Assessment and Evaluation of Advanced Solid Waste Management Technologies for Improved Recycling Rates. Nurcin Celik

Transcription

1 Assessment and Evaluation of Advanced Solid Waste Management Technologies for Improved Recycling Rates February 2016 Nurcin Celik University of Miami, Coral Gables, FL, USA Department of Industrial Engineering And Duygu Yasar and Mehrad Bastani University of Miami, Coral Gables, FL, USA Department of Industrial Engineering Hinkley Center for Solid and Hazardous Waste Management University of Florida P. O. Box Gainesville, FL Report # i

2 TABLE OF CONTENTS LIST OF FIGURES... iv LIST OF TABLES... v LIST OF ACRONYMS... vii ABSTRACT... viiii EXECUTIVE SUMMARY... xi RESEARCH TEAM... xiv DISSEMINATION ACTIVITIES... xv INTRODUCTION... 1 BACKGROUND AND LITERATURE REVIEW Biochemical Treatment Technologies Anaerobic Digestion Depolymerization Windrow Composting Static Pile Composting In-vessel Composting Advanced Thermal Solid Waste Management Technologies Gasification Plasma Arc Gasification Pyrolysis Physical Technologies... 8 DATA COLLECTION Defining Criteria Set Contacting SMEs Categorization of Counties Municipal Solid Waste Types in Floridian Counties Floridian County Categories for AHP Technology Data METHODOLOGY Analytical Hierarchy Process (AHP) AHP RESULTS Criteria Weights Global Priorities of Technologies ii

3 6. SENSITIVITY ANALYSIS CURRENT STATE OF WASTE MANAGEMENT IN FLORIDA Waste to Energy Facilities in Florida Composting and AD Facilities RECOMMENDATIONS Current Recycling Rates of Counties Maximum and Minimum Capacities of Alternatives LIMITATIONS AND CONCLUSION APPENDICES iii

4 LIST OF FIGURES FIGURE 1. Pictures from events... xviivi FIGURE 2. Management phases of a MSW landfill throughout life-cycle... 1 FIGURE 3. Traditional open loop (left) and advanced disposal landfills close loop cycles (right)... 3 FIGURE 4. Categorization of advanced solid waste management technologies... 4 FIGURE 5. Harvest s Energy Garden in Central Florida... 5 FIGURE 6. AHP structure for ATSWMT evaluation FIGURE 7. AHP structure for ABSWM technology evaluation FIGURE 8. Grouping process of Floridian counties FIGURE 9. Florida map displaying groups of counties FIGURE 10. Explanation of 1-9 Saaty Scale FIGURE 11. Criteria weights for evaluation of ATSWMT FIGURE 12. Overall inconsistency ratios (IR) (<<0.1) for evaluation of ATSWMT FIGURE 13. Criteria weights for evaluation of ABSWMT FIGURE 14. Overall inconsistency ratios (IR) (<<0.1) for evaluation of ABSWMT FIGURE 15. Global priorities of ATSWMT FIGURE 16. Global priorities of ABSWMT FIGURE 17. Sensitivity analysis results for ATSWMT FIGURE 18. Sensitivity analysis results for ABSWMT FIGURE 19. Palm Beach Renewable Energy Facility FIGURE 20. Organic waste treatment facilities in Florida (Zimms and Ver Eecke, 2012) FIGURE 21. Okeechobee composting facility FIGURE 22. Counties with annually 400,000 tons or greater waste landfilled FIGURE 23. Groups of counties in the final recommendations iv

5 LIST OF TABLES TABLE 1. WTE facilities in Florida TABLE 2. AHP results and technology capacity interaction TABLE 3. Recycling rates and waste generation of Floridian counties TABLE B.1. Consolidated matrix of Group 1 for criteria pairwise comparisons TABLE B.2. Consolidated matrix of Group 2 for criteria pairwise comparisons TABLE B.3. Consolidated matrix of Group 3 for criteria pairwise comparisons TABLE B.4. Consolidated matrix of Group 4 for criteria pairwise comparisons TABLE B.5. Consolidated matrix of Group 5 for criteria pairwise comparisons TABLE B.6. Consolidated matrix of Group 6 for criteria pairwise comparisons TABLE B.7. Consolidated matrix of Group 7 for criteria pairwise comparisons TABLE B.8. Consolidated matrix of Group 8 for criteria pairwise comparisons TABLE C.1. Consolidated matrix of Group 1 for criteria pairwise comparisons TABLE C.2. Consolidated matrix of Group 2 for criteria pairwise comparisons TABLE C.3. Consolidated matrix of Group 3 for criteria pairwise comparisons TABLE C.4. Consolidated matrix of Group 4 for criteria pairwise comparisons TABLE C.5. Consolidated matrix of Group 5 for criteria pairwise comparisons TABLE C.6. Consolidated matrix of Group 6 for criteria pairwise comparisons TABLE C.7. Consolidated matrix of Group 7 for criteria pairwise comparisons TABLE C.8. Consolidated matrix of Group 8 for criteria pairwise comparisons v

6 LIST OF ACRONYMS ABSWMT ATSWMT ASWMT AIJ AD AHP C&D FDEP GHG IVC MSW SWM SMEs TPY USEPA WTE : Advanced biological solid waste management technologies : Advanced thermal solid waste management technologies : Advanced solid waste management technologies : Aggregation of individual judgments : Anaerobic digestion : Analytical Hierarchy Process : Construction and demolition : Florida Department of Environmental Protection : Greenhouse gas : In-vessel composting : Municipal solid waste : Solid waste management : Subject matter experts : Tons per year : United States Environmental Protection Agency : Waste-to-energy vi

7 FINAL REPORT (November November 2015) PROJECT TITLE: Assessment and Evaluation of Advanced Solid Waste Management Technologies for Improved Recycling Rates PRINCIPAL INVESTIGATOR(S): Nurcin Celik, Ph.D. AFFILIATION: Department of Industrial Engineering, University of Miami celik@miami.edu PHONE NUMBER: PROJECT WEBSITE: COMPLETION DATE: November 2015 TAG MEMBERS: KEY WORDS: Alberto Caban-Martinez, Brenda S. Clark, Bryan Tindell, Helena Solo- Gabriele, Jeremy O Brien, Kathleen Woods- Richardson, Kendra F. Goff, Kenneth P. Capezzuto, Lora Fleming, Michael J. Fernandez, Nurcin Celik, Patti Hamilton, Paul J. Mauriello, Paul Valenti, Ram Narasimhan, Samuel B. Levin, Scott Harper, Sean Williams, Shihab Asfour, Stanley D. Gray, Tim Vinson, Timothy G. Townsend Advanced solid waste management technologies, analytical hierarchy process, sustainability, improved recycling rates vii

8 ABSTRACT The burgeoning growth observed in the solid waste generation combined with the increase in the regulation of disposal operations and dwindling availability of suitable disposal sites, have made the planning and operation of integrated solid waste management systems progressively more challenging. As a result of these factors, and growing pressures for environmental protection and sustainability, the State of Florida has established an ambitious 75% recycling goal, to be achieved by the year This study aims to identify and evaluate new and emerging advanced solid waste management technologies and their potential to help state reach its recycling goal by 2020, in a manner that is structurally unified, and useful for practitioners in terms of various criteria such as revenue, tipping fee, capital cost, operation cost, development period, flexibility of process, land requirement, net conversion efficiency, ease of obtaining permits, marketability, environmental impact, public acceptability, number of facilities. In the first phase of the study, new and emerging solid waste technologies which can help Florida reach its recycling goal in an environmentally friendly and economically feasible way, were identified. The advanced solid waste management technologies considered in this study includes gasification, plasma arc gasification, pyrolysis, windrow composting, static piles composting, in-vessel composting, and anaerobic digestion. Data regarding the identified technologies were collected. Analytical Hierarchy Process, which is a multi-criteria evaluation method were utilized for a comprehensive evaluation of technologies. In order to implement the AHP methodology for the evaluation, solid waste management divisions of 67 counties in Florida along with several facilities that embrace these technologies were contacted. Following the AHP analysis, a sensitivity analysis is conducted to evaluate how input uncertainty might impact the AHP results. In the final phase of the study, recommendations were provided at the county level by considering the combined results from the AHP, sensitivity analysis as well as the current waste management practices and recycling rates of the counties, their geographical proximity to each other, and waste treatment capacities of the recommended technologies. Larger counties are grouped with adjacent small counties to treat their waste jointly. The total potential improvement in the recycling rates (through the presented recommendations) is estimated to be as large as 17.9%. viii

9 METRICS: 1. List graduate student or postdoctoral researchers funded by THIS Hinkley Center project Last name, first name Rank Department Professor Institution Bastani, Mehrad Ph.D. Candidate Department of Industrial Engineering Yasar, Duygu Ph.D. Student Department of Industrial Engineering 2. List undergraduate researchers working on THIS Hinkley Center project Name: Gregory Collins Department: Department of Industrial Engineering Professor: Dr. Nurcin Celik Institution: University of Miami Prof. Nurcin Celik Prof. Nurcin Celik University of Miami University of Miami 3. List research publications resulting from THIS Hinkley Center project (use format for publications as outlined in Section 1.13 of this Report Guide). Journal Paper: Yasar, D., Celik, N., and Sharit, J. Evaluation of advanced thermal solid waste management technologies for sustainability in Florida, International Journal of Performability Engineering 12(01) (2016). Book Chapter: Yasar, D. and Celik, N., Assessment of Advanced Biological Treatment Technologies for Sustainability, IGI Global, PA, 2015, Joo, S. H. (Eds.), Applying Nanotechnology for Environmental Sustainability, IGI Global, accepted. Yasar, D. and Celik, N., Assessment of advanced thermal solid waste management technologies, Talking Trash Newsletter of the SWANA Florida Sunshine Chapter p.8 (2015). 4. List research presentations (as outlined in of this Report Guide) resulting from THIS Hinkley Center project. Our team has presented the progress of the first phase of this work during our TAG I meeting in February 20, Our team has presented the progress of the second and third phases of this work during our TAG II meeting in August 18, Aristotelis Thanos presented two of our projects including this one during Hinkley Center Colloquium, Tallahassee, FL, USA in September 24, Duygu Yasar, Gregory Collins, and Mehrad Bastani attended SWANA s National Solid Waste Design Competition (SWDC) on August 24, 2015 in Orlando, FL. Three hydrogen sulfide removal technologies namely SulfaTreat, Bio-trickling filter, and LO-CAT which reduce hydrogen sulfide in the collected landfill gas were evaluated ix

