超声与碱预处理低有机质剩余污泥特性分析

以某城市污水处理厂低有机质剩余污泥（VSS/SS为0.42）为对象，通过实验研究了超声与碱（NaOH和CaO）预处理对其特性的影响，分析了加碱和未加碱时污泥上清液中pH值、ORP（氧化还原电位）、SCOD、TP和NH₃-N等随超声处理时间的变化规律。结果表明，在超声处理30～120 min范围内，超声加碱处理可使污泥上清液中ORP明显下降；超声加碱处理可明显提高污泥上清液中的SCOD释放量，且加NaOH比加CaO更为明显；NaOH加超声处理可促进污泥中TP的释放，但CaO加超声处理则与此相反；无论是否加碱，超声处理对污泥上清液中NH₃-N释放影响较小；超声加碱处理剩余污泥可明显改善污泥絮体，使其更为紧密。

Characteristics of waste activated sludge with low VSS content by ultrasonic and alkaline pretreatment

The pretreatment process of waste activated sludge (WAS) with low organic content (VSS/SS=0.42) from wastewater treatment plant (WWTP) was carried out using ultrasonic treatment and the combination of ultrasonic and alkaline treatment, and the changes of pH, ORP, SCOD, TP, NH₃-N in liquid phase vs. ultrasonication time were determined. The results showed that the ORP decreased greatly within the range of 30 min to 120 min by the combination of ultrasonic and alkaline treatment. The release of SCOD was increased by the combination treatment of ultrasonic and alkaline, and the SCOD concentration released from the sample by adding NaOH was higher than that by adding CaO. The pretreatment of NaOH combined ultrasonics enhanced the release of TP, and there existed a slight release of TP from the sample with the addition of CaO. The NH₃-N concentration released into the liquid phase was lower. According to the scanning electron microscope (SEM) photograph, the floc structure of treated sludge was improved and became tight.