Effects of organic loading rate and temperature fluctuation on the microbial community and performance of anaerobic dige
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RESEARCH ARTICLE
Effects of organic loading rate and temperature fluctuation on the microbial community and performance of anaerobic digestion of food waste Qin Yu 1 & Lei Feng 1 & Xiaofei Zhen 2 Received: 1 June 2020 / Accepted: 4 November 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Semi-continuous anaerobic fermentation of food waste was carried out using a solar-assisted heat reactor to explore effects of temperature fluctuation and organic loading rate (OLR: 2.0, 4.0, 6.0, 7.0 kg/(m3 day)VS on the reactor performance and microbial community structure. The results showed that the best methane production was achieved when OLR was 6.0 kg/(m3 day)VS because the reactors did not operate stably at 7.0 kg/(m3 day)VS. Compared with fluctuation of fermentation temperature, methane production at stable fermentation temperature increased by 21.72%, but higher power consumption occured. The results of high-throughput sequencing showed that OLR played a decisive role in succession of microbial community structure, while temperature fluctuation was more likely to affect microbial activity. When OLR was lower than 4.0 kg/(m3 day)VS, aceticlastic methanogens Methanosaeta were the dominant bacteria, while at 6.0 kg/(m3 day)VS, relative abundance of hydrogenotrophic methanogens Methanoregula and Methanospirillum increased. Keywords Organic loading rate . Temperature fluctuation . Food waste . Solar-assisted anaerobic reactor . Microbial community
Highlights 1. The combination of solar energy system and anaerobic fermentation reactor can save more than 4 times the consumption of electric energy. 2. The fluctuation of fermentation temperature suppresses the activity of microorganisms, resulting in poor stability of reactor operation and methane production. 3. When OLR is 2.0 kg/(m3 day)VS, the relative abundance of aceticlastic methanogens Methanosaeta is dominant, but increasing OLR promotes the conversion of aceticlastic methanogens to hydrogenotrophic methanogens. 4. When the concentration of OLR is 6.0 kg/(m 3 day)VS, the accumulation of organic acid will occur in the anaerobic digestion of food waste, and the stable operation can be restored by artificial control of pH, but the reactor cannot bear the OLR of 7.0 kg/(m3 day)VS. Responsible Editor: Gerald Thouand * Lei Feng [email protected] 1
College of Energy and Environment, Shenyang Aerospace University, 37 Daoyi South Street, Shenyang 110136, Liaoning, China
2
School of New Energy and Power Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
Introduction Food waste (FW) management becomes more and more important as its annual output continues to grow. In 2018, China’s food waste production reached 103 million tons (Braguglia et al. 2018). According to statistics, 8% of global greenhouse gas emissions come from food waste in sanitary landfills (Thyberg and Tonjes 2016). Food waste has high organic contents and excellent biodegradability (41–62%), and its characteristics govern the choice of disposal strategy. Anaerobic digest
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