基于活化过硫酸盐与可控骨架形态的污泥调理与脱水机理研究

Commonly sewage sludge is mechanically dewatered after conditioned by the organic polymer, which can only obtain high water content of dewatered cake, leading to a high run-cost of the following treatment and disposal. How to improve sludge dewatering performance and enhance dewatering efficiency has became a challenge topic in the field of sewage and sludge. A novel sludge composite conditioning method based on Fe2+/S2O82- combined with gypsum phase as skeleton builder is proposed for sludge conditioning. Preliminary studies indicate that the dewatering effect is obviously good. However, there are still some unclear key points in competitive reactions of free radicals between solubility organic matter in the liquid phase and sludge floc, as well as the regulatory mechanism of the newly generated skeleton builder in the composite system. The fundamental researches in this proposal are presented as follows: (1) the existing state of free radicals as well as competitive reactions of the organic matter in solid-liquid phase, and establishes the degradation kinetics model of dissolving organic matter and extracellular polymeric substances with free radicals; (2) the effects of the morphology and particle size distribution of regenerated gypsum phase during composite conditioning to achieve the controlled particle size and morphology; (3) set up a multi-objective assessment method model between floc physicochemical properties and dewatering performance; and (4) the migration and transformation tendency of, carbon, nitrogen, phosphorus, organics and heavy metals in liquid-solid phase during dewatering. The achievements of this proposal will provide a theoretical basis for the application of advanced oxidation in sludge treatment.

市政污泥普遍采用高分子絮凝剂调理，机械脱水获得高含水率泥饼导致后续处理与处置困难。如何改善污泥脱水性能是污水与污泥领域的共性难题。本项目提出基于Fe2+/S2O82-高级氧化与石膏相作为骨架构建体用于污泥复合调理，前期研究表明脱水效果明显，但其关键问题是活性自由基在污泥复杂体系中与液相溶解性有机物和固相污泥絮体之间的竞争性反应，以及对骨架形貌的调控机制尚不明确。首先研究活性自由基的存在状态以及与污泥固-液两相中有机物的竞争性反应，建立自由基对液相溶解性有机物、胞外聚合物的降解动力学模型。其次，研究复合调理对新生石膏相的形貌、粒径、分布影响，实现其粒度和形貌可控。最后，建立多目标下复合调理污泥絮体物化特性与可脱水性能评价方法映射模型，并对脱水过程中碳、氮、磷、有机物、重金属等组分在液-固两相的迁移转化规律进行研究。项目成果可为高级氧化-骨架构建体复合调理技术用于污泥处理处置提供理论依据。

市政污泥普遍采用高分子絮凝剂调理，机械脱水获得高含水率泥饼导致后续处理与处置困难。如何改善污泥脱水性能是污水与污泥领域的共性难题。本项目提出基于Fe2+/S2O82-高级氧化与石膏相（S-P）作为骨架构建体用于污泥复合调理。首先，研究确定了主要控制参数并建立了与污泥脱水效率、含水率等参数的多目标评价模型。系统考察了复合调理污泥的可脱水性与污泥特性相关指标间的关系，发现了当原污泥含固率大于3%、有机物含量低于50%时，有利于复合调理脱水。明确了原泥含固率和有机物是影响污泥特性的最重要两个参数，为评价复合调理污泥脱水指标提供方法。其次，进一步验证了以有机物为投加剂量标准的优化方法对不同来源、不同有机物含量的污泥具有普适性，而以污泥干基为投加剂量标准的优化方法受泥质来源影响大。复合调理污泥的可脱水性与松散胞外聚合物存在显著相关性，与氧化作用对有机物的破坏有关。发现以有机物含量为药剂投加量单位比以干基含量为药剂投加量的依据较为合理，解决了污泥化学调理剂投加量控制方法受污泥种类及污泥含水率变化大影响等问题。最后，研究了重金属在复合调理脱水过程中滤液和泥饼中的分布以及固化泥饼的土工性能、力学强度以及重金属浸出和形态分布。获得了固化泥饼中Cu、Zn、Pb、Cd和Cr的TCLP和柱浸出规律，提出了提高重金属固化效果方法。项目成果可为高级氧化-骨架构建体复合调理技术用于污泥处理处置提供依据。