10 in the competition design report. The methodology used in this project for the evaluation of advanced SWM technologies were applied to the problem solved in SWANA s National Solid Waste Design Competition (SWDC). Hydrogen sulfide removal technology and evaluation criteria identification were completed in the way defined in this project. Only the technologies that are currently implemented in US were considered. 5. List who has referenced or cited your publications from this project? The journal paper entitled "Evaluation of Advanced Thermal Solid Waste Management Technologies for Sustainability in Florida" by Duygu Yasar and Nurcin Celik has been cited in the M.S. thesis authored by Gregory Richard Hinds at University of South Florida: G. R. Hinds, 2015, High-Solids Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste State of the Art, Outlook in Florida, and Enhancing Methane Yields from Lignocellulosic Wastes. (Graduate Thesis). Retrieved from University of South Florida Scholar Commons Database, How have the research results from THIS Hinkley Center project been leveraged to secure additional research funding? PI Celik and her team have applied for a foundational grant on January and July 2015, respectively and are awaiting response on their proposal. Another further proposal is currently being developed for NIOSH/NIH in a multi-institution collaboration, and will be submitted by the end of this year. 7. What new collaborations were initiated based on THIS Hinkley Center project? Paul Mauriello, Deputy Director for Waste Operations, Department of Public Works and Solid Waste Management at the Miami-Dade County has designated Michael J. Fernandez, Assistant Director of Disposal Operations as the future direct point of contact for our on-going relationship with UM. He has a wealth of experience in solid waste collection and disposal operations in both the public and private sectors. Scott Harper, Solid Waste Services Manager of Hernando County has been very helpful in both our TAG meetings and afterwards follow-ups. He has also been instrumental in providing us with expertise rankings of the criterion. Sally Palmi, Solid Waste Director of Alachua County has been very helpful for providing necessary information. She has been very interested in our project since they have just completed a similar task in developing criteria for a project they are working on. Mark A. Paisley, P.E., Vice President of Taylor Biomass Energy has been very x

11 helpful for providing the necessary data regarding gasification technology. He provided detailed information on development period, conversion efficiency, environmental impact, ease of obtaining permits, and land requirement of the Taylor Gasification Process. Kathleen A. Prather, P.E., Environmental Engineer in Division of Materials Management, New York State Department of Environmental Conservation has been very helpful for providing Technical/Operational Documents for JBI, Inc. Susan Warner, Diversion Manager of Salinas Valley Solid Waste Authority has provided detailed information and relevant reports about Autoclave Technology Testing Program. Mike Sims, Solid Waste Director of the Marion County has requested to be informed on the findings when the project is completed. 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). The results obtained from this study have not been presented yet. xi

12 EXECUTIVE SUMMARY PROJECT TITLE: PRINCIPAL INVESTIGATOR: AFFILIATION: PROJECT WEB SITE: PROJECT TAG MEMBERS: Assessment and Evaluation of Advanced Solid Waste Management Technologies for Improved Recycling Rates Nurcin Celik, Ph.D. Department of Industrial Engineering, University of Miami Alberto Caban-Martinez, Brenda S. Clark, Bryan Tindell, Helena Solo- Gabriele, Jeremy O Brien, Kathleen Woods- Richardson, Kendra F. Goff, Kenneth P. Capezzuto, Lora Fleming, Michael J. Fernandez, Nurcin Celik, Patti Hamilton, Paul J. Mauriello, Paul Valenti, Ram Narasimhan, Samuel B. Levin, Scott Harper, Sean Williams, Shihab Asfour, Stanley D. Gray, Tim Vinson, Timothy G.Townsend COMPLETION DATE: November 2015 OBJECTIVES: In recent years, a significant increase has been observed in the variety and quantity of municipal solid waste (MSW) worldwide, with the greatest rate of growth, both overall and per-capita, exhibited by the United States. Due to this burgeoning growth as well as the accompanying increase in strict regulations of disposal operations and the dwindling availability of disposal sites, solid waste management (SWM) has become increasingly more challenging. Discharging waste to landfills and incineration of waste are not sustainable options due to several environmental problems. Landfills release greenhouse gas (GHG) emissions even 30 years after their closure. Incineration technology provides a reduction in the total volume of waste to be discarded in landfills, yet, releases emissions of pollutant organic compounds such as NOx, SOx. In the light of aforementioned reasons, the State of Florida has established an ambitious 75% recycling goal to be achieved by Advanced solid waste management technologies (ASWMT) such as gasification, plasma arc gasification, pyrolysis, anaerobic digestion, and invessel composting are capable of achieving this goal as well as reducing the GHG emissions. In this project, advanced SWM technology options are identified and evaluated using Analytical Hierarchy Process (AHP) which is a multi-criteria decision making method. Technologies are evaluated with respect to several criteria including revenue, tipping fee, capital cost, operation cost, development period, flexibility of process, land requirement, net conversion efficiency, ease of obtaining permits, marketability, environmental impact, public acceptability, number of facilities. SWM divisions of each county were contacted to obtain their criteria preferences. Following the quantitative analysis, recommendations are provided by considering AHP results, sensitivity analysis results as well as the current recycling rates of counties, and the amount of waste landfilled by each county. xii

13 METHODOLOGY: The study is composed of the following phases: 1. Identification of ASWMT: New and emerging solid waste management technologies that were under the scope of this study were identified as technologies that are not currently in widespread commercial use in the State of Florida, or that have only recently become commercially operational (USEPA, 2014). To this end, we had performed an extensive review on the current literature of ASWMT to identify such technologies, and categorize them to the extent possible. The category of advanced thermal SWM technologies includes gasification, plasma arc gasification, and pyrolysis and the category of advanced biological SWM technologies includes windrow composting, static piles composting, in-vessel composting, and anaerobic digestion. Technologies in their early phases of investigation (whether being investigated in US or abroad) and have not been applied in commercial practice were not considered in the evaluation based on the feedback given by the committee during our first TAG meeting in February, Data Collection: Various data regarding the advanced thermal and biological SWM technologies were collected by utilizing multiple data collection techniques. Data were collected by reviewing materials and interviewing county waste management divisions and technology providers. Related works on the literature were collected from on-line databases at University of Miami and County Waste Management Plans, Florida Department of Environmental Protection (FDEP) and County government websites. In order to implement the AHP methodology for evaluation, we contacted solid waste management divisions of 67 counties along with several facilities that embrace these technologies such as Taylor Biomass Energy, Salinas Valley Solid Waste Authority, JBI Niagara Falls Pyrolysis Facility, and Lee County Compost Production Facility. requests and follow-up phone conversations for evaluation of criterion set by subject matter experts (SMEs) were sent to all Floridian counties, and received a 71 percent response rate. 3. Quantitative Assessment: AHP was conducted to assess gasification, plasma arc gasification, pyrolysis, windrow composting, static piles composting, in-vessel composting, and anaerobic digestion technologies for 67 counties in Florida with an aim to recommend the best technology for each county to improve their recycling rates. The model is hierarchically structured, consisting of objectives, criteria, sub-criteria, and alternatives. Technologies were evaluated with respect to several criteria including capital cost, revenue, net conversion efficiency, public acceptability, tipping fee, operation/maintenance cost, development period, flexibility of process, land requirement of facility, ease of obtaining permits, marketability of recovered products, number of facilities, and environmental impact. Expert Choice Decision Support Software was utilized as the evaluation tool. Following the derivation of the AHP results, we conducted a sensitivity analysis to evaluate how input uncertainty might impact the outputs. Our aim was to show how the reduction in the weight of the highest ranked criterion affects the technology evaluation results. xiii

14 4. Recommendations: Upon the conduct of the quantitative analysis, recommendations are provided at the county level by considering the combined results from the AHP, sensitivity analysis, current recycling rates of counties, and the amount of waste landfilled. Miami Dade, Broward, Orange, Duval, Polk, and Volusia counties are recommended to install a gasification facility. Palm Beach County is not recommended to invest in a new facility since it has recently opened a WTE facility in Furthermore, Lee County is not recommended to make an investment since it has already reached 75% recycling rate. The rest of the counties are considered for anaerobic or in-vessel composting based on the food waste generation amounts and the results of AHP and sensitivity analysis. xiv

15 RESEARCH TEAM Nurcin Celik (P.I.) is an assistant professor at the Department of Industrial Engineering at the University of Miami. She received her M.S. and Ph.D. degrees in Systems and Industrial Engineering from the University of Arizona. Her research interests lie in the areas of integrated modeling and decision making for large-scale, complex and dynamic systems. Her dissertation work is on architectural design and application of dynamic data-driven adaptive simulations for distributed systems. She has received several awards, including AFOSR Young Investigator Research Award (2013), University of Miami Provost Award (2011), IAMOT Outstanding Research Project Award (2011), IERC Best Ph.D. Scientific Poster Award (2009), and Diversity in Science and Engineering Award from Women in Science and Engineering Program (2007). She can be reached at Duygu Yasar is a Ph.D. student at the Department of Industrial Engineering at the University of Miami. She earned her bachelor's degree in the field of Industrial Engineering from Yildiz Technical University, Turkey in June She graduated in the top 5 percent of her class. Her research interests evolve around the queuing system simulations, data envelopment analysis, sustainable solid waste treatment, evaluation of solid waste management technologies, multi-criteria decision analysis, advanced thermal treatment of municipal waste, and modeling of integrated large-scale and complex systems. She can be reached at duyguyasar@miami.edu Mehrad Bastani is a Ph.D. student at the Department of Industrial Engineering from University of Miami. His research interests include the applied operation research, simulation and statistics. He earned his bachelor's degree from the Department of Industrial Engineering at the Sharif University of Technology, Iran in September of He also earned his master's degree in Industrial Engineering at the University of Tehran, Iran in July of He can be reached at m.bastani@umiami.edu. xv

16 DISSEMINATION ACTIVITIES JOURNAL PAPERS AND BOOK CHAPTERS: 1. Yasar, D., Celik, N., and Sharit, J. Evaluation of advanced thermal solid waste management technologies for sustainability in Florida, International Journal of Performability Engineering 12(01) (2016). 2. Yasar, D. and Celik, N., Assessment of Advanced Biological Treatment Technologies for Sustainability, IGI Global, PA, 2015, Joo, S. H. (Eds.), Applying Nanotechnology for Environmental Sustainability, IGI Global, accepted. 3. Yasar, D. and Celik, N., Assessment of advanced thermal solid waste management technologies, Talking Trash Newsletter of the SWANA Florida Sunshine Chapter (2015). PRESENTATIONS, CONFERENCES AND INVITED TALKS: 1. The team presented the work accomplished before the Technical Awareness Group (TAG) committee on Friday, February 20, The team presented the work accomplished before the Technical Awareness Group (TAG) committee on Tuesday, August 18, Duygu Yasar, Gregory Collins, and Mehrad Bastani attended SWANA s National Solid Waste Design Competition (SWDC) on August 24, 2015 in Orlando, FL. Three hydrogen sulfide removal technologies namely SulfaTreat, Bio-trickling filter, and LO-CAT which reduce hydrogen sulfide in the collected landfill gas were evaluated in the competition design report. The evaluation criteria were footprint, monitoring requirements, electrical power requirements, water requirements, system complexity, H2S variability, turndown, H2S removal efficiency, capital and operation costs of the technologies. The poster of the project was also presented during WASTECON Aristotelis E. Thanos presented our current project during Hinkley Center Colloquium, Tallahassee, FL on September 24, Dr. Nurcin Celik had an interview for NPR/WLRN Radio discussing the potential impact of a new recycling program in Hollywood, FL. Her interview was published by Wilson Sayre on October 6th, 2015 and aired on October 7th at 7:43 am, 9:35 am, and 5:44 pm. The audio and text version of the story are also available online at the local WLRN website. xvi

