污泥的超声破解及其对微生物活性的影响

同步测定了超声处理过程中污泥破解程度、微生物活性、颗粒大小等参数的变化,并分析了不同参数之间的内在联系及超声参数对污泥微生物活性的影响.结果表明,污泥颗粒的超声处理过程可以分为2个阶段:首先絮体破碎为直径十几μm的小凝集体,胞外有机质溶出,微生物游离出来,活性增强;随后小凝集体被进一步破坏,污泥颗粒直径降至10μm以下,微生物胞内有机质溶出,活性明显下降.由于污泥的不均匀性,2个阶段并非截然分开,短时间内,污泥破解程度低于20%时,以絮体破碎为主,污泥活性提高20%以上;当污泥破解程度在20%~40%之间时,部分微生物开始受到损伤,污泥活性提高不到20%;当污泥破解程度高于40%时,大部分微生物受到损伤,污泥活性迅速下降.低强超声可以在较长处理时间内使大部分污泥颗粒停留在絮体破碎阶段,有效避免微生物的破坏,因此适用于增强污泥微生物活性.

Ultrasonic Sludge Disintegration and Its Influence on Sludge Microbial Activity

The changes of sludge disintegration degree, microbial activity and particle size were examined synchronously, and the relationships between the changes and the effect of ultrasonic parameters on microbial activity were also analyzed. The results show that the process of ultrasonic sludge treatment can be divided into two stages: at the first stage, sludge flocs are disrupted into small micro-floc aggregates with the diameter of 10-20 μm, the extracellular organic substances are dissolved, bacteria are dissociated from flocs, and the microbial activity is enhanced; at the second stage, the micro-floc aggregates are disintegrated further into bacteria bodies with the diameter less than 10μm, the intracellular organic substances are released, and the microbial activity are decreased. The two stages are not entirely separated because sludge is inhomogeneity. When sludge disintegration degree is lower than 20 % , sludge floc disruption is the main effect and the microbial activity can increase over 20 % ; when sludge disintegration degree is between 20 % -40 % , some bacteria are hurt and the microbial activity can increase by less than 20% ; when sludge disintegration degree is over 40% , most bacteria are damaged and sludge activity would decrease quickly. Because low energy ultrasonic can disrupt sludge floc with no damage to microorganism in a long treatment duration time, it is suitable to stimulate sludge microbial activity.