Influence of pH controlling on fermentation performance in kitchen waste and cow manure

ABSTRACT

In order to make the process more sustainability and more efficient in co-digestion of kitchen waste (KW) and cow manure (CM), the effect of pH controlling at initial fermentation time (I), first gas stagnation time (A), and combination of both times (C) were investigated. Five pH values (6.5, 7.0, 7.5, 8.0 and 8.5) were set in each case to find out the optimal way of pH regulation with the consideration of changes in biogas and methane production, volatile solid (VS) reduction, and lag-phase time. The results show that adjusting pH of the co-digestion system could significantly improve biogas production except when pH was set to 6.5 in groups I and A. Adjusting pH twice (group C) could increase the system stability. When pH value was set to 7.5 twice, highest methane production (16501.10 mL), the highest methane yield of 287.64 mL/g VS_added, and a relatively short lag-phase time (27.3d) were obtained by C^7.5.

KEYWORDS:

• Kitchen waste
• cow manure
• anaerobic co-digestion
• pH
• biogas

Acknowledgments

We thank Dr. Zhai Ninginig, Dr. Liu Wei and Li jianfeng for critical reading of this manuscript and editorial guidance.

Additional information

Funding

This project is supported by Key Scientific Research Project for University in Henan Province (17A416004), Key projects in Henan Province (182102311052) and the Project for National Natural Science Foundation of China (No. 81803659).

Notes on contributors

Dongxue Yin

Dongxue Yin graduated from the College of Forestry of Northwest A&F University in 2015 and got her doctorate of science. Now she works in College of Agricultural Engineering, Henan University of Science and Technology, China. She has coauthored 10 publications including Renewable & Sustainable Energy Reviews, Bioresource Technology,PLoS ONE, et al. Her current research focuses on (1) The resource utilization of agricultural waste; (2) Harmless treatment of Agricultural waste.

Wei Liu

Wei Liu graduated from the College of Forestry of Northwest A&F University in 2015 and got his doctorate of science. Now he works in College of Agriculture, Henan University of Science and Technology, China. Academic papers were published in international journals, such as Scientific Reprts, PLoS ONE, Chemistry & Biodiversity, Renewable & Sustainable Energy Reviews, Bioresource Technology, et al. His current research focuses on (1) Biological Resource; (2) The resource utilization of agricultural waste; (3) Harmless treatment of Agricultural waste.

Ningning Zhai

Ningning Zhai graduated from the College of Agronomy of Northwest A&F University in 2016. Academic papers were published in international journals, such as Waste Management, Renewable & Sustainable Energy Reviews et al. Her current research focuses on (1) The digestion of kitchen waste; (2) Co-digestion of kitchen waste and manure.

Jianfeng Li

Jianfeng Li graduated from College of Agronomy of Huazhong Agricultural University in 2007. Now he works Rural Cooperative Economy and Energy and Environmental Protection Station of Luoyang. His current research focuses on rural environment and energy engineering.