
- Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV 89193-9954, USA.
| | - Rebecca A Trenholm
- Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV 89193-9954, USA
| | - Bruce Hale
- Denver Water, 1600 West 12th Avenue, Denver, CO 80204-3412, USA
| | - Zeke Campbell
- Denver Water, 1600 West 12th Avenue, Denver, CO 80204-3412, USA
| | - Eric R V Dickenson
- Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV 89193-9954, USA.
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18
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Marti EJ, Pisarenko AN, Peller JR, Dickenson ERV. N-nitrosodimethylamine (NDMA) formation from the ozonation of model compounds. Water Res 2015; 72:262-270. [PMID: 25241951 DOI: 10.1016/j.watres.2014.08.047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/19/2014] [Accepted: 08/26/2014] [Indexed: 06/03/2023]
Abstract
Nitrosamines are a class of toxic disinfection byproducts commonly associated with chloramination, of which several were included on the most recent U.S. EPA Contaminant Candidate List. Nitrosamine formation may be a significant barrier to ozonation in water reuse applications, particularly for direct or indirect potable reuse, since recent studies show direct formation during ozonation of natural water and treated wastewaters. Only a few studies have identified precursors which react with ozone to form N-nitrosodimethylamine (NDMA). In this study, several precursor compound solutions, prepared in ultrapure water and treated wastewater, were subjected to a 10 M excess of ozone. In parallel experiments, the precursor solutions in ultrapure water were exposed to gamma radiation to determine NDMA formation as a byproduct of reactions of precursor compounds with hydroxyl radicals. The results show six new NDMA precursor compounds that have not been previously reported in the literature, including compounds with hydrazone and carbamate moieties. Molar yields in deionized water were 61-78% for 3 precursors, 12-23% for 5 precursors and <4% for 2 precursors. Bromide concentration was important for three compounds (1,1-dimethylhydrazine, acetone dimethylhydrazone and dimethylsulfamide), but did not enhance NDMA formation for the other precursors. NDMA formation due to chloramination was minimal compared to formation due to ozonation, suggesting distinct groups of precursor compounds for these two oxidants. Hydroxyl radical reactions with the precursors will produce NDMA, but formation is much greater in the presence of molecular ozone. Also, hydroxyl radical scavenging during ozonation leads to increased NDMA formation. Molar conversion yields were higher for several precursors in wastewater as compared to deionized water, which could be due to catalyzed reactions with constituents found in wastewater or hydroxyl radical scavenging.
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Affiliation(s)
- Erica J Marti
- Southern Nevada Water Authority, Applied Research & Development Center, PO Box 99954, Las Vegas, NV 89193, USA; University of Nevada, Las Vegas, Civil & Environmental Engineering and Construction, Las Vegas, NV, USA.
| | | | - Julie R Peller
- Indiana University Northwest, Chemistry Department, Gary, IN, USA.
| | - Eric R V Dickenson
- Southern Nevada Water Authority, Applied Research & Development Center, PO Box 99954, Las Vegas, NV 89193, USA.
