Biological Impacts and Ecotoxicity Testing of Waste Sludge from Alumina Production

Abstrakt

Red or brown waste sludge from alumina production creates a serious environmental hazard due to its caustic nature. The review deals with leaching and extraction tests of treated or untreated waste red sludge in order to evaluate its dangerous properties and to assess its environmental impact. The characteristics and efficiency of leaching tests are investigated in the light of further red sludge utilization and recycling. The ecological tests of treated red sludge showed no significant evidence of toxic effects on multiple trophic levels. The tests could enable, e.g., red sludge disposal on the sea floor, its use in agriculture for remediation of contaminated soils and for treatment of liquid waste.