Zhang Guangming, Zhang Panyue, Yang Jinmei, Chen Yanming
School of Municipal & Environmental Engineering, Harbin Institute of Technology, 150090, China.
J Hazard Mater. 2007 Jul 16;145(3):515-9. doi: 10.1016/j.jhazmat.2007.01.133. Epub 2007 Feb 3.
Sludge treatment has long become the most challenging problem in wastewater treatment plants. Previous studies showed that ozone or chlorine effectively liquefies sludge into substrates for bio-degradation in the aeration tank, and thus reduces the excess sludge. This paper employs ultrasound to reduce the excess sludge from the sequential batch reactor (SBR) system. Partial sludge was disintegrated into dissolved substrates by ultrasound in an external sono-tank and was then returned to the SBR for bio-degradation. The results showed that ultrasound (25kHz) effectively liquefied the sludge. The most effective conditions for sludge reduction were as following: sludge sonication ratio of 3/14, ultrasound intensity of 120kW/kgDS, and sonication duration of 15min. The amount of excess sludge was reduced by 91.1% to 17.8mg/(Ld); the organic content and settleability of sludge in the SBR were not impacted. The chemical oxygen demand (COD) removal efficiency was 81.1%, the total nitrogen (TN) removal efficiency was 17-66%, and high phosphorus concentration in the effluent was observed.
污泥处理长期以来一直是污水处理厂中最具挑战性的问题。先前的研究表明，臭氧或氯气能有效地将污泥液化成曝气池中生物降解的底物，从而减少剩余污泥。本文采用超声波来减少序批式反应器（SBR）系统中的剩余污泥。部分污泥在外部超声槽中通过超声波分解成溶解性底物，然后返回SBR进行生物降解。结果表明，超声波（25kHz）能有效地液化污泥。污泥减量的最有效条件如下：污泥超声处理比例为3/14，超声强度为120kW/kgDS，超声处理时间为15分钟。剩余污泥量减少了91.1%，降至17.8mg/(L·d)；SBR中污泥的有机物含量和沉降性能未受影响。化学需氧量（COD）去除效率为81.1%，总氮（TN）去除效率为17 - 66%，且出水磷浓度较高。
