The Effect of Microwave Radiation Treatment on Flowing Sewage Sludge in a Dynamic Manner

Impact on characters of flowing sewage sludge by microwave radiation in a dynamic manner was inspected. The changes in settling and vacuum filtration dewaterability of sewage sludge in 3 minutes of microwave radiation were investigated,influences on volatile suspended solid(VSS)dissolving ratio, COD in supernatant and micro-morphology of sewage sludge by microwave radiation were investigated as well. Low intensity radiation had little effect on settling and vacuum filtration dewaterability of sewage sludge because it can´t transformed the structure of the sludge fundamentally. The settling and dewaterability of sewage sludge could be improved dramatically by adaptable microwave radiation. The adaptable radiation durations of 500W, 700W, 900W were 180s, 150s, 60s respectively. At these adaptable radiation durations,the specific resistance was about 0.3x10⁹S²/g, decreasing 88% compared to the sludge without radiation, and the water content of the sludge cake after vacuum filtration decreased from 82.5% of original sludge direct filtration to 70%. VSS dissolving ratio and COD in supernatant increased with extending radiation duration and strengthening radiation intensity. Under the radiation intensity of 700W and 900W, there was a sudden increasing process of COD in supernatant at the time of 150s and 60s respectively. Appropriate radiation could accelerate conglomeration and flocculation of sludge particles, while ultra radiation damaged the structure of cells, which caused sludge smarshed, the increase of the mixture viscosity and the dewaterability became worse. The study of the impact on characters of flowing sewage sludge by microwave radiation in dynamic manner can provide a theoretical basis for the practical utilization of microwave in the sewage sludge treatment.