Sun Yongjun, Ji Yuhan, Wang Rui, Wu Kun, Sun Wenquan
College of Urban Construction, Nanjing Tech University, Nanjing, China.
Water Environ Res. 2025 Jun;97(6):e70123. doi: 10.1002/wer.70123.
This study aimed to develop a novel sludge conditioner (CPAD) based on carboxymethyl chitosan (CTS) to address the low efficiency of municipal sludge dewatering. CPAD was prepared by grafting acrylamide (AM) and dimethyldiallylammonium chloride (DADMAC) onto CTS, resulting in a honeycomb-like porous structure, and its flocculation and dewatering performance were validated through laboratory and pilot-scale tests. The novelty of CPAD lies in its combination of the environmental friendliness of natural polymers and the high efficiency of synthetic polymers, significantly reducing the specific resistance to filtration (SRF) and moisture content of sludge. Experimental results showed that at a pH of 6 and a CPAD dosage of 3 kg/t dry sludge (DS), the SRF of the sludge decreased by 90.15%, and the moisture content decreased by 11.85%. Under pilot-scale conditions, with a filtration pressure of 1.2 MPa and a filtration time of 90 min, CPAD reduced the sludge moisture content to 59.3%. Additionally, CPAD effectively neutralized the sludge's electronegativity, reduced electrostatic repulsion between particles, promoted sludge particle bridging and aggregation, and lowered the chemical oxygen demand (COD) and total organic carbon (TOC) of the filtrate as well as the sludge viscosity. This study provides new insights and technical support for developing low-cost, efficient, and environmentally friendly sludge conditioners. SUMMARY: CPAD promotes sludge particle aggregation and reduces sludge viscosity. The mud cake produced by CPAD were environmentally friendly. Sludge conditioner CPAD is nontoxic and harmless and does not cause secondary pollution. CPAD can effectively reduce the moisture content of sludge cake.
本研究旨在开发一种基于羧甲基壳聚糖（CTS）的新型污泥调理剂（CPAD），以解决城市污泥脱水效率低下的问题。通过将丙烯酰胺（AM）和二甲基二烯丙基氯化铵（DADMAC）接枝到CTS上制备了CPAD，形成了蜂窝状多孔结构，并通过实验室和中试规模试验验证了其絮凝和脱水性能。CPAD的新颖之处在于它将天然聚合物的环境友好性与合成聚合物的高效性相结合，显著降低了污泥的过滤比阻（SRF）和含水率。实验结果表明，在pH值为6且CPAD投加量为3 kg/t干污泥（DS）时，污泥的SRF降低了90.15%，含水率降低了11.85%。在中试规模条件下，过滤压力为1.2 MPa，过滤时间为90 min时，CPAD将污泥含水率降至59.3%。此外，CPAD有效中和了污泥的负电性，降低了颗粒间的静电排斥力，促进了污泥颗粒的架桥和聚集，同时降低了滤液的化学需氧量（COD）和总有机碳（TOC）以及污泥粘度。本研究为开发低成本、高效且环境友好的污泥调理剂提供了新的见解和技术支持。总结：CPAD促进污泥颗粒聚集并降低污泥粘度。CPAD产生的泥饼对环境友好。污泥调理剂CPAD无毒无害，不会造成二次污染。CPAD能有效降低污泥饼的含水率。
