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Difficult problem for our wastewater treatment plant sludge treatment, on the basis of the sludge digestion process, the sludge anoxic / aerobic digestion (Anoxic / Aerobic Digestion, A / AD) process improvement of ultrasonic pre- deal with the introduction of the sludge digestion process, seeking a low cost of treatment, run good, digestion cycle is short, simple to operate, easy to manage excess sludge ultrasonic - anoxic / aerobic digestion combined process, various process conditions Sludge Reduction. First, study the concentration of 10g / L of living sludge by the frequency the 28kHz ultrasonic pretreatment, different ultrasonic sound energy density and ultrasonic time of sludge oxygen consumption rate (SOUR) and crack rate (DDCOD) of the impact. The results show that, in a suitable acoustic energy density and ultrasonic time, ultrasonic pretreatment can significantly improve the rate of sludge cracks, while improving the biological activity of the sludge. Best acoustic energy density and ultrasonic time 0.1W/mL × 15min, and 0.15W/mL x 10min, DDCOD 18.74% and 17.03%, respectively, △ SOUR respectively 11.69 and 12.55mgO2/gMLSS · h energy consumption are 9.47kJ/gSS. Secondly, the introduction of ultrasonic pretreatment sludge anoxic / aerobic digestion process to explore ultrasonic - anoxic / aerobic digestion combined process (UA / AD) operating parameters. The test selected ultrasonic sound energy density, ultrasonic time, ultrasonic interval of three factors orthogonal design, ultrasonic sludge anoxic / aerobic digestion. The results show that, the ultrasonic pretreatment sludge, anoxic / aerobic digestion after 9 days, MLVSS removal rates of up to 50.9%, without ultrasound pretreatment increased 14.4%. Ultrasonic enhancement sludge anoxic / aerobic digestion and optimal ultrasound parameters: ultrasonic energy density 0.15W/mL, ultrasonic time 10min, ultrasonic interval 12h. Ultrasound interval digestion effect influencing factors, followed by ultrasonic energy density, the ultrasonic time with minimal impact. Finally, the joint process laboratory test trials, independent design volume of the a 30L sludge ultrasonic - anoxic / aerobic digestion test system. The ultrasound pretreatment parameters for the ultrasonic frequency 28kHz, sound energy density 0.15W/mL, ultrasonic time 10min, ultrasonic interval 12h, 30% of the proportion of sludge ultrasound. The results show that the introduction of ultrasonic pretreatment significantly shorten the stabilization time of the sludge, to improve the efficiency of the sludge digestion. Sludge digestion for 10 days has reached a stable standard, shorter than the introduction of ultrasonic pretreatment 12 days, while the the MLVSS maximum removal rate 11%, to 55.10%. Introduction of ultrasonic sludge anoxic / aerobic digestive system the sludge supernatant solubility COD (SCOD) trends more obvious, and the pH of the supernatant and ammonia, TP trend is no obvious impact.
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