Intermittent running was carried out in a 6 L ASBR by using glucose as substrate

and with influent COD 6700 mg·L-1.Alkalinity added into the influent was gradually lowered down

and the ratios of COD0 to alkalinity (COD0/Alk) were respectively 1.0∶1

2.0∶1

2.5∶1

3.4∶1

4.2∶1 and 4.8∶1.The aim of this work was to investigate the change of pH

volatile fatty acid (VFA)

bicarbonate alkalinity (BAlk) and CO2 pressure in anaerobic sequencing batch reactor （ASBR）for treating high-strength carbohydrate wastewater

and demonstrate the efficiency and stability of ASBR process at a lower pH.The results showed that alkalinity dosage had significant influences on VFA

BAlk

CO2 pressure and pH

especially acid-production rate within the first 0.5 h of reaction periods.When COD0/Alk was 1.0∶1

the pH values were always above 7.20.There was a higher acid-production rate and partial pH below 6.5 at the ratio of 3.4∶1

which indicated that the digested-liquid became acidic.It was found that the pH values were almost maintained at less than 6.5 while the ratios were 4.2∶1 and 4.8∶1

but methanogenic process was stable.During the whole operation

the process behavior was steady with COD removal efficiency higher than 97%

which proved the feasibility of methane production with ASBR at a low pH and low alkalinity.