黑臭底泥处理余水的强化絮凝脱氮

Nitrogen removal by enhanced coagulation of dredging water from black and odor river sediment

针对黑臭水体疏浚余水氮素难去除问题,在聚合氯化铝(poly aluminum chloride,PAC)为絮凝剂、聚丙烯酰胺(polyacrylamide,PAM)为助凝剂的基础上,采用新型共价键型絮凝剂(hybrid covalent coagulant,HCC)强化疏浚余水絮凝脱氮过程,并通过超磁分离技术进行固液分离,实现氮素的快速与高效脱除。在优化的复合絮凝剂投加量条件下,该强化絮凝过程可达到氨氮的完全脱除和总氮80%的去除率。动力学研究结果表明,在较短的15min絮凝操作时间内,即可达到较好的氮素去除效果。当初始pH为7.0时,絮凝分散体系具有较低的Zeta电位值,利于有效降低水体浊度。FTIR图谱验证了羟基参与的氨氮絮凝反应,表明NH_3^+为氨氮被絮凝剂絮凝后的主要存在形式。

This study aimed to address the difficulties in nitrogen removal from dredging water. As an efficiently and economically feasible protocol, poly aluminum chloride （PAC） was employed as the coagulant and polyacrylamide （PAM） as the aiding agent for enhanced coagulation of nitrogen pollutants. With the implementation of a novel hybrid covalent coagulant （HCC） combined with certain magnetic addictive, an efficient and rapid separation of solid chemicals from aqueous solution was proven applicable under an ultra-magnetic field. At optimal dosage of coagulant, aiding and enhancing agents, complete ammonia removal and up to 80% elimination of total nitrogen were obtained successfully. The kinetic studies showed that higher removal efficiency could be achieved for nitrogen removal within a short operating period of 15 min. The flocculation system had a lower Zeta potential which facilitated a higher removal efficiency of turbidity at the initial pH of 7.0. FTIR analysis indicated that NH3＋ was involved as the major form of ammonia to interact with hydroxyl groups in the flocculation process.