title: Reuse of wastewater sludge with marine clay as a new resource of construction aggregates.
abstract: The disposal of sludge from wastewater treatment presents highly complex problems to any municipality. Most of the sludge disposal methods have varying degrees of environmental impact. Hence, it is necessary to explore potential areas of reuse in order to alleviate sludge disposal problems and to conserve natural resources. Industrial sludge and marine clay are two forms of high-volume wastes. Using these wastes as a resource of raw materials to produce construction aggregates would enable large-scale sludge reuse. The aggregates were produced at various sludge-clay combinations containing 0, 20, 50, 80 and 100% clay contents, respectively. The pelletized aggregates displayed lower particle densities ranged between 1.48 and 2.25 g/cm3, compared to the density of granite at 2.56 g/cm3. Good 28-day concrete compressive strength of 38.5 N/mm2 achieved by the 100% sludge aggregate was comparable to the value of 38.0 N/mm2 achieved of the granite control specimens. The leachate contamination levels from the aggregates after 150 days were found acceptable when used in concrete, indicating insignificant environmental contamination. The heat flow study showed increases in heat flow at the temperatures of 480 degrees C and between 660 degrees C and 900 degrees C, indicating a need for the extension of heating time around these temperatures.
authors.affiliation: Division of Environmental and Water Resources Engineering, School of Civil and Environmental Engineering, Nanyang Technological University, Block N1 #1A-29, Nanyang Avenue, Singapore 639798, Republic of Singapore. cjhtay@ntu.edu.sg
authors.forename: J H
authors.initials: JH
authors.lastname: Tay
authors.forename: K Y
authors.initials: KY
authors.lastname: Show
authors.forename: D J
authors.initials: DJ
authors.lastname: Lee
authors.forename: S Y
authors.initials: SY
authors.lastname: Hong
mesh_terms: D000538:Aluminum Silicates / Q000032:analysis / Q000737:chemistry*; D000077215:Clay; D019245:Compressive Strength; D003247:Conservation of Natural Resources; D003252:Construction Materials / Q000032:analysis / Q000592:standards; D003300:Copper; D019015:Geologic Sediments / Q000737:chemistry*; D007220:Industrial Waste; D012722:Sewage / Q000032:analysis / Q000737:chemistry*; D012767:Ships
chemical_list: D000538:Aluminum Silicates; D007220:Industrial Waste; D012722:Sewage; D003300:Copper; D000077215:Clay