适用于焚烧飞灰卫生填埋场共处置的浸出毒性鉴别程序研究

选取2种代表性垃圾焚烧飞灰,通过常规酸中和容量浸出实验和多级浸取实验,研究了酸中和容量消耗和浸出液pH值的变化规律.结果表明,现有的单批次浸出毒性鉴别程序对飞灰的酸中和容量消耗程度低,浸出液pH值高,不利于评价飞灰中重金属的潜在危险性.对比常规酸中和容量浸取实验和多级浸取实验结果,得出在垃圾焚烧飞灰与生活垃圾共处置情景（过流系统）下,中和过程与洗出过程同时发生,飞灰中有1/3左右的碱性物质参与了中和反应.在合理设定卫生填埋场参数的基础上,通过模拟计算,提出了适用于我国卫生填埋场飞灰共处置情景的浸出程序,其主要参数为：浸取液为乙酸溶液,酸度（以H⁺计）为0.3　mol·L^-1（pH=2.64）,液固比（L/S）为20.该浸出毒性鉴别程序可为我国垃圾焚烧飞灰的安全处置提供有效管理和可靠保障.

Extraction procedure for leaching toxicity of fly ash from municipal solid waste incinerators under Co-disposal scenario in landfill

The behavior of acidity neutralization capacity (ANC) depletion and change of pH values in leachate from two representative samples were investigated with test of general acidity neutralization capacity (GANC) and multistage extraction test (MET). The results indicated that low estimation of potential environmental risk would be conduced with low depletion of ANC and high pH values of leachate in such actual batch test. Comparing the results of GANC with that of MET, neutralization and wash-out process would take place at the same way under the flow-through scenarios of co-disposal, and there is one-third alkaline components reacting in the neutralization process. With simulative calculation basing on reasonable hypothesis of parameter in sanitary landfill, the extraction procedure for leaching toxicity of fly ash from MSWI under co-disposal scenario was proposed, using leachant of 0.3 mol·L^-1 HAc solution and L/S=20. This procedure would definitely provide disposal of MSWI fly ash in China with reliable safeguard and effective management.