Fate of Organic Matter from Leachate Discharged to Wastewater Treatment Plants (Year 1)

Transcription

1 Fate of Organic Matter from Leachate Discharged to Wastewater Treatment Plants (Year 1) November 2015 Debra Reinhart University of Central Florida Office of Research and Commercialization Civil, Environmental, and Construction Engineering and Stephanie C. Bolyard University of Central Florida Civil, Environmental, and Construction Engineering Hinkley Center for Solid and Hazardous Waste Management University of Florida P. O. Box Gainesville, FL Report # 10285

2 TABLE OF CONTENTS 1 Introduction Literature Review Dissolved Organic Carbon Dissolved Organic Nitrogen Co-Treatment of Leachate and Domestic Wastewater Methodology Database Development of Leachate Generation, Management, and Disposal In Florida Leachate and Wastewater Characterization Characterization Study Dilution Study Field Studies Estimation of Leachate Impacts on WWTP Effluent Quality Data Analysis Chemical Analysis Results and Discussion Database Development of Leachate Generation, Management, and Disposal In Florida Leachate and Wastewater Characterization Characterization Studies Dilution Studies Field Studies Leachate Fingerprint in Wastewater Evaluation of Leachate Impacts on WWTP effluent Quality Conclusions References Appendix ii

3 LIST OF FIGURES Figure 1. Treatment and Sampling Scenario... 7 Figure 2. Summary of Landfills and Impaired Water (Nutrients) Bodies Figure 3. Identification of Landfills within Twelve Miles of an Impaired Water (Nutrients) Bodies Figure 4. Leachate disposal practice Figure 5. Leachate Pretreatment Prior to Discharge to a WWTP Figure 6. FTIR Spectrum of Dried Leachate Samples Figure 7. PCA Scores Plot of FTIR Spectrum of Leachate Samples Figure 8. UV254 Transmittance of Leachate and Wastewater Influent Dilution Tests Figure 9. UV254 Transmittance of Leachate and Wastewater Effluent Dilution Tests Figure 10. UV254 Absorbance of WWTP 2A and 2B Influent Figure 11. WWTP Effluent (WWTP 2A) with and without Leachate (WWTP 2B) Figure 12. UV254 Percent Transmittance of Wastewater Effluent with and without Leachate at WWTP Figure 13. DOC in Wastewater with Leachate (WWTP 2B) Normalized by Wastewater without Leachate (WWTP 2A) Figure 14. UV-Vis Scan (200 nm to 800 nm) of Wastewater Influent and Effluent Samples with and without Leachate (WWTP 2C) Figure 15. UV-Vis Scan (200 nm to 800 nm) of Wastewater Influent Samples with Leachate and Effluent without Leachate (WWTP 3) Figure 16. Excitation-Emission Figures for WWTP 2A and 2B Effluent Samples Collected at 12:00 am and 4:00 am Figure 17. Relationship between FI, UV254 nm, and Color for Wastewater Effluent with (2B) and without (2A) Leachate Figure 18. Wastewater Effluent Total Nitrogen Calculated based on a Plant Performance in the 95 th Percentile and a Leachate Volumetric Ratio of 10% iii

4 LIST OF TABLES Table 1. Comparison of Wastewater and Leachate Characteristics... 2 Table 2. Summary of WWTP Sampling Events and Leachate Presence or Absence... 6 Table 3. Summary of Wastewater Treatment Plant Biological Processes for Hypothetical Analysis... 8 Table 4. Comparison of Leachate (13 Samples) and Influent Wastewater (5 Samples) Table 5. WWTP Effluent Sample Analysis Table 6. Summary of Leachate Functional Groups Table 7. Principal Component Scores Related to Loading Plots * Table 8. Leachate Detection Based on Increase in UV254 Absorbance Table 9. Estimated Volumetric Ratio Using Known Addition of Leachate Added to Wastewater Influent (without Leachate) Table 10. WWTP 2B Leachate Impacted Samples Normalized by WWTP 2A* Table 11. WWTP 2B Leachate Impacted Samples* Normalized by Non-Impacted Samples for WWTP2B Table 12. Estimation of Leachate Impact on Effluent Quality (WWTP 2B) Table 13. Fluorescence Index of WWTP 2A and 2B Effluent Samples Collected at 12:00 am and 4:00 am Table 14. Summary of Effluent Characteristics of Samples Collected at 12:00 am and 4:00 am from WWTPs 2A (without leachate) and 2B (with leachate) Table 15. Summary of Wastewater Effluent Total Nitrogen as a Function of Leachate Volumetric Loadings and Fluctuations in Daily Plant Performance (Shaded Values Exceed Typical Discharge Limits) iv

5 LIST OF ABBREVIATIONS, ACRONYMS & UNITS OF MEASUREMENT ASP abs cbod5 COD DBPs DI DNAS DOC DON E4/E6 FA FDEP FTIR GIS HA HRAS LOM NAS NH3-N Activated Sludge Process Absorption units Carbonaceous Five-Day Biochemical Oxygen Demand Chemical Oxygen Demand Disinfection By-Products Deionized DeNitrification Activated sludge Dissolved Organic Carbon Dissolved Organic Nitrogen UV 465 nm Absorbance/ UV 665 nm Absorbance Fulvic Acid Florida Department of Environmental Protection Fourier Transform Infrared Geographic Information System Humic Acid High rate activated Leachate Organic Matter Nitrification Activated Sludge Ammonia-Nitrogen NMDA N-Methyl-D-aspartate NMR Nuclear Magnetic Resonance Spectrometry NNC Numeric Nutrient Criteria NO3-N Nitrate-Nitrogen OM Organic Matter PCA Principal Component Analysis scod Soluble COD (<0.45 µm) SUVA Specific UV Absorbance TN Total Nitrogen TOC Total Organic Carbon TP Total Phosphorus UCF University of Central Florida UV Ultraviolet UV254 UV Absorbance (254 nm) UV-Vis UV-Visible WQBELs Water Quality Based Effluent Limits WWTP Wastewater Treatment Plant v

6 Year 1 Final REPORT Dates covered in this report PROJECT TITLE: Fate of Organic Matter from Leachate Discharged to Wastewater Treatment Plants PRINCIPAL INVESTIGATOR: Debra R. Reinhart, PhD, PE, BCEE AFFILIATION: University of Central Florida Debra.Reinhart@ucf.edu PHONE NUMBER: COMPLETION DATE: September 30, 2015 TAG MEMBERS: Name Company Ron S. Beladi Neel-Schaffer, Inc. rbeladi@neel-schaffer.com Dan Courcy Orange County Utilities Daniel.Courcy@ocfl.net Derya Dursun Middle East Technical University dderya@metu.edu.tr Timur Deniz CDM Smith denizt@cdmsmith.com Sarina Ergas University of South Florida sergas@usf.edu Ruth Hazard Seminole County rhazard@seminolecountyfl.gov Mark Hudgins CRA/GHD mhudgins@craworld.com Brian Karmasin CDM Smith KarmasinBM@cdmsmith.com John Ladner CDM Smith LadnerJG@cdmsmith.com Sam Levin S2Li Slevin@S2Li.com Robert Mackey S2Li bmackey@s2li.com Rosalyn Matthews Hazen and Sawyer rmatthews@hazenandsawyer.com Terry McCue Seminole County tmccue@seminolecountyfl.gov Lisa Prieto AMEC lisa.prieto@amec.com Hala Sfeir Brown and Caldwell sfeir@brwncald.com Woo Hyoung Lee UCF WooHyoung.Lee@ucf.edu Bryan Staley EREF bstaley@erefdn.org Sara Arabi EOSi sarabi@microc.com Kevin Torrens Brown and Caldwell KTorrens@Brwncald.com Kyle Dorris AMEC kyledorris@amecfw.com Tim Ware American Water Timothy.warepe@gmail.com Gary Hater Waste Management ghater@wm.com Al Castro Orange County Al.Castro@ocfl.net KEY WORDS: Leachate Treatment, UV Transmittance, Wastewater Treatment, Leachate Organic Matter, effluent nitrogen, color vi

7 ABSTRACT: Leachate management is an expensive and challenging task for landfill operators. Wastewater treatment plants are more frequently refusing to accept leachate due to operational challenges even though the specific impacts on effluent quality are not well understood. The goal of this research was to study the nature and fate of recalcitrant, UV-absorbing, and nitrogen-containing organic compounds in leachate that is co-treated with domestic wastewater. This study aimed to quantify leachate dissolved organic nitrogen (DON), to evaluate the extent to which leachate DON contributes to effluent WWTP total nitrogen (TN) concentration and at what volumetric ratios under various wastewater treatment processes, and to understand the potential for leachate organic matter (LOM) to interfere with meeting UV transmittance requirements in WWTP effluents. Leachate and wastewater combinations were evaluated in the laboratory and in the field using both traditional analysis and advanced spectroscopic tools to explore the structural and biochemical properties of LOM and their behavior at WWTPs. For field studies, two different scenarios were evaluated: in Scenario 1, WWTPs do not accept leachate (control) and in Scenario 2, WWTPs accept leachate. By analyzing and comparing samples with and without leachate, the persistence in the treatment process and effects of leachate addition on effluent quality can be assessed. Raw leachate was collected at the landfills just prior to the point of discharge into the municipal sewer system. Wastewater was sampled at the WWTP influent and after clarification and disinfection every 4 hours over a 24-hour period. Data collected in this study were analyzed to understand the fate of DON and dissolved organic carbon (DOC) during various WWTP unit processes. Leachate detection limits in wastewater were determined by dilution studies; leachate can be detected and quantified using ultraviolet visible (UV-Vis) spectroscopy in wastewater down to 0.01% by volume. This dilution study also brought to light that even at a leachate volumetric ratio of 0.01% the UV transmittance was below the minimum 65% requirement for disinfection when using membrane filtration prior to disinfection (NWRI, 2003). This behavior was also observed in the field as the UV transmittance of wastewater effluent was 55% at a leachate volumetric ratio of 0.1%. It is apparent from this study that leachate can have significant effects on wastewater quality at relatively low volumetric ratios. These effects were detected by a decrease in UV transmittance and color (which can interfere with disinfection), an increase in effluent DOC which can lead to violations in permits or the production of disinfection byproducts (DBPs), and an increase in influent DON. UV and fluorescence were both useful in fingerprinting the leachate. These effects, however, can be managed by ensuring that leachate discharge is maintained at acceptable dilution ratios and evenly spread out over the discharge period taking into consideration variability in wastewater flow throughout the day. More data will be collected during Year 2 of the study to validate these observations as they were based on a limited number of observations. vii

