Zhai N.,Northwest University, China |
Zhai N.,Research Center for Recycling Agriculture Engineering Technology of Shaanxi Province |
Zhang T.,Northwest University, China |
Zhang T.,Research Center for Recycling Agriculture Engineering Technology of Shaanxi Province |
And 9 more authors.
This study investigated the effects of different initial pH (6.0, 6.5, 7.0, 7.5 and 8.0) and uncontrolled initial pH (CK) on the lab-scale anaerobic co-digestion of kitchen waste (KW) with cow manure (CM). The variations of pH, alkalinity, volatile fatty acids (VFAs) and total ammonia nitrogen (NH4+-N) were analyzed. The modified Gompertz equation was used for selecting the optimal initial pH through comprehensive evaluation of methane production potential, degradation of volatile solids (VS), and lag-phase time. The results showed that CK and the fermentation with initial pH of 6.0 failed. The pH values of the rest treatments reached 7.7-7.9 with significantly increased methane production. The predicted lag-phase times of treatments with initial pH of 6.5 and 7.5 were 21 and 22days, which were 10days shorter than the treatments with initial pH of 7.0 and 8.0, respectively. The maximum methane production potential (8579mL) and VS degradation rate (179.8mL/g VS) were obtained when the initial pH was 7.5, which is recommended for co-digestion of KW and CM. © 2015 Elsevier Ltd. Source