| dc.description.abstract | Taiwan, being a densely populated country with limited land, has faced increasing challenges in waste management since the 1980s due to difficulties in acquiring landfill sites and growing waste volumes. To address these issues, the government implemented the ＂incineration as primary, landfilling as supplementary＂ waste treatment policy, making incinerators the mainstream solution for municipal waste disposal. However, during the temporary storage of waste in incinerators, highly concentrated leachate is generated. This leachate, rich in organic matter, appears dark brown and emits a foul odor. Its fluctuating pollutant concentrations pose significant challenges to wastewater treatment systems. Historically, incinerators have relied on thermal treatment methods, using atomizing nozzles to spray the leachate into flue gas ducts as a means of cooling.
With advancements in wastewater treatment technologies and the inclusion of municipal waste incinerators in renewable energy projects, enhancing thermal recovery efficiency has become a focal point for the design of new incinerators. Consequently, alternative treatment methods that avoid spraying leachate into incinerators are being explored. However, limited studies on the characteristics of incinerator leachate hinder the evaluation of such alternatives. This study investigated the variations in pollutant concentrations of incinerator leachate through sampling and analysis, establishing the primary pollutant range, including pH, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Suspended Solids (SS), and heavy metals. The study further quantified energy loss during the thermal treatment of leachate using its Chemical Energy Potential (CEP). Additionally, multiple regression analyses were employed to examine the potential effects of leachate treatment on bottom ash, fly ash, and flue gas emissions from incinerators.
Results indicated that the characteristics and pollutant concentrations of leachate resemble the transitional phase of landfill leachate. The leachate exhibited weak alkalinity, with BOD concentrations ranging from 50 to 100 mg/L, COD concentrations between 1,500 and 4,000 mg/L, and SS concentrations varying from 50 to 1,200 mg/L, along with significant chloride ion content. Thermal treatment of leachate required approximately 0.25–0.60 MWh of electricity per ton, accounting for 1–2.3% of daily electricity generation. With improvements in thermal conversion efficiency, energy losses in newly constructed incinerators may increase to 0.41–1 MWh. Although leachate treatment reduces electricity generation, it can potentially decrease fly ash production and reduce emissions of acidic and nitrogen oxide gases, thereby lowering the consumption of operational chemicals | en_US |