导致用户大量投诉的给水管网水质问题（如变色水、浑浊水等）往往与管网中颗粒物的生成直接有关。除出厂水中的残余颗粒物外，目前对管网输配过程中颗粒物的生成机制缺乏足够的认识，即使达到现行《生活饮用水卫生标准》的出厂水并不能有效避免管网颗粒物的生成。本项目以管网颗粒物的4种主要无机成分（铁、铝、锰、钙）在水中的形态转化为重点，系统探讨单一组成无机颗粒物、无机-无机复合颗粒物、无机-天然有机物复合颗粒物生成的关键影响因素，揭示由元素价态转变、水解聚合、饱和沉淀等导致的管网颗粒物形成、聚集和老化等相关过程机制；同时针对水中普遍存在的微量有机、无机污染物，探讨其与管网颗粒物之间的相互作用，明确具有不同组成和粒度分布特征的颗粒物对微量污染物在管网中传输过程影响的作用机制；提出控制管网输配过程颗粒物生成、避免水质二次污染的技术方案，为出厂水水质调控、管网优化维护及末端水质提升提供理论依据和技术支持。

Distribution system water quality problems (such as discolored water, turbid water) usually triggered consumer complaints are basically resulted from particles formed in drinking water distribution system (DWDS). Besides residual particles in finished water, the particle formation mechanism within DWDS is still not well understood at present. Even finished water could meet the current drinking water quality standards, particle formation in DWDS could not be effectively inhibited. This project will focus on the speciation transformation pathways of four main inorganic constituents (Fe, Al, Mn, Ca, etc.) of DWDS particles. The factors influencing the formation of different type of particles will be systematically investigated, including simple inorganic matter particles, inorganic complex particles, and inorganic – natural organic matter complex particles. The particle formation mechanisms in DWDS, which might involve elemental valence change, hydrolysis speciation transformation, and the precipitation under saturation will be elucidated. Meanwhile, the interaction of particles with organic and inorganic micropolltants commonly present in drinking water will be addressed, and the effect of particles with different constituents and size distributions on the transport of micropollutants in DWDS will be revealed. Based on the results of this project, feasible measures for particle formation control and second pollution prevention in DWDS would be proposed, which could provide scientific support for water industry to develop practical measures for approperiate finished water quality adjustment, DWDS operation/maintenance program and tap water quality improvement techniques.