8 PROJECT WEBSITE: DOM/main.html METRICS: The following information should be included with each quarterly report, adding to the previous quarters information. 1. List graduate or postdoctoral researchers funded by THIS Hinkley Center project. Last name, first name Bolyard, Stephanie Rank Department Professor Institution PhD Candidate Civil, Environmental, and Construction Engineering Debra Reinhart 2. List undergraduate researchers working on THIS Hinkley Center project. University of Central Florida Last name, first name Alexis Mauerman a Duncan Lozinski b Christina Pilato c Rank Department Professor Institution Third Year Third Year Third Year Civil, Environmental, and Construction Engineering Civil, Environmental, and Construction Engineering Biology a. Fall 2014 Semester Only b. Spring and Summer 2015 Semesters c. Not funded through this project (Spring 2015 Semester Only) Debra Reinhart Debra Reinhart Debra Reinhart University of Central Florida University of Central Florida University of Central Florida 3. List research publications resulting from THIS Hinkley Center projects (use format for publications as outlined in this Report Guide). None 4. List research presentations resulting from THIS Hinkley Center project (use format for presentations as outlined in this Report Guide). Fall Hinkley Board Meeting September 26, TAG Meetings: November 7, 2014 and May 1, Project discussed in presentations at Tsinghua University and Tianjing University in China (November 13 and 14, 2014). SWANA Florida Winter Waste Meeting 2015 by Debbie Reinhart on February 10, Bolyard, Stephanie C.*, Reinhart, Debra R., and Lozinski, D., Effect of Leachate Organic Matter on Wastewater Effluent Quality, Proceedings of the Fifteenth International Waste Management and Landfill Symposium, S. Margherita di Pula, Italy, October 5-9, viii

9 5. List who has referenced or cited your publications from this project? Sara Arabi (GWMS Abstract) 6. How have the research results from THIS Hinkley Center project been leveraged to secure additional research funding? National Science Foundation: MSW Leachate Organic Matter Generation and Removal 7. What new collaborations were initiated based on THIS Hinkley Center project? None 8. How have the results from THIS Hinkley Center funded project been used (not will be used) by FDEP or other stakeholders? (1 paragraph maximum). Information our TAG meeting was used in a recent EREF presentation made by Kevin Torrens (Brown and Caldwell) Information requested by John Banks (Atkins) for a client regarding leachate interference with UV Transmittance and potential pretreatment options were suggested. Slides from TAG presentations were provided. ix

10 EXECUTIVE SUMMARY September 30, 2014 to September 30, 2015 PROJECT TITLE: Fate of Organic Matter from Leachate Discharged to Wastewater Treatment Plants PRINCIPAL INVESTIGATOR(S): Debra R. Reinhart, PhD, PE, BCEE AFFILIATION: University of Central Florida PROJECT WEB SITE: PROJECT TAG MEMBERS: Name Company Ron S. Beladi Neel-Schaffer, Inc. Dan Courcy Orange County Utilities Derya Dursun Middle East Technical University Timur Deniz CDM Smith Sarina Ergas University of South Florida Ruth Hazard Seminole County Mark Hudgins CRA/GHD Brian Karmasin CDM Smith John Ladner CDM Smith Sam Levin S2Li Robert Mackey S2Li Rosalyn Matthews Hazen and Sawyer Terry McCue Seminole County Lisa Prieto AMEC Hala Sfeir Brown and Caldwell Woo Hyoung Lee UCF Bryan Staley EREF Sara Arabi EOSi Kevin Torrens Brown and Caldwell Kyle Dorris AMEC Tim Ware American Water Gary Hater Waste Management Al Castro Orange County COMPLETION DATE: September 30, 2015 x

11 Leachate generated from a landfill shortly after waste is placed typically has high organic compound concentrations (measured as Chemical Oxygen Demand (COD) from 6-60 g/l). As the landfilled waste ages, leachate volume declines from as high as 14,000 L/ha/d to below 900 L/ha/d (Worrell et al., 2002). However, leachate COD remains high (e.g., up to 4.5 g/l) for many decades (Ehrig, 1984; Kjeldsen et al., 2002). Concomitantly, the composition of leachate organic matter (LOM) transitions from dominance by aliphatic, low molecular weight compounds to primarily complex and recalcitrant organic compounds (Batarseh et al., 2007; Morris et al., 2003; Robinson et al., 2013). The leachate biochemical oxygen demand (BOD) to COD ratio becomes very low as the landfill ages, suggesting LOM recalcitrance (Kjeldsen et al., 2002). Other leachate constituents such as metals tend to decline to low levels in aged leachate, although ammonia is also persistent in the anaerobic landfill environment (Kjeldsen et al., 2002). Leachate is frequently discharged to local municipal wastewater treatment plants (WWTPs) because of the cost and complexity of onsite treatment. LOM can be problematic for these WWTPs; because of their recalcitrance, they may pass through conventional treatment processes and potentially negatively affect effluent quality (Zhao et al., 2013). For example, if leachate containing 1000 mg/l of organic matter (measured as COD) accounted for 10 percent of the influent flow and these organic compounds were not removed, then the WWTP effluent COD concentration would increase by 100 mg/l. Chlorination of these organic compounds can lead to the formation of toxic DBPs. Aromatic compounds absorb ultraviolet (UV) light, which has been shown to interfere with the alternative method of wastewater disinfection using UV at volumetric contributions as low as 2-5% of the WWTP influent (Zhao et al., 2012). As of 2012, just over 25% of the WWTPs in the United States used UV disinfection; equating to approximately 4,000 facilities (Faber, 2012; Whitby and Scheible, 2004). Nitrogen in leachate may pose additional challenges if ultimately discharged to nutrient limited water bodies (Chen et al., 2011). Leachate ammonia-nitrogen concentrations were found to be between mg/l in this study (Table 4) and can increase the oxygen demand at a WWTP while subsequently increase nitrate-nitrogen concentrations in the effluent. Generally less than 15% of the compounds contributing to dissolved organic nitrogen (DON) can be identified (Dotson and Westerhoff, 2009). Nitrogen is limited more and more frequently in WWTP effluents discharged to compromised water bodies. The Numeric Nutrient Criteria (NNC) for Florida s waters are aimed at lowering the total nitrogen (TN) and phosphorus (TP) discharges (Chapter , F.A.C.). These regulations will affect the effluent limits for WWTPs if there is reasonable potential for these sites to discharge nitrogen and phosphorus in concentrations that can cause or contribute to nutrient impairment in receiving water bodies. Therefore, pass-through of leachate DON could limit the discharge to impacted receiving waters. The specific impacts of leachate on WWTP effluent quality are not well known, particularly at field-scale. The goal of this research was to increase our understanding of the nature and fate of recalcitrant, UV-absorbing, and nitrogen containing organic compounds in leachate that is cotreated with domestic wastewater. It is expected that organic compound characteristics will depend on their source, whether leachate or domestic wastewater (Korak et al., 2015). Research questions, therefore, included: (1) can a leachate "fingerprint" be identified in domestic wastewater, (2) will leachate DON contribute to effluent WWTP TN concentration permit xi

12 exceedances and at what volumetric ratio, and (3) to what extent does LOM interfere with meeting UV transmittance requirements in WWTP effluents? xii

13 To meet these objectives, the following tasks were performed: A database of the leachate generation, management, and disposal practices in Florida was developed. These practices were summarized for all active landfills in Florida. Active landfills are defined as sites that are operating and not under long-term care. This information includes (1) the volume generated, (2) pretreatment methods (if applicable), and (3) the ultimate disposal method for each landfill site. The location of each WWTP and water body with water quality-based effluent limits (WQBELs) was plotted using geographic information system (GIS; ArcMap 10.3) along with the location of each landfill discharging leachate to a WWTP. Overall this information can be used to identify WWTPs where more stringent effluent limits could be implemented that could be affected by the NNC. These data were compiled from the Florida Department of Environmental Protection (FDEP) public electronic document management system OCULUS and, where necessary, by contacting landfill and WWTP owners/operators. Leachate and wastewater samples were characterized with the objective of identifying a leachate molecular fingerprint, determining the fate of LOM and nitrogen at a WWTP, and understanding the effects of leachate discharge rates on WWTP effluent quality. To accomplish this task, leachate and wastewater samples were analyzed in the laboratory by employing traditional analysis and advanced spectroscopic tools to explore the structural and biochemical properties of LOM and their behavior at WWTPs. Leachate was collected and characterized to develop baseline data from eight landfills (13 samples) and two WWTPs (effluent and influent, five samples). In addition, field studies were designed to compare WWTP performance in the presence and absence of leachate and the persistence of LOM and other leachate constituents through the WWTP. Two different scenarios were evaluated over the study period: Scenario 1, two WWTPs that did not receive leachate during the sampling period (controls) and Scenario 2, two WWTPs receiving leachate. Leachate characteristics from this study and TN removal efficiencies for operating WWTPs from the literature were used to determine the hypothetical effect of various leachate volumetric loadings on WWTP effluent TN concentrations. From the leachate database, we determined that the majority (92%) of Florida active landfill operators discharge to wastewater treatment plants (WWTP) while 3% discharge directly to a water body after onsite treatment. Florida wastewater generation is roughly 1.5 billion gallons per day (FDEP, 2014), therefore leachate contributes, on average, approximately 1% by volume. On a mass basis, leachate contributes approximately 3%, 9%, and 22% of the cbod5, COD, and TN discharged to WWTPs daily (average leachate values from Table A-1 and medium strength wastewater characteristics from (Metcalf & Eddy, 2003)). Of those discharging to a WWTP, the majority (61%) do not treat leachate prior to discharge (Figure 5). The remaining landfills use aerated storage or sequencing batch reactors. From the leachate and wastewater characterization study, we concluded the following: Leachate characteristics varied significantly, even from the same landfill at different sampling times, Leachate samples were less biodegradable than wastewater influents and effluents, in general, xiii

