Effect of Increasing Total Solids Contents on Anaerobic Digestion of Food Waste under Mesophilic Conditions: Performance and Microbial Characteristics Analysis
Dai X (2014) Effect of Increasing Total Solids Contents on Anaerobic Digestion of Food Waste under Mesophilic Conditions:
Performance and Microbial Characteristics Analysis. PLoS ONE 9(7): e102548. doi:10.1371/journal.pone.0102548
Effect of Increasing Total Solids Contents on Anaerobic Digestion of Food Waste under Mesophilic Conditions: Performance and Microbial Characteristics Analysis
Jing Yi. 0
Bin Dong. 0
Jingwei Jin 0
Xiaohu Dai 0
Dwayne Elias, Oak Ridge National Laboratory, United States of America
0 National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University , Shanghai , People's Republic of China
The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum Chloroflexi decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. Methanosarcina absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies.
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Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. All sequences have been deposited into the
NCBI short read archive (SRA) under the accession number SRX484115 for bacteria and SRX485028 for archaea.
Funding: This research has been supported financially by National Key Technologies R&D Program of China (2010BAC67B04) and the key projects of National
Water Pollution Control and Management of China (2011ZX07316-004). The funders had no role in study design, data collection and analysis, decision to publish,
or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
. These authors contributed equally to this work.
Food waste (FW), usually from residential, commercial
establishments, institutional and industrial sources, is generated at an
ever-increasing rate (higher than 10% every year) with the rapid
population growth and rising living standards in China [1]. It
seems to be a good idea to reuse this favorable feedstock for energy
recovery and municipal solid waste (MSW) reduction because FW
contains high moisture and biodegradable organics and accounts
for 4050% of the weight of MSW. Anaerobic digestion (AD) is
the most attractive and cost-effective technology for treating sorted
organic fraction of MSW, especially food wastes [2]. Various AD
processes have been widely developed in many countries for the
treatment of FW.
So far, three main types of AD technologies have been
developed according to the total solids (TS) content of feedstocks:
conventional wet (!10% TS), semi-dry (1020% TS) and modern
dry (20% TS) processes. Dry anaerobic digestion, so called
high-solids technology, has become attractive and was applied
widely because it requires smaller reactor volume, lower energy
requirements for heating, less material handling, and so on [24].
The TS content of solid waste influences anaerobic digestion
performance, especially biogas and methane production efficiency
[5]. Previous reports have investigated that role of TS content on
AD performance in order to determine conditions for optimum
gas production. Abbassi-Guendouz et al., showed that the total
methane production decreased with TS contents increasing from
10% to 25% in batch anaerobic digestion of cardboard under
mesophilic conditions [6]. The results obtained by Duan et al.,
showed that high-solids system could reach much higher
volumetric methane production rate compared with low-solids
system at the same solid retention time (SRT) in mesophilic
anaerobic reactors treating sewage sludge [3]. Forster-Carneiro et
al., showed that the biogas and methane production decreased
with the total (...truncated)