Stabilization of Residues Obtained from the Treatment of Laboratory Waste. Part 1—Treatment Path of Metals in a Plasma Melting System

Abstract

The objective of this study is to investigate the treatment path of metals during the plasma vitrification of fly ash, bottom ash, sludge, and activated carbon collected from a laboratory waste treatment plant. Sampling, digestion, and analysis procedures that followed the standard methods of the Taiwan Environmental Protection Administration were used to determine the composition of the input and output materials. The microstructure was qualitatively examined using a scanning electron microscope. The results show that the vitrification process successfully vitrified the toxic input materials into a stable, glassy, amorphous slag. During vitrification, metals with low boiling points (As, Cd, Hg, Pb, and Zn) were vaporized into the flue gas. Metals with high boiling points and high specific weights went into the ingot, and the residual metals remained in the molten materials as the slag. The distribution of metals shows their behavior during vitrification and can provide a reference for vitrifying hazardous materials.

Polychlorinated Dibenzo-p-dioxin and Dibenzofuran (PCDD/F) Emission Behavior during Incineration of Laboratory Waste. Part 1: Emission Profiles Obtained Using Chemical Assay and Bioassay

“…Therefore, a highly sensitive recombinant hepatoma cell method (adenoviral vector-dioxin response (Ad-DR) bioassay), which takes much less time, was also adopted to analyze the PCDD/F concentration of specimens. Ad-DR bioassay has been demonstrated as a possible screening tool and has been shown to produce results consistent with those of high-resolution gas chromatography/ high-resolution mass spectrometry (HRGC/HRMS) (Chao et al, 2010(Chao et al, , 2012Lin et al, 2013). This study confirms the feasibility of this quick method for ash samples.…”

“…According to the linear regressions, the BEQ can serve as an index of PCDD/F emission to quickly predict the approximate PCDD/F concentration for HRGC/HRMS analysis. In addition, the PCDD/F distributions for I-TEQs and BEQs have similar profiles (Chao et al 2010(Chao et al , 2012Lin et al, 2013). Therefore, Ad-DR bioassay may be a promising method for investigating PCDD/F emission behavior with reduced time and the cost.…”

Stabilization of Residues Obtained from the Treatment of Laboratory Waste: Part 2—Transformation of Plasma Vitrified Slag into Composites

“…The details of the three systems were given in Part 1 of this study. 13 The objective of this plant is to treat LW with the minimum amount of emission of byproducts. Therefore, slag recycling is an important aspect of achieving this goal.…”

“…Figure 1 (extracted from Figure 3 of Part 1) shows the process diagram of the plasma melting system. 13 Ashes, sludge, waste activated carbon, and cullet are mixed and melted at a surface temperature of above 2200°C by a plasma torch. The torch, which has a center temperature of 6000 to 10,000°C, uses air as a carrier gas.…”

Polychlorinated Dibenzo-p-dioxin and Dibenzofuran (PCDD/F) Emission Behavior during Incineration of Laboratory Wastes. Part 2: PCDD/F Profiles and Characteristics of Output Materials

“…The plasma melting system is designed to treat sludge, toxic ash, and other wastes from the two former systems. This system, with an addition of cullet, transforms hazardous materials into stable slag using vitrification (Kuo et al, 2010). A previous study reported that the slag could be mixed with polyester resin to remake composites (Kuo et al, 2011).…”