5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

Assessment Of Various Waste Resources For The Stabilization Of Pb Contaminated Mine Tailings

Lead (Pb) toxicity is known to be a very serious problem to human beings. It can harm the brain, red blood cells, kidneys and the nervous system. In the Republic of Korea, there are approximately 2,600 abandoned mines and about 50% of them have potential lead toxicity problems. The mine tailings generated from ore dressing are usually stored in a mine tailing dam. However, the loss of mine tailings occurs often due to heavy rains and landslides. This leads to rice paddy soil contamination for locations near mine sites. Therefore, remedial action should be taken to prevent Pb release problems. Among various remedial techniques, the stabilization/solidification (S/S) process is one of the viable techniques to effectively immobilize Pb in the contaminated mine tailings. The S/S process has been widely applied to hazardous waste with effective remedial results. Waste resources including waste oyster shells, starfish and the biochar derived from spent coffee grounds were used as stabilizing agents. For waste oyster shells, two types of oyster shells were used; natural state (WOS) and calcined state (COS). The calcination process for WOS was performed at high temperatures (900oC, 2 hours) to transform the calcite to quicklime. The starfish (SF) was used in a natural state. The spent coffee grounds derived biochar (SCGB) was generated using the pyrolysis process at 200oC. The contaminated mine tailings were treated with various waste resources in the range of 0 to 10 wt% and cured for 28 days. The effectiveness of the stabilization process was evaluated by the toxicity characteristic leaching procedure (TCLP) test. The stabilization results showed that the TCLP Pb concentrations decreased upon increasing dosage of waste resources. The most effective agent for effective Pb immobilization was COS and only 2wt% COS was required to pass the TCLP limit of 5 mg/L. For the case of WOS treatment, 4wt% was required to pass the TCLP limit. The least effective agent was found to be SCGB. The effectiveness of Pb immobilization increased in the following order: SCGB < SF < WOS < COS.
Deok Hyun Moon, Ki Joon Kim, Kyung Hoon Cheong, Jeehyeong Khim, Hyun Jin In, Jeong-Hun Park