14 Aromatic, organic, inorganic, and nitrogen functional groups were identified in most of the leachate samples, which suggested well-stabilized organic matter. Three leachates were diluted with wastewater influent and effluent to examine the ability to detect leachates in wastewater. By comparing the UV transmittance of diluted and undiluted leachate to wastewater, it was possible to calculate a lower limit of detection. Leachate was detectable in wastewater influents at dilutions below 0.01% by volume. In effluents, the UV transmittance was just below the minimum 65% necessary to meet the disinfection requirement of less than 200 fecal coliform values per 100 ml for public-access reuse (F.A.C ; National Water Research Institute, 2012) at dilutions greater than 1%. The field study of leachate co-treatment with wastewater was completed over five sampling events at three WWTPs. Grab samples were collected every 4 hours over a 24-hour period at the influent composite samples, and after clarification and disinfection. Leachate detection for each field study was determined using UV254 absorbance measurements. Each samples with a significant increase in absorbance, relative to samples without leachate, was identified as a leachate detection and subsequent impacts were further evaluated. Changes in influent characteristics were observed for all three WWTPs receiving leachate; however leachate was only evident in one effluent (WWTP 2B). This was attributed to the longer than expected hydraulic retention periods of these WWTPs. Sampling will be repeated during year 2 of the study. Effluent impacts were detected based on UV254 absorbance and confirmed through visual observation and apparent color measurements. The impacts of leachate on DON, scod, and DOC for WWTP 2B were evaluated by normalizing measured concentrations (1) using WWTP 2A data and (2) using non-impacted samples from WWTP 2B. DOC was slightly impacted (i.e., normalized values were above 1), but DON was not impacted by leachate (i.e., normalized values were below 1). On the other hand, when comparing the leachate-impacted samples for WWTP 2B to non-impacted samples during the same sampling event these parameters were significantly impacted (normalized values were greater than 1). These observations may be attributed to variations in wastewater characteristics from one day to another. The DON ratio decreased through the WWTP suggesting that this parameter was effectively removed in the plant, while DOC persisted. DOC pass-through coincided with an increase in color and UV absorption. Samples from WWTPs with and without leachate were analyzed with the objective of identifying a leachate fingerprint. The following observations were made: Leachate arrival during a sampling event led to a UV-Vis spectral shift due to an increase in UV254 nm absorbance, Leachate-impacted wastewater showed a higher concentration of humic-like peaks during fluorescence measurements relative to wastewater without leachate, and UV254 nm absorbance and a fluorescence index were higher for leachate-impacted samples and increases in color and DOC were observed. A hypothetical study using leachate characteristics measured during this study and nitrogen removal data for WWTPs reported in the literature using three different biological nitrogen xiv

15 removal schemes was completed. From this study, it is clear that nitrogen limits of 3 mg/l and 10 mg/l would be regularly exceeded at a leachate volumetric loading of 10%. Separate and multi-stage processes were more effective than combined stage nitrogen removal processes. In conclusion, it is apparent from this study that leachate can have significant effects on wastewater quality at relatively low volumetric ratios. These effects were detected by a decrease in UV transmittance and increase in color (which can interfere with disinfection), an increase in effluent DOC which can lead to violations in permits or the production of DBPs, and an increase in influent DON. Ammonia-nitrogen concentrations also increased in leachate-impacted influents which would increase oxygen requirements and potentially require an addition of carbon for a WWTP to achieve low TN limits. Spectroscopic data from both UV and fluorescence were useful in fingerprinting the leachate. These effects, however, can be managed by ensuring that leachate discharge is maintained at acceptable dilution ratios and evenly spread out over the discharge period while taking into consideration the variability in wastewater flow throughout the day. More data will be collected during Year 2 of the study to validate these observations as they were based on a limited number of observations. xv

16 1 INTRODUCTION Leachate generated from a landfill shortly after waste is placed typically has high organic compound concentrations (measured as Chemical Oxygen Demand (COD) from 6-60 g/l). As the landfilled waste ages, leachate volume declines from as high as 14,000 L/ha/d to below 900 L/ha/d (Worrell et al., 2002). However, leachate COD remains high (e.g., up to 4.5 g/l) for many decades (Ehrig, 1984; Kjeldsen et al., 2002). Concomitantly, leachate organic matter (LOM) transitions from dominance by aliphatic, low molecular weight compounds to primarily complex and recalcitrant organic compounds (Batarseh et al., 2007; Morris et al., 2003; Robinson et al., 2013). The leachate biochemical oxygen demand (cbod) to COD ratio becomes very low as the landfill ages, suggesting LOM recalcitrance (Kjeldsen et al., 2002). Other leachate constituents such as metals tend to decline to low levels in aged leachate, although ammonia is also persistent in the anaerobic landfill environment (Kjeldsen et al., 2002). In situ landfill processes remove readily degradable organic matter in the leachate; however persistent and recalcitrant organic matter may necessitate management of leachate well beyond the closure of the landfill, potentially for hundreds of years (Ehrig and Krümpelbeck, 2001)(Belvi and Baccine, 1989). LOM is problematic because it is highly colored (Matilaninen et al., 2011; He et al., 2006; de Morais et al., 2005), may lead to disinfection byproducts (DBPs) when treated (Kang et al., 2002; Katsumata et al., 2008; Leenheer and Croué, 2003; Matilaninen et al., 2011), and is known to transport heavy metals (Tan et al., 2003; Bolyard et al., 2013a) and hydrophobic organic contaminants (Tan et al., 2003; De Paolis and Kukkonen, 1997). Landfill leachate is frequently discharged to local municipal wastewater treatment plants (WWTPs) because of the cost and complexity of onsite treatment. LOM can be problematic for these WWTPs; because of its recalcitrance, it may pass through conventional treatment processes and potentially negatively affect effluent quality (Zhao et al., 2013). For example, if leachate containing 1000 mg/l of organic matter (measured as COD) accounted for 10 percent of the influent flow and if these organic compounds were not removed, then the WWTP effluent COD concentration would increase by 100 mg/l. Chlorination of some of these organic compounds can lead to the formation of toxic DBPs. Aromatic compounds absorb ultraviolet (UV) light, which has been shown to interfere with the alternative method of wastewater disinfection using UV at volumetric contributions as low as 2-5% of the WWTP influent (Zhao et al., 2012). As of 2012, just over 25% of the WWTPs in the United States used UV disinfection; equating to approximately 4,000 facilities (Faber, 2012; Whitby and Scheible, 2004). In Florida approximately 2% of the permitted domestic WWTPs utilize UV disinfection. Nitrogen in leachate may pose additional challenges if ultimately discharged to nutrient limited water bodies (Chen et al., 2011). Generally fewer than 15% of the compounds contributing to dissolved organic nitrogen (DON) can be identified (Dotson and Westerhoff, 2009). Nitrogen is limited more and more frequently in WWTP effluents discharged to nutrient (i.e., nutrients exceed background concentrations) compromised water bodies. The Numeric Nutrient Criteria (NNC) for Florida s waters are aimed at lowering the total nitrogen (TN) and phosphorus (TP) discharges (Chapter , F.A.C.). These regulations will affect the effluent limits for WWTPs if there is reasonable potential for these sites to discharge nitrogen and phosphorus in 1

17 concentrations that can cause or contribute to nutrient impairment in receiving water bodies. Therefore, pass-through of leachate DON could limit the discharge to impacted receiving waters. Relevant literature and UCF data for wastewater and leachate characteristics are presented in Table 1. Leachate tends to have higher concentrations of recalcitrant compounds relative to domestic wastewater effluent, which, are measured as higher dissolved organic carbon (DOC) and DON concentrations. These metrics can be seen to vary considerably between leachate and wastewater and can serve as signatures of leachate contributions to effluent COD and DON. Metric Total Dissolved Nitrogen (TDN), mg-n/l Dissolved Organic Nitrogen (DON), mg-n/l Dissolved Inorganic Nitrogen, mg-n/l UV absorption Table 1. Comparison of Wastewater and Leachate Characteristics Wastewater Effluent Leachate (Zhao et al., 2012) Leachate (Bolyard et al., 2013b) 2 Leachate from a Local Landfill (Closed Cell) * * * (UVA), cm * Dissolved Organic Carbon (DOC), mg * C/L Specific UV Absorbance (SUVA) (UVA/DOC), L/mgm Humic Acid (HA) Concentrations (mg/l) * DOC/DON DON/TDN *Chen et al., 2011; TDN: Total Dissolved Nitrogen Observations Leachate is orders of magnitude greater Leachate nitrogen is related to humic substances, not proteins Leachate high ammonia content Indicator of aromatics, leachate is greater Leachate is orders of magnitude greater Lower SUVA (<2) is indicative of greater hydrophilic nature Leachate is orders of magnitude greater Leachate organic matter is dominated by carbon Higher value indicates greater proportion of organic nitrogen Goals and Objectives The specific impacts of leachate on WWTP effluent quality are not well known, particularly at field-scale. The goal of this research was to increase our understanding of the nature and fate of recalcitrant, UV-absorbing, and organic-nitrogen containing compounds in leachate that is cotreated with domestic wastewater. It is expected that organic compound characteristics will depend on their source, whether leachate or domestic wastewater (Korak et al., 2015). Research questions therefore included: (1) Can a leachate "fingerprint" be identified in domestic wastewater? (2) Will leachate DON contribute to effluent WWTP TN concentration permit exceedances? and at what volumetric ratio? And (3) to what extent does LOM interfere with meeting UV transmittance requirements in WWTP effluents?

