Characterization of sewage sludge in Muscat and estimation of their energy recovery

Abstract

There is a pressing need to address Oman's sludge management issues. It is crucial to establish a reliable database of solid waste compositions, properties, and energy content in order to implement an effective waste management. This study examines the wastewater treatment sludge (WWTS) from Muscat Governorate's wastewater treatment plants. This study examines two wastewater treatment plants, namely, AL Ansab, and Al Seeb. Sludge samples were collected in February, March, and June 2020. Physiochemical characteristics of WWTS collected from 1 kg samples have been examined after being mixed several times thoroughly. In both treatment plants, the MC of dewatered sludge ranged from 51 to 94%. In WWTS, the volatility ratio ranged from 73.6 to 93.1%, but the loss of ignition ratio was 76.2 to 90.4%, which meant that 9.6 to 26.4% was considered ash. According to WWTS, silica was the most prevalent oxide, followed by ferric oxide. A low carbon to nitrogen (C/N) ratio was found in WWTS. Dulong's equations were used to estimate their high heating values, which varied between 10,800 and 42300 kJ per kg. Therefore, WWTS has a high energy content and a low C/N ratio which can be burned up as a fuel.