Study On The Dewatering Performance Of Sludge Under Synergetic Treatment Of Modified Coal Gasification Slag And Ultrasonic Energy

Activated sludge method is widely used in urban sewage treatment,The current sewage treatment industry is in a high-speed development stage,the production of plant sludge increases,Due to high moisture content in sludge and large volume,resulting in the difficulty of these sludge treatment,sludge disposal has become an environmental problem cannot be ignored.In the process of sludge disposal and resources,the sludge dewatering is an indispensable pre-treatment link.Sludge was conditioned under the modified coal gasification slag?MCGS?cooperates with ultrasonic in order to improve sludge dewatering performance in this dissertation.Select of the concentrated sludge in Hefei Economic Development Zone wastewater treatment plant for this study,The use of hydrofluoric acid modified coal gasification ash and ultrasonic treatment of the excess sludge,Specific resistance to filtration?SRF?and capillary suction time?CST?were used as the main evaluation indexes of sludge dewatering performance,The variation of soluble organic matter,Zeta potential in sludge filtrate and particle size was studied.The main experimental research contents and conclusion are as follows:?1?Sludge was conditioned by MCGS.The effect of dosage of MCGS on sludge dewatering performance was investigated.The results indicated that the dewatering performance has a significant effect with an increase in the dosage of MCGS.The dewatering performance of sludge showed a tendency to increase first and then decrease.Sludge dewatering achieved the best performance with the ratio of MCGS to dewatered sludge of 20%,SRF and CST were 5.11×10¹¹m.kg,51.2s,respectively.In comparison with untreated sludge,SRF and CST decreased 49.9%?29.5%,respectively.MCGS with framework skeleton and adsorption is contributed to improving the dewatering performance.?2?Sludge was treated by ultrasonic.The effects of ultrasonic power and time on sludge condition effect were studied.Appropriate ultrasonic energy can significantly improve the sludge dewatering performance.while the energy is too high,sludge dewatering performance will deteriorate.With ultrasonic of 60 W and contact time of20 s,SRF and CST decreased to7.2×10¹¹m/kg and 66 s,respectively.In comparison with untreated sludge,SRF and CST decreased 29.4% and 15.4%,respectively.Ultrasonic can destroy the sludge floc structure to release the gap water,crack the sludge cell structure to release the intracellular water,improve the sludge dewateringperformance.?3?Sludge was treated synergy of MCGS and ultrasonic and orthogonal tests?dosage of MCGS?ultrasonic power and contact time?was performed to determine the best parameter.The results indicate that best parameter was ultrasonic power of 60 W,contact time of 30 s and the amount of 30%.Under the best parameter,SRF and CST decreased to 3.7×10¹¹m/kg and 45 s,respectively.In comparison with untreated sludge,SRF and CST decreased 63.7% and 42.3%,respectively.Ultrasonic can destroy the floc structure,Cracking cell structure causes intracellular material to dissolve.MCGS with framework skeleton and adsorption to EPS of sludge is contributed to improving the dewatering performance.