Waste Sites as Biological Reactors: Characterization and Modeling

INTRODUCTION The Nature and Control of Waste Disposal Sites The Bioreactor Concept Reactor Configurations of Relevance to Practical Description of a Waste Site The Waste Site as a Biological Reactor PHYSICAL CHARACTERISTICS OF WASTE SITES Waste Site Bioreactor Concepts Porosity of a Waste Site Density and Other Properties of Mixed Soil and Waste Materials Applicability of Conductivity and Permeability Relations for Packed Beds Permeability k of a Mixed Porous Media Permeability (k) Correction for Packed Bed Flow Correction of Packed Column Pressure Drop for Wall Effects Corrections for Pressure Drop Relations for Fluid Flow through a Waste Site Waste Site Particle Properties: Size and Shape References CHARACTERIZATION OF DISPOSED WASTES: PHYSICAL AND CHEMICAL PROPERTIES, AND BIODEGRADATION FACTORS Determination of Physical and Chemical Characteristics of Wastes MSW Composition vs. Landfill Layer Depth or Age: Data for Initialization Individual Wastes and Characteristics Characteristics of Paper Wastes Characteristics of Food Wastes Characteristics of Yard Wastes Characteristics of Plastics Wastes Plastics Deterioration in Landfills Landfill Leachate and Landfill Gas Characteristics WASTE SITE ECOLOGY Influence of the Waste Site Environment on Types of Organisms Present Species Competition for Food at a Waste Site The Range of Organisms at Waste Sites Organisms Found in Compost Piles Trophic Relations and Environmental Factors Determining Organisms at Waste Sites Influence of Site Environmental factors on Organism Types The Waste Site as an Environment for Organisms Definition of Impact of Organisms at Disposed Waste Site Organisms Reported at Landfills, Dumps, and Other Waste Sites: Considerations Waste Site Scavengers Waste Removal Impact of Animals at Disposal Sites Waste Removal by Insects and Soil Mesofauna References MOISTURE AND HEAT FLOWS Moisture as a Control of Processes in the Waste Site Water Film Thickness on Solid Materials under Sorption Regime Method 1 for Liquid Film Thickness Determination Method 2 for Moisture Film Thickness Water Potential vs. Water Activity of Soils and Solid Porous Materials The Issue of Mixed Water Saturation or Varied Water Potential in Wastes Maximum Moisture Sorption by a Material Effect of Waste Moisture Content on Soil Organisms Water Availability to Organisms Hydraulic Conductivity Capillary Effects in Waste Sites Waste Site Moisture Retention Characteristics Full Range Moisture Capillarity Middle Moisture Content Range Moist to Saturation of Wet Moisture Content Section of Curve Moisture Retention Curve in the Dry Range for Landfilled Waste Boundary Conditions Estimation of Constants Full-Range (Wet to Dry) Reliability of Estimated Values Relevance of the Lower Curve Junction to Bioreactor Simulation Development of Moisture Capillarity-Hydraulic Summary of Extended Range Conductivity Relationships Moisture Inflow and Moisture Balance Locations Used for Landfill Cover Moisture Impact Simulations Microorganism Rate vs. Water Content and Water Activity Limitations of Applying Water Potential Concepts Discussion References HEAT GENERATION AND TRANSPORT Introduction The Heat Model Definition of Waste Site System Heat Capacity Heat Content of System: Landfill Gas or Air as Saturating Fluid The Volumetric Heat Generation Term q" Heat Impact of Moisture Uptake and Flows Evaporation Enhancement Due to Thermal Gradient in Pore Structure Temperature vs. Water Vapor Diffusion, Latent Heat and Density Variation Definitions of Waste Site System Tortuosity Energy Balance at Atmospheric Boundary of Bioractor Effect of Surface Albedo Incoming Longwave Radiation Outgoing Longwave Radiation Latent Heat Flow of a Bioreactor System Temperature Variation with Depth Sensible Heat Flow from the Bioreactor System Development of the Heat Generation Model Solution to the Heat Equation Temperature at the Waste Site Surface Variables of the Heat Generation Model Landfill Thermal Conductivity Km Thermal Conductivity and Diffusivity Values Estimating the Mean Thermal Conductivity of Mixed Waste Materials References THE KINETICS OF DECOMPOSITION OF WASTES Introduction Anaerobic and Aerobic Decomposition Patterns Anaerobic Decomposition The Kinetics of Aerobic Decomposition at a Waste Site Aerobic Hydrolysis Product Generation, Incorporation and Use Diffusivity Coefficients for Liquid and Gas Solutes A Stoichiometric Approach to Decomposition Values of Decompositiom Kinetic Constants References DECOMPOSITION ISSUES Introduction Information from Previous Waste Site Studies Landfill Soils Sampling Studies Landfill Soil Microorganism Studies Mass Transfer Considerations Application of Transport Model to Gas Flux Gas-Liquid Transfers Mass Flux Removal of Chemical in Liquid Film Application of Transport Model to Gas Chemicals Flux Mass Transfer Rate at Interface Biodegradation Rates for Landfill Organic Chemicals Partitioning Between Gas and Liquid Waste Site Settlement References SENSITIVITY ANALYSIS AND CONCLUSIONS Introduction Information in Database for MSW Fractions as Substrate Range of Anaerobic and Hydrolysis Rates Chemical Characterization of Waste Fractions Moisture Sorption Factors for Municipal Waste Materials Moisture Response of Materials to the Environment Testing Approach Other Properties Estimated for the Database Constants for Aerobic and Anaerobic Decomposition Soil Moisture Content Moisture Inflow Effect of Cover Temperature as a Decomposition Factor Biofiltration Effect Settlement Effect Discussion Moisture Input Conclusions Appendix 1: Waste-Properties Appendix 2: Landfill Gas Properties