Characterization of wastes from construction and demolition sector.

In Republic of Korea, construction and demolition (C&D) waste accounts for 49.9% of the total waste. In the present work, the mineralogical composition, the concentrations of 11 heavy metals, 19 PAH, and 7 polychlorinated biphenyl (PCB) congeners present in the 6 broad category (9 subcategories) of C&D hazardous waste were discussed along with their leaching characteristics. In concrete/mixed cement waste, the concentrations of As, Cr(6+), Hg, and Zn were in the range of 1.76-7.86, ND-1.63, 0.026-0.047, and 110.90-280.17 mg/kg, respectively. The asphalt waste sample A1 possessed relatively high concentrations of phenanthrene, fluoranthene, pyrene, benz(a)anthracene, benzo(a)pyrene, and indeno(1,2,3-cd)pyrene comparing to the other samples and it contains 0.08-0.1% of coal tar. Hazardous nature of the C&D wastes greatly depends on the source of the collection. Zn concentration was above 1000 mg/kg for road asphalt waste samples A4 and A5. Total PCB concentration were high in the soil waste sample S1 (130 µg/kg) as it was the excavated soil obtained from the premises of an oil station. Leaching of As, Ba, CN(-), and F(-) were observed in most of the C&D waste samples.

Hazardous waste characterization among various thermal processes in South Korea: a comparative analysis.

Ministry of Environment, Republic of Korea (South Korea) is in progress of converting its current hazardous waste classification system to harmonize it with the international standard and to set-up the regulatory standards for toxic substances present in the hazardous waste. In the present work, the concentrations along with the trend of 13 heavy metals, F(-), CN(-) and 19 PAH present in the hazardous waste generated among various thermal processes (11 processes) in South Korea were analyzed along with their leaching characteristics. In all thermal processes, the median concentrations of Cu (3.58-209,000 mg/kg), Ni (BDL-1560 mg/kg), Pb (7.22-5132.25mg/kg) and Zn (83.02-31419 mg/kg) were comparatively higher than the other heavy metals. Iron & Steel thermal process showed the highest median value of the heavy metals Cd (14.76 mg/kg), Cr (166.15 mg/kg) and Hg (2.38 mg/kg). Low molecular weight PAH (BDL-37.59 mg/kg) was predominant in sludge & filter cake samples present in most of the thermal processes. Comparatively flue gas dust present in most of the thermal processing units resulted in the higher leaching of the heavy metals.