Heavy Metal Contamination of Soil with Domestic Sewage Sludge

The disposal of urban sewage sludge from wastewater-treatment plants is the most difficult and increasingly financially draining problem confronting sanitary district staffs in countries throughout the world. Sludge management authorities have had to accept dramatic increases in disposal costs. For example, in the US in the 1970s, costs were generally less than $US110 per metric ton. By the late 1980s, however, estimates often had jumped to $US550 per metric ton or more. Some short-term contracts have run as high as $US880 per metric ton (Bastian, 1997).