18 2 LITERATURE REVIEW 2.1 DISSOLVED ORGANIC CARBON Most of the organic carbon that is leachable in landfilled MSW is biodegradable, and therefore can be treated biologically. However, as the waste in landfills matures, the remaining organic matter is predominately nonbiodegradable (Kjeldsen et al., 2002). Humic substances account for over 60% of the total organic carbon (Artiola-Fortuny and Fuller, 1982) in leachate, apparently dominating leachate recalcitrant organic compounds. HS are categorized by three main components; humic acid (HA; base soluble and acid insoluble), fulvic acid (FA; acid and base soluble), and humin, which is insoluble in water at any ph (Ghabbour et al., 2001; IHSS, 2007). FA is predominately found in young leachates and the concentration decreases over time (Artiola-Fortuny and Fuller, 1982). The change in concentration of HA is inversely proportional to changes in FA and the concentration will increase as the landfill waste matures (Fan et al., 2007). The accumulation of HA most significantly contributes to the shift in the degree of biodegradability of leachate (Kjeldsen et al., 2002; Renou et al., 2008). HA is known to affect the behavior of trace and emerging contaminants in aquatic environments (McPhedran et al., 2013) and also plays a role in the degradation of water quality as HA can contribute to odor, taste, color, and disinfection byproducts (Kang et al., 2002; Katsumata et al., 2008). Leachate HA concentration will increase over time in a landfill but is consistently higher than that found in aquatic environments; concentrations in leachate range from 94 mg/l to well over 1,000 mg/l (Bolyard et al., 2013; Fan et al., 2007). 2.2 DISSOLVED ORGANIC NITROGEN DON is primarily comprised of complex compounds, including amides, peptides, amino acids, urea, heterocyclic N (e.g., pyridine, piperidine, pyrrole), and other compounds that could not be characterized (Stepanauskas et al., 1999; Stepanauskas et al., 2002). The increase of DON in the aquatic environment is predominately from human activity (McDowell et al., 1998; Seitzinger and Sanders, 1997) which includes wastewater, algae in eutrophic waters, runoff of organic fertilizers, landfill leachate, and urban stormwater (Currie et al., 1996; Westerhoff and Mash, 2002). DON is quantified by subtracting the total inorganic nitrogen (ammonia, nitrate and nitrite) from the total nitrogen and ranges from 37 mg/l to 150 mg/l in leachate but is typically less than 2.5 mg/l in domestic wastewater (Robinson et al., 2013; Zhao et al., 2013; Zhao et al., 2012). Approximately 4% (by wt.) of the HA elemental composition is nitrogen which suggests that much of DON in landfill leachates is bound up in HA (Knox and Goddard, 2013). 2.3 CO-TREATMENT OF LEACHATE AND DOMESTIC WASTEWATER A number of studies have reported successful co-treatment of leachate and wastewater at volumetric ratios less than ~10-20% of influent flow rates (Cecen and Cakiroglu, 2001; Reinhart et al., 1994). The removal of leachate constituents during co-treatment is a function of the leachate characteristics and the processes provided (Bu et al., 2010). Biological treatment removes readily degradable organics including DON related to proteins and amino acids. A literature review by Kurniawan et al. (2010), however, concluded that no single physicalchemical process was capable of completely removing organic contaminants in stabilized leachates. Studies by Robinson et al. (2013) reported poor removal of hard COD by 3

19 sequencing batch reactors and that ultrafiltration was necessary for treatment to acceptable levels. Because of the inefficiency of single treatment processes, some of these recalcitrant contaminants will likely pass through WWTPs with only conventional secondary treatment. Advanced treatment processes such as reverse osmosis would be necessary to remove these recalcitrant contaminants. Much of the recalcitrant organic constituents in leachate are aromatic and UV absorbing (Zhao et al., 2013) and capable of mobilizing metals and other organic contaminants (Kjeldsen et al., 2002). A 2011 report to the Water Environment Research Foundation (WERF) (Bott and Parker, 2011) evaluated the performance of 22 WWTPs designed to remove nitrogen and phosphorous. The study reported that the reliability for achieving organic nitrogen levels of mg/l ranged from 10 to 91%. Removal of nitrogen is highly dependent on the type of technology provided. For example, Bott and Parker (2011) reported that separate-stage N removal outperforms combined N removal facilities and four or five-stage Bardenpho plants were effective in achieving low TN goals. The warm climate typical of Florida contributed to higher reliability and lower effluent nitrogen. Leachate DON, which is characterized by small molecular weight compounds that may not be removed effectively in conventional activated sludge processes (Chen et al., 2010), will be particularly problematic for WWTPs with low TN limits. Further, chlorination of DON has been attributed to the formation of N-Nitrosodimethylamine, a potent carcinogen, and other disinfection by-products (DBPs) and to membrane fouling (Pehlivanoglu- Mantas and Sedlak, 2008). Pehlivanoglu-Mantas and Sedlak also reported that DON in the environment can be converted to forms that support microbial growth, leading to eutrophication. 4

20 3 METHODOLOGY 3.1 DATABASE DEVELOPMENT OF LEACHATE GENERATION, MANAGEMENT, AND DISPOSAL IN FLORIDA A database of the leachate generation, management, and disposal practices in Florida was developed. These practices were summarized for all active landfills in Florida. Active landfills are defined as sites that are operating and not under long-term care. This information includes (1) the volume generated, (2) pretreatment methods (if applicable), and (3) the ultimate disposal method for each landfill site. The location of each WWTP and water body with water qualitybased effluent limits (WQBELs) was plotted using geographic information system (GIS; ArcMap 10.3) along with the location of each landfill discharging leachate to a WWTP. Overall this information can be used to identify WWTPs that could be affected by leachate and/or the NNC. These data were compiled from the Florida Department of Environmental Protection (FDEP) public electronic document management system OCULUS and, where necessary, by contacting landfill and WWTP owners/operators. 3.2 LEACHATE AND WASTEWATER CHARACTERIZATION This task focused on characterizing leachate discharged to a WWTP, identifying a leachate molecular fingerprint, determining the fate of nitrogen and LOM in a WWTP, and understanding the effects of leachate discharge rates on WWTP effluent quality. A recognizable leachate molecular fingerprint will allow for the rapid identification of wastewater effluent impacted by LOM Characterization Study This subtask evaluated leachate and wastewater characteristics in the laboratory by employing traditional analysis and advanced spectroscopic tools to explore the structural and biochemical properties of LOM and their behavior at WWTPs. Leachate was collected and characterized to develop baseline data from eight landfills (13 samples) and two WWTPs (effluent and influent, five samples). Analytical procedures are summarized in Section Dilution Study This subtask allowed us to determine lower bounds on detection of leachate in wastewater. Raw leachate was collected at three landfill sites at a point just prior to discharge into the municipal sewer system. Influent and effluent wastewater samples were also collected from three WWTPs in the absence of leachate. Leachate, as collected, was mixed with wastewater influent and effluent samples at volumetric loadings of 0.01%, 0.1%, 1.0%, and 10%. These values reflect both published and field data regarding the co-treatment of leachate and wastewater (Cecen and Cakiroglu, 2010; Abbas et al., 2009; Reinhart et al., 1994). UV transmittance was measured for each of these mixtures. Additionally distilled (DI) water was added to wastewater samples at the same aforementioned volumetric loadings to serve as experimental blanks. Detection of leachate was confirmed by detecting a difference between the wastewater UV transmittance and the diluted leachate Field Studies Field studies were designed to compare WWTP performance in the presence and absence of leachate and the persistence of LOM and other leachate constituents through the WWTP. Two different scenarios were evaluated over the study period: Scenario 1, two WWTPs that did not 5

21 receive leachate during the sampling period (controls) and Scenario 2, two WWTPs receiving leachate (as presented in Table 2). Raw leachate was collected at the landfills just prior to the point of discharge into the municipal sewer system. Wastewater was sampled at the WWTP influent and at various points within the treatment train (Figure 1). Grab samples were collected every 4 hours over a 24-hour period with the assistance of WWTP operators. Leachate and wastewater were placed in clean high-density polyethylene plastic containers, which were iced during collection as well as transport and stored at 4ºC until analyzed (see Chemical Analysis section 3.4). Table 2. Summary of WWTP Sampling Events and Leachate Presence or Absence Sampling Event Leachate Present or Absent WWTP 1 Absent WWTP 2A Absent WWTP 2B Present WWTP 2C a Present WWTP 3 Present b a. Modified sampling event targeted influent and effluent sampling at times leachate arrival was expected. b. Leachate was discharged to WWTP 3 and observed in the influent, however leachate was not captured in the WWTP clarifier or effluent during sampling period as plant retention period was longer than the sampling period. The total volume and discharge rate of leachate to a WWTP can vary day to day which can affect the effluent quality. Typically, leachate discharges are reported as the total daily volume and loadings are calculated relative to the total wastewater influent daily volume. These data do not provide sufficient information to elucidate the effects of variable volumetric loadings on the WWTP effluent quality. Total landfill discharges and hourly flow data from the receiving WWTPs were collected during the above-described 24-hour sampling period. UV absorbance at 254 nm was measured on all influent and effluent samples collected during the field studies. UV absorption was correlated with known additions of leachate added to wastewater without leachate, as described in section 3.2.2, to estimate the volumetric ratio at the time of sample collection. These data are critical to making recommendations regarding discharge practices aimed at reducing the impact of leachate on WWTP operations and effluent quality. 6