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19
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20
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Blaine AC, Rich CD, Sedlacko EM, Hyland KC, Stushnoff C, Dickenson ERV, Higgins CP. Perfluoroalkyl acid uptake in lettuce (Lactuca sativa) and strawberry (Fragaria ananassa) irrigated with reclaimed water. Environ Sci Technol 2014; 48:14361-8. [PMID: 25386873 DOI: 10.1021/es504150h] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Using reclaimed water to irrigate food crops presents an exposure pathway for persistent organic contaminants such as perfluoroalkyl acids (PFAAs) to enter the human food chain. This greenhouse study used reclaimed water augmented with varying concentrations (0.2-40 μg/L) of PFAAs, including perfluorocarboxylates (C3F7COO(-) to C8F17COO(-)) and perfluorosulfonates (C4F9SO2O(-), C6F13SO2O(-), C8F17SO2O(-)), to investigate potential uptake and concentration-response trends in lettuce (Lactuca sativa) and strawberry (Fragaria ananassa). In addition, studies were conducted to evaluate the role of soil organic carbon concentrations on plant uptake of PFAAs. PFAA concentrations in lettuce leaves and strawberry fruit were measured for each aqueous PFAA concentration applied. PFAA plant concentrations increased linearly with the aqueous concentration for all PFAAs, with PFCAs bioaccumulating to a greater degree than PFSAs in the edible portions of the tested plants. Chain-length-dependency trends were evident in both lettuce shoot and strawberry fruit, with decreasing concentrations associated with increasing chain length. Perfluorobutanoate (PFBA) and perfluoropentanoate (PFPeA), both short-chain PFAAs (<8 carbon chain length), accumulated the most compared with other PFAAs tested in the edible parts of both lettuce and strawberry. PFAA concentrations in strawberry root and shoot were also measured at selected PFAA aqueous concentrations (0.4, 4, and 40 μg/L). Short-chain perfluorocarboxylates were the dominant fraction in the strawberry fruit and shoot compartments, whereas a more even distribution of all PFAAs appeared in the root compartment. Lettuce grown in soils with varying organic carbon contents (0.4%, 2%, 6%) was used to assess the impact of organic carbon sorption on PFAA bioaccumulation. The lettuce grown in soil with the 6% organic carbon content had the lowest bioaccumulation of PFAAs. Bioaccumulation factors for lettuce were correlated to carbon chain length of PFAAs, showing approximately a 0.4 to 0.6 log decrease per CF2 group. This study confirms that PFAAs can enter and bioaccumulate in food crops irrigated with reclaimed water. Bioaccumulation potential depends on analyte functional group and chain length, concentration in the reclaimed water, and organic carbon content of the soil.
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Affiliation(s)
- Andrea C Blaine
- Department of Civil and Environmental Engineering, Colorado School of Mines , Golden, Colorado 80401, United States
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21
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Appleman TD, Higgins CP, Quiñones O, Vanderford BJ, Kolstad C, Zeigler-Holady JC, Dickenson ERV. Treatment of poly- and perfluoroalkyl substances in U.S. full-scale water treatment systems. Water Res 2014; 51:246-55. [PMID: 24275109 DOI: 10.1016/j.watres.2013.10.067] [Citation(s) in RCA: 208] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/25/2013] [Accepted: 10/27/2013] [Indexed: 05/20/2023]
Abstract
The near ubiquitous presence of poly- and perfluoroalkyl substances (PFASs) in humans has raised concerns about potential human health effects from these chemicals, some of which are both extremely persistent and bioaccumulative. Because some of these chemicals are highly water soluble, one major pathway for human exposure is the consumption of contaminated drinking water. This study measured concentrations of PFASs in 18 raw drinking water sources and 2 treated wastewater effluents and evaluated 15 full-scale treatment systems for the attenuation of PFASs in water treatment utilities throughout the U.S. A liquid-chromatography tandem mass-spectrometry method was used to enable measurement of a suite of 23 PFASs, including perfluorocarboxylic acids (PFCAs) and perfluorosulfonic acids (PFSAs). Despite the differences in reporting levels, the PFASs that were detected in >70% of the source water samples (n = 39) included PFSAs, perfluorobutane sulfonic acid (74%), perfluorohexane sulfonic acid (79%), and perfluorooctane sulfonic acid (84%), and PFCAs, perfluoropentanoic acid (74%), perfluorohexanoic acid (79%), perfluoroheptanoic acid (74%), and perfluorooctanoic acid (74%). More importantly, water treatment techniques such as ferric or alum coagulation, granular/micro-/ultra- filtration, aeration, oxidation (i.e., permanganate, ultraviolet/hydrogen peroxide), and disinfection (i.e., ozonation, chlorine dioxide, chlorination, and chloramination) were mostly ineffective in removing PFASs. However, anion exchange and granular activated carbon treatment preferably removed longer-chain PFASs and the PFSAs compared to the PFCAs, and reverse osmosis demonstrated significant removal for all the PFASs, including the smallest PFAS, perfluorobutanoic acid.