17 FIGURE 1. Pictures from events. TECHNICAL AWARENESS GROUP (TAG) MEETINGS: The project team hosted two TAG meetings, on February 20, 2015 and August 18, WEBSITE: The team worked on and posted an enhanced website describing the project, accessible at FEEDBACKS FROM TECHNICAL AWARENESS GROUP (TAG) MEETINGS: Our first TAG meeting took place on February 20 th, 2015 at the McArthur Engineering Building of the University of Miami. We also had set up a conference call for those attending the meeting remotely. Several comments were given during our first TAG meeting. Attendees suggested our team to consider whether technologies have been applied earlier in the US or not, and focus on those implemented in the US. Inspection of several data sources including company and county reports as well as the websites of technology providers about technologies has revealed that some particular advanced SWM technologies (i.e., anaerobic digestion and composting) have long been tested and implemented within the US for several years whereas there are also others (i.e., hydrothermal carbonization) with a single demonstration facility in the entire world. As a sign of the existing of their vendors and market demand, the commercial implementations of technologies may have a significant impact on their future applicability for a given county. As such, the alternative technologies were revised based on these comments to include only the technologies which have been implemented or investigated in the US. To this end, steam classification, hydrothermal carbonization, catalytic cracking, and depolymerization were removed from the alternatives. Attendees also suggested focusing on the technologies and related facilities within the US as the regulations, waste types, and markets are more similar to those within the State of Florida. Also of attention were the concerns regarding the gas level that any technology might produce. It is an important issue since our main goal is to find a technology to manage the waste of Floridian counties in a more environmentally friendly way than traditional landfilling or other conventional treatment methods. As such, environmental impact was considered as one of the criteria in AHP evaluation. During the TAG, it was also discussed that the county goals should be considered in evaluation. As suggested in the TAG meeting, the recommendations were differentiated for the counties based on the results obtained from AHP and sensitivity analysis, current recycling rates of counties, and the least amount of waste that should be diverted from landfills to reach 75% recycling rate of a given county. The results obtained from the AHP and sensitivity analysis were considered equally importantly when composing county-specific recommendations. xvii

18 Our second TAG meeting took place on August 18 th, 2015 with a similar communication set up to hold a conference call for those attending the meeting remotely. Several comments were received and discussed during this meeting following our presentation on the current project progress. Attendees suggested the team to consider conventional waste treatment methods and their current capabilities, and benchmark the current conventional waste management method of a given county against possible advanced SWM technologies while giving recommendations. For instance, if a county has just started a combustion facility it may not be feasible for that county to invest in a completely different advanced SWM technology. Also, it may be more feasible to recommend the implementation of advanced SWM technologies for counties that dispose significant amounts of waste to landfills and do not have an active plan to manage their waste. As per the extent of this practicality discussion, in the final phase of the study, the team decided to take the conventional waste management methods into consideration while investigating county-based recommendations. Here, another clarification was made on the approach taken to reach 75% recycling rate in each and every considered county (i.e., every county having a recycling rate that is greater than 75%) rather than focusing only on the waste treatment of large counties in order to obtain such a recycling rate at the State level (i.e., some counties having greater than 75% recycling rate compensating for those having a rate that is less than that). It was also suggested by attendees to double-check the tipping fees of technologies since they seemed lower than expected. This may affect the recommendations when conventional methods were taken into consideration. However, the recommendations given here are only among the advanced SWM technologies. Due to this fact, the increase in the tipping fees of all alternatives will not affect the evaluation. It was also suggested that the counties that are close to each other should be grouped together while giving the recommendations. It is more feasible to jointly establish a facility for the neighboring counties, since they can transfer their waste to a single location easily. In the recommendations part, geographical proximity of the counties were taken into consideration and mainly the counties which share a border were grouped together. The thermal technologies are also suggested to be considered as a single option since the only main difference between them is the process temperature. Our results obtained from the AHP model suggested the same thermal treatment technology for all groups of counties. The sensitivity analysis further demonstrated that change in the criteria weights do not create a major difference in results. Sensitivity analysis was conducted after the second TAG meeting. The results obtained from the AHP and sensitivity analysis pointed to gasification for thermal treatment technology evaluation and anaerobic digestion or in-vessel composting for biological treatment technology evaluation. The capacities that the alternative technologies can operate in an economically feasible way were investigated. Furthermore, the least amount of waste that needs to be treated in each county to reach 75% recycling goal was calculated to compare with the maximum and minimum capacities of the recommended technologies. Final recommendations were provided based on these calculations as well as the current waste management practices in the counties. xviii

19 Landfill Construction Waste Disposal Post-disposal Final Capping Aftercare (Post-closure care) Surveillance No Care INTRODUCTION Over the past several decades, both the volume and diversity of MSW generation has increased markedly worldwide, with the United States exhibiting the greatest rate of growth, both overall and per-capita, by a significant margin. In 2006, the total amount of MSW generated globally reached 2.02 billion tons, representing a 7% annual increase since 2003 (Key Note Publications Ltd., 2007). It is further demonstrated that after 2010 global generation of municipal solid waste has exhibited approximately a 9% increase per year. This burgeoning growth, combined with the concomitant increase in the regulation of disposal operations and dwindling availability of suitable disposal sites, has made the planning and operation of integrated SWM systems progressively more challenging. According to the concept of sustainable waste disposal, a successful treatment of MSW should be safe, effective, and environmentally friendly (Sakai et al., 1996). However, existing waste-disposal methods namely landfills and incineration technology cannot achieve this goal. As a result of these factors, and growing pressures for environmental protection and sustainability, the State of Florida has established an ambitious 75% recycling goal, to be achieved by the year At present, the recycling rate in the State of Florida is approximately 30% (the amount of waste combusted is not included), based on a goal set by the landmark Solid Waste Management Act of However, MSW landfills represent the dominant option for waste disposal in many parts of the world. Based on 2013 MSW management data, combustion and landfilling has constituted the 62% of Florida waste management method (FDEP, 2013). Conventional waste landfills occupy large amounts of land and lead to serious environmental problems (Belevi and Baccini, 1989) such as release of leachate to the environment. Even though modern landfills are required to use liners, some chemicals dumped in landfills and tons of garbage on top of them deteriorate liners over time (Zarske et al., 2016). Furthermore, landfill facilities lead to significant operational and postoperational care period and costs (Figure 2). Operational Period Post-operational care period FIGURE 2. Management phases of a MSW landfill throughout life-cycle. On the other hand, incineration technology was developed to reduce the total volume of waste and make use of the chemical energy of MSW for energy generation. However, the emissions of pollutant species such as NOx, SOx, and HCl, harmful organic compounds (Holmgren, 2006 and de Holanda & Balestieri, 1999) and heavy metals (McKay, 2002 and Suksankraisorn et al. 2003) are high in the incineration process. Another problem with MSW incineration is the serious corrosion of the incineration system by alkali metals in solid residues and fly ash (McKay, 2002). Furthermore, due to the low incineration temperature related to the low energy density of MSW, the energy efficiency of MSW incineration is relatively low (Wiles, 1996). Due to aforementioned problems of conventional technologies, many stakeholders such as utilities, regulators, governmental agencies, municipalities, and private firms, have recognized the 1

20 necessity of establishing advanced solid waste management technologies to treat the solid waste and convert it into energy or marketable products. Implementing these technologies is essential for the State of Florida for several reasons. These technologies have the potential to enable the State to reduce its waste, and increase its recycling rate such that its goal of reaching 75% recycling rate by 2020 can be achieved, not by particular counties that have strong solid waste management structure in place, but by the majority of the State of Florida counties, including the ones currently struggling with their waste operations. The new and emerging solid waste management technologies also show potential to create new jobs, produce renewable energy, and promote economic growth. In addition, while higher recycling rates may enable lower disposal rates in the landfills, which reduces the land sources utilization and leaves more room for humans and wildlife, improper implementation of these new technologies may cause serious problems such as infectious diseases, waste contamination, toxic emissions, and occupational health issues for solid waste workers. Moreover, current implementation of these technologies is limited by aspects such as regional divergence, political factors, market forces, technical supports, amongst many others. Thus, a comprehensive top-tobottom assessment of each of these significant technologies in terms of environmental, economical, and social aspects as well as their comparison against each other becomes crucial before their applications are discussed for or appear in the counties of the State of Florida. However, in light of the inherently challenging nature of the MSW stream and management, combined with the fiscal difficulties befalling municipalities throughout the state, numerous technical and social challenges to all parties of solid waste management are presented. Because these technologies are emerging or being researched in different geographical locations (other states or maybe other countries), a unified and consistent evaluation scheme has to be developed before these technologies are considered to be implemented (in part or fully) in the State of Florida counties. To this end, the purpose of this study is to identify and evaluate new and emerging advanced solid waste management technologies and their potential to help state reach its recycling goal by 2020 in a manner that is structurally unified, and useful for practitioners in terms of various criteria such as cost, impact on the recycling rates, impact on the landfill emissions, and impact on the promotion of sustainable economic development. The most challenging phase of this work was to collect consistent data for the technologies. Their characteristics varies among different applications and are not changed proportionally by the rate of change in inputs. In addition to this, available data for these technologies are limited due to the fact that they are emerging technologies and their applications on solid waste processing are not widespread. The tool utilized for the evaluation, AHP, pose another challenge for the study. The ranking of the technologies are determined based on the judgments by the subject matter experts which might be biased. The SMEs who are specialists in their fields were selected for criteria ranking in order to reduce such a bias. At the end, application of the technologies to different sites and different waste compositions may result in different performances. The performances of technologies, their operation costs, environmental impacts, and waste conversion rates might be different than expected when implemented in a specific site. BACKGROUND AND LITERATURE REVIEW Solid waste generation and the importance and social and economic complexity of problems related to solid waste management in industrialized countries have increased during the last three 2

21 decades (Hokkanen and Salminen, 1997 & Antmann, 2011). The ideal of completely eliminating waste is highly unrealistic; therefore, the best approach is to handle solid waste in sustainable way to protect the environment and conserve the natural resources. Accordingly, significant modifications to existing waste management technologies and programs have become necessary in order to achieve the 75% recycling goal established by the Florida State government and obtain most optimal handling of municipal solid waste for all stakeholders, including environmental managers, regulators, policy makers, and the affected communities in the state. As a general definition, integrated SWM systems are systems that provide the collection, transfer, and disposal or recycling of waste materials from a given region. These systems handle a wide variety of materials collected from the generation units and require numerous specialized facilities and technologies to process, recycle and dispose the collected waste. Therefore, researchers have conducted a series of studies on the technologies required for the integrated SWM systems throughout the MSW life-cycle. For any solid waste treatment method, the primary implementation goal is to ensure that the public health is protected while cost effectiveness is maintained. Compared to traditional disposal landfills which provide an open loop of MSW life cycle, the advanced disposal technologies usually combine the recycling and recovery methods, leading to a closed loop of MSW life cycle (see Figure 3) and thereby improving the recycling rate. Manufacture Manufacture Customers (Residents) Recycling Reuse Recovery Customers (Residents) Landfill (End of Line) Collection Fleets Advanced Disposal Landfill Collection Fleets Transfer Station Transfer Station FIGURE 3. Traditional open loop (left) and advanced disposal landfills close loop cycles (right). Several researchers have performed evaluation of advanced technologies and analysis for MSW processing and disposal, in order to decrease landfill utilization and increase the waste recycling and recovery (Regional Municipality of Halton, 2007 & Moustakas and Loizidou, 2010). Advanced SWM technologies can be categorized in three major groups including thermal, biological/chemical, and physical technologies. These technologies are known to be environmentally sound, cost-effective and implementation acceptable (Suksankraisorn et al., 2003 and Wiles, 1996). Aforementioned technologies are categorized in Figure 4 to show the technologies in each group. A similar study that was conducted in New York by the New York City Economic Development Corporation and Department of Sanitation (2004) provided information for future planning of SWM systems. The evaluation considered 43 technologies in total and was conducted based on a set of criteria that included readiness and reliability, size and flexibility, beneficial use of waste, marketability, public acceptability, and cost. The City of Los Angeles and URS Corporation collaborated to carry out an assessment project for identifying 3

