Reusing Drinking Water Sludge: Physicochemical Features, Environmental Impact and Applications in Building Materials: A Mini Review

The current drinking water treatment processes generate a significant amount of alumina sludge. These alumina sludges are costly to dispose of and store, which may take up a lot of space. The physicochemical properties of the generated waste, its environmental impact, and its eventual destinations have all been examined in the present paper, with a special focus on its applications in building materials. The chemical composition of the alumina sludge is primarily aluminium and silica hydroxides, with minor amounts of iron, calcium, potassium, and magnesium hydroxides, which may result in some intriguing physicochemical properties. Several methods for reusing sludge in construction materials have been proposed in the literature, including the production of Portland and belite cement as a substitute in cement mortars, the production of concrete, and the production of bricks and ceramic materials. The current investigation reveals the interesting probable destination of drinking water sludge as a source of local raw material rich in alumina with a dryness of 20% that does not require grinding and saves energy costs for the cement industries. The useful materials produced, such as clinkers, bricks, and concrete, have shown interesting physico-mechanical qualities (lightweight, corrosion resistance, and mechanical resistance), which might make them worth commercializing as building materials. Graphical Abstract