The analysis on bio-drying potential of sewage sludge in the North of China
This paper analyzes the overview of northern sewage sludge, focusing on the potential of bio-drying of sewage sludge in northern China by adopting the technology of biological drying to dispose the sewage sludge. Owning great development potential is the conclusion obtained by the experimental study of the northern sludge.
Transport processes and unit operations
I. TRANSPORT PROCESSES: MOMENTUM, HEAT, AND MASS. 1. Introduction to Engineering Principles and Units. 2. Principles of Momentum Transfer and Overall Balances. 3. Principles of Momentum Transfer and Applications. 4. Principles of Steady-State Heat Transfer. 5. Principles of Unsteady-State Heat Transfer. 6. Principles of Mass Transfer. 7. Principles of Unsteady-State and Convective Mass Transfer. II. UNIT OPERATIONS. 8. Evaporation. 9. Drying of Process Materials. 10. Stage and Continuous Gas-Liquid Separation Processes. 11. Vapor-Liquid Separation Processes. 12. Liquid-Liquid and Liquid-Solid Separation Processes. 13. Membrane Separation Processes. 14. Mechanical-Physical Separation Processes. III. APPENDICES. A1. Fundamental Constants and Conversion Factors. A2. Physical Properties of Water. A3. Physical Properties of Inorganic and Organic Compounds. A4. Physical Properties of Foods and Biological Materials. A5. Properties of Pipes, Tubes, and Screens. Notation. Index.
Composting of mushroom substrate in a fermentation tunnel: compost parameters and a mathematical model
Phase II of composting of mushroom substrate was studied in bulk fermentation tunnels. Compost data are given on heat production, settling and mass reduction, porosity and thermal conductivity. Mass and moisture determinations at the end of the process indicated slightly positive gradients in the direction of the air stream. The highest rate of degradation occurred during the first 2 days. A mathematical model of mass and heat transfers was devised. Differential equations were solved with time-dependent analysis using a Continuous Simulation and Modelling Program (CSMP). In the calculations, the substrate was divided into theoretical layers of equal thickness but of different density and porosity. The model predicts the time-course of the process taking into account the moisture content and the filling height of the compost, and the amounts of supplied fresh air and recirculated air. The calculated data include the oxygen demand, the water and dry matter losses, the temperatures in the various layers, and the loss of conductive heat through the walls of the containers in the tunnel. Calculated data corresponded with actual process data. Temp. were correct within 3 degrees C and weight losses within 5%.