典型酞酸酯类塑化剂在尾水入河混合区的分配及衰减机制

城市尾水作为再生资源补给天然水体是缓解我国水资源短缺的重要途径之一，但尾水中含有酞酸酯等新型污染物，不可避免地给水环境带来生态和健康风险。尾水中酞酸酯进入河流后，其归宿取决于一系列的物理、化学和生物过程，掌握尾水入河区酞酸酯的归趋特性是保障尾水再生利用安全的关键。本课题拟以太湖流域典型污水处理厂尾水受纳水体为研究区域，以河流中普遍检出的邻苯二甲酸二异辛酯（DEHP）为研究对象，采用野外观测和室内模拟实验相结合的方法，首先研究混合区中DEHP在水-悬浮颗粒物-生物膜-沉积物等介质中的时空分布规律；其次考察DEHP在不同介质中的吸附特性，以及动水条件下的再分配过程，探究吸附过程和生物降解过程对DEHP衰减的交互作用关系；在此基础上，研究扩散-吸附-降解多机制耦合作用下DEHP在多介质体系中的衰减规律，建立多机制耦合作用下DEHP的衰减方程，为河流水体中酞酸酯类塑化剂的预测和防控提供依据。

Wastewater reuse has been one of the most important ways to alleviate water crisis in China. However, the presence of phthalate esters in reused wastewater could inevitably bring health and ecological risks to aquatic systems. The decay of phthalate esters in rivers is mainly attributed to hydraulic diffusion, adsorption of various media, and biodegradation. The aim of this research is to study the decaying mechanism of typical phthalate esters, i.e., di(2-ethylhexyl) phthalate in a multimedia system in typical river mixing zone receiving treated water. Field tests and model experiments in laboratory will be used to study the distribution of DEHP in water-particulates-biofilm-sediment system. The adsorption characteristics of DEHP in various media and its redistribution behaviors under hydrodynamic conditions will be explored. The contributions and relationship of adsorption and biodegradation to the decay of DEHP will be clarified. The decay coefficient of DEHP would be obtained based on the equations of mass conservation, adsorption and desorption, as well as biodegradation. The results can provide the scientific basis for predicting the fate of phthalate esters in the river and guaranteeing the security of natural water.