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Affiliation(s)
- Timothy D Appleman
- Civil and Environmental Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401, USA
| | - Christopher P Higgins
- Civil and Environmental Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401, USA.
| | - Oscar Quiñones
- Applied Research and Development Center, Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA
| | - Brett J Vanderford
- Applied Research and Development Center, Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA
| | - Chad Kolstad
- Minnesota Department of Health, St. Paul, MN 55155, USA
| | - Janie C Zeigler-Holady
- Applied Research and Development Center, Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA
| | - Eric R V Dickenson
- Civil and Environmental Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401, USA; Applied Research and Development Center, Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA.
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22
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Appleman TD, Dickenson ERV, Bellona C, Higgins CP. Nanofiltration and granular activated carbon treatment of perfluoroalkyl acids. J Hazard Mater 2013; 260:740-6. [PMID: 23846124 DOI: 10.1016/j.jhazmat.2013.06.033] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/27/2013] [Accepted: 06/15/2013] [Indexed: 05/18/2023]
Abstract
Perfluoroalkyl acids (PFAAs) are of concern because of their persistence in the environment and the potential toxicological effects on humans exposed to PFAAs through a variety of possible exposure routes, including contaminated drinking water. This study evaluated the efficacy of nanofiltration (NF) and granular activated carbon (GAC) adsorption in removing a suite of PFAAs from water. Virgin flat-sheet NF membranes (NF270, Dow/Filmtec) were tested at permeate fluxes of 17-75 Lm(-2)h(-1) using deionized (DI) water and artificial groundwater. The effects of membrane fouling by humic acid on PFAA rejection were also tested under constant permeate flux conditions. Both virgin and fouled NF270 membranes demonstrated >93% removal for all PFAAs under all conditions tested. GAC efficacy was tested using rapid small-scale columns packed with Calgon Filtrasorb300 (F300) carbon and DI water with and without dissolved organic matter (DOM). DOM effects were also evaluated with F600 and Siemens AquaCarb1240C. The F300 GAC had <20% breakthrough of all PFAAs in DI water for up to 125,000 bed volumes (BVs). When DOM was present, >20% breakthrough of all PFAAs by 10,000 BVs was observed for all carbons.
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Affiliation(s)
- Timothy D Appleman
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA
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Hoppe-Jones C, Dickenson ERV, Drewes JE. The role of microbial adaptation and biodegradable dissolved organic carbon on the attenuation of trace organic chemicals during groundwater recharge. Sci Total Environ 2012; 437:137-144. [PMID: 22940041 DOI: 10.1016/j.scitotenv.2012.08.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Revised: 08/01/2012] [Accepted: 08/02/2012] [Indexed: 06/01/2023]
Abstract
It is widely recognized that efficient biological attenuation of bulk organic matter and trace organic chemicals (TOrC) can occur in managed aquifer recharge (MAR) systems receiving reclaimed water. The heterotrophic microbial activity in these subsurface systems is a function of the availability of biodegradable dissolved organic carbon (BDOC) present in reclaimed water. This study examined the influence of environmental factors, such as BDOC-rich (>1.6 mg/L) and BDOC-starving (<1mg/L) conditions and microbial adaptation, on the attenuation of TOrC, including clofibric acid, dichlorprop, gemfibrozil, ibuprofen, ketoprofen, mecoprop, and naproxen, within soil-columns mimicking groundwater recharge. Under conditions that were characterized by a lack of BDOC and a biocommunity that was not yet adapted to these conditions, attenuation of biodegradable TOrC was less than 15%. After a three-month adaptation period, biotransformation increased to more than 80% for the biodegradable TOrC. This suggests that adaptation likely initiates enzyme expressions that eventually results in TOrC transformations even under seemingly less favorable conditions (i.e., lack of biodegradable carbon). For both non-adapted (stressed) and adapted conditions in the presence of higher concentrations of BDOC and travel times of 7 days, the degree of biotransformation was variable across compounds but generally exceeded 25%. This suggests that BDOC above a minimum level (>1.6 mg/L) can provide favorable microbial conditions resulting in TOrC removal, even for non-adapted systems. However, it is noteworthy that adapted MAR systems that were fed with low BDOC levels performed similarly or better with respect to TOrC biotransformation than systems that received BDOC levels above 1.6 mg/L. These findings are important for field-scale applications. They suggest that MAR facilities that are microbiologically active and are fed with highly treated water with effluent concentrations of less than 1 mg/L (i.e., nanofiltration permeate) can still attenuate biodegradable TOrC.