22 Figure 1. Treatment and Sampling Scenario Estimation of Leachate Impacts on WWTP Effluent Quality Leachate characteristics from this study and TN removal efficiencies for operating WWTPs from the literature were used to determine the hypothetical effect of various leachate volumetric loadings on WWTP effluent TN concentrations. TN removal efficiencies were determined using a mass balance approach and published removal efficiencies for four WWTPs located across the U.S. (Bott and Parker, 2011). This analysis focused on TN removal for four WWTPs, four leachate volumetric ratios (10%, 1%, 0.1%, and 0.01%), three TN removal efficiencies determined from literature plant data, and the twelve leachates summarized in Table A-1. The removal efficiencies were calculated by Bott and Parker from summary statistics for the 50 th (median), 95 th, and 99 th percentiles determined from historical plant data. These summary statistics reflect the fluctuation in overall plant performance. The 95 th percentile is typically considered to capture the reliable performance measure (Bott et al., 2012). The actual removal efficiencies will depend on the available technology at the WWTP, average performance, and permit regulations; therefore, to adequately understand plant performance, multiple statistical values must be evaluated. The WWTPs were selected based on their nitrogen removal processes, categorized as separate stage, multiple stage, and combined. Plants utilizing separate stage for nitrogen removal achieve nitrification and denitrification in two separate processes. For example, nitrification could occur through an activated sludge process while denitrification would be achieved through a denitrification filter. When nitrification and denitrification occur in one stage (i.e., same sludge system) this system is considered a combined stage. A multiple-stage nitrogen removal facility traditionally achieve nitrification through an activated sludge process and denitrification using a biological filter (Bott et al., 2012). Table 3 summarizes the plants evaluated in this paper along with their respective biological processes. 7

23 Table 3. Summary of Wastewater Treatment Plant Biological Processes for Hypothetical Analysis Wastewater Treatment Plant A B C D Nitrogen Removal Separate System Separate System Combined Stage (Single Sludge System) Multiple Stage Biological Processes ASP with denitrification filters, suspended growth cbod demand removal and nitrification, and denitrification filters with methanol addition. High rate activated sludge (HRAS), nitrifying activated sludge (NAS), and denitrification activated sludge (DNAS). 4-stage Bardenpho processes Oxidation ditch and denitrification filters with methanol addition 3.3 DATA ANALYSIS Data collected in Task 2 were analyzed to better understand the fate of DON and DOC during various WWTP unit processes. Concentrations of wastewater samples with leachate were normalized by that of samples without leachate to understand the contributions of leachate to wastewater effluent quality. Mass balances were used to estimate the contribution of leachate to influent and effluent quality. Data were normalized to compare scenarios and volumetric loadings. 3.4 CHEMICAL ANALYSIS All collected samples were filtered using a 0.45-µm filter prior to chemical analysis. The filtered samples were analyzed for scod, ph, ammonia-n, nitrate-n, nitrite-n, total Kjeldahl nitrogen, UV absorbance, DOC, and true color according to Standard Methods (APHA, 2005). Various spectroscopic techniques were used to identify the molecular fingerprint of leachate and wastewater. The specific methods and instruments were selected because there is a growing leachate database of characteristics using these instruments, the research team has expertise in their use, and they have rapid throughput. Leachate and wastewater samples were characterized using UV Vis Spectroscopy (measuring absorbed energy based on the electronic transition in the molecule). Dried leachate samples were characterized using Fourier Transform Infrared spectroscopy (FTIR) to identify vibrational groups. Selected wastewater samples were characterized using fluorescence. UV-Vis Spectroscopy was used to measure the absorbed energy based on the electronic transition in the molecules. Leachate and wastewater samples were placed in a 1.0-cm cell and the absorbance was measured at 254 nm, 465 nm, and 665 nm using a HACH DR-5000 UV-Vis Spectrophotometer. Full wavelength scans (200 nm 800 nm) were performed on a Cary Win 8

24 UV spectrometer (Agilent Technologies, Inc). Samples with readings exceeding 3.5 absorbance units were diluted to less than 2.0 abs. Leachate was dried at 105 C and analyzed using a Perkin Elmer Spectrum 100 Series FTIR. A background scan was taken before each analysis to remove any contribution of air from the spectrum. A spectrum was acquired by placing a small amount of the sample on a diamond ATR device (attenuated total reflectance) then applying the pressure arm until the force gauge reads approximately 80. Three spectra were acquired for all samples. Transmittance peaks were labeled and identified based on published assignments for FTIR spectral peaks. FTIR data were further analyzed using Principal Component Analysis (PCA) to understand the variance in the data. Overall this method was used to identify patterns in the data sets and highlight differences and similarities (Smidt and Schwanninger, 2007; Smidt et al., 2002). Wastewater fluorescence was measured using a NanoLog Fluorescence spectrometer (HORIBA Scientific) with a 1-cm path-length quartz cuvette. Each liquid sample was diluted to the same absorbance at 350 nm to remove any concentration-dependent effects on the fluorescence measurements. Spectra were measured at the four primary excitation peaks/emission peaks: Peak A (Ex/Em = 260/ nm; humic-like), Peak C (Ex/Em = 350/ nm; humiclike), Peak M (Em/Ex = 312/ nm; marine-like) and Peak T (Em/Ex 275/340 nm, tryptophan/ tyrosine-protein-like material). The fluorescence values of each peak were used to identify differences in spectral characteristics of OM. 9

25 4 RESULTS AND DISCUSSION 4.1 DATABASE DEVELOPMENT OF LEACHATE GENERATION, MANAGEMENT, AND DISPOSAL IN FLORIDA Information on the volume of leachate generated, pretreatment methods (if applicable), and the ultimate disposal method for each landfill site was compiled for all active sites that are not in long-term care (file available upon request). A geographic information system (GIS) database has been developed with all active landfills, nutrient impaired (i.e., by excess nitrogen and phosphorus) water bodies, and domestic wastewater facilities. Figure 2 summarizes the location of all landfills (active and in long-term care) and impaired water bodies by excess nutrients. Twenty-three landfills were located within approximately twelve miles of an impaired water body (Figure 3). One landfill was located in the middle of an area identified as an impaired water body while the second closest landfill was 1.7 miles away from an impaired water body. On average, these 23 landfills were within 5.3 miles of an impaired water body. Ten out of the twenty-three landfills were located near multiple impaired water bodies with one site located next to seven. These data support the need to focus on the effect leachate has on WWTPs. Figure 2. Summary of Landfills and Impaired Water (Nutrients) Bodies 10

26 Figure 3. Identification of Landfills within Twelve Miles of an Impaired Water (Nutrients) Bodies Leachate generation data for 2013 and 2014 were requested from all active landfill owners. It should be noted that most landfills in long-term care are unlined and therefore do not have any means of collecting leachate per OCULUS. Therefore, the effects of these landfills on impaired water bodies were not determined, but may be problematic. To date, volumetric flow from roughly half of the active landfills has been collected. Leachate volume totaled 2.2 billion gallons in 2013 and 2.1 billion gallons in From the database we determined that the majority (92%) of Florida active landfill operators discharge to wastewater treatment plants (WWTP) while 3% discharge directly to a water body after on-site treatment (Figure 4). Florida wastewater generation is roughly 1.5 billion per day (FDEP, 2014), therefore leachate contributes, on average, approximately 1% by volume. On a mass basis, leachate contributes approximately 3%, 9%, and 22% of the cbod5, COD, and TN discharged to WWTPs daily (average leachate values from Table A-1 and medium strength wastewater characteristics from (Metcalf & Eddy, 2003)). Of those discharging to a WWTP, the 11

27 majority (61%) do not treat leachate prior to discharge (Figure 5). The remaining landfills use aerated storage or sequencing batch reactors. During Year 2, we will continue to collect leachate volume data and normalize the data with respect to landfill footprint area. Disposal Method for Active Landfills 6% 27% 67% Sewer System Trucked Deep Injection Well Figure 4. Leachate disposal practice Leachate Pretreatment for Active Landfills 14% 18% 7% 61% Aerated Storage (Tank or Pond) Sequencing Batch Reactor Plants (SBRs) No Pretreatment Other Figure 5. Leachate Pretreatment Prior to Discharge to a WWTP 12

28 4.2 LEACHATE AND WASTEWATER CHARACTERIZATION Characterization Studies This task focused on characterizing leachate and wastewater. The following samples were collected and characterized to develop baseline data: (1) leachate from eight landfills (total thirteen samples, Table 4) and (2) WWTP samples in the absence of leachate (five locations, Tables 4 and 5). A complete set of data for leachate can be found in the appendix (Table A-1). Table 4. Comparison of Leachate (13 Samples) and Influent Wastewater (5 Samples) Leachate Wastewater Influent Parameter Min Max Average (13 samples) Std. Dev. WWTP 1 Sample A WWTP 1 Sample B WWTP 3 Total cbod NA Total COD (mg/l) cbod5/cod NA ph (S.U.) Total NH3-N (mg/l) Total NO3-NO2 (mg/l) Total TKN (mg/l) Total Nitrogen (mg/l) DON (mg/l) DOC (mg/l) DOC/DON SUVA (L/mg-m) Dissolved UV E4/E6 (unitless) Total UV NA: not available 13

