超声能量密度对污泥脱水性能的影响

Effect of ultrasonic energy density on sludge dewatering performance

近年来，生物法在城市污水处理中得到广泛的应用，然而在处理过程中产生了大量的污泥，污泥中含有50％～70％的有机物和较多的氮、磷等营养成分以及致病菌、寄生虫卵等有害物质。其化学性质极不稳定，如不加处置或处置不当，就会形成二次污染，散发臭气，甚至传播疾病。

In this paper the effect of ultrasonic energy density on sludge dewatering performance was investigated and the related mechanism was discussed. Experimental results showed that time of ultrasonic action had little influence on sludge dewatering performance at the lower energy density. Sludge dewatering performance was improved when energy density increased from 0.25 kW · L^-1 to 0.5 kW ~ L 1. At the ultrasonic energy density of 0. 5 kW · L^-1 , sludge dewatering performance reached the highest at the time of 10 s with mud cake water content 83.8%, specific resistance filtration （SRF） 0.8× 10^9 s^2 · g^-1 , viscosity 16.8 mPa · s and capillary suction time （CST） 10.7 s. At the higher energy density, sludge floc was destroyed and dispersed which resulted in the increase of filtration resistance and the deterioration of sludge dewatering performance. At the energy density of 4 kW · L 1, and time of ultrasonic action 120 s, mud cake water content, SRF, viscosity andCSTwere up to 89.4G, 3.1×10^9 s^2 · g ^-1, 43.2 mPa ·s and 56.2 s, respectively.