Characteristics of Kitchen Waste and the Formation of Floating Brown Particles (FBP) in the Anaerobic Digestion Process
Yeqing Li1, Hao Jiang1, Hong Liu1, 2, Sen Luo1, Hong Nie1, 3, Yafei Wang1, Mingyu Qian1, 4, Jiangtao Ding1, Hongjun Zhou1
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1Institute of New Energy, State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Biogas Upgrading
Utilization, China University of Petroleum Beijing (CUPB), Beijing, P. R. China, 102249
2Beijing Jeegreen Technology Development Co., Ltd., Beijing, P. R. China, 102200
3Institute of Agricultural Applied Microbiology, Jiangxi Academy of Agricultural Sciences,
Nanchang, P. R. China, 330200
4Faculty of Agricultural and Environmental Sciences, University of Rostock,
Justus-von-Liebig-Weg 6, 18059 Rostock, Germany
Submission date: 2017-03-14
Final revision date: 2017-06-15
Acceptance date: 2017-06-15
Online publication date: 2017-11-07
Publication date: 2018-01-02
Pol. J. Environ. Stud. 2018;27(1):155–161
Five types of kitchen waste (KW) from China – including hop pot (HP), fast food (FF), Hebei cuisine (HC), university canteen (UC), and other mixed KW (Other) – were investigated as feedstock for potential biogas and methane production. The biodegradability of KW was measured using batch anaerobic digestion (AD) tests and feedstock at an inoculum ratio (F/I) of 0.5. Gompertz and Cone models were used to determine the kinetic parameters of KW degradation, biogas, and methane production. Results showed that HP had the highest lag phase time of 5.46 days. Methane production varies with different sources of KW. HP had the highest methane yield of 363.9 mL/g-VSadded as compared to a sample of FF (334.8 mL/g-VSadded), other ( 278.5 mL/g-VSadded), UC (239.2 mL/g-VSadded), and HC (236.0 mL/g-VSadded). The biodegradability of KW ranged from 39.5% to 50.4%. During the AD process a certain amount of floating brown particles (FBP) were formed, which may be the main inhibiting factor of methane production. Analysis of 13C NMR and FTIR revealed that the main component of FBP was calcium stearate. The formation mechanism of calcium stearate may contribute to the relatively high lipid content (18.6% to 30.9%) of the KW sample, which subsequently resulted in over-accumulation of long-chain fatty acids (LCFAs) and reaction with Ca2+. Using lipid-rich substrates as feedstock may be an efficient approach to adding Ca2+ artificially for reducing the inhibition of LCFAs.