22 alternative MSW processing technologies that could improve landfill diversion in an environmentally sound manner. They concluded that the technologies best suited for processing unrecyclable MSW on a commercial level were the thermal technologies (URS Corporation, 2005). Chirico (2009) conducted a study with the purpose of evaluation, analysis, and comparison of SWM technologies. This study investigated the capability of SWM technologies to decrease landfill utilization and emissions, promote sustainable economic development, and generate renewable energy in Georgia. It was concluded that plasma arc gasification is the most sustainable option, but with reservations toward its economic profitability. Gasification Plasma Arc Gasification Thermal Treatment Pyrolysis Steam Classification Hydrothermal Carbonization MSW Technologies Windrow Composting Biomechanical Treatment Aerobic Process Anaerobic Digestion Static Piles Composting In-vessel Composting Physical Technologies Waste Convertor FIGURE 4. Categorization of advanced solid waste management technologies. In this report, initially a brief description of advanced SWM technologies are provided. Data collection stages are presented in Section 3. It is followed by the description of methodology in Section 4. Section 5 and 6 present the AHP and sensitivity analysis results. Recommendations, limitations of the study, and the conclusion are provided in Sections 8 and 9 respectively. 2.1 Biochemical Treatment Technologies Advanced Biological Solid Waste Management Technologies (ABSWMT) can be used to process biodegradable materials such as food and green waste. They operate at low reaction rates and low temperature. ABSWMT offer the opportunity to process the organic rich fraction of MSW. Organic rich fraction of MSW should be separated from mixed waste before they are used as feedstock for ABSWMT processes. During the biological treatment of MSW, biodegradable 4

23 waste is decomposed by living microbes. Aerobic and anaerobic conditions are two types of environment where microbes are able to live. Organic portion of MSW should be separated from mixed waste before they are used as feedstock for ABSWM processes. Pretreatment requirement is a disadvantage of ABT technologies since it increases operating costs. ABSWMT are divided into two major groups as aerobic and anaerobic processes. Windrow composting, static pile composting, and in-vessel composting (IVC) are evaluated under the category of aerobic processes as can be seen in Figure Anaerobic Digestion Anaerobic digestion (AD) is a method engineered to decompose organic matter by a variety of anaerobic microorganisms under oxygen-free conditions. The process should be carried out in a closed vessel to keep the process environment out of oxygen. Process is performed in three major stages: hydrolysis, acetogenesis, and methanogenesis. First insoluble portion of organic matter is hydrolyzed into soluble molecules. Secondly, the outputs of first step is converted into carbon dioxide, hydrogen and simple organic acids. In the final phase, methane formers produce methane. The end product of AD includes biogas (60 70% methane) and an organic residue rich in nitrogen. Produced biogas which consists of methane 5 FIGURE 2. Harvest s Energy Garden in Central Florida. and carbon dioxide can be converted into heat and electricity, or its quality can be improved to be distributed to electrical grid system. The optimal process temperature is around o C. AD can be classified based on the number of reactors used: single or multiple reactors. In multistage systems, hydrolysis takes place in a separate vessel. The most important advantage of the multistage systems is that the process parameters can be customized in each stage, however, they have higher capital costs. This technology has been successfully implemented in the treatment of agricultural wastes, food wastes, and wastewater sludge due to its capability of reducing chemical oxygen demand and biological oxygen demand from waste streams and producing renewable energy (Chen et al., 2008). Harvest s Energy Garden in Central Florida uses low solids AD to convert bio solids and food waste into clean energy and natural fertilizers (Figure 4) Depolymerization A significant, valuable percentage of today's municipal solid waste stream consists of polymeric materials, for which almost no economic recycling technology currently exists. This polymeric waste is incinerated, landfilled or recycled via downgraded usage. Thermal plasma treatment is a potentially viable means of recycling these materials by converting them back into monomers or into other useful compounds (Guddeti, 2000) Windrow Composting One of the most prevalently used methods for large scale composting is windrow composting. Rows of turning piles are the main components of the windrow systems. Organic waste is fed

24 into piles as they turn periodically. Periodic turning reduces the odor problems and creates aeration inside the windrows; however, it increases the operating costs. There should be enough space between the windrows to let the equipment rotation. Due to this requirement and the nature of the equipment, the system needs to be installed in a large land area. The width and height of the windrows are defined based on several parameters such as feedstock characteristics and aeration conditions. The system can easily be affected by the weather changes since it is an open system. It takes 8 to 12 months to produce a compost Static Pile Composting Static pile composting process is similar to windrow composting however, they do not have the windrows that need to be turned. Their sizes are not limited by the turner and can be larger than windrows. They can process large amounts of waste since they can be designed in larger capacities. Their process parameters should be monitored and controlled closely to provide the distribution of heat over the pile system In-vessel Composting IVC systems are closely monitored aeration systems which produces compost in an enclosed container like a reactor. Their appearances are similar to AD systems. The most important advantage they provide is that the system temperature, moisture, and other parameters can be closely monitored and controlled. However, they have higher capital and operating costs compared to other composting methods. Odor control is easier and emission is lower than open systems since the emitting surface is decreased to the lowest. 2.2 Advanced Thermal Solid Waste Management Technologies The most important reason for the growing popularity of thermal processes for the treatment of MSW is the increasing environmental and technical concerns and public dissatisfaction with the performance of conventional incineration processes. Thermal technologies operate in high temperatures which usually ranges from 700 o F to 10,000 o F. They can operate in smaller scales compared to combustion process. They typically process carbon-based waste such as paper, petroleum-based wastes like plastics, and organic materials such as food scraps. Organic waste needs to be dried to decrease the moisture content before thermal processes. The main output (byproduct) of thermal technologies is syngas which can be converted into electricity. In this section, information about thermal technologies is presented Gasification The technology data for gasification were obtained from Montgomery Project Gasification Facility and publicly available online sources. Gasification technology mainly involves the reaction of carbonaceous feedstock with an oxygen-containing reagent, usually oxygen, air, steam or carbon dioxide, generally at temperatures above 1400 o F. It contains the partial oxidation of a substance which indicates that the amount of oxygen is not sufficient for entire oxidization of fuel. The process is largely exothermic but some heat may be required to initialize and sustain the gasification process. Gasification has several advantages when compared to combustion for treatment of MSW. It operates in a low oxygen environment that bounds the 6

25 release of emissions, and the hydrocarbon pollutants are removed in an additional gas cleanup process. Hydrocarbon pollutants are either not formed or removed in the gas clean-up process. Additionally, it requires just a fraction of the stoichiometric amount of oxygen necessary for combustion. As a result, it requires less expensive gas cleaning equipment. In terms of efficiency, 90% of energy generated is available for end use. Finally, gasification generates a fuel gas that can be integrated with reciprocating engines, combined cycle turbines, and potentially, with fuel cells that convert fuel energy to electricity more efficiently than conventional steam boilers. Commercial gasification plants that use MSW as input have been implemented in several countries including Japan, Europe, and North America Plasma Arc Gasification Plasma gasification is a multi-stage process which starts with inputs ranging from waste to coal to plant matter, and can include hazardous wastes. Feedstock is not combusted since the environment inside the vessel is deprived of oxygen. Rather feedstock is broken down into elements such as hydrogen, carbon monoxide, and water. The initial step in plasma arc gasification is to process the feedstock to make it uniform and dry, and have the usable recyclables sorted out. The second step is gasification, where extreme heat from the plasma torches is applied inside a sealed, air-controlled reactor. During gasification, carbon-based materials break down into gases and the inorganic materials melt into liquid slag which is poured off and cooled. The heat destroys the poisons and hazards completely. The gas that is created is called synthesis gas or syngas. The syngas created in the gasifier undergoes a clean-up process to clean dust and other undesirable elements like mercury. It is followed by the generation of clean fuel, and heat exchangers recycle the heat back into the system as steam. In the final stage, the output ranges from electricity to a variety of fuels, hydrogen, and polymers. The entire conversion process constitutes a closed system so no emissions are released. According to the Westinghouse Plasma Corporation Report, only about 2-4% of the material introduced into their plasma gasification plant was disposed in landfills. This technology was going to be implemented in St. Lucie County for the first time in the U.S. in 2007, however the project was cancelled in Pyrolysis Pyrolysis systems thermally break down solid waste in the absence of air or oxygen at temperatures of approximately 1100 F and 1500 F. It is a relatively simple and flexible process that can receive a wide variety of feedstock, and produces several usable outputs from typical waste streams. Pyrolysis produces gases and a solid char product such as activated carbon, international grade diesel, and synthetic gas as byproduct. Pyrolysis can convert a wide variety of waste including hazardous waste since it can generate excess heat to reduce moisture content of waste below 10%. However, solid fuel must be shredded and the moisture content inside solid waste must be reduced to below 10%. This is one of the reasons that pyrolysis plants have not been successfully implemented in large scale. Although pyrolysis of biomass keeps developing on a relatively small scale, no commercial plants for the pyrolysis of MSW are operating in the United States currently. 2.3 Physical Technologies 7

26 Physical technologies are used to alter the physical characteristics of the MSW feedstock. These materials in MSW may be shredded, sorted, and dried in a processing facility. The output material is referred to as refuse-derived fuel (RDF). It may be converted into high dense homogeneous fuel pellets and transported and combusted as a supplementary fuel in utility boilers. DATA COLLECTION Advanced thermal and biological SWM technologies were evaluated for the counties in Florida. The collection of reliable data from various sources comprises a major task in this work, since these technologies are not currently in widespread commercial use. Data collection is composed of four stages. In the first stage, advanced solid waste management technologies were identified and the criteria set were defined for AHP. In the second stage of data collection, subject matter experts (SMEs) from Floridian counties were contacted to compute the criteria weights. In the third stage, FDEP SWM 2013 annual reports were explored to obtain the annual waste generation for each waste disposal type of Floridian counties. This data were used to categorize the counties. In the last stage of data collection, necessary data about technologies were collected from publicly available sources and facilities in US. 3.1 Defining Criteria Set The criteria set was defined after inspection of a wide range of journal and white papers in the first phase of data collection. Several issues such as environmental policies, regulations, public health, and characteristics of the technologies were also taken into consideration. The criteria set and the explanations are given below: Revenue is the profit that the facility earns by selling the outputs of the process. There are three potential sources of revenue from a MSW conversion facility which are energy sales, sales of other outputs, and tipping fees. Revenue from the sale of energy highly depends on the price for electricity and the net amount of electricity generated. Selling the energy and products should provide a satisfactory profit. Tipping fee is a charge for a given quantity of waste received at a waste processing facility. For financial feasibility of project, tipping fees should be cost competitive and should provide a significant contribution to the revenue of the facility. Tipping fees typically constitute the largest source of revenue for a waste disposal facility. Capital cost of the project is the amount of money which is invested in SWM project. Operation cost is the ongoing expenses for maintenance of the facility. Development period is the time period between the design/proposal of the project and starting the facility. A long development period might cause the competitors jump into the market since the solid waste industry is very competitive even in the public sector. Flexibility of process is another important factor since the municipal solid waste has a highly variable nature. The process should be flexible enough to keep up with the changes of the content of the waste. Flexibility of process may affect operation costs and tipping fees. The ability of converting different waste types through a single process lowers the costs. Land requirement of the facility might be an important issue for some counties that do not own an available land to establish the facility. 8

