| In recent years, along with economic development, people raise awareness ofenvironmental protection and pay attention to the environment. Sewage treatmentindustry has developed rapidly，Various sewage treatment plants were upgradedgradually，then the efficiency of wastewater treatment Gradually increased. Whiletaking this initiative has led to increase the amount of sludge. After a conventionalsludge dewatering sludge moisture content remains at about75%.The high moisturecontent of dewatering sludge, which take difficult to the treatment and disposal ofsewage sludge and Sludge utilization.Through the use of ferric chloride, PAM, ultrasound, ferric chloride and PAMcomposite role, and ferric chloride enhanced ultrasound combined with PAM, this papertakes dehydration effect into study. Through analysis of the SRF, VSS/SS of sludge, aswell as sludge filtrate COD, turbidity moisture content of Sludge cake,and otherindicators. We investigate the impact of various ways of conditioning sludge dewateringperformance. The experimental results are as follows:（1）Ferric chloride combined PAM： With the dosage of1500mg/L, sludgedewatering has best performance. At this time,SRF reached0.38×109s2/g, VSS/SSreached0.599, turbidity moisture content of Sludge cake reached to82.05%,sludgefiltrate COD was520mg/L, sludge filtrate turbidity was17.19NTU.These indicationsdecreased to4.17%，0.67%，the Percent of1.35and3.53%,Compared with the besttreatment effect of Ferric chloride alone conditioning.（2）Ultrasound combined PAM：In the ultrasonic time of3min, the ultrasonicpower is60W and100W， sludge dewatering performance achieve the best results。SRF reached to0.59×109s2/g and0.73×109s2/g, respectively, the VSS/SS ofsludge reached to0.558and0.570respectively. In the ultrasonic time of4min, theultrasonic power were the40W and80W, sludge dewatering performance achieve thebest results. SRF reduced to0.66×109s2/g and0.69×109s2/g, the VSS/SS ofsludge reduced to0.589and0.568respectively. After ultrasonic treatment the COD ofsludge filtrate was significantly increased, and the filtrate turbidity increased accordingly. When ultrasonic time was6min,the ultrasonic power were40W,60W,80W,100W,the COD of sludge filtrate increased to3.20×103mg/L，3.26×103mg/L，3.47×103mg/L and3.54×103mg/L,Compared with the original sludge,the COD of sludge filtrate increase61.88%，62.58%，64.84%and65.54%。.Whenultrasonic time was3min,the ultrasonic power were60W and100W,Increase thevalue of the sludge filtrate turbidity maximum, respectively reached to176.71NTU and199.8NTU after treatment. When ultrasonic time was4min,the ultrasonic power were40W and80W,Increase the value of the sludge filtrate turbidity maximum, respectivelyreached to148.5NTU and202.0NTU after treatment. With the extension of ultrasonictime, pH value of the sludge filtrate appeared decreased slightly, changes in the range ofpH value of between7.1-7.36. Ultrasonic plus PAM conditioning，the effect of sludgeremoval surgery is better than PAM conditioning plus ultrasonic. When the dosage ofPAM was150ppm, sludge dewatering has best performance. At this time,SRF reachedto0.29×10^9s2/g,VSS/SS reached to0.580,the moisture content of sludge cake reachedto82.09%and the filtrate turbidity of sludge reached to31.22NTU with ultrasoundcombined PAM conditioning;（3）Ferric chloride, ultrasound combined with PAM: Based on the orthogonal testof ferric chloride, PAM and ultrasonic of three factors，Three kinds of factors on theorder of improving sludge dewatering performance impact for ferric chloride>PAM>ultrasonic.When the dosage sludge was1500mg/L, sludge has best sludge dewatering.At this point the sludge specific resistance decreased to0.18×109S2/g, VSS/SSdecreased to0.564,and the moisture content of sludge cake reached to79.06%,the SRFdecreased by79.59%, VSS/SS decreased by9.03%and13.29%compared with theRaw sludge. the best combination of Ferric chloride, PAM and ultrasound was Ferricchloride(1500mg/L),PAM(150ppm) and ultrasound(3min). |
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