[Factors affecting residual sludge reducing by anaerobic hydrolysis-acidification and aerobic oxidation process of A1/A2/O bio-treatment system].

Hydrolysis-acidification and aerobic oxidation process could realize sludge reducing without those strengthening conditions such as high temperature, high pressure, strong oxidant or alkali which may destroy the cell structure of microorganisms, so it has good maneuverability and is economical. The purpose of sludge reducing system is mainly to degrade the pollutants in it ant its reducing effect is related to organic loading, HRT and temperature, etc. In the A1/A2/O bio-treatment system dealing with alkali minimization and dyeing-printing wastewater, residual sludge can be reduced effectively by recycling sludge to A1 segment. It proved that sludge could be reduced effectively and treated water could reach the grade I standard of GB8978-96 for long time operation of the system, when the volume loading of A1 (COD) was 2.54 kg x (m3 x d)(-1), the HRT of A1 was 7.56 h and the temperature of the system was 25 degrees C - 40 degrees C. The sludge reducing could be realized through recycling to A1 segment, and the N, P released from the broken bacteria cell could compensate the shortage of N and P of alkali minimization and dyeing-printing wastewater, and then the cost of adding the nutrition of N and P to the system could be reduced greatly.