Abstract:
Dry fermentation has become a hot spot due to characteristics as low water requirements, high gas production rates, and low costs. In this work, high temperature dry fermentation of chicken manure and straw was conducted at 55±0.2oC to analyze the changes of CODT, CODS, and the ammonium nitrogen concentration as well as their relationships. It was shown that according to the changes of the loading frequency, the biogas production rate, pH, CODT, CODS, and the ammonium nitrogen concentration, the whole experimental process of high temperature dry fermentation of chicken manure and straw was divided into four periods such as the stagnant adaptation period (20 d, from 1-20 d), the quick start period (30 d, from 21-50 d), the stable period (70 d, from 51-120 d), and the overload period (20 d, from 121-140 d). During the stable period (70 d, from 51120 d), CODT concentration in the high temperature dry fermentation digestive liquor in reactors R1-R4 increased with the increase of the loading frequency from 13.45, 15.32, 16.11, and 18.11 g/L on the 51st d to 17.89, 20.32, 22.65, and 25.87 g/L on the 120th d, respectively. The proportion of CODS to CODT in the fermentation liquor in R1-4 reactors increased and was maintained at 45.65-47.21, 51.01-55.32, 44.12-48.82, and 32.01-39.15%, respectively. The ammonium nitrogen concentration increased to 2688.91 ± 68.35, 2479.45 ± 244.36, 2307.01 ± 175.36, and 1445.22 ± 88.32 mg/L on the 120th d, respectively, with the increase of the loading frequency.
Keywords:
COD
,
mechanism study
,
straw
,
High temperature dry fermentation