Kjeldsen P, Christensen T H
Environment & Resources DTU, Technical University of Denmark, Lyngby.
Waste Manag Res. 2001 Jun;19(3):201-16. doi: 10.1177/0734242X0101900303.
A simple mathematical model (MOCLA: Model for Organic Chemicals in Landfills) is presented, describing the distribution of organic chemicals between leachate, gas and solid waste. The model also predicts the fate of the chemicals in terms of emissions with leachate and landfill gas and in terms of degradation and transformation in the landfill. Local equilibrium is assumed for the distribution of the chemicals in the landfill as expressed by Henry's Law for the leachate-gas interface, and by the linear partition coefficient based on the waste solid organic carbon content for the waste-leachate interface. Degradation of the chemicals is expressed as a first order reaction. Annual specific leachate and gas generation data in combination with data on landfill area and volume allow for prediction of main emission routes. Model simulations involving two landfill scenarios for a number of chemicals with different physico-chemical characteristics indicate that volatilisation is a likely route for some chemicals (e.g. vinyl chloride, and some of the freons), while other chemicals (e.g. phenol, lower chlorinated aliphatic compounds) more likely will appear as dissolved in the leachate. However, many chemicals will be strongly associated with the solid waste (e.g. dichlorobenzene, naphthalene, and higher Polycyclic Aromatic Hydrocarbons (PAHs), and the pool available will be able to supply the landfill gas and leachate with organic trace components for decades unless these are degraded in the landfill. The model suggests that, in addition to the physico-chemical characteristics of the organic chemical, the presence of free phases of organic chemicals and the degradability of the chemicals are the main factors controlling the fate and emissions of organic chemicals in the landfill environment.
本文提出了一个简单的数学模型（MOCLA：垃圾填埋场有机化学品模型），用于描述有机化学品在渗滤液、气体和固体废物之间的分布。该模型还根据渗滤液和垃圾填埋气中的排放情况以及垃圾填埋场中的降解和转化情况预测化学品的归宿。假设垃圾填埋场中化学品的分布处于局部平衡状态，这在渗滤液 - 气体界面由亨利定律表示，在废物 - 渗滤液界面由基于废物固体有机碳含量的线性分配系数表示。化学品的降解表示为一级反应。结合垃圾填埋场面积和体积数据的年度特定渗滤液和气体产生数据可用于预测主要排放途径。对具有不同物理化学特性的多种化学品的两种垃圾填埋场景进行的模型模拟表明，挥发可能是某些化学品（如氯乙烯和一些氟利昂）的排放途径，而其他化学品（如苯酚、低氯代脂肪族化合物）更可能以溶解在渗滤液中的形式出现。然而，许多化学品将与固体废物紧密结合（如二氯苯、萘和高级多环芳烃（PAHs）），并且除非这些化学品在垃圾填埋场中降解，否则现有的库将能够在数十年内为垃圾填埋气和渗滤液提供有机痕量成分。该模型表明，除了有机化学品的物理化学特性外，有机化学品自由相的存在以及化学品的可降解性是控制垃圾填埋场环境中有机化学品归宿和排放的主要因素。
