The influence of pH adjustment methods on hydrolysis and acidogenesis of kitchen wastes in two-hase anaerobic digestion
pH调节方法对厨余垃圾两相厌氧消化中水解和酸化过程的影响

Batch experiments were carried out to determine the effect of pH adjustment methods on the accumulation of Na+ in the effluent, hydrolysis and acidogenesis of kitchen wastes in the two-phase anaerobic digestion. Three pH adjustment methods included the initial adjustment of pH using NaOH, batch pH adjustment using NaOH and Ca(OH)2 and the pH adjustment with regulating the ratio of carbon and nitrogen. The results showed that the effluent Na+ concentration in the hydrolysis-acidogenesis liquid could be reduced at three pH adjustment methods. However, compared to the other two pH adjustment methods, the pH adjustment method with regulating the ratio of carbon and nitrogen increased the hydrolysis and acidogenesis rates of kitchen wastes with the first-order hydrolysis rate constant of 0.199d-1 and VFA concentration of 35g?L-1. The lactic acid concentration decreased to 6g?L-1 after the maximum lactic acid concentration of 24 g?L-1 was achieved on the second day of the experiment. And the propionic acid didn't predominate over the VFA constituents.