Effect of Temperature and CaO Addition on the Removal of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Fly Ash from a Medical Waste Incinerator

Abstract

The effects of thermal treatment temperature and CaO addition on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) content in the fly ashes from a medical waste incinerator with high chlorine content (7.5%) were investigated. Two kinds of batch mode were examined: without CaO addition under the temperature range of 50-850°C, and with CaO addition at various Ca/Cl molar ratios (CCR = 0.8-44.3) at 250°C.The results show that the PCDD/F content in raw fly ash was 6.20 ng I-TEQ/g. When elevating the temperature from 50 to 400°Cwithout CaO addition, the PCDD/F content dramatically increased from 5.38 to 575 ng I-TEQ/g. Even at 850°C, the PCDD/Fs were not destructed apparently and were still with a concentration of 401 ng I-TEQ/g. However, with the addition of CaO at CCR = 17.7 at only 250°C, the removal ratio of PCDD/Fs reached to 87.2% and the PCDD/F content was significantly reduced to 0.889 ng I-TEQ/g, which meets the soil pollution standard of Taiwan EPA (1 ng I-TEQ/g) and could be considered as backfill. CaO addition was proven efficiently to enhance the reduction rate of PCDD/Fs in fly ashes during the thermal treatment at a low temperature, as well as inhibit the formation of PCDD/Fs.

Effects of Surfactants on the Removal of Carbonaceous Matter and Dioxins from Weathered Incineration Fly Ash

“…Since organic compounds such as polychlorinated biphenyls (PCBs), CBs and dioxins are hydrophobic (Wang et al, 2012;Liao et al, 2014;Chen et al, 2014), flotation technology has been also used to remove these organic compounds from municipal solid waste incinerator (MSWI) fly ash (Cheruiyot et al, 2015;Lee et al, 2016;Cheruiyot et al, 2016). Furthermore, organic pollutant removal and UC removal have good linear relationship during flotation of MSWI fly ash (Huang et al, 2007).…”

Characteristics and Treatment Methods of Medical Waste Incinerator Fly Ash: A Review

“…MW contains a high amount of chlorinated plastics. The typical chlorine level in MW is 1.1-2.1%, whereas it is 0.2-0.8% in MSW [7]. After incineration, chlorines in plastics easily migrate to MWIFA leading to the high chlorine content in MWIFA.…”

CO2 Capture by Using Blended Hydraulic Slag Cement via a Slurry Reactor

“…TGA is commonly used in determining the physico-chemical properties of solid wastes (Lekakh et al, 2008;Chang et al, 2012;Wang et al, 2012). Approximately 15-25 mg aliquots of the BHC samples were placed inside a platinum crucible, and then the samples were heated linearly in the temperature range from 50 to 900°C at a heating rate of 10 °C/min in an inert atmosphere with a nitrogen flow rate of 10 mL/min.…”