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Affiliation(s)
- Christiane Hoppe-Jones
- Advanced Water Technology Center (AQWATEC), Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401-1887, USA
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Hyland KC, Dickenson ERV, Drewes JE, Higgins CP. Sorption of ionized and neutral emerging trace organic compounds onto activated sludge from different wastewater treatment configurations. Water Res 2012; 46:1958-1968. [PMID: 22316557 DOI: 10.1016/j.watres.2012.01.012] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 01/11/2012] [Accepted: 01/16/2012] [Indexed: 05/31/2023]
Abstract
The objective of this study was to examine sorption of a suite of 19 trace organic contaminants (TOrCs) to activated sludge. Compounds examined in this study included neutral, nonionized TOrCs as well as acidic TOrCs which may carry a negative charge and basic TOrCs which may carry a positive charge at the pH of wastewater. These TOrCs were evaluated to examine how sorptive behavior might differ for TOrCs in different states of charge. Additionally, multiple sludges from geographically and operationally different wastewater treatment plants were studied to elicit how solid-phase characteristics influence TOrC sorption. Characterization of sludge solids from 6 full scale treatment facilities and 3 bench-scale reactors showed no significant difference in fraction organic carbon (f(oc)) and cation exchange capacity (CEC). Sorption experiments demonstrated that sorption of TOrCs also exhibits little variation between these different sludges. Organic carbon normalized partition coefficients (logK(oc)) were determined as a measure of sorption, and were found to correlate well with octanol-water partition coefficients (logK(ow)) for nonionized TOrCs, and logD(ow) for anionic TOrCs where logD(ow) is greater than 2. These data were used to construct a linear free energy relationship (LFER), which was comparable to existing LFERs for sorption onto sludge. No trend in sorption was apparent for the remaining anionic TOrCs or for the cationic TOrCs. These data suggest that predicting sorption to activated sludge based on K(ow) values is a reasonable approach for neutral TOrCs using existing LFERs, but electrostatic (and likely other) interactions may govern the sorptive behavior of the charged organic chemicals to sludge.
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Affiliation(s)
- Katherine C Hyland
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA
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25
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Stevens-Garmon J, Drewes JE, Khan SJ, McDonald JA, Dickenson ERV. Sorption of emerging trace organic compounds onto wastewater sludge solids. Water Res 2011; 45:3417-3426. [PMID: 21536314 DOI: 10.1016/j.watres.2011.03.056] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 03/14/2011] [Accepted: 03/30/2011] [Indexed: 05/30/2023]
Abstract
This work examined the sorption potential to wastewater primary- and activated-sludge solids for 34 emerging trace organic chemicals at environmentally relevant concentrations. These compounds represent a diverse range of physical and chemical properties, such as hydrophobicity and charge state, and a diverse range of classes, including steroidal hormones, pharmaceutically-active compounds, personal care products, and household chemicals. Solid-water partitioning coefficients (K(d)) were measured where 19 chemicals did not have previously reported values. Sludge solids were inactivated by a nonchemical lyophilization and dry-heat technique, which provided similar sorption behavior for recalcitrant compounds as compared to fresh activated-sludge. Sorption behavior was similar between primary- and activated-sludge solids from the same plant and between activated-sludge solids from two nitrified processes from different wastewater treatment systems. Positively-charged pharmaceutically-active compounds, amitriptyline, clozapine, verapamil, risperidone, and hydroxyzine, had the highest sorption potential, log K(d)=2.8-3.8 as compared to the neutral and negatively-charged chemicals. Sorption potentials correlated with a compound's hydrophobicity, however the higher sorption potentials observed for positively-charged compounds for a given log D(ow) indicate additional sorption mechanisms, such as electrostatic interactions, are important for these compounds. Previously published soil-based one-parameter models for predicting sorption from hydrophobicity (log K(ow)>2) can be used to predict sorption for emerging nonionic compounds to wastewater sludge solids.
