超声波联合化学调理改善疏浚底泥脱水性能的研究

摘要

以长沙市圭塘河疏浚底泥为研究对象,分别采用聚合氯化铝(PAC)、阳离子聚丙烯酰胺(CPAM)和超声波改善疏浚底泥脱水性能.结果表明,单一PAC、CPAM对疏浚底泥脱水性能均有一定程度的改善作用,CPAM效果优于PAC,经两种药剂联合化学调理后,疏浚底泥脱水性能进一步改善,调理结束后疏浚底泥属较易脱水污泥;超声波联合化学调理疏浚污泥时,宜先采用化学调理(先投加3 g/L PAC再投加100 mg/L CPAM,搅拌静置30 min),再进行超声波调理(超声频率40 kHz,声能密度0.8 W/mL,超声时间20 s),调理结束后疏浚底泥比阻值降至0.38×109 s2/g,属于易脱水污泥,疏浚底泥脱水性能大大改善.疏浚底泥脱水性能与其微形态结构相关,疏浚底泥二维分形维数越大 、中值粒径越大,其脱水与沉降性能越好.%Taking the sediment of Guitang River dredged from Changsha City as the research object ,the single polymerized aluminum chloride (PAC) ,cationic polyacrylamide (CPAM ) ,ultrasonic and their combination were used to improve the dewatering performance of the dredged sediment .The results showed that both single PAC and CPAM could improve the dewatering performance of dredged sediment to a certain degree ,and the CPAM effect was better than that of PAC .The dewatering performance of dredged sediment was further improved by the combination of two chemical agents ,and the dredged sediment belonged to easier to dewatered sludge after combination conditioning .Ap-plying combination conditioning of ultrasonic with chemical conditioning to treat dredged sludge ,the chemical condi-tioning (adding 3 g/L PAC first and then adding 100 mg/L CPAM and stirring for 30 min) should be adopted before ultrasonic treatment (ultrasonic frequency 40 kHz ,acoustic energy density 0 .8 W/mL ,ultrasonic time 20 s) .The spe-cific resistance of dredged sediment dropped to 0 .38 × 109 s2 /g after conditioning ,the dewatering performance was greatly improved .The dewatering performance of dredged sediment was related to its micromorphological structure . The specific resistance and sedimentation performance of dredged sediment increased with the increase of fractal di-mension and median diameter .