27 Net conversion efficiency shows how much of the received waste is diverted into energy/marketable products. Net conversion efficiency directly affects the tipping fees since less efficient processes lead to higher operating costs which are generally paid by higher tipping fees. Ease of permitting is the criterion to measure how capable the process is at obtaining the necessary local and state permits. Marketability of recovered products shows how much demand exists in the current market for the outputs of the process. It is not possible to generate the necessary revenue to support the process if the markets for the outputs being produced do not have market demand or current markets are too unstable. Environmental impact of the process indicates the level of damage that the process or its byproducts have on the environment. The process itself should not contradict one of its main purposes which is to reduce the damage on the environment. Public acceptability measures the level of public support to the alternative technology. It is not possible for a solid waste management facility to function properly without public support. Number of facilities affects the availability of data and the size of vendors for ASWMT. AHP structures for ATSWMT and ABSWMT are given in Figure 6 and 7, respectively. AHP structure was designed in a way that environmental, social, economic, technical, and regulatory issues can be adequately considered. In the second stage of the data collection, criteria weights were determined after contacting SWM of Floridian counties and FDEP through communication. 9

28 Criterion Set Revenue Goal Selecting an Appropriate ATSWM Technology Tipping Fees Capital Cost Operation/Maintenance Development Period Flexibility of Process Land Requirement of Facility Net Conversion Efficiency Ease of Permitting Marketability Environmental Impact Public Acceptability Number of Facilities Alternatives Gasification Plasma Arc Gasification Pyrolysis FIGURE 3. AHP structure for ATSWMT evaluation. The set of criteria was re-arranged for the evaluation of ABSWMT (Figure 7). Capital cost, operating cost, operation time, land requirements of the facility, conversion efficiency, environmental impact, and public acceptance were taken into consideration. The reason for elimination of the rest of the criteria was that for the rest of the criteria, ABSWMT performances were very close and their impacts on the evaluation were negligible. Goal Selecting an Appropriate ABSWM Technology Criteria Set Capital Cost Operating Cost Land Requirement Operation Time Public Acceptance Efficiency Environmental Impact Alternatives Windrow Composting Static Pile Composting In-vessel Composting Anaerobic Digestion FIGURE 4. AHP structure for ABSWM technology evaluation. 10

29 3.2 Contacting SMEs In the second stage of data collection, criteria weights were determined after contacting SMEs from SWM divisions of Floridian counties and FDEP via surveys. Here, a total of 173 requests were placed to waste management experts in 67 different counties within the state of Florida namely Alachua, Baker, Bay, Bradford, Brevard, Broward, Calhoun, Charlotte, Citrus, Clay, Collier, Columbia, Desoto, Dixie, Duval, Escambia, Flagler, Gadsden, Gilchrist, Glades, Gulf, Hamilton, Hardee, Hendry, Highlands, Holmes, Indian River, Jackson, Jefferson, Lafayette, Lake, Lee, Leon, Levy, Liberty, Madison, Manatee, Marion, Martin, Miami Dade, Monroe, Nassau, Okaloosa, Okeechobee, Orange, Osceola, Palm Beach, Pasco, Pinellas, Polk, Putnam, Santa Rosa, Sarasota, Seminole, St. Johns, St. Lucie, Sumter, Suwannee, Taylor, Volusia, Wakulla, Walton, Washington counties. Since the counties were categorized into groups, each SME ranking contributed to the computation of criterion weight of its corresponding county group. Experts contacted from given counties come from various backgrounds related to solid waste. Their backgrounds and job titles include solid waste specialists, solid waste managers, environmental service directors, public works directors, solid waste recycling coordinators, hazardous waste professional engineers, recycling coordinators, utility operations directors, solid waste facility directors, sanitation directors, and environmental managers. Their opinions represent the preferences of SWM divisions of Floridian counties on the evaluation of technologies. 3.3 Categorization of Counties In the third stage of data collection, similar counties were categorized based on their ability to manage waste using similar advanced SWM technology. This categorization of counties into different groups was conducted based on the waste disposal types and annual waste generation. FDEP SWM 2013 annual reports were used to obtain solid waste disposal types and waste generation data of each count (FDEP, 2013). The first step was to classify counties based on least recycled disposal types. The formed groups were then divided into subgroups based on their annual waste generation amounts Municipal Solid Waste Types in Floridian Counties According to United States Environmental Protection Agency (USEPA), MSW heavily consists of everyday items that are discarded by the residents and businesses, such as newspapers, office papers, paper napkins, plastic films, clothing, food packaging, cans, bottles, food scraps, yard trimmings, product packaging, grass clippings, furniture, wood pallets, appliances, paint, and batteries (USEPA, 2015). In this study, the definition provided by the EPA for MSW is used to categorize the counties based on the waste types. Waste types that are not considered in categorization of counties and reasons for not using them are discussed in this section. For the waste types that are 100% recyclable, recycling technologies are already well established with their associated markets. For instance non-ferrous metals such as brass, stainless steel, copper, aluminum are, overall, 100% recyclable and can be easily recovered by the recycling process. They perform well when used in new products since they retain their properties when 11

30 recovered. Moreover, 48% of Floridian counties have a recycling rate greater than 50% for nonferrous metals. As such, these wastes do not need to be converted by advanced SWM technologies and therefore are not considered as part of the categorization. Construction and demolition (C&D) debris is comprised of waste that is generated during new construction, renovation, and demolition of buildings, roads, and bridges. C&D debris often contains massive materials such as concrete, asphalt, doors, windows, gypsum, and bricks. C&D waste is primarily sent to landfılls that are permitted to accept only C&D waste or that receive primarily MSW. C&D debris waste includes building related construction, renovation, and demolition debris whereas non-msw C&D debris contains roadways, bridges, and other nonbuilding related C&D debris generation. The largest percentage of C&D debris generation and recovery is made up of non-msw C&D debris. In addition, C&D debris has a separate disposal stream than MSW. For these reasons, C&D debris is also not considered as one of the waste types to categorize the counties Floridian County Categories for AHP The main purpose of using advanced SWM technologies is to reduce the amount of waste discarded in landfills. For this reason, categorization was performed based on the least recycled waste type in each county. The counties that have the lowest recycling rates of yard trashes were categorized in the same group while the counties that have the lowest recycling rates of various paper waste including newspaper, office paper, cardboard were categorized in another group. AHP calculations were performed for each group and suggested the same technology for the counties in the same group. For instance, if in X County food waste and plastic waste have 30% recycling rate and are the least recycled waste types, we choose the group of X County based on its waste generation amount. If food waste generation is 14,000 TPY while plastic waste generation is 10,000, then X County is categorized in the food waste group. Three groups, food-yard trash, paper, and plastic trash, were obtained in the first categorization as these were the three waste types that have the lowest recycling rates in each county. Subgroups were obtained in the second step based on the waste generation amount of each county. Grouping procedure is also shown in Figure Solid Waste Annual Report County MSW and Recycling Data were used for grouping these counties. The grouping process can be rearranged as the more annual waste generation data becomes available. 12

31 FDEP 2013 Solid Waste Annual Report County MSW and Recycling Data Waste type which has the least recycling rate during 2013 Food Paper Plastic annual waste generation annual waste generation annual waste generation ,000 15,000-80,000 80, ,000 10, , , , , , ,000-1,000, million FIGURE 5. Grouping process of Floridian counties. County groups are as follows (see Figure 9): Group 1 consists of 10 counties: Lafayette, Holmes, Liberty, Dixie, Gilchrist, Wakulla, Union, Hamilton, Madison and Calhoun. They have the least recycling rates for food where their annual waste generation varies from 4500 to 15,000 tons. Group 2 consists of 10 counties: Glades, Taylor, Franklin, Desoto, Levy, Washington, Hendry, Okeechobee, Gadsden and Columbia. They have the second least recycling rates for food where their annual waste generation varies from 15,000 to 80,000 tons. Group 3 consists of 10 counties: Nassau, Walton, Citrus, Flagler, Clay, Okaloosa, Osceola, Marion, Bay and Alachua. They have the least recycling rates for food and yard trash where their annual waste generation varies from 100,000 to 400,000 tons. Group 4 consists of 7 counties: Escambia, Lake, Manatee, Seminole, Collier, Volusia and Polk. They have the least recycling rates for food where their annual waste generation varies from 450,000 to 950,000 tons. Group 5 consists of 8 counties: Lee, Brevard, Pinellas, Duval, Hillsborough, Orange, Broward and Dade. They have the least recycling rates for food where their annual waste generation varies from 1,000,000 to 3,500,000 tons. 13

32 Group 6 consists of 6 counties: Jefferson, Baker, Bradford, Jackson, Putnam and Highlands. They have the least recycling rates for paper product where their annual waste generation varies from 10,000 to 100,000 tons. Group 7 consist of 10 counties: Gulf, Hardee, Suwannee, Charlotte, Sarasota, Indian River, Palm Beach, Santa Rosa, St. Johns and St. Lucie. They have the least recycling rates mainly for plastic products where their annual waste generation varies from 15,000 to 300,000 tons. Group 8 consists of 6 counties: Sumter, Hernando, Monroe, Martin, Leon and Pasco. They have the least recycling rates for other paper products where their annual waste generation varies from 100,000 to 700,000 tons. Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 FIGURE 6. Florida map displaying groups of counties. 14

33 3.4 Technology Data In the last stage, data for advanced thermal and biological SWM technologies were collected from publicly available sources and from facilities in the U.S. The Montgomery gasification facility in Orange County, St. Lucie plasma arc gasification project and JBI Niagara Falls pyrolysis facility were contacted to obtain the necessary data for technologies. ABSWMT data were collected from publicly available sources. Necessary data are the capital cost and operation cost of technologies, revenue that the facility obtain by selling the outputs of the process, tipping fees of the facility, permitting issues of project, efficiency and the flexibility of the process. Some of the criteria were based on verbal assessments prior to their conversion into numerical values (e.g., environmental impacts of technologies were assessed in the available sources as low, medium, or high, and converted into numerical values using a scale of 1 to 9, with 9 indicating the highest performing alternative). Technology data were used for pairwise comparison of alternatives under each criterion. For each group of counties, 13 pairwise comparison matrices were formed using the technology data obtained during the study. Local priorities of alternatives under each criterion were then calculated. Finally, the local priorities were used to calculate global priorities of alternatives. Steam classification, hydrothermal carbonization, catalytic cracking, and depolymerization technologies are not commercially used for processing the MSW. However, there are demonstration facilities, a steam classification facility in California and a hydrothermal carbonization facility in Germany. Facilities were contacted, but information required for our evaluation was not provided by them. Furthermore, the committee suggested in the first TAG meeting that the technologies that has never been implemented in US should not be considered in the study. For these reasons, they were not evaluated in this study. METHODOLOGY Our aim in this research project is to assess the emerging ASWMT for Floridian counties. Considering SWM literature, AHP was chosen for evaluation of ASWMT and find the best technology to manage counties wastes for each one of them. After ASWMT were defined, the inputs obtained from solid waste management divisions of Floridian counties were incorporated into a pairwise comparison matrix to rank the identified technologies. Our methodology was defined in the following subsections. 4.1 Analytical Hierarchy Process (AHP) The AHP method is a strong and effective tool that deals with complex decision making problems using a set of criteria to find the best alternative (Saaty, 1980). The model is hierarchically structured, consisting of objectives, criteria, sub-criteria, and alternatives. Alternatives are compared with respect to the criteria set which is defined consistent with the objective. After defining criteria set, the first step of an AHP is to weigh them by averaging the SME opinions. Each criterion has a different impact on the selection of best alternative. Their impacts are determined with a weighing process conducted using pairwise comparison matrices. Pairwise comparison matrices are built based on SMEs opinions. SMEs rank the criterion set based on their importance and the rankings are converted into values in a 1-9 scale. A 1-9 scale 15

