Expermental Study On Degradation Of Organic Matter In Water Purification Precipition Sludge By Ultrasonic Technique

The precipitated sludge in waterworks is commonly used in the return sludgeenhanced on coagulation process, but sludge stay for a long time in the treatmentprocess, which will keep a variety of organic matter enriched and increase thesecurity risks of drinking water. In order to effectively improve the safety ofprecipitated sludge and drinking water, it’s very important to develop research onprecipitated sludge.The study use simulated water in lab and precipitated sludge in waterworks asobjectives, and select tank type ultrasonic reactor to analyze degradation of organicson ultrasonic and water quality conditions, under the low sound energy density at0.03W/mL.A series of static experiments is done to research organics degradation ofsingle-frequency ultrasound and dual-frequency ultrasound in the simulated water.The main experimental achievement are as follows: organics removal rate isgradually increased with time; under the same sound energy density, low frequencyultrasound has better degradation efficiency than high frequency ultrasound; thedegradation efficiency of dual-frequency ultrasound is superior to single-frequencyultrasound, and the degradation efficiency of X-Y axial orthogonal ultrasound issuperior to X-X axis parallel to the axial ultrasound.The research results of organics degradation about pH and solid content in thesimulated water show that the pH at6has better degradation efficiency than the pH at8and10, the solid content at1%has better degradation efficiency than the solidcontent at0%and5%.The pH is reduced slightly, and the decrease of pH at10islarger than pH at8. The turbidity is increased slightly, and the increment of solidcontent at1%is larger than solid content at5%.The dynamic test of precipitated sludge in waterworks indicated that ultrasonichas a significant impact with cracking performance of precipitated sludge. Under thelow energy density of sound, the cell inclusion is dissolved after splitting of bacterialcytoderm, and the organic content is increased. In addition,The degradation efficiencycan achieve best under the low-frequency at25kHz after the sludge has beendisposed10min, which is consistent with the results of the test in simulated water.