Sewage can make Portland cement: a new technology for ultimate reuse of sewage sludge

From the viewpoint of environmental and energy problems, it is desirable that the organic and inorganic components of sewage sludge can be reused cost-effectively. A process is described which can meet this need. The process was investigated in a large-scale industrial trial, involving the pelletizing-drying of sewage sludge, combined with burning in a Portland cement kiln. Special attention was paid to product quality; plant safety; simple operation and maintenance; ability to process different sludge and water contents; and low consumption of energy. There were no odour and dust emissions. The study demonstrated that dried sewage sludge pellets could gainfully be used by Portland cement manufacturer.