Effects of waste sources on performance of anaerobic co-digestion of complex organic wastes: taking food waste as an example

Xingang Lu,Xiaojiao Wang,Wengang Jin,Shengrong Xue

doi:10.1038/s41598-017-16068-z

Xingang Lu, Xiaojiao Wang + Show 2 more

Open Access

https://doi.org/10.1038/s41598-017-16068-z

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Abstract

Few studies have addressed how to blend wastes for anaerobic co-digestion. This study investigated the effects of waste sources on anaerobic co-digestion (AcoD) performance, by varying the quality of food wastes (FWs) from six sources in Xi’an region, China that were individually co-digested with pre-treated corn straw and cattle manure. These effects were analysed in terms of their volatile solid (VS) ratios, C/N ratios, and the chemical composition of the FWs. The results indicated that the VS ratios were not suitable as a common mixture method because the VS ratios at which the best methane potentials occurred differed significantly among the six FW groups. The C/N ratios within a 17–24 range resulted in better methane potentials when the FWs were co-digested with other wastes. Synergistic effects were found among the carbohydrates, proteins, and lipids of the FWs; however, the optimum ratios of these components could not be determined. Thus, the C/N ratio is recommended as a mixture method when co-digesting FWs with other organic wastes in selected region.

Highlights

The technology of anaerobic digestion (AD) has attracted a great deal of attention over the past decade because of its important role in protecting the environment, reducing the consumption of fossil fuels, and supplying clean energy[1]
The results indicate that the six food wastes (FWs) had extremely variable chemical compositions
Carbohydrates accounted for nearly one-half of the total chemical composition of the selected FWs, which is in accordance with most previous studies

Summary

Introduction

The technology of anaerobic digestion (AD) has attracted a great deal of attention over the past decade because of its important role in protecting the environment, reducing the consumption of fossil fuels, and supplying clean energy[1]. Most of these studies tested whether mixing different wastes could synergistically improve the methane potential, or they tried to identify the best waste mixing ratios during AcoD To achieve these goals, different wastes were always mