Effects of air-flow rate and easily biodegradable organic contents on water removal in bio-drying process

Abstract

This work focuses on investigating the interactive influence of easily biodegradable organic content and air-flow rate on drying phenomena and water removal in bio-drying process.
The lab-scale experiments were carried out using the dog food representing the degradable organic contents ratios (10, 25, 50, 75, and 100) under 3 different air-flow rates (0.4, 0.7, and 1.1 L/kg-VS/min) provision. During the experiment, the temperature of simulated waste, temperature and relative humidity of inlet/outlet air was monitored. Exhausted gas was sampled periodically to calculate the organic degradation and followed metabolic water generation by analyzing the CO2 concentration. A simple model was established based on the experiment to see the drying phenomena.
As a result, high air-flow rate provides greater replacement effects and in case of high organic contents, the more water is removed as longer the period of high temperature is maintained. However, the fast decrease in moisture content would limit the microbial activity and terminate the biodegradation earlier