29 Table 5. WWTP Effluent Sample Analysis Sample WWTP 1 WWTP 3 Total cbod Total COD (mg/l) cbod5/cod ph (S.U.) Total NH3-N (mg/l) Total NO3-NO2 (mg/l) Total TKN (mg/l) Total Nitrogen (mg/l) DON (mg/l) DOC (mg/l) DOC/DON SUVA (L/mg-m) Dissolved UV E4/E6 (unitless) 8 ND Total UV Thirteen leachate samples collected from seven landfills yielded a wide variation of values for the leachate parameters outlined in Table 4 and A-1. Some of the observed differences can be attributed to landfill operation (e.g., conventional liner system vs. slurry wall, age of the landfill, waste characteristics). Leachate overall has a low biodegradability (cbod5/cod >0.3) relative to wastewater influent (>0.30). Wastewater effluent biodegradability decreased to less than 0.19 after treatment (Table 5). Higher COD, TN, DOC, DON, UV254 absorbance, and ph were measured in leachate relative to wastewater effluent. SUVA is typically higher in leachate than in wastewater (Chin et al., 1994). In this study, SUVA was similar for wastewater and leachate as DOC and UV absorbance at 254 nm were proportionally lower in wastewater. Samples collected from WWTP 1 may be affected by the presence of anaerobic digester supernatant. Prior to anaerobic digestion, solids were dewatered though a gravity belt thickener. 14

30 The spectral characteristics of the collected leachate samples were determined using FTIR. Figure 6 summarizes the spectra of all thirteen samples Transmittance Leachate A Leachate B Leachate C Leachate E Leachate F Leachate G Leachate H Leachate I Leachate J Leachate K Leachate L Leachate M Leachate N Wavenumbers [1/cm] Figure 6. FTIR Spectrum of Dried Leachate Samples Aromatic, organic, inorganic, and nitrogen functional groups were identified in most of the samples. Table 6 summarizes the identified functional groups, based on wavenumbers, and the leachates containing those groups. Aromatic functional groups were present in samples collected from closed landfill cells and have been shown to reflect a well-stabilized leachate based on our previous work (Reinhart and Bolyard, 2013). Aliphatic methylene groups were also present in the same samples and represent organic matter linked in straight/branched chains suggesting a complex organic matter such as humic substances. The SUVA values of these three samples were above 2.0, which also signifies the presence of humic substances. Nitrate groups were present in all samples. Leachate L transmittance at 1397 cm -1 was 69% and was the most significant peak at this wavelength. This sample also had the highest concentration of NOx, which correlates well with the FTIR data. The remaining functional groups that were identified were inorganic. As a landfill stabilizes the FTIR spectrum of leachates shifts from organic to inorganic (Schmidt et al., 2011; Reinhart and Bolyard, 2013). 15

31 Table 6. Summary of Leachate Functional Groups Wavenumber (cm -1 ) Functional Group Leachates 2981 cm -1 Aromatic A, B, C 2920 cm -1 and 2850 cm -1 Aliphatic methylene A, B, C 1556 cm -1 Amides II A, B, C, F, G, H, I, and L 1397 cm -1 Nitrate All 1054 cm -1, 1033 cm -1, A, C, H, K, M, and and 1012 cm -1 Inorganics N 1033 cm -1 Inorganics G 1022 cm -1 Inorganics (Silicate) Leachate(s) 879 cm -1 Carboxylic; Carbonate (COO-) (monovalent anion site) G, I, K, M, and N 871 cm -1 Carboxylic; Carbonate (COO-) (divalent anion site) H and J Principal Component Analysis (PCA) was used to evaluate the variance in the acquired data. PCA is specifically useful to identify patterns in FTIR data sets and highlight differences and similarities (Smidt and Schwanninger, 2007; Smidt et al., 2002). Figure 7 shows some variation among the leachate samples. The positive and negative PCs and associated functional groups based on PCA loading plots are summarized in Table 7. Leachates A, B, C, and E were influenced by negative PC 1 (84% variance) and positive PC 2 (6% variance) which represent amide (1559 cm -1 ), nitrate (1397 cm -1 ), and carboxylic/carbonate (COO-) (divalent anion site, 871 cm -1 ) groups. The remaining leachates (G, H, I, J, K, M, and N) were influenced by a negative PC 1 and negative PC 2. The differences are mainly attributed to the dominance of inorganic functional groups relative to Leachates A, B, C, and E. Leachates A, B, and E were collected from the same landfill and would explain the similar characteristics picked up through FTIR. 16

32 Figure 7. PCA Scores Plot of FTIR Spectrum of Leachate Samples Table 7. Principal Component Scores Related to Loading Plots * PC (+/-) Wavenumbers (cm -1 ) Leachates PC 1 (-) 1556 cm -1 and 1397 cm -1 A, B, C, E, G, H, J, K, M, and N PC 2 (+) 1397 cm -1 and 871 cm -1 A, B, C, E, F, and L PC 2 (-) 1556 cm -1, 1054 cm -1, 1033 cm -1, and 1012 cm -1 G, H, I, J, K, M, and N PC 3 (+) 1556 cm -1 A, B, C, E, G, H, J, and K PC 3 (-) 1054 cm -1, 1033 cm -1, 1012 cm -1, and 871 cm -1 F, L, M, and N *Loading plots can be found in Appendix (Figures A-2-A-3) Dilution Studies Leachate detection limits in wastewater influent and effluent were determined by dilution studies using samples collected from Leachate A and WWTP 1, Leachate F and WWTP 2, and Leachate H and WWTP 3. By comparing the UV-Vis transmittance of leachate diluted with wastewater influent to wastewater alone, leachate could be detected in wastewater at values equal to or below 0.01% by volume for all three facilities (Figure 8). Leachate could potentially be detected at less than 0.01% for WWTPs 2 and 3 as their UV transmittance was still below wastewater without leachate. At 0.01% by volume, the UV transmittance of leachate diluted by wastewater effluent was ~25%-36% lower than wastewater diluted by DI water or leachate diluted by DI water (Figures A-5 and A-6). This dilution study also brought to light that even at a leachate to wastewater volumetric ratio of 0.01% for Leachate A/WWTP 1, the UV transmittance was just below the minimum 65% necessary to meet the disinfection requirement of less than 200 fecal coliform values per 100 ml for reuse (F.A.C ; National Water Research Institute, 2012) (Figure 9). Combinations of Leachate F/WWTP 2 and Leachate H/WWTP 3 were able to 17

33 Transmittance (%) Transmittance (%) meet the 65% requirement at a volumetric ratio of 0.1% and higher which is attributed to the lower UV254 nm leachate absorbance. 35% 30% 30% 28% 30% 25% 20% 18% 15% 10% 5% 0% 11% Wastewater (100%) 0% 0% 1% Leachate (100%) 12% 2% 6% 11% 9% 7% 7% 10% 1% 0.10% 0.01% WWTP 1 WWTP 2 WWTP 3 Figure 8. UV254 Transmittance of Leachate and Wastewater Influent Dilution Tests 90% 80% 70% 60% 50% 66% 78% 74% 61% 75% 75% 70% 64% 58% 49% 40% 30% 20% 10% 0% Wastewater Effluent (100%) 13% 9% 5% 0% 0% 0% Leachate (100%) 10% 1% 0.10% 0.01% WWTP 1 WWTP 2 WWTP 3 Figure 9. UV254 Transmittance of Leachate and Wastewater Effluent Dilution Tests 18

34 4.2.3 Field Studies The field study of leachate co-treatment with wastewater was completed over five sampling events at three WWTPs (see Table 2). Grab samples were collected every 4 hours over a 24-hour period at the influent composite samples, and after clarification and disinfection. Results from WWTP 2 were used to evaluate the fate of leachate throughout the WWTP. Results from WWTP 1 and 2A, without leachate, showed the relative flatness of DON, scod, and DOC (Figures A-9 and A-10). This trend for WWTP 2A was used to normalize leachate-impacted samples by nonimpacted samples. Leachate detection for each field study was determined using UV254 absorbance measurements and compared to flow data received from each landfill. Each samples with a significant increase in absorbance, relative to samples without leachate, was identified as a leachate detection and subsequent impacts were further evaluated. Table 8 identified samples where leachate was detected. Leachate was detected in influent, clarifier, and effluent samples for WWTP 2B. Figure 10 illustrates the relative change in UV254 absorbance when leachate arrived compared to WWTP 2A without leachate. Leachate was detected in WWTP 2C and 3 influent between 12:00 am-4:00 am and 8:00 pm, respectively, but the sampling plan did not capture the leachate leaving the plant because the HRT exceeded the sampling duration. WWTP 3 will be resampled to capture leachate in the clarifier and after disinfection. Figure A-11 shows the wastewater influent UV absorbance for WWTP 3. The UV254 absorbance of influent and effluent samples was also observed to be relatively constant when leachate was not discharged to the WWTP 2A and WWTP 1. Table 8. Leachate Detection Based on Increase in UV254 Absorbance Leachate Detection Influent Clarifier Effluent WWTP 2B 4:00 pm-12:00 am 12:00 am-4:00 am 12:00 am-4:00 am WWTP 2C 12:00 am-4:00 am No Data Not Detected WWTP 3 8:00 PM Not Detected Not Detected 19

