双频超声波促进剩余污泥的破解

Double frequency ultrasonic pretreatment on dewaterability of waste activated sludge

超声波破解技术在污泥厌氧消化预处理领域的研究广泛且深入,其中超声频率作为影响污泥破解效果的重要因素更是得到充分重视。为了探索双频超声波预处理对剩余污泥破解的影响,选择单独频率20和25 k Hz和双频20/25 k Hz3种,通过序批式实验研究了不同超声能量水平(0~12 000 k J·(kg TS)^(-1))下粒径、有机质释放和污泥比阻的变化情况。结果表明,污泥破解效果随超声能量的增加而增加,在超声能量为12 000 k J·(kg TS)^(-1)条件下,20和25 k Hz和20/25 k Hz3种频率的SCOD破解度较原泥增加了20.4%、17.3%和26.8%,平均粒径较原泥分别降低了29.68%、26.33%和33.39%。双频(20/25 k Hz)、低能量(400 k J·(kg TS)^(-1))的超声预处理能够有效降低污泥比阻,污泥脱水性能得到最大程度改善,该条件下污泥比阻降低了46.6%。随着超声能量进一步增加,污泥脱水性能迅速恶化。

Pretreatment method of ultrasonic disintegration is a new technology used to accelerate anaerobic digestion of waste activated sludge（ WAS）. Frequency is one of the most important parameters influencing the disintegration degree of WAS. The effects of ultrasonic pretreatment on the reduction of WAS were evaluated based on the disintegration degree of Soluble COD,sludge particle diameter,and specific resistance of filtration（ SRF）. Frequency（ 20 k Hz,25 k Hz,and 20/25 k Hz） and specific energy（ 0 to 12 000 k J·（ kg TS）-（-1）） of ultrasonic pretreatment were the main controlled parameters. The results showed that the DD of pretreated sludge increased by 20. 4%,17. 3%,and 26. 8% more than that of untreated WAS under frequencies of 20 k Hz,25 k Hz,and 20/25 k Hz. The mean diameter decreased 29. 68%,26. 33%,and 33. 39%,respectively,at the specific energy of 12 000 k J·（ kg TS）^-1. The dewaterability of WAS slightly improved at a double frequency（ 20/25 k Hz） and low specific energy（ 400 k J·（ kg TS）^-1）,which were also the optimal parameters. When the pretreatment is carried out at the optimal condition,the SRF of the pretreated sludge effectively decreased by46. 6% more than that of raw sludge. The study proved the feasibility of double frequency ultrasonic pretreatment to improve the disintegration performance of WAS.