Sewage sludge has its own specific composition in different countries. In Hong Kong, the last sewage sludge characterization was conducted by Environmental Resources Management Limited (ERM) a decade ago, without any published update of data....[ Read more ]

Sewage sludge has its own specific composition in different countries. In Hong Kong, the last sewage sludge characterization was conducted by Environmental Resources Management Limited (ERM) a decade ago, without any published update of data.

Nowadays, sewage sludge, generated in Hong Kong, is taken to landfills for co-disposal with MSW which is the only disposal method available. Due to the filling up of the existing landfills and only limited land space available for new landfills in Hong Kong, it is important to look for alternative methods to solve this problem. The dewatered sewage sludge cake taken from the Stonecutter Island Treatment Work in Hong Kong is going to be characterized this study.

Besides the different routes for sludge cake disposal, the possibility of direct sludge ash disposal or recycling is another focus on this study. In order to investigate the possibility to use sewage sludge ash after combustion, sewage sludge ash is characterized to determine its composition. Sludge ash was found to contain materials such as calcium, silica, alumina and iron oxide that could be used as raw materials for cement production. In addition, lab-cement clinkers have been produced and characterized in order to evalute the possibility of using sludge ash in cement clinker production.

In order to predict the amount of ash produced from dried sewage sludge cake and the composition of the ash under different combustion temperature, the correlation of the results on sludge combustion between ash content/ chemical compositions and ashing temperatures has also been performed in this research.