35 UV Absorbance (abs) Leachate Arriving at the WWTP Influent 8:00 am Influent 12:00 pm Influent 4:00 pm Influent 8:00 pm Influent 12:00 am Influent 4:00 am WWTP 2A WWTP 2B Figure 10. UV254 Absorbance of WWTP 2A and 2B Influent Effluent impacts detected based on UV254 absorbance were also confirmed through visual observation and apparent color measurements (absorbance at 456 nm). Figure 11 shows effluent bottles organized by sampling time; two samples appeared to be impacted by leachate (i.e., 12:00 am and 4:00 am). This persistence of color suggests that the leachate organic matter was resistant to biological degradation at this facility. This color change also affected the measured UV254 transmittance causing this facility to fall below the required 65% transmittance for disinfection (Figure 12; note this facility does not utilize UV disinfection). 20

36 Transmittance (%) Figure 11. WWTP Effluent (WWTP 2A) with and without Leachate (WWTP 2B) 80% 70% WWTP #2 65% Transmittance Requirement 60% 50% 40% 30% 20% 10% 0% Effluent 8:00 am Effluent 12:00 pm Effluent 4:00 pm Effluent 8:00 pm Effluent 12:00 am Effluent 4:00 am WW w/o Leachate WW with Leachate Figure 12. UV254 Percent Transmittance of Wastewater Effluent with and without Leachate at WWTP 2 21

37 Studies on the co-treatment of leachate and wastewater report the leachate volumetric loading rate relative to the total wastewater influent daily flow and leachate discharges and do not necessarily represent the loading at the time of sampling. The landfills studied do not record hourly leachate flows to each WWTPs therefore a method to estimate this information was needed. The UV absorbance at 254 nm was measured for all WWTPs influents evaluated in this study as a baseline (i.e., leachate volumetric ratio of 0%). Known additions of leachate to the WWTP influent were prepared and a calibration curve was developed to estimate the volumetric ratio of the field samples. UV absorbance at 254 nm was measured on all influent samples collected in the field studies and the volumetric ratio was calculated based on their respective calibration curves (Figures A-7 and A-8). The leachate volumetric ratios for WWTPs 2B and 2C and WWTP 3 are summarized in Table 9. Table 9. Estimated Volumetric Ratio Using Known Addition of Leachate Added to Wastewater Influent (without Leachate) Sampling Time WWTP 2B WWTP 2C WWTP 3 Volumetric Ratio (%) 8:00 am 0.0 NS :00 pm (2:00 pm a ) :00 pm 0.59 NS :00 pm (7:00 pm a ) :00 am :00 am NS c 2.2 NS 4:00 am (5:00 am) NS 0.00 a. WWTP 2C b. WWTP 3 c. No sample The impacts of leachate on DON, scod, and DOC for WWTP 2B were evaluated by normalizing measured concentrations (1) using WWTP 2A data (without leachate; Table 10) and (2) using non-impacted samples, collected during the same sampling period, from WWTP 2B (Table 11). When comparing the sampling event without leachate (WWTP 2A) and with leachate (WWTP 2B), DOC was slightly impacted (i.e., normalized values were above 1), but DON was not impacted by leachate (i.e., normalized values were below 1) (Table 10). On the other hand, when comparing the leachate-impacted samples for WWTP 2B to non-impacted samples during the same sampling event these parameters were significantly impacted (normalized values were greater than 1). These observations may be attributed to variations in wastewater characteristics from one day to another (i.e., a higher nitrogen loading was captured while sampling at WWTP 2A). DON ratio decreased through the plant suggesting that this parameter was effectively removed in the plant, while DOC persisted. DOC pass-through coincided with an increase in color and UV absorption. 22

38 Table 10. WWTP 2B Leachate Impacted Samples Normalized by WWTP 2A* Influent Clarifier Effluent DON scod DOC * Same WWTPs Table 11. WWTP 2B Leachate Impacted Samples* Normalized by Non-Impacted Samples for WWTP2B Influent Clarifier Effluent DON scod DOC *See Table 9 Figure 13 show that there was a minimal change in DOC after biological treatment (~6 hr HRT) and clarification (~4-5 hr HRT) which would be expected as the organic matter found in the DOC fraction would not settle out. DOC and scod captures organic matter that can be responsible for the colored effluent samples which is most likely recalcitrant and will pass through the WWTP. Data on the organic matter present in these effluent samples will be discussed in Section

39 Figure 13. DOC in Wastewater with Leachate (WWTP 2B) Normalized by Wastewater without Leachate (WWTP 2A) The impact of leachate on WWTP effluent quality was estimated using a mass balance approach (Table 12). Leachate characteristics and wastewater effluent quality without leachate were used and no removal of leachate constituents was assumed. The predicted effluent quality for WWTP 2B was within the measured values. COD was higher than predicted but the differences were not significant. The minor differences between COD can presumably be attributed to the differences in the biodegradable fraction of this component. A slight increase in effluent TN was observed as leachate arrived at the WWTP but results support that the facility was able to remove the additional TN loading from the leachate. 24

40 Table 12. Estimation of Leachate Impact on Effluent Quality (WWTP 2B) Effluent Actual (12 Effluent Predicted Volumetric hour HRT) Effluent Sampling Time Ratio (%) COD TN COD TN Sampling (mg/l) (mg/l) (mg/l) (mg/l) 8:00 AM :00 PM :00 PM :00 AM :00 PM :00 AM Leachate Fingerprint in Wastewater Detecting the changes in wastewater characteristics specifically from leachate impacts will depend on obtaining the following information: (1) wastewater baseline without leachate (2) and data on color (UV456 nm), DOC, UV254 nm, and fluorescence (i.e., characterization of the organics present). These parameters were selected specifically due to their sensitivity to leachate arriving at a WWTP. For example, UV-Vis absorbance for WWTP 2A had minimal variations in absorbance across the measured range (200 nm-800 nm) without leachate (Figure 14). A similar trend was observed for WWTP 3 (Figure 15). When leachate arrived at WWTP 2 during a different sampling event (2B) the spectra shifted due to the increase in UV254 nm absorbance. The presence of leachate in WWTP 2B effluent was only evident with a minor shift in the spectra as can be observed in Figure

41 Figure 14. UV-Vis Scan (200 nm to 800 nm) of Wastewater Influent and Effluent Samples with and without Leachate (WWTP 2C) Figure 15. UV-Vis Scan (200 nm to 800 nm) of Wastewater Influent Samples with Leachate and Effluent without Leachate (WWTP 3) 26

42 When fluorescence measurements are coupled with UV254 nm absorbance measurements the specific compounds presence in a sample can be identified. During this project, we focused on three humic-like peaks and tryptophan/tyrosine protein-like material. Figure 16 shows fluorescence data on the four peaks present in effluent samples with (red; WWTP 2B) and without leachate (blue; WWTP 2A). Prior to analysis, all samples were diluted to a UV254 nm of 0.01 to avoid any concentration dependent effects on fluorescence. Leachate impacted wastewater showed a higher concentration of humic-like peaks at 350 nm and 312 nm. The humic-like peak at 260 nm appears to be present in wastewater effluent with and without leachate and only 1.22 times higher with leachate present. Lastly, the tryptophan/tyrosineprotein-like peak was relatively the same for both samples. The literature supports that effluent fluorescence typically shows protein-like organic matter (Kazner et al., 2012). Table 13 presents the fluorescence index (FI) of all four samples and reveals that the organic matter present in both samples was autochthonous (microbial originating) in nature (FI of ~1.7-~2.0) (Kazner et al., 2012). There was a slight increase in the FI of the samples affected by leachate but could be significant since the absorbance at 254 nm was the same for both samples. WWTP 2A 12 AM WWTP 2A 4 AM WWTP 2B 12 AM WWTP 2B 4 AM Figure 16. Excitation-Emission Figures for WWTP 2A and 2B Effluent Samples Collected at 12:00 am and 4:00 am 27

43 Table 13. Fluorescence Index of WWTP 2A and 2B Effluent Samples Collected at 12:00 am and 4:00 am Sample ( Fluorescence Index Emission at 450 nm Emission at 500 nm WWTP 2A 12:00 am 2.3 WWTP 2A 4:00 am 2.2 WWTP 2B 12:00 am 2.5 WWTP 2B 4:00 am 2.5 ; excitation of 370 nm) Table 14 summarizes the characteristics of wastewater effluent samples with and without leachate. Our data show that UV254 nm absorbance and FI were higher for leachate-impacted samples, and an increase in color and DOC was observed. A clear separation between leachate impacted wastewater effluents is illustrated in Figure 17 by plotting color, UV254 nm absorbance, and FI. Table 14. Summary of Effluent Characteristics of Samples Collected at 12:00 am and 4:00 am from WWTPs 2A (without leachate) and 2B (with leachate) Sample Color (Pt-Co units) UV 254 (abs) FI (unitless) DOC (mg-c/l) 2A 2B 2A 2B 2A 2B 2A 2B 12:00 am :00 am WWTP 2B 2.5 FI 2.4 WWTP 2A UV Color Figure 17. Relationship between FI, UV254 nm, and Color for Wastewater Effluent with (2B) and without (2A) Leachate 28

