重金属废水化学沉淀颗粒污泥的形成与调控机制

Heavy metal wastewater is the main source of water pollution. Currently, chemical precipitation is the most widely used heavy metal wastewater treatment method. During this process, flocculent sludge with high percentage of moisture content is formed, leading to the poor settling performance and difficult to be separated. The above mentioned problems limit eligible emission of the treated water and the save disposal of sludge. Inspired by the formation mechanism of biological granular sludge during the urban sewage treatment, a novel idea for the formation and control of abiological granular sludge during heavy metal wastewater treatment was proposed. This study includes the following three aspects: ①the formation mechanism of abiological granular sludge during heavy metal wastewater treatment using chemical precipitation, ②the control theory for the granulation of chemical precipitation sludge, ③the interface reactions for granulation of chemical precipitation sludge. Therefore, the formation and control mechanism of abiological granular sludge during heavy metal wastewater treatment was clarified. The obtained results will enrich the fundamental theory for heavy metal wastewater treatment by chemical precipitation. The technique prototype was developed for improving the settling and separating performance of the chemical precipitation sludge.

重金属废水是水体的主要污染源，目前最常用的处理方法是化学沉淀法，但其形成的污泥呈絮状、含水率高，沉降性能差，固液分离难，极大地影响了净化水稳定达标及污泥安全处置。受城市污水处理生物颗粒污泥形成机制的启发，率先提出调控形成重金属化学沉淀颗粒污泥的新思路，拟研究：①重金属废水化学沉淀颗粒污泥的形成机制，②化学沉淀污泥颗粒化的调控原理，③化学沉淀污泥颗粒化过程的界面作用。旨在阐明重金属化学沉淀颗粒污泥的形成与调控机制，丰富重金属废水化学沉淀法处理的基础理论，形成强化重金属废水化学沉淀污泥沉降与固液分离的技术原型。

化学沉淀法是目前最常用的重金属废水处理方法，但处理后产生大量絮状污泥，含水率高、占地面积大，极大地影响了水质稳定达标及污泥安全处置。受生物颗粒污泥形成诱导核假说的启发，本项目对重金属废水化学沉淀颗粒污泥的形成机制进行了重点研究，详细阐明了氧化锌晶种在晶种诱导并流加料法污泥颗粒化过程中的内核骨架作用。此外，针对污泥颗粒化调控原理，本项目拓展并完善了经典DLVO理论模型，研究并揭示出颗粒间的架桥引力和疏水引力是影响污泥聚沉效率的实质，并基于此，建立了化学沉淀污泥架桥-疏水模型调控颗粒化的方法。同时，针对化学沉淀污泥颗粒化过程的界面作用，详细阐述了污泥形成过程的形态演化规律，提出了氧化锌晶种表面反应方程，建立了污泥结构与沉降性能之间的联系。研究表明晶种诱导并流加料法过程中，污泥结构转变为晶态颗粒和高分子紧密聚集，相互缠绕形成的大尺寸团聚体，提高了密实度和颗粒尺寸，进而实现了污泥沉降性能的显著提升。本项目研究阐明了重金属化学沉淀颗粒污泥的形成与调控机制，丰富了重金属废水化学沉淀法处理的基础理论，形成了重金属废水化学沉淀污泥沉降与固液分离的技术原型，为后续化学沉淀污泥快速沉降研究提供了理论指导与技术支撑。