With continuing economic growth and industrial development, the population served by the sewer system has been increasing in Taiwan. To promote the service popularity, a ＂Sewer System Development Plan＂ has been launched, aiming at an 3% annual service increase. It is estimated that the daily generation of sewage sludge will amount to 400,000 cubic meter by the year 2009, as reported by Ouyang (1998). This substantial amount of sewage sludge will require proper treatment, disposal, and/or recycling.
This study investigated the treatment characteristics of sewage sludge, using a high-temperature, high-pressure pyrolysis process, with a focus on the effects of operational parameters, such as the pyrolysis temperature, pressure, and duration, on the properties of the pyrolysis products. The organic contents in the residues, accordingly, were decreased after pyrolysis. However, heavy metals with refractory volatility were concentrated. The results showed that at 400-450ºC, the main products in liquid and gaseous products were aliphatic compounds, whereas at 500ºC, various aromatic and naphthene organic compounds dominated. Most concentration of gaseous products increased with increasing temperature, but decreased with increasing pressure, with the exception that Propylene and Butane products increased with increasing temperature.||en_US|