44 4.3 EVALUATION OF LEACHATE IMPACTS ON WWTP EFFLUENT QUALITY Table 15 displays the minimum, maximum, and average TN effluent concentrations for four hypothetical WWTPs and the leachates characterized as a function of assumed influent volume contributions and daily plant performance based on summary statistics. Permit limits for WWTP effluent TN are typically between 3.0 and 10 mg/l depending on the discharge location. Values exceeding 10 mg/l of TN are highlighted in Table 15. Exceedances were found for leachate contributions of 10% based on all three performance statistics. There was an increase in the number of effluent values exceeding 10 mg/l at lower leachate volumetric ratios for the 95 th and 99 th percentiles. This trend is attributed to the fluctuations in plant performance reflecting poor removal efficiencies captured by the 95 th and 99 th percentiles. Consequently, there are scenarios where reliably achieving TN concentrations of less than 10 mg/l, even at low leachate volumetric ratios, is not possible. The differences in removal efficiencies are explained by the biological processes at each WWTP, as previously stated. This behavior is illustrated in Figure 18 where significant differences in effluent TN concentrations for each WWTP receiving the same leachate (Table 15) at a volumetric ratio of 10% are seen. Figure 18 shows that separate and multiple stage biological processes are more efficient at TN removal relative to combined processes. The maximum leachate TN concentration that can be accepted at WWTPs A-D without exceeding 10 mg/l is 870 mg/l, 520 mg/l, 125 mg/l, and 1,280 mg/l, respectively (volumetric ratio of 10%). Separate and multiple stage processes have been described to be more efficient due to the higher degree of control over the denitrification step and carbon addition (Bott and Parker, 2011). The lowest TN that can be accepted from a landfill is at WWTP C, which operates using a combined stage biological process for nitrogen removal. Table 15. Summary of Wastewater Effluent Total Nitrogen as a Function of Leachate Volumetric Loadings and Fluctuations in Daily Plant Performance (Shaded Values Exceed Typical Discharge Limits) Volumetric Ratio of Leachate 50 th Percentile 95 th Percentile 99 th Percentile Total Nitrogen (mg/l) Total Nitrogen (mg/l) Total Nitrogen (mg/l) Min Max Average Min Max Average Min Max Average 10% % % %

45 TN (1 unit = 10 mg/l) 8 7 Combined Stage Separate Stage 3 2 Multiple Stage 1 0 WWTP A WWTP B WWTP C WWTP D Leachate A Leachate B Leachate C Leachate D Leachate E Leachate F Leachate G Leachate H Leachate I Leachate J Leachate K Leachate L Figure 18. Wastewater Effluent Total Nitrogen Calculated based on a Plant Performance in the 95 th Percentile and a Leachate Volumetric Ratio of 10% 5 CONCLUSIONS The benefits of this research relate to leachate generation, management, and disposal. WWTPs are cautious when accepting leachate, because the variability in characteristics and flows could lead to increased complexity for domestic wastewater treatment (e.g., potential pass through of constituents leading to permit violations, inhibition of biological processes). This research will provide a better understanding of potential implications of accepting leachate for both the landfill and WWTP operators; for example, evaluating the expected bioavailability of DON in leachates will clarify the potential impact on receiving water bodies. Additionally, disinfection in the presence of LOM will be better understood and recommendations will be made to ensure that performance complies with permit requirements. From the leachate database, we determined that the majority (92%) of Florida active landfill operators discharge to wastewater treatment plants (WWTP) while 3% discharge directly to a water body. Florida wastewater generation is roughly 1.5 billion per day (FDEP, 2014), therefore leachate contributes, on average, approximately 1% by volume. On a mass basis, leachate contributes approximately 3%, 9%, and 22% of the cbod5, COD, and TN discharged to WWTPs daily. Of those discharging to a WWTP, the majority (61%) do not treat leachate prior to discharge. The remaining landfills use aerated storage or sequencing batch reactors. From the leachate and wastewater characterization study, we concluded the following: Leachate characteristics varied significantly, even from the same landfill at different sampling times, Leachate samples were less biodegradable than wastewater influents and effluents, in general, Aromatic, organic, inorganic, and nitrogen functional groups were identified in most of the leachate samples, which suggested well-stabilized organic matter. 30

46 Three leachates were diluted with wastewater influent and effluent to examine the ability to detect leachates in wastewater. By comparing the UV transmittance of diluted and undiluted leachate to wastewater, it was possible to calculate a lower limit of detection. Leachate was detectable in wastewater influents at dilutions below 0.01% by volume. In effluents, the UV transmittance was just below the minimum 65% necessary to meet the disinfection requirement (i.e., if membrane filtration is utilized) of less than 200 fecal coliform values per 100 ml for reuse (F.A.C ; National Water Research Institute, 2012) at dilutions greater than 1%. The field study of leachate co-treatment with wastewater was completed over five sampling events at three WWTPs. Grab samples were collected every 4 hours over a 24-hour period at the influent composite samples, and after clarification and disinfection. Leachate detection for each field study was determined using UV254 absorbance measurements. Each sample with a significant increase in absorbance, relative to samples without leachate, was identified as a leachate detection and subsequent impacts were further evaluated. Changes in influent characteristics were observed all three WWTPs receiving leachate; however leachate was only evident in one effluent (WWTP 2B). This was attributed to the longer than expected hydraulic retention periods of these WWTPs. Sampling will be repeated during Year 2 of the study. Effluent impacts were detected based on UV254 absorbance and confirmed through visual observation and apparent color measurements. The impacts of leachate on DON, scod, and DOC for WWTP 2B samples receiving leachate by normalizing measured concentrations using non-impacted samples from WWTP 2B. When comparing the leachate-impacted samples for WWTP 2B to non-impacted samples during the same sampling event, these parameters were significantly impacted (normalized values were greater than 1). The DON ratio decreased through the WWTP suggesting that this parameter was effectively removed in the plant (WWTP 2B), while DOC persisted. DOC pass-through coincided with an increase in color and UV absorption. Samples from WWTPs with and without leachate were analyzed with the objective of identifying a leachate fingerprint. The following observations were made: Leachate arrival during a sampling event led to a UV spectral shifted due to an increase in UV254 nm absorbance, Leachate-impacted wastewater showed a higher concentration of humic-like peaks during fluorescence measurements, and UV254 nm absorbance and a fluorescence index were higher for leachate-impacted samples and an increase in color and DOC was observed. A hypothetical study using leachate characteristics measured during this study and nitrogen removal data for WWTPs reported in the literature using three different biological nitrogen removal schemes was completed. From this study, it is clear that nitrogen limits of 10 mg/l would be regularly exceeded at a leachate volumetric loading of 10%. Separate and multi-stage processes were more effective than combined stage nitrogen removal processes. It is apparent from this study that leachate can have significant effects on wastewater quality at relatively low volumetric ratios. These effects were detected by a decrease in UV transmittance and color (which can interfere with disinfection), an increase in effluent DOC which can lead to 31

47 violations in permits or the production of DBPs, and an increase in influent DON. Spectroscopic data from both UV and fluorescence were useful in fingerprinting the leachate. These effects, however, can be managed by ensuring that leachate discharge is maintained at acceptable dilution ratios and evenly spread out over the discharge period. More data will be collected during Year 2 of the study to validate these observations as they were based on a limited number of observations. 32

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51 Sample Source 7 APPENDIX Table A-1. Summary of Leachates Characterized in Year 1 Leachate A Leachate B Leachate C Leachate E Leachate F Leachate G Leachate H Leachate I Leachate J Leachate K Leachate L Leachate M Leachate N Combined Leachate 1 Leachate from a Closed Cell Combined Leachate 1 Aerated Leachate from a Closed Cell Combined Leachate 1 Combined Leachate 1 Combined Leachate 1 Combined Leachate 1 Combined Leachate` Leachate from a Closed Cell Leachate from a Closed Cell Leachate from Closed Cell Stored in an Open Tank Total cbod Total COD (mg/l) cbod 5/COD ph (S.U.) Total NH3-N (mg/l) Total NO3- NO2 (mg/l) Total TKN (mg/l) Total Nitrogen (mg/l) DON (mg/l) DOC (mg/l) DOC/DON SUVA (L/mg-m) Dissolved UV E4/E6 (unitless) Total UV Combined Active and Closed Cells Leachate from a Closed Cell 36

52 Figure A-1. Principal Component Analysis of Leachate FTIR Spectra (Score Plots PC1 vs PC3) Figure A-2. Principal Component Analysis of Leachate FTIR Spectra (Loading Plots PC1; 84% Variance) 37

53 Figure A-3. Principal Component Analysis of Leachate FTIR Spectra (Loading Plots PC2; 6% Variance) Figure A-4. Principal Component Analysis of Leachate FTIR Spectra (Loading Plots PC3; 4% Variance) 38

54 UV Transmittance UV Transmittance 100% 96% 99% 100% 100% 97% 80% 60% 40% 49% 78% 64% 20% 0% 0% 0% 5.4% 9% 10% 1.0% 0.10% 0.01% Percent by Volume Leachate/Wastewater WW/DI Leachate/DI Figure A-5. UV Transmittance of Leachate and Wastewater Effluent Dilution Tests (Plant 1) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 9% 99% 100% 100% 98% 100% 100% 81% 75% 75% 61% 11% 10% 1% 0.10% 0.01% Percent by Volume Leachate/Wastewater WW/DI Leachate/DI Figure A-6. UV Transmittance of Leachate and Wastewater Effluent Dilution Tests (Plant 3) 39

55 UV Abs at 254 nm UV Abs at 254 nm Leachate Volumetric Ratio Influent NF Figure A-7. Leachate Volumetric Calibration Curve for Leachate F and WWTP 2B and 2C Influent Leachate Percent Influent Figure A-8. Leachate Volumetric Calibration Curve for Leachate H and WWTP 3 Influent 40

56 Figure A-9. WWTP 1 Influent DOC, scod, and DON Concentrations Figure A-10. WWTP 1 Effluent UV254 Absorbance 41

57 UV254 Absorbance (abs) Wastewater Influent Influent 8:00 am Influent 12:00 pm Influent 4:00 Influent 8:00 pm pm Influent 12:00 am Figure A-11. WWTP 3 Effluent UV254 Absorbance Influent 4:00 am 42

58 Figure A-12. DON in Wastewater with Leachate (WWTP 2B) Normalized by Wastewater without Leachate (WWTP 2A) 43