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Affiliation(s)
- John Stevens-Garmon
- Advanced Water Technology Center (AQWATEC), Environmental Science and Engineering Division, Colorado School of Mines, Golden, CO 80401, USA
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26
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Laws BV, Dickenson ERV, Johnson TA, Snyder SA, Drewes JE. Attenuation of contaminants of emerging concern during surface-spreading aquifer recharge. Sci Total Environ 2011; 409:1087-94. [PMID: 21211820 DOI: 10.1016/j.scitotenv.2010.11.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 11/16/2010] [Accepted: 11/19/2010] [Indexed: 05/23/2023]
Abstract
The attenuation of a diverse suite of contaminants of emerging concern (CECs) and bulk water quality changes was evaluated at a surface-spreading aquifer recharge operation across a detailed subsurface profile (9 locations), representing both short- and long-travel times (10 h to 60 days). Seventeen CECs were detected in the recharge basin and the concentrations of all were reduced during soil aquifer treatment (SAT), with 11 of the target compounds attenuated by >80% after 60 days of travel time. Select CECs (atenolol, gemfibrozil, N,N-diethly-3-methylbenzamide, meprobamate, tris(2-chloroethyl)phosphate, and primidone) and bulk water organic-carbon measurements (total organic carbon, biodegradable organic carbon, size-exclusion chromatography and fluorescence excitation-emission matrices) were identified as monitoring parameters that can be used to assess SAT performance at surface-spreading operations.
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Affiliation(s)
- Bonnie V Laws
- Advanced Water Technology Center (AQWATEC), Environmental Science and Engineering Division, Colorado School of Mines, Golden, CO 80401, USA
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27
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Dickenson ERV, Snyder SA, Sedlak DL, Drewes JE. Indicator compounds for assessment of wastewater effluent contributions to flow and water quality. Water Res 2011; 45:1199-212. [PMID: 21144546 DOI: 10.1016/j.watres.2010.11.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Revised: 10/30/2010] [Accepted: 11/09/2010] [Indexed: 05/17/2023]
Abstract
Numerous studies have reported the presence of trace (i.e., ng/L) organic chemicals in municipal wastewater effluents, but it is unclear which compounds will be useful to evaluate the contribution of effluent to overall river flow or the attenuation processes that occur in receiving streams. This paper presents a new approach that uses a suite of common trace organic chemicals as indicators to assess the degree of impact and attenuation of trace organic chemicals in receiving streams. The utility of the approach was validated by effluent monitoring at ten wastewater treatment plants and two effluent-impacted rivers with short retention times (<17 h). A total of 56 compounds were particularly well suited as potential indicators, occurring frequently in effluent samples at concentrations that were at least five times higher than their limit of quantification. Monitoring data from two effluent-impacted rivers indicated that biotransformation was not important for these two river stretches, whereas photolysis attenuation was possibly important for the shallow river. The application of this approach to receiving waters and water reclamation and reuse systems will allow for more effective allocation of resources in future monitoring programs.
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Affiliation(s)
- Eric R V Dickenson
- Advanced Water Technology Center (AQWATEC), Environmental Science and Engineering Division, Colorado School of Mines, Golden, CO 80401, USA
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Dickenson ERV, Drewes JE, Stevens-Garmon J, Khan S, McDonald J. Evaluation of QSPR Techniques for Wastewater Treatment Processes. ACTA ACUST UNITED AC 2010. [DOI: 10.2175/193864710798181629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Dickenson ERV, Drewes JE. Quantitative structure property relationships for the adsorption of pharmaceuticals onto activated carbon. Water Sci Technol 2010; 62:2270-2276. [PMID: 21076212 DOI: 10.2166/wst.2010.497] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Isotherms were determined for the adsorption of five pharmaceutical residues, primidone, carbamazepine, ibuprofen, naproxen and diclofenac, to Calgon Filtrasorb 300 powdered activated carbon (PAC). The sorption behavior was examined in ultra-pure and wastewater effluent organic matter (EfOM) matrices, where more sorption was observed in the ultra-pure water for PAC doses greater than 10 mg/L suggesting the presence of EfOM hinders the sorption of the pharmaceuticals to the PAC. Adsorption behaviors were described by the Freundlich isotherm model. Quantitative structure property relationships (QSPRs) in the form of polyparameter linear solvation energy relationships were developed for simulating the Freundlich adsorption capacity in both ultra-pure and EfOM matrices. The significant 3D-based descriptors for the QSPRs were the molar volume, polarizability and hydrogen-bond donor parameters.
