Utilization of sewage sludge ashes in the brick and tile industry

Several aspects of using ashes from sew-age sludge incineration in the brick and tile industry have been examined. After discussing the item of ash production in Germany, the impact of different wastewater treatment methods is described: for instance, the use of precipitation agents containing iron will considerably influence the ash quality. Depending on their respective chemical composition, different ashes have different effects on the ceramic qualities of the bricks made of clay blended with ashes. These effects will be shown in regard to the major ceramic parameters. Similarly, the quality of the ashes also influences the elution behaviour and the mineral fixation of heavy metals. (C) 1997 IAWQ. Published by Elsevier Science Ltd.