INTEGRATED SOLID WASTE MANAGEMENT MODEL: THE CASE OF CENTRAL OHIO DISTRICT DISSERTATION Presented in Partial Fulfillment of the Requirement for The Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Rudy S. Prawiradinata, B.S., M.C.R.P * * * * The Ohio State University 2004 Dissertation Committee: Approved by Professor Burkhard Von Rabenau, Adviser Professor Jean-Michel Guldmann (Adviser) Professor Philip A. Viton City and Regional Planning Program ABSTRACT Solid waste management is an increasing problem, both because of rising waste generation and a declining supply of adequate disposal sites. To deal with the problem waste management methods aim at waste reduction and waste diversion, through increased recycling, composting, and incineration, and changes in consumer behavior. The dissertation develops an integrated solid waste management (ISWM) model that extends existing models in several ways. First, it uses a more realistic formulation of cost functions allowing economies of scale in waste collection, facility development, and facility operation, but allowing diseconomies associated with separate collection of yard waste, recyclables and mixed waste. Second, the model adds flexibility and realism to facility management options, including the simultaneous use of several disposal facilities, each with its own locational advantages; the export of waste; and the closure and replacement of facilities over time. Third, it allows for the promotion of recycling and hence, the modification of consumer’s propensity to recycle, and it permits these policies to be applied in a spatially differentiated way. As an initial step, the dissertation develops an analytical model that uses control theory to solve for optimal waste management policies. The system operates in a single waste collection area, has a single disposal site, and waste is either recycled or deposited at the landfill site. The model is solved for different assumptions about cost, including economies of scale. Based on these initial findings, ISWM is formulated as a mixed integer- programming model, using GAMS for implementation and solution. The model is calibrated to the Central Ohio Solid Waste Management District (the District) and solved under a variety of scenarios. The model is tested and sensitivity analysis is used to determine the impact of changes in disposal capacity, interest rate, and growth of waste generation on recycling policy and landfill life. The model is then applied to the investigation of two further issues. First, the model is used to derive an aggregate cost of waste management, as a function of key variables such as the size of the system, population density, number of facility options, and recycling tastes. Some of these variables have been found to be ii significant in empirical research on the cost of municipal waste management. The cost function estimated here is used to confirm these empirical findings. The function also may be used to serve as a benchmark and as a shorthand method in waste management design. To derive the function, ISWM model is run, generating 2,916 observations (systematically varying eight parameters). The resulting set of pseudo-data is used to regress aggregate cost on the eight variables. The results confirm empirical findings on economies of scale and density. They also suggest the importance of other variables in determining waste management cost, including facility options and recycling taste. Second, the model is used to derive policy advice for the State of Ohio and the Central Ohio Waste Authority (the Authority). Model findings suggest that the State- mandated 10-15 year planning horizon for waste authorities should be modified to be longer and/or require a minimum terminal disposal capacity. For the Authority, the findings indicate that current recycling levels are close to optimal (based on a 30-year planning horizon), but will have to be redoubled within the next five years. Further, the Authority composting subsidies appear to be excessive, based on an ISWM-estimated shadow price of landfill capacity. iii Untuk orang tuaku, isteriku Isti, dan anakku, sahabatku Irfan iv ACKNOWLEDGMENTS I would like to thank my adviser, Professor Burkhard von Rabenau, for his support, encouragement, and patience in guiding me over the years. My dissertation would not have been completed without his help. I have learned greatly not only from his professional knowledge but also from his considerate personality. I am deeply indebted to him. I am also deeply appreciated and thank to the other member of my dissertation committee Professor Jean-Michel Guldmann and Professor Philip A. Viton for their valuable comments and suggestions on my dissertation. I would like to express my gratitude to my colleague and supervisors at the National Development Planning Agency, the Republic of Indonesia for their support. I really appreciated for the opportunity that they have given me. I want to express my indebtedness and appreciation to my parents for their endless love and encouragement throughout my life. Finally, my deeply appreciation go to my beloved wife Isti Surjandari and my best friend, my handsome son Irfan Prawiradinata for their sacrifice and tremendous understanding over the years. I would have given up a long time ago without their encouragement and support. v VITA February 14, 1963.