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Affiliation(s)
- E R V Dickenson
- Advanced Water Technology Center, Colorado School of Mines, Golden, CO, USA.
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Dickenson ERV, Drewes JE, Sedlak DL, Wert EC, Snyder SA. Applying surrogates and indicators to assess removal efficiency of trace organic chemicals during chemical oxidation of wastewaters. Environ Sci Technol 2009; 43:6242-7. [PMID: 19746720 DOI: 10.1021/es803696y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
To respond to concerns associated with wastewater-derived contaminants water utilities are looking for new approaches for monitoring trace organic chemicals in conventional and advanced water treatment processes. This study examines the use of a combination of surrogate parameters and indicator compounds tailored to monitor the removal efficiency of advanced oxidation processes employed by treatment plants engaged in indirect potable water reuse programs. Potential surrogate parameters and indicator compounds, identified by reviewing previous publications and classified by their structural properties, were tested in pilot- and full-scale treatment systems. Dilantin, DEET, meprobamate, and iopromide are good indicators to assess optimized oxidation conditions while ozonating tertiary-treated wastewaters. UVA reduction, ozone byproduct formation, such as simple organic acids, and ozone exposure correlated with "sweet spot" compounds, where ozone exposure correlated with trace organic removal across five tertiary-treated wastewaters. Findings indicate that the proposed framework can serve as a conservative monitoring approach for advanced oxidation processes as well as other indirect potable reuse processes to ensure proper removal of identified and unidentified wastewater-derived organic contaminants, to detect failures in system performance, and is protective of public health.
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Affiliation(s)
- Eric R V Dickenson
- Advanced Water Technology Center (AQWATEC), Environmental Science and Engineering Division, Colorado School of Mines, Golden, Colorado 80401, USA
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Dickenson ERV, Summers RS, Croué JP, Gallard H. Haloacetic acid and trihalomethane formation from the chlorination and bromination of aliphatic beta-dicarbonyl acid model compounds. Environ Sci Technol 2008; 42:3226-3233. [PMID: 18522098 DOI: 10.1021/es0711866] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
While it is known that resorcinol- and phenol-type aromatic structures within natural organic matter (NOM) react during drinking water chlorination to form trihalomethanes (THMs), limited studies have examined aliphatic-type structures as THM and haloacetic acid (HAA) precursors. A suite of aliphatic acid model compounds were chlorinated and brominated separately in controlled laboratory-scale batch experiments. Four and two beta-dicarbonyl acid compounds were found to be important precursors for the formation of THMs (chloroform and bromoform (71-91% mol/mol)), and dihaloacetic acids (DXAAs) (dichloroacetic acid and dibromoacetic acid (5-68% mol/mol)), respectively, after 24 h at pH 8. Based upon adsorbable organic halide formation, THMs and DXAAs, and to a lesser extent mono and trihaloacetic acids, were the majority (> 80%) of the byproducts produced for most of the aliphatic beta-dicarbonyl acid compounds. Aliphatic beta-diketone-acid-type and beta-keto-acid-type structures could be possible fast- and slow-reacting THM precursors, respectively, and aliphatic beta-keto-acid-type structures are possible slow-reacting DXAA precursors. Aliphatic beta-dicarbonyl acid moieties in natural organic matter, particularly in the hydrophilic fraction, could contribute to the significant formation of THMs and DXAAs observed after chlorination of natural waters.
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Affiliation(s)
- Eric R V Dickenson
- Civil, Environmental and Architectural Engineering Department, University of Colorado, 428 UCB, Boulder, Colorado 80309, USA.
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