Thermal Drying of Malaysian Sewage Sludge

Abstract

Sewage sludge or biosolids is a type of solid waste that has been left after wastewater is treated in a domestic wastewater treatment facility. The most common way of sludge disposal is to dispose them on the land, sea or air. However, these methods are not environmentally-friendly, costly and time consuming, which requires expertise and knowledge. An ideal way to manage sewage sludge is to convert the sludge into energy. Conversion of this waste material into solid fuel can be an effective solution, as it does not only contribute as an energy source, but also solves environmental issues related to sewage sludge disposal. The main problem for sewage sludge is the high moisture content, which is higher than 80%. In order to convert the waste into useful energy, the moisture content of the sludge needs to reduce to an acceptable level. The aim of this study is to develop a horizontal indirect dryer that can be effectively used to dry sewage sludge and convert it into solid fuel in briquette form. A new design of thermal dryer was developed, which could dry a huge volume of sludge in a short time with less energy consumption. In this study, 240kW, 200kW, 160kW, 120kW and 80 kW of power provided by the burner were used to investigate the effect of heat on the final moisture content of sewage sludge.The results show that the burner must provide more than 200kW of power in order to dry the sewage sludge to less than 20% of moisture content.