School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
Sci Total Environ. 2020 Apr 20;714:136627. doi: 10.1016/j.scitotenv.2020.136627. Epub 2020 Jan 11.
At present, wastewater and sludge management departments are in urgent of the sludge deep-dewatering technique, which can substantially reduce sludge volume, enhance sludge calorific value and save costs. Ozonation pre-oxidation and chitosan (CT) re-flocculation conditioning have been verified to be an efficacious and environmental-friendly approach to realize sludge deep-dewatering. This paper focused on the novel insights into sludge properties under ozonation and CT conditioning. With 60 mg/gTS O and 20 mg/gTS CT, the water content of the conditioned sludge cake satisfied the deep-dewatering level (<60%). The ozone dosage of 60 mg/gTS effectually enhanced the release of soluble COD and retained the inherent organic matters simultaneously, and subsequently, CT could further reduce extracellular biopolymers, especially proteins. Fluorescence analysis indicated that the protein-like substances were largely decomposed into fulvic acid-like and humic acid-like substances after ozonation, and CT could further remove humic acid-like components. Macromolecules were observed to form by CT combining with ozonated extracellular polymers. Low-field NMR technique monitored sludge water states and suggested that water movability weakened after ozonation and enhanced again through CT conditioning. SEM images reflected that CT was available as junction link for ozonated polymers to aggregate into large flocs. Furthermore, the calorific value of conditioned sludge cake increased and sludge cake drying time was saved pronouncedly. The findings provided the systematic and comprehensive insights into the sludge properties in pre-oxidation and re-flocculation conditioning, which would aid in a better understanding of the in-depth dewatering mechanism and developing new dewatering technique.
目前，废水和污泥处理部门急需污泥深度脱水技术，该技术可以大幅度减少污泥体积，提高污泥热值，降低成本。臭氧预氧化和壳聚糖（CT）再絮凝调理已被证明是实现污泥深度脱水的有效且环保的方法。本文重点研究了臭氧和 CT 调理条件下污泥性质的新见解。用 60mg/gTSO 和 20mg/gTSCT，调理后的污泥饼的含水率满足深度脱水水平（<60%）。60mg/gTS 的臭氧剂量有效地促进了可溶性 COD 的释放，同时保留了固有有机物，随后 CT 可以进一步减少细胞外生物聚合物，特别是蛋白质。荧光分析表明，臭氧处理后，蛋白质样物质大部分分解成富里酸样和腐殖酸样物质，CT 可以进一步去除腐殖酸样成分。宏观分子观察到 CT 与臭氧化细胞外聚合物结合形成。低场 NMR 技术监测了污泥的水状态，并表明臭氧处理后水的流动性减弱，CT 调理后又增强。SEM 图像反映出 CT 可用作臭氧化聚合物的连接点，将其聚集成长大的絮体。此外，调理后的污泥饼的热值显著增加，干燥时间明显缩短。这些发现为预氧化和再絮凝调理过程中的污泥性质提供了系统而全面的见解，有助于更好地理解深度脱水机制并开发新的脱水技术。
