Characterization of Lead Contaminated Gypsum Sludge
Characterization of industrial waste materials and by-products is a crucial step in their assessment for reuse or for their safe disposal in environmental friendly and economical manner. The objective of the present study is to characterize the chemical, mineralogical and toxicity properties of lead contaminated gypsum sludge. Neutralization of acidic effluent with lime in an effluent treatment plant (ETP) of a lead-acid storage battery industry produced the lead contaminated gypsum sludge. The storage and safe disposal of the lead contaminated gypsum sludge is posing a problem. Chemical analysis and XRD analysis of the air-dried gypsum sludge revealed it to essentially contain gypsum (CaSO <,4>.2H<,2>O), the gypsum content in the sludge corresponded to 90％. ASTM water leach test with the air-dried sludge showed the dominant presence of sulfate (908mg/l) and calcium (720mg/l) ions. The ASTM water leach test did not reveal the presence of leachable lead. Toxicity characteristic leaching procedure (TCLP) test indicated that lead content in the sludge exceeded the critical level (5mg/l) specified for hazardous wastes, hence the gypsum sludge is characterized as hazardous waste based on the toxicity characteristics. Acid digestion revealed the air-dried sludge to contain total lead content of 2960mg/kg of sludge. Laboratory experiments are in progress to chemically stabilize the lead in the gypsum sludge and re-use the stabilized sludge in civil engineering applications.
ETP Sludge Gypsum TCLP Test Lead Hazardous Waste
Raju G. C Sudhakar M Rao B. V. Venkatarama Reddy
Research Student, Dept. of Civil Engineering, Indian Institute of Science, Bangalore-560012, India Professor and Dept. of Civil Engineering & Associate Faculty, Center for Sustainable Technologies, I Associate Professor, Dept. of Civil Engineering & Associate Faculty, Center for Sustainable Technolo
国际会议
北京
英文
203-209
2007-08-20（万方平台首次上网日期，不代表论文的发表时间）