Anaerobic digestion of kitchen wastes in a single-phased anaerobic sequencing batch reactor (ASBR) with gas-phased absorb of CO_2

Article type: Research Article

Authors: ZHANG, Bo | HE, Zheng-guang | ZHANG, Li-li | XU, Jian-bo | SHI, Hong-zhuan | CAI, Wei-min^;

Affiliations: School of Environmental Science and Engineering, Shanghai Jiaotong University, Shanghai 200240, China | Harbin Institute of Technology, Harbin 150001, China

Note: [] Corresponding author. E-mail: [email protected]

Abstract: The performance of the single-stage anaerobic digestion of kitchen wastes was investigated in an anaerobic sequencing batch reactor (ASBR) with gas-phased absorb of CO_2. The ASBR was operated at four chemical oxygen demand (COD) loading rates, 2.8, 5.1, 6.2 and 8.4 g/(L·d) respectively. The COD loading rate was increased with the TS concentration and HRT changing. At maximum COD loading rate of 8.4 g (L·d), The COD, total solid (TS) removal rate and methane gas yield were 69%, 68% and 2.5 L(L·d) respectively. The operation of the reactor with gas-phased absorb of CO_2 was stable in spite of the low pH (2.6–3.9) and high concentration of TS (142 g/L) of input mixture. The output volatile fatty acid (VFA) concentration was between 2.7–4.7 g/L and had no inhibition on the methanogenic microorganism. The reactor without gas-phased absorb of CO_2 became acidified when the total COD alkaline will be required to keep pH in the appropriate range for the methanogenic microorganism based on theoretical calculation. Gasphased absorb of CO_2 effectively reduced the alkaline consumption, hence avoided excessive cation into the reactor.

Keywords: kitchen wastes, methanogenesis, gas-phased, CO[TeX:] _2

Journal: Journal of Environmental Sciences, vol. 17, no. 2, pp. 249-255, 2005