34 is used to create a pairwise comparison matrix of the criterion set and is shown in Error! Reference source not found.10. If activity i has one of the non-zero numbers in 7 assigned to it when compared with activity j, then j has the reciprocal value when compared with i Equal Slight Moderate Strong Extreme More Important FIGURE 7. Explanation of 1-9 Saaty scale. Subject matter expert judgments provided from each county are converted into pairwise comparison matrices. Aggregation of individual judgments (AIJ) is completed using geometric mean of corresponding elements. Each matrix element of the consolidated decision matrix is the geometric mean of corresponding elements of SMEs individual decision matrices. The consolidated matrix is used to compute the global priorities of criteria for each group of counties. Meanwhile, their consistencies need to be checked in order to achieve a consistent result. In this study, Expert Choice Decision Support Software is used to establish the AHP model. Global priorities of technologies are determined by combining criteria weights and performance scores of alternatives. 5.1 Criteria Weights 5. AHP RESULTS The next step is to compute the weights of criteria for each group of counties. In this study, criteria weights are computed using Expert Choice Decision Support Software. SME judgments obtained from each county were converted into pairwise comparison matrices (Appendix B). Aggregation of individual judgments (AIJ) is completed using geometric means. Each matrix element of the consolidated decision matrix is the geometric mean of corresponding elements of SMEs individual decision matrices. The consolidated matrix is used to compute the global priorities of criteria for each group of counties. The Software uses the consolidated matrix to compute the weights of criteria. After pairwise comparison matrices were incorporated into the AHP model, results were obtained from the Software for each group. Eight square pairwise comparison matrices were created in total. The computed criteria weights of each groups of counties for ATSWMT are shown in Figure

35 Criteria Weights Criteria Weights Criteria Weights Criteria Weights Criteria Weights Criteria Weights Group 1 Group Group 3 Group Group 5 Group

36 Inconsistency Ratios Criteria Weights Criteria Weights Group 7 Group FIGURE 8. Criteria weights for evaluation of ATSWMT. Using computed criteria weights, gasification, pyrolysis, and plasma arc gasification technologies were compared. According to AHP results obtained from our model, the best alternative with respect to given criteria set is gasification and the poorest one is the pyrolysis for all groups. The inconsistency ratio which indicates the amount of inconsistency of comparisons is computed for each group of counties. Inconsistency ratio below 0.1 indicates that the pairwise comparisons are consistent and do not require revision. Results show that the overall inconsistencies for all groups are below 0.1 as shown in Figure Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 FIGURE 9. Overall inconsistency ratios (IR) (<<0.1) for evaluation of ATSWMT. In order to evaluate ABSWMT, a different set of criteria were used. Criteria weights were computed using the same procedure as the evaluation of ATSWMT. The criteria weights can be seen in Figure

37 Criteria Weights Criteria Weights Criteria Weights Criteria Weights Criteria Weights Criteria Weights Group 1 Group Group 3 Group Group 5 Group

38 Inconsistency Ratio Criteria Weights Criteria Weights Group 7 Group FIGURE 10. Criteria weights for evaluation of ABSWMT. Using computed criteria weights, ABSWMT are compared. The inconsistency ratio which indicates the amount of inconsistency of comparisons is computed for each group of counties. Results show that the overall inconsistencies for all groups are below 0.1 as shown in Figure Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 FIGURE 11. Overall inconsistency ratios (IR) (<<0.1) for evaluation of ABSWMT. 5.2 Global Priorities of Technologies AHP results for ATSWM technologies show that gasification has the highest ranked global priority for all groups as shown in Figure 15. However, it can be seen that weights of the plasma arc gasification and gasification technologies for groups 5 and 8 are approximately the same. For these counties capital cost is among the most important criteria. Because capital cost criterion has been quite highly ranked for Groups 5 and 8, and plasma arc gasification technology comes at the expense of high capital cost, this technology cannot be recommended for these groups. For the first and seventh groups, where the most important criterion is public acceptability, plasma arc gasification is not a favorable option unless a public outreach to inform the public 20

39 ATSWMT Global Weights about plasma arc gasification is done. There is still public concern about this technology. The most important criterion for second group is environmental impact. Gasification and plasma arc gasification perform similarly on reducing greenhouse gas emissions. Either of these two technologies can satisfy this criterion well. Revenue is the most important criterion for the third and sixth groups. Plasma arc gasification brings the highest revenue among alternatives and plasma arc gasification may serve better to increase revenue in long term. Capital cost is the most important criterion for fourth group. Hence, gasification is the most viable option providing that counties ranked this criterion as among the most important Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 Pyrolysis Plasma Arc Gasification Gasification FIGURE 12. Global priorities of ATSWMT. Counties which are interested in output of the process may select any of alternatives since all of the thermal technologies generate syngas as output which can be converted into energy. When technology supplier availability is considered, gasification technology has been commercially used worldwide and vendors can be found in the US. On the other hand, AHP results for ABSWMT show that static pile composting has the highest global priority for Group 5, IVC has the highest global priority for Groups 1 and 7, AD has the highest global priority for Groups 2,3,4,6, and 8 as can be seen in Figure

40 ABSWMT Global Weights Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 Windrow composting Static pile composting In-vessel composting Anaerobic digestion FIGURE 13. Global priorities of ABSWMT. In Section 8, recommendations are given based on the results obtained from AHP models. These evaluations and recommendations provide a robust basis and structural framework for the counties which will initiate an advanced solid waste management project. In the following section, sensitivity analysis results are presented. 6. SENSITIVITY ANALYSIS Following the derivation of the AHP results, we performed a sensitivity analysis to evaluate how the input uncertainty might impact the outputs. Sensitivity analysis is a technique which is used to determine how different values of an independent variable impact a particular dependent variable under a given set of assumptions. In our case, dependent variables are the global priorities of the alternative technologies whereas the independent variables are the criteria weights which are determined based on the SME opinions. This analysis was confined to all groups of counties for advanced thermal and biological SWM technologies. Our aim was to show how the reduction in the weight of the highest ranked criterion affects the AHP results. Here, two criteria weights, marketability and the highest ranked criterion, were switched in each group. In AHP, the total weight of all criteria should be equal to 1. Therefore, a sensitivity analysis for a given criteria can only be conducted by changing the weight of at least one other criterion weight (while keeping the criteria weights other than those two constant). In our case, we selected to switch the weights of capital cost and marketability for all 8 groups. This enables us better observe the impact of changing the weight of capital cost since changing the weight of marketability is rather insignificant. Modifying criteria weights have changed the highest ranked technology in only Groups 5 and 8. Alternative technology weights before and after the analysis can be seen in Figure 17. For Group 5, the weight of capital cost was decreased to whereas the weight of marketability was 22

41 first case second case first case second case first case second case first case second case first case second case first case second case first case second case first case second case ATSWMT Global Weights increased to As shown in Figure 17, these changes resulted in plasma arc gasification being ranked the highest among three technologies. Specifically, the global weight of plasma arc gasification increased from to 0.407, the weight of gasification decreased from to 0.373, and the weight of pyrolysis increased from to Thus the effects of high capital cost on the global weights of plasma arc gasification and pyrolysis were decreased following a decrease in the weight of the capital cost criterion. That means that if the capital cost becomes insignificant in the selection of technology for decision makers (county and state governments, stakeholders), this changes the best technology recommended by the AHP analysis. This is an advantage of AHP due to its flexibility based on decision makers preferences as well as being a disadvantage in terms of its subjective nature. The same process was followed for Group 8. The weight of capital cost was decreased from to The global weight of plasma arc gasification increased from to 0.420, the weight of gasification decreased from to 0.381, and the weight of pyrolysis increased from to Plasma arc gasification turned out to be the best technology based on revised criteria weights. However, there was a small difference, as small as 0.001, between the global weights of gasification and plasma arc gasification in the first case. So small modifications in criteria weights are expected to cause a change in global priorities and rankings of technologies. Plasma Arc Gasification Gasification Pyrolysis Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 FIGURE 14. Sensitivity analysis results for ATSWMT. Figure 18 shows the sensitivity analysis results for windrow composting, static piles composting, IVC, and anaerobic digestion. Sensitivity analysis was conducted by switching the weights of the highest ranked criterion and the lowest ranked criterion. 23

42 first case second case first case second case first case second case first case second case first case second case first case second case first case second case first case second case ABSWMT Global Weights Windrow Composting Static Pile Composting In-vessel Composting Anaerobic Digestion Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 FIGURE 15. Sensitivity analysis results for ABSWMT. For Groups 1, 4, 7, and 8, the highest ranked and lowest ranked technologies did not change whereas for the remaining groups, the highest ranked technology changed following a modification in the criteria weights. Before and after sensitivity analyses IVC was recommended by AHP for Groups 1 and 7 whereas AD was recommended for Groups 4 and 8. The lowest ranked technology remained as windrow composting in the first and second cases. For Groups 2, 3, and 6 the highest ranked technology became IVC while in the first case it was AD. For Group 5, the highest ranked technology became AD whereas it was static piles composting in the first case. Consequently, after the sensitivity analysis was conducted, the highest ranked technology has become either IVC or AD for all groups. Due to the sensitivity analysis results, static piles composting and windrow composting were not considered as alternatives in recommendations section. It is not astonishing that only AD and IVC were ranked the highest when the reasons behind this fact are investigated. They are more environmentally friendly due to their closed system design which also increases the public acceptance rate of a possible facility project and reduces the emissions. Based on sensitivity analysis and AHP results, gasification, IVC, and AD have remained to consider as alternatives in recommendations phase. 7. CURRENT STATE OF WASTE MANAGEMENT IN FLORIDA Current waste management practices of Floridian counties were investigated before the final recommendations were provided. Information regarding currently operating waste-to-energy and composting facilities are presented in the following sub-sections. 24

