污泥碱解和超声破解预处理的效果研究

为提高污水厂污泥的厌氧消化速率,采用多频率多功率槽式超声发生器,研究了超声波、碱解、以及两者的组合作用对污泥破解预处理效果的影响.结果表明,碱和超声波的组合预处理方式,对污泥溶解性COD的释放效果和VSS减少效果明显优于单独的超声波和单独的碱处理.单独超声预处理,污泥VSS的最大减少率为15.98%;单独碱解(NaOH/TS=0.04)时为22.12%;先碱解(NaOH/TS:0.04,24 h),再超声(60 min)以及碱(NaOH/TS=0.04)和超声(60 min)同时作用的预处理方式,可将污泥VSS减少率分别提高到51.45%和54.45%.破解作用引起污泥的水解分为快速水解和缓慢水解2个阶段,对快速水解阶段进行动力学分析可知,同时采用碱和超声的预处理方式不但可以获得最高的水解速率,而且降低了碱的投加量,缩短了超声破解的时间.

Effect of Alkaline and Ultrasonic Pretreatment on the Sludge Disintegration

In order to enhance the efficiency of anaerobic digestion, the effects of ultrasonic pretreatment, alkaline pretreatment and the combination of these two methods have been studied on sludge disintegration by using multifrequency ultrasonic batch. The results showed that the combining of ultrasonic and alkaline treatment was more effective than alkaline or ultrasonic treatment alone in releasing SCOD and VSS solubilization. The VSS reduction rate was 15.98% with ultrasonic pretreatment alone, 22.12% with alkaline pretreatment alone(NaOH/TS = 0.04). When the sludge was pretreated by the alkaline treatment (NaOH/TS = 0.04) for 24 h followed by ultrasonic vibration for 60 min, and simultaneous ultrasonic (60 min) and alkaline( NaOH/TS = 0.04) treatment, the VSS reduction rate could reach 51.45% and 54.45% respectively. Two distinct phases of hydrolysis were observed. The first phase was a very rapid increase in solubilization, followed by a much slower second phase. According to kinetic analysis for first rapid phase, the simultaneous alkaline and ultrasonic treatment could not only get the highest hydrolysis rate among these methods, but also reduce the pretreatment time in ultrasonic pretreatment and alkaline dose in alkaline treatment.