“粘滞现象”是城镇污泥脱水干化过程中面临的主要问题之一，污泥在干化设备中的粘附和结团，导致干化设备运行效率大幅降低。胞外聚合物（EPS）是污泥有机物的重要组成部分，本申请试图从EPS的角度探讨污泥粘滞现象的形成和影响机理，并建立污泥降粘的方法。为此，本课题将研究热力、机械力作用下EPS组分及表面物化特性（包括官能团、表面电荷、润湿角、表面张力等）的变化机理，对污泥和固体壁面之间的分子间力和液桥力进行研究分析，探明粘附力的形成和影响机理。运用机理分析和实验研究相结合的方法，对粘附力和结团力进行宏观表征，探究EPS和污泥粘附力、结团力的关联机理。本课题的难点和关键问题在于探求EPS组分特征、表面物化特性、分子间力、液桥力、结团力、粘度之间的内在联系，并依此建立污泥降粘的有效方法。项目的成功实施，将对污泥干化处理工程实践产生积极影响，对实现城镇污泥无害化、减量化和资源化有重要意义。

“Sticky phenomenon” is one of the main problems encountered during dewatering and drying of sewage sludge (SS). The operating efficiency of drying equipments will be greatly influenced by adhesion and cohesion of SS. Extracellular polymer substances (EPS) are important organic composition of SS. In this project, the formation and influencing mechanism of “sticky phenomenon” will be studied from EPS point of view, and a method for sticky reduction will be established. For this purpose, the effects of thermal and mechanical forces on the composition and surface physicochemical characteristics (including surface functional groups, surface charge, wetting angle, surface tension) of EPS will be studied. The intermolecular force and liquid bridge force between SS and solid wall will be analyzed, and the formation and influencing mechanism of adhesive force will be explored. Based on mechanical analysis and experimental research, macroscopic characterization of adhesive and cohesive force will be conducted, and correlation mechanism between EPS and adhesive/cohesive force will be investigated. The main difficulties and key problems of the project are to reveal the internal relations of EPS composition, surface physicochemical characteristics, intermolecular force, liquid bridge force, cohesive force, and viscosity, and to establish an effective method for sticky reduction. Successful implementation of the project will pose a positive effect on engineering practice of sludge drying, and is meaningful for detoxification, reduction and reclamation of SS.