| Anaerobic hydrolysis and acidification、endogenous respiration uncoupling metabolism are the principal factors of sludge reduction in an A+OSA process. These factors of sludge reduction is always present in the whole process, influence each other in different process conditions,play a different role within the system together to achieve reduction of excess sludge. In recent years, applying ultrasound to reduce sludge production has been a new route and way. Residual sludge achieve effective emission reduction are important.The main purpose of this paper is groping research on the decompounding sludge and cognition of the releasing effect, influencing factors and mechanism, which lays the foundations of the applications and the facilitating the techniques of stabilization, reduction, resourcing. After disposed by ultrasonic, by comparing the ultrasonic with sludge return A+OSA system and without ultrasonic sludge recycle system, A+OSA system residual sludge reduction effect and the system in the remaining sludge of biological treatment system running effect is that the qualities of sludge altered, sludge Decomposed, substances in cell released, the COD, nitrogen Phosphorus, etc. rise by a wide margin in the filtrated sludge,and moreover, the substances released are apt to be decomposed, which are the conditions for reduction and disposing ulteriorly. Therefore, the action of sludge decomposed by ultrasonic is reflected in the future experiments with a view to research on the variety of COD、TN、TP and the monitoring activity of dehydrogenises、alkaline phosphates in the filtrate.The major achievements in the paper are as follows:(1) Sludge increased solubility after the Ultrasonic treatment. Ultrasonic time longer, the sludge is to decipher the effect to be better. Within the14min time, COD concentration and TN concentration was increased with the ultrasonic time. Sludge disruption rate is higher, the energy consumption is greater than the ultrasonic energy consumption ratio, and ultrasonic time is linear.(2) The Effect of ultrasonic on the sludge will destroy the sludge floc structure. Ultrasonic processing time is longer, the sludge floc structure destroyed were more obvious. In different energy density and ultrasonic time, ultrasonic sludge, particle size, sludge by ultrasonic treatment in a relatively short period of time can be achieved on the sludge floc structure disintegrate, and ultrasound effect on sludge particle size decreased almost inoperative, as intermediate turning point (after8min sludge average particle size repeated phenomenon), may be released from the contents were gradually absorbed in the sludge granules, showed a slight increase average particle diameter.(3) Sludge after ultrasonic treatment, temperature rise, in which sludge dehydrogenase activity and activity of alkaline phosphatase. Dehydrogenase activity in a short period of time (0～14min) are significantly decreased, and then fall or rise again change, overall is downward trend. A high energy density conditions, alkaline phosphatase activity at the beginning of fall are very strongly, then there is a relatively slow recovery and increasing tendency.(4) Ultrasonic sludge recycle decrement process for A+OSA process COD,chroma,TN,TP removal efficiency will produce certain effect. The whole system effluent effect tends to be stable, maintain in80mg/L fluctuate around, set up to match the good treatment effect of wastewater.(5) Long term ultrasonic sludge return to the Al’ period of reduction of excess sludge reduction system, A+OSA aerobic microbial activity is higher than that without ultrasound treatment sludge return system. During the experiment, an ultrasonic reflux reactor accumulated sludge discharge for46.981g, ultrasonic reflux reactor is40.452g, and the former reactor is compared, the latter accumulative mud volume reduced6.529g, namely the ultrasound-treated ultimate disposal of the sludge volume reduction of13.90%. Therefore, ultrasonic+"A+OSA" technology can obtain relatively good effect of sludge reduction.(6) A+OSA sludge reduction in each reaction zone dehydrogenase activity and alkaline phosphatase activity changes were similar, showing increased first and then decreased, but the dehydrogenase activity of alkaline phosphatase activity was more stable than the. The aerobic section (O/O’) of the dehydrogenase activity and alkaline phosphatase activity was the highest, A2’and A2dehydrogenase activity and activity of alkaline phosphatase is the lowest. Aerobic section (O/O’) section of catalase activity also experienced increased at first and then decrease, A1’/A2’,A1segment and A2segment of catalase activity fluctuate fluctuation, each corresponding section of approximately the same change trend. |
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