43 7.1 Waste to Energy Facilities in Florida Waste-to-energy (WTE) facilities combust MSW to produce electrical energy. A great range of waste types from semisolid to liquid can be processed using WTE technologies. Currently, the most commonly known WTE technology for MSW processing is incineration of the material in a combined heat and power (CHP) plant. The efficiencies for the incineration process are approximately 20-25%, in terms of energy production (World Energy Council, 2013). The size of the plants can vary significantly, both in terms of waste input capacity and power output obtained from the incineration of feedstock. The advantage of WTE technologies over advanced SWM technologies is that there is less uncertainty about their markets and process characteristics since they are established technologies, especially in Florida. When it comes to apply advanced SWM technologies for treatment of waste, their efficiencies, costs, and markets are subject to uncertainty. Both the operational and the financial risks are high; however, they are more environmentally friendly than incineration. The information on WTE facilities in Florida are shown in Table 2 (Michaels, 2014). Florida started with one small WTE facility in 1982 and increased the number of its facilities up to 11 operating WTE facilities as of Florida has established the largest capacity to burn MSW of any state in the country. TABLE 1. WTE facilities in Florida. Name of Facility Opening Year Design Capacity (TPD) Operating Status Technology # of Boilers Gross Electric Capacity (MW) # of Houses Bay County WTE Facility Hillsborough County Resource Recovery Facility Lake County Resource Recovery Facility Lee County Resource Recovery Facility McKay Bay Refuse to Energy Facility Operating Mass Burn Operating Mass Burn , Operating Mass Burn ,836 Operating Mass Burn Operating Mass Burn ,000 25

44 Miami Dade County Resource Recovery Facility Palm Beach Renewable Energy Facility # Operating RDF , Operating RDF ,000 Palm Beach Renewable Energy Facility # Under Construction Mass Burn ,000 Pasco County Solid Waste Resource Recovery Facility Pinellas County Resource Recovery Facility Wheelabrator South Broward Inc Operating Mass Burn Operating Mass Burn , Operating Mass Burn ,000 Palm Beach Renewable Energy Facility #2 (Figure 19) is the largest WTE facility in the country based on its gross electric capacity. The net electrical energy produced by the facility is enough to power 40,000 homes. There are various environmental equipment in the facility for removal of particulates, acid gases, nitrogen oxides, and mercury. According to the U.S. EPA, a new WTE facility similar to Facility #2 would produce 63 percent less CO2, 94 percent less SO2, and 10 percent less NOx than a traditional coal-fired power plant (Greenwalt, 2015). Palm Beach County is not recommended to install any advanced technology since its recently opened WTE facility. The WTE facilities of other counties were launched in or before Hence, they are considered for implementation of an advanced SWM technology. 26

45 FIGURE 16. Palm Beach Renewable Energy Facility (courtesy by Babcock & Wilcox Power Generation Group, Inc., 2014). 7.2 Composting and AD Facilities It was stated in Florida 75% Recycling Report that organics (food waste, yard trash and paper) represent 40% of MSW and also must be recycled at dramatically higher rates to meet the 2020 goal (FDEP, 2010). According to the Florida Department of Environmental Protection (FDEP) database, 11 facilities (out of a total of 24 full-scale facilities) are permitted or registered to accept food waste for composting (Figure 20) (Zimms and Ver Eecke, 2012). Recently in 2011, two facilities were opened in Florida by the Waste Management Inc, one in Okeechobee serving southwest Florida and another one in Apopka serving central Florida. Both facilities are utilizing the AC Composter covered composting technologies supplied by Engineered Compost Systems (ECS). 27

46 Jacksonville Zoological Gardens Franklin County Central Landfill Vista Landfill Reedy Creek Improvement District (Disney) Agricyle WW One Stark BS Ranch & Farm 1 Stop Landscape Supply Okeechobee Landfill, Inc. Weekley Bros. Industrial Park FIGURE 17. Organic waste treatment facilities in Florida (Zimms and Ver Eecke, 2012). $2 million was invested in Okeechobee composting facility which was opened in November 2011 (Figure 21). The Okeechobee facility is the first fully-dedicated organics composting facility in South Florida accepting yard trimmings and preconsumer food waste (Zimms and Ver Eecke, 2012). The site is configured to accommodate 11 adjacent aerated static piles with a capacity permitted to process up to 30,000 tons/year (15,000 tons of yard trimmings and 15,000 tons of preconsumer food waste). Publix provided the organic waste from its stores in Miami Dade and Palm Beach. It has almost reached its capacity after 10 months of operation. Currently, finished compost is being sold to Garick which is a lawn and garden products manufacturer. 28

47 FIGURE 18. Okeechobee composting facility (courtesy by Onsite Services, $4 million was invested in 150-acre Apopka Vista composting facility which is permitted to process up to 45,000 TPY of material and currently operating at approximately 22,000 TPY. The facility receives yard trimmings from Orange County as well as pre and postconsumer food waste (including meat and dairy proteins). The Vista facility utilizes the same covered ASP system in use at the Okeechobee facility. Currently, finished compost is only being used on the neighboring landfill as cover (Zimms and Ver Eecke, 2012). Another recently opened organic waste treatment facility was launched in 2014 by Harvest Power. The facility uses AD technology to convert organic waste into energy in Reedy Creek Improvement District (RCID). It was reported by Harvest Power that the facility can process more than 120,000 tons of organic materials annually while generating 5.4 megawatts of combined heat and power. Orange County is not recommended to open an ABSWMT since an AD facility has recently launched in the county. Even if the facility is privately owned, it receives the food scraps from supermarkets, restaurants, and the municipality in Orange County. Consequently, the composting facilities presented here were opened in 2011 whereas our recommendations were based on 2014 annual food waste generation data. Only Orange County is not recommended to invest in an ABSWMT. While there are recently opened composting facilities in Florida, based on 2014 reports, their residing counties are still under 75% recycling rate. Hence, they will need to do further improvements in order to reach that goal, some which are discussed in the recommendations section of this report. 8. RECOMMENDATIONS The final part of this study is to provide recommendations for the implementation of advanced SWM technologies based on the results obtained from AHP analysis, sensitivity analysis results combined with the current waste management practices of the counties. Other important issues that are elaborated in this section are the current recycling rates of counties, the amount of waste that should not be disposed in landfills to reach 75% recycling goal, and waste treatment capacities of the technologies. Final recommendations are given considering these issues as well as the proximity of counties to each other. These evaluations and recommendations provide a robust structural framework for the counties to develop insights on their potential advanced SWM projects. 29

48 8.1 Current Recycling Rates of Counties Our approach here is to assume that all counties are required to reach 75% recycling goal to achieve the statewide goal county by county. In the first place, current recycling rates and the least amount of waste that should be treated to reach 75% recycling goal are determined and shown in Table 3 for all 67 counties. According to the 75% Recycling Goal Report (FDEP, 2010), amount of waste currently combusted in WTE facilities should be included in the overall 75% recycling goal as legislatively directed. The recycling rates for the counties were calculated based on this assumption. TABLE 2. Recycling rates and waste generation in Floridian counties A: County name, B: Current recycling rate, and C: The least amount of waste that should not be disposed in landfills (TPY). A B C A B C A B C Broward 57% 659,901 Clay 28% 86,552 Desoto 19% 21,733 Orange 51% 659,579 Osceola 31% 83,368 Levy 16% 17,088 Miami-Dade 58% 623,149 Sumter 25% 78,066 Franklin 35% 14,145 Duval 47% 512,472 Walton 6% 77,945 Hardee 6% 12,806 Polk 26% 483,236 Hernando 27% 76,889 Taylor 25% 10,948 Volusia 48% 305,490 Flagler 21% 65,714 Baker 19% 10,853 Palm Beach 65% 264,914 Highlands 14% 64,708 Washington 3% 10,458 Brevard 57% 240,047 Hillsborough 71% 62,477 Putnam 70% 9,459 Seminole 37% 207,725 Alachua 64% 60,518 Bradford 39% 9,166 Sarasota 53% 177,532 Nassau 33% 54,728 Hamilton 6% 7,947 Escambia 31% 167,457 Suwannee 43% 45,781 Dixie 3% 7,529 St. Johns 24% 162,850 Gadsden 12% 42,041 Gulf 28% 7,402 Manatee 48% 154,261 Martin 62% 39,001 Jefferson 29% 6,939 Collier 53% 134,533 Okeechobee 15% 36,723 Calhoun 22% 6,869 Lake 39% 126,922 Citrus 45% 36,314 Wakulla 17% 6,417 Santa Rosa 19% 125,644 Bay 65% 36,184 Union 21% 5,683 Leon 45% 124,321 Columbia 36% 34,477 Madison 22% 5,446 Charlotte 35% 118,147 Monroe 45% 33,902 Gilchrist 13% 5,257 St. Lucie 39% 114,572 Glades 2% 29,355 Liberty 2% 4,523 Okaloosa 22% 113,338 Pasco 71% 28,754 Lafayette 25% 2,129 Indian River 34% 111,004 Jackson 10% 28,403 Holmes 29% 2,101 Marion 44% 100,363 Pinellas 73% 23,840 Hendry 74%

49 Lee county which is the only county with a recycling rate (78%) higher than 75% as of 2014 was not recommended to invest in a SWM project; however, it might send its waste to the adjacent counties. The least amount of waste that should be treated in an advanced SWM facility is less than 3000 TPY for Lafayette, Holmes, and Hendry counties. These counties are not recommended to install an advanced SWM facility. The reason behind this suggestion is that any of the technologies suggested by AHP (IVC, AD, and gasification) are not suggested to operate under 3000 TPY to operate in an economically feasible way. However, they might transfer their waste to adjacent counties to reach 75% recycling goal. 8.2 Maximum and Minimum Capacities of Alternatives Three technologies including gasification, AD, and IVC were recommended as the best technologies by the AHP and sensitivity analysis results. There are upper and lower limits for the capacities that these technologies can operate in an economically feasible way. The recommended minimum capacity for an AD system is 15,000 tons per year (TPY) (Davis, 2014) whereas the largest AD system that is commercially available can process 300,000 TPY. Currently available design capacities for IVC in North America is between 3000 and 160,000 TPY (Ulloa, 2008 & Spencer, 2007). A minimum capacity of approximately 400, ,000 TPY is needed for gasification to be economically feasible (Aguado and Serrano, 1999). However, there are no existing facilities in the world that provide the minimum capacity necessary for the economic feasibility and the largest gasification facility in the world can convert up to 350,000 TPY in practice, which is Air Products' Tees Valley Renewable Energy Facility in England (Air Products, 2015). Larger capacity gasifiers are suggested for treatment of solid waste since they perform better at variable fuel feed processing. Furthermore, they can maintain uniform process temperature that increases the output quality. The counties with the largest waste disposed in landfills were considered for gasification technology since the minimum gasification capacity is assumed as 400,000 TPY. In Figure 22, annual waste generation and amount of waste landfilled for the counties considered to install a gasification technology are shown. The least amount of waste that needs to be treated to reach 75% recycling rate were previously presented in Table 3 and as a result, Broward, Orange, Miami-Dade, Duval, and Polk counties need to treat more than 400,000 TPY. Volusia is also considered for gasification technology since it needs to treat more than 300,000 TPY and can be grouped with an adjacent county to provide 100,000 TPY. The rest of the counties in Figure 22 should treat less than 300,000 TPY to reach 75% recycling rate. Due to this fact, they are not recommended to install a gasification facility. Establishing gasification facility only in Broward, Orange, Miami-Dade, Duval, Polk, and Volusia may enable the facility receive minimum required amount of waste to operate in an economically feasible way. 31

