低强度超声场促进剩余污泥好氧消化

为了提高剩余污泥好氧消化效率,在消化过程中对剩余污泥进行超声辐射,声强为0.53 W/cm2,频率28 kHz,分别选用0.045 W/mL、0.09 W/mL两个功率密度,每次超声辐射时间20 min或10 min,辐射频次选用4次或2次,组成4个组合.研究表明,未经超声处理的污泥在消化第17天达到稳定,而经超声作用的污泥消化稳定时间较前者提前3～7 d.在相同好氧消化时间内,经超声波处理后污泥能获得更高的有机物降解率.同时对超声波促进污泥好氧消化工艺进行了工程经济评价.

Low intensity ultrasonic treatment to enhance aerobic digestion of excess sludge

In order to enhance the efficiency of aerobic digestion, the excess sludge was irradiated by low intensity ultrasound at a frequency of 28 kHz and acoustic intensity of 0.53 W/cm2 during the process. Four groups of the same excess sludge treated by different ultrasonic parameters including acoustic density (0.045 W/mL or 0.09 W/mL), irradiation time (within 20 min or 10 min) and frequency of treatment during digestion cycle (four or two times) were arranged. The results showed that sludge stabilization without ultrasonic treatment could achieve after 17 days digestion, whereas the ultrasonic groups could shorten the stabilization of 3 to 7 days. Higher MLVSS removal rate in ultrasonic groups could be obtained during the same digestion elapsing than that of the control group. An economical evaluation on the ultrasound assisted process has been made.