…………….. Born – Bandung, Indonesia 1987………………………… B.S., Civil Engineering, Bandung Institute of Technology, Indonesia 1997…………………………… M.C.R.P., Department of City and Regional Planning The Ohio State University, Columbus, Ohio 1987 – 1990…....………………. Junior Engineer, Several Private Firms 1998 – 2002……………………. Intern, Public Utilities Commission of Ohio, Columbus, Ohio 2003 – 2004……………………. Teaching Assistant, Department of Mathematics, The Ohio State university, Columbus, Ohio 1990 – Present ………………… Urban Planner, National Development Planning Agency, the Republic of Indonesia. FIELD OF STUDY Major Field: City and Regional Planning Minor Fields: Engineering Economics and Quantitative Method vi TABLE OF CONTENTS Page Abstract………………………………………………………………………………... ii Dedication……………………………………………………………………………... iv Acknowledgments…………………………………………………………………….. v Vita……………………………………………………………………………………. vi List of Tables………………………………………………………………………….. xii List of Figures…………………………………………………………………………. xiv Chapters: 1. Introduction…………………….……………………………………………... 1 1.1. Purpose of the Study……………………………………………………… 2 1.2. Research Methodology and Outline of the Study…………………….. 3 1.2.1. Methodology of the Study………..……..………….………… 3 1.2.2. Outline of the Study…………………………………………... 6 2. Literature Review.…………………………………………………………….. 10 2.1. Waste Management Models…..……………………………………..... 10 2.1.1. Waste Generation Prediction…………………………………. 12 2.1.2. Facility Planning and Operation Scheduling.……………….… 14 2.1.3. Manpower Assignments………………………………………. 26 2.1.4. Vehicle Management…………………………………………. 28 2.2. Economics of Solid Waste Management……………………………... 31 vii Page 3. Analytical Model: Optimization of a Single Landfill’s Life – A Hypothetical Case of Facility Planning……………………………………………………... 42 3.1. Background………………………………………………………….... 42 3.2. Model Formulation………………………………………………….… 44 3.2.1. Fixed Landfill Life……………………………………………. 44 3.2.2. Variable Landfill Life……………………………………….... 49 3.3. Numerical Analysis…………………………………………………… 51 3.3.1. Mathematical Formulation of the Model……………………… 52 3.3.2. Fixed Landfill Life……………………………………………. 53 3.3.3. Variable Landfill Life……………………………………….... 57 3.4. Result Discussion……………………………………………………... 59 4. Integrated Solid Waste Management Model (ISWM)………………………... 62 4.1. Extensions of the Model………..…….……………………………….. 62 4.1.1. Composting………………………………………………….… 63 4.1.2. Landfill Closure and Replacement………………………….… 64 4.1.3. Multiple Landfill Operations………………………………….. 65 4.1.4. Economies of Scale…………………………………………… 66 4.1.5. Promotion of Waste Diversion.……………………………….. 68 4.1.6. Variety of Collections……………….………………………… 70 4.2. Statement of the Model……………………………………………….. 71 4.2.1. Illustration of Network Flows……………………………….... 71 4.2.2. Objective Function………………………………………….… 75 4.2.2.1. Collection and Transportation Costs………………... 76 4.2.2.2. Operating Costs……………………………………... 79 4.2.2.3. Landfill Closure and Replacement Costs…………… 81 4.2.2.4. New Landfill and Expansion Costs…………………. 82 4.2.2.5. Revenues…………………………………………….. 85 4.2.3. Constraints…………………………………………………….. 87 4.2.3.1. Mass Balance Constraints………..……………….. 87 4.2.3.2. Capacity Limitation Constraints…………………... 92 5. Model Implementation: The Solid Waste Management System in Central Ohio District……………………..……………………………………………. 100 viii Page 5.1. Central Ohio Solid Waste Management System……………………… 101 5.1.1. The Authority……………………………………………….… 101 5.1.2. Waste Generation……………………………………………... 103 5.1.3. Waste Collection and Transport…….………………………… 105 5.1.4. Waste Transfer……….………………………………………... 109 5.1.5. Waste Processing and Diversion……………………………… 110 5.1.6. Waste Disposal………………………………………………... 113 5.2. Model Calibration……………………….……………………………. 116 5.2.1. Systemic Issues……………………………………………….. 119 5.2.2. Model Calibration…………………………………………….. 120 5.3. Parameter Estimates and Data Sources………………………………. 128 6. Model Testing………………………………………………………………..... 142 6.1. Single Disposal Site - Landfill with Constraint Capacity……………... 143 6.1.1 Capacity Expansion Under Constant Returns to Scale………… 144 6.1.2 Capacity Expansion With Economies of Scale………………... 144 6.2. Multiple Disposal Sites………………………………………………..