| Anaerobic digestion is one of the important processing means of urban sludge stabilization. In many first and second tier cities in large-scale sewage treatment plant which, for sludge treatment is basically mesophilic anaerobic digestion technology. But stage of anaerobic digestion due to the hydrolysis reaction is slow, resulting in anaerobic digestion of long cycle, high operating costs and management. So, to solve the problem of anaerobic digestion for its limiting factor, namely the hydrolysis stage problem.Select single 20kHz,25kHz and dual-frequency 20+25kHz to conduct a ultrasonic pretreatment, draw best of the three ultrasonic pretreatment of good or bad. Ideal parameters with alkali solutions of different dosage. (0.02-0.3gNaOH/gTS). After pretreatment with test pilot, mesophilic anaerobic digestion test to get the desired results.12000,18000,24000kJ/kg TS under the added value of SCOD were 3532.2, 3611.3,3677.2mg/L, dissolution rate,26.8%,27.4%,27.9%, respectively, after the ultrasound energy 12000KJ/kg TS, SCOD flat growth trends. Both single-frequency ultrasound treatment and in the dual-frequency ultrasound treatment can increase the solubility of solid organic matter in sludge, accelerate the hydrolysis rate of sludge. Under the same specific energy consumption, dual-frequency ultrasonic cracking better than the single-frequency ultrasound to sludge.20+25kHz, at the time of input energy for the 12000KJ/kg TS optimum. Combination with the alkali solution, crack effect has significantly improved. In the alkali content of 0.08gNaOH/g TS, best, SCOD dissolution and changes of EPS have raised. However, the larger ultrasonic ultrasonic energy input is not easy to dehydration from the changes in dewatering performance... |
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