50 Annual Waste Generation Recycling Rates Landfilled Collected Minimum Gasification Capacity Recycling Rates 4,000,000 3,500,000 3,000,000 2,500,000 2,000,000 1,500,000 1,000, , % 65% 55% 45% 35% 25% 15% 5% Counties FIGURE 19. Counties with annually 400,000 tons or greater waste landfilled. Small and larger counties that share a border were grouped together. Transferring waste to long distances increases the cost, number of waste trucks on the road, and environmental pollution caused by the trucks. 6 gasification facilities were recommended to be installed in Miami-Dade, Broward, Orange, Duval, Polk, and Volusia counties. The least amount of waste that needs to be treated by these 6 gasification facilities is approximately 4M TPY and the contribution to the 75% recycling goal is estimated as 13% in total. This contribution increases current recycling rate from 53% (including combusted waste) to 66%. The details for each of the recommended facility are given as follows: Miami-Dade County Miami Dade and Monroe counties are recommended to install a gasification facility to treat their waste jointly. The facility is recommended to be located in Miami Dade because of the fact that the amount of waste that needs to be transferred to the gasification facility from Miami Dade is larger than Monroe County. Transportation costs are higher for large amounts of waste as well as the safety risks. The least amount of waste that needs to be treated in the gasification facility is approximately 650,000 TPY to achieve 75% recycling goal. In such a case, their estimated contribution to overall state goal is estimated to be 2.04%. Broward County Broward and Collier counties are recommended to install a gasification facility to treat their waste. The facility is recommended to be located in Broward because the amount of waste that needs to be transferred to the gasification facility from Broward is larger than Collier. The least 32

51 amount of waste that needs to be treated in the gasification facility is approximately 795,000 TPY to achieve 75% recycling goal. If conducted, their contribution to overall state goal is estimated to be 2.46%. Orange County Orange County needs to treat 660,000 tons waste instead of discarding them in landfills to reach 75% recycling goal. Orange County has border to Seminole, Lake, Osceola, and Brevard Counties. Orange and Osceola Counties are grouped together and need to treat at least 745,000 TPY in a gasification facility. Under such a scenario, their contribution to overall state goal is estimated as 2.30%. Duval Duval County needs to treat at least 510,000 TPY. The County has borders to Nassau, Baker, Clay, and St. Johns Counties. Nassau County has border only to Duval County in Florida. For that reason, Nassau is grouped with Duval County. They need to treat 565,000 TPY in a gasification facility. Under such a scenario, their contribution to overall state goal is estimated as 1.76%. Polk Polk County needs to treat at least 480,000 TPY. It shares a border with Osceola, Lake, Sumter, Pasco, Hillsborough, Hardee, and Highlands Counties. Osceola was previously grouped with Orange County. There is also Manatee County in southwest of the Polk. They were in the same group in the first county categorization. They need to treat at least 640,000 TPY in a gasification facility. Under such a scenario, their contribution to overall state goal is estimated as 1.98%. Volusia Volusia County has border to Lake, Seminole, Brevard, Marion, Putnam, and Flagler counties. Volusia, Seminole, and Lake Counties fell under the same group in the first categorization. They are grouped together. They need to treat at least 640,000 TPY in a gasification facility. Under such a scenario, their contribution to overall state goal is estimated as 1.98%. The rest of the counties are considered for AD or IVC. In the light of the information given about the technology capacities, the counties that have annual landfilled waste amount less than 350,000 tons are recommended to install IVC or AD (whichever is suggested by the AHP results) to increase their recycling rates up to 75%. Table 4 displays the counties for technology capacity and AHP results interaction. It can be seen in the Table 4, that the counties which send more than 160,000 tons food waste per year to landfills was recommended to install AD whereas for the counties which send less than 15,000 tons of food waste per year to landfills are recommended to install IVC. Washington, Bradford, Taylor, Baker, Jefferson, Liberty, Wakulla, Hamilton, Dixie, Hardee, Madison, Okeechobee, Gulf, Union, Calhoun, Glades, Holmes, and Lafayette are the counties which are not recommended to install AD or IVC; however, they can transfer their waste to adjacent counties. Because, the amount of food waste that they send to 33

52 landfills is less than 3000 TPY which is lower than the minimum suggested capacity for AD and IVC. TABLE 3. AHP results and technology capacities. Amount of food waste landfilled (TPY) The highest ranked technology based on AHP and sensitivity analysis IVC AD IVC / AD ,000 TPY (IVC) Gilchrist Santa Rose Suwannee St. Lucie Sumter Hernando Martin Levy Franklin Desoto Gadsden Jackson Putnam Highlands Columbia Walton Flagler Citrus 15, ,000 TPY (IVC or AD) Charlotte St. Johns Indian River Sarasota Palm Beach Escambia Pasco Leon Brevard Pinellas Hillsborough Bay Alachua Clay Okaloosa Marion The counties that are considered for gasification technology are also not included here (Miami- Dade, Monroe, Broward, Collier, Orange, Osceola, Duval, Nassau, Polk, Manatee, Volusia, Seminole, and Lake). Under the 160, ,000 tons of food waste per year category, there is no county since Orange, Broward, and Miami-Dade are recommended to install gasification technology because of the large amount of waste that they discard in landfills each year. Considering the interaction cells in the Table 4, Gilchrist, Santa Rose, Suwannee, St. Lucie, Charlotte, St. Johns, Indian River, Sarasota, and Palm Beach counties are recommended to implement IVC since the highest ranked technology in both AHP and sensitivity analyses was IVC. The capacity of in vessel composting is appropriate for the amount of food waste that they send to landfills. Levy, Gadsden, Highlands, Flagler, Franklin, Jackson, Columbia, Citrus, Desoto, Putnam, and Walton counties are also recommended to implement IVC because the amount of food waste landfilled annually is best suited to IVC and sensitivity analysis suggests IVC. Even though AHP suggested AD, either of them can be implemented based on our approach. AD is recommended for Escambia, Pasco, Leon, Brevard, Pinellas, and Hillsborough counties because the highest ranked technology in both AHP and sensitivity analyses was AD. The amount of food waste landfilled is higher than 15,000 TPY for these counties. The capacity of AD is best suited to this amount. The counties that have not been yet recommended any technology are then grouped with the counties that have been recommended a technology based on their geographical proximity. Furthermore, any county that has been suggested to implement the same technology are grouped together if they have a border to each other and their total amount of food waste landfilled annually does not exceed the capacity of the recommended technology. Further groupings are as follows: 34

53 Santa Rosa, Okaloosa, and Walton counties are in close proximity to each other. All of them were recommended to install IVC. The total amount of food waste that they landfill is approximately 29,000 TPY. Okaloosa constitutes the highest amount with 16,000 TPY and shares a border with the two other counties. These three counties are grouped together. If conducted, their contribution to the overall state goal is estimated as 0.09%. Holmes, Washington, Bay, Jackson, Calhoun, and Gulf counties are recommended to install IVC. The amount of food waste that is landfilled is approximately 31.5 thousand TPY. Bay County constituted the highest amount with 22.5 TPY. These six counties are grouped together. If conducted, their contribution to overall state goal is estimated as 0.1%. Gadsden, Liberty, Franklin, and Wakulla counties are grouped together and recommended to install IVC. The amount of food waste that is landfilled is approximately 15,000 TPY. Gadsden constituted the highest amount with approximately 9,000 TPY. These four counties are grouped together. Under such a scenario, their contribution to overall state goal is estimated as 0.05%. Leon, Taylor, and Jefferson counties are grouped together and recommended to install an AD facility. The amount of food waste that is landfilled is approximately 28,000 TPY. Leon constituted the highest amount with approximately 24,000 TPY. These three counties are grouped together. Under such a scenario, their contribution to overall state goal is estimated as 0.09%. Suwannee County is recommended to install an IVC facility to manage 6840 tons of food waste landfilled annually. The county shares a border with Madison, Hamilton, Gilchrist, Lafayette, Columbia, and Dixie counties. They are suggested to transfer their food waste to Suwannee County. The total food waste that is supposed to be treated with this grouping is 20,000 TPY. Under such a scenario, their contribution to overall state goal is estimated as 0.06%. An IVC facility is recommended to be established by Alachua and Marion counties jointly to treat the food waste of also Union, Bradford, Levy, Putnam, Clay, Baker, St. Johns, and Flagler counties. The total food waste that is supposed to be treated with the proposed way is approximately 106,000 TPY. Due to the close proximity of three counties with a high food waste landfilled, the amount of food waste that should be treated in the recommended facility is higher than others. Under such a scenario, their contribution to overall state goal is estimated as 0.33%. An AD facility is recommended to be installed by Citrus, Hernando, Sumter, Pasco, Hillsborough, and Pinellas. The total amount of food waste which is landfilled by these counties is 326,000 TPY. Pinellas County constitutes the highest amount with 155,000 TPY. Under such a scenario, their contribution to overall state goal is estimated as 1.01%. At the end, Palm Beach should treat at least 265,000 tons of waste per year. This large amount of waste can be treated using gasification. However, Palm Beach has recently opened a WTE facility with a capacity of 3000 TPD. Its waste can be treated in its recently opened facilities with adjacent counties namely Glades, Hendry, Charlotte, and Sarasota. The contribution of this proposed grouping to the overall recycling rate is estimated as 1.83%. The most important consideration for this facility is that long distances are supposed to be travelled by Charlotte and Sarasota counties. Brevard should treat at least 240 thousand tons of waste to reach 75% recycling goal. Highlands, Indian River, St. Lucie, Okeechobee, Martin, Hardee, and Desoto counties are grouped with Brevard. The total amount of waste that should be treated in the recommended 35

54 gasification facility is approximately 576,000 TPY. The contribution of this proposed facility to the overall recycling rate is estimated as 1.75%. Escambia is recommended to install AD whereas the adjacent counties are recommended to install IVC based on both sensitivity analysis and AHP results. Escambia might install a small scale AD facility to treat 24,000 tons of food waste annually. The contribution of this proposed facility to the overall recycling rate is estimated as 0.07%. It is assumed that no residual is landfilled after waste conversion by gasification, AD, and IVC. The calculation of the contribution to the overall state recycling rates are completed based on this assumption. The proposed grouping for joint waste management in Floridian counties can be studied further to investigate the economic and environmental costs of transferring waste to the suggested counties. It should be considered that transferring waste to the counties in long distances increases not only costs but also the number of required waste transfer stations which increases local air pollution, waste trucks in traffic, and the greenhouse gas emissions released by them. Our recommendation here is to establish the facility in a county with the highest amount of waste to be treated and transfer the waste from other counties that share a border with it. Figure 23 shows the new grouping as well as the technologies suggested for each groups of counties. FIGURE 20. Groups of counties in the final recommendations. 9. LIMITATIONS AND CONCLUSION In this study, advanced solid waste management technologies that may help the State of Florida reach its 75% recycling goal were identified and evaluated. To this end, Analytical Hierarchy Process which is a multi-criteria decision making method was utilized to evaluate the technologies with respect to several criteria including their capital cost, revenue, environmental impact, etc. In order to conduct the method, subject matter experts from solid waste management departments of 67 Floridian counties were contacted. Furthermore, sensitivity analysis was conducted to investigate the impact of changing criteria weights on the evaluation results. Recommendations were provided based on the analysis results, current waste management 36