ABSTRACT
Microwave peroxide oxidation (MPO) is an energy-efficient and low GHG emission technology to destroy the hazardous organic compounds in solid waste. The objective of this paper is to explore the reduction feasibility of PCDDs/Fs in MSWI fly ash using the MPO in H2SO4/HNO3 solution. Nearly all PCDDs/Fs, 99% in the original fly ash, can be reduced in 120min at the temperature of 150°C using the MPO treatment. It was also found that a change occurred in the content distribution profiles of 17 major PCDD/F congeners before and after MPO treatment. This provides the potential to reduce the actual PCDDs/Fs content more than I-TEQ contents of PCDDs/Fs. The percentile distribution profile has a tendency of higher chlorinated PCDDs/Fs moving to the lower ones. It concludes that a significant reduction efficiency of I-TEQ toxicity was achieved and showed sufficient reduction of toxic level to lower than 1.0ngI-TEQ(gdw)(-1). The treatment temperature would be a critical factor facilitating the dissolution because higher temperature leads more inorganic salt (parts of fly ash) dissolution. Some problems caused by the MPO method are also delineated in this paper.
Subject(s)
Benzofurans/chemistry , Coal Ash/chemistry , Nitric Acid/chemistry , Peroxides/chemistry , Polychlorinated Dibenzodioxins/analogs & derivatives , Refuse Disposal/methods , Sulfuric Acids/chemistry , Benzofurans/isolation & purification , Cities , Dibenzofurans, Polychlorinated , Environmental Pollutants/chemistry , Environmental Pollutants/isolation & purification , Feasibility Studies , Microwaves , Oxidation-Reduction , Polychlorinated Dibenzodioxins/chemistry , Polychlorinated Dibenzodioxins/isolation & purification , SolutionsABSTRACT
This work presents the enforcement performance of recent Haulien County, Taiwan municipal solid waste (MSW) recycling management programs. These programs include: Mandatory Refuse Sorting and Recycling, Diverse Bulk Waste Reuse, Pay-as-you-Discharge, Total Food Waste Recycling, Restricted Use on Plastic Shopping Bags & Plastic Tableware, Recycling Fund Management, and Ash Reuse. These programs provide incentives to reduce the MSW quantity growth rate. It was found that the recycled material fraction of MSW generated in 2001 was from 6.8%, but was 32.4% in 2010 and will increase stably by 2-5% yearly in the near future. Survey data for the last few years show that only 2.68% (based on total MSW generated) of food waste was collected in 2001. However, food waste was up to 9.7% in 2010 after the Total Food Waste Recycling program was implemented. The reutilization rate of bottom ash was 20% in 2005 and up to 65% in 2010 owing to Ash Reuse Program enforcement. A quantified index, the Total Recycle Index, was proposed to evaluate MSW management program performance. The demonstrated county will move toward a zero waste society in 2015 if the Total Recycle Index approaches 1.00. Exact management with available programs can lead to slow-growing waste volume and recovery of all MSW.
Subject(s)
Recycling/methods , Refuse Disposal/methods , Solid Waste , Food , Household Articles , Incineration , Plastics , TaiwanABSTRACT
Different from most previous studies with quantity-limited data, this paper presents PCDD/F content characterization in the fly ash discharged from sixteen large-scale commercial MSWIs. From the results with over hundreds of data using periodically sampling and analysis, it was found that the PCDD/F contents in the fly ash were from 9.07 to 46.68ng/g, d.w., and if based on international toxicity equivalent quantity, they were from 0.78 to 2.86ng I-TEQ/g, d.w. The higher chlorinated PCDDs likely dominated more than lower chlorinated PCDDs, but this tendency was not for PCDFs. The OCDD had the highest contribution to the total PCDD/F content, but if based on I-TEQ content, 2,3,4,7,8-PeCDF is the PCDD/F congener with the highest toxicity contribution. Moreover, the PCDD/F characteristic index (DCI) is suggested using the representative congener content of 2,3,4,7,8-PeCDF to characterize the fly ash. The DCI is 0.875±7.6% for the fly ash discharged from the MSWI with the APCD assembly of SD, AC and BF. The findings obtained in this work provide overview information on the PCDD/F content characterization in fly ash. They will provide PCDD/F fingerprint information to distinguish from other PCDD/F sources, like steel refinery industry, hazardous waste incinerators, or cement kilns, and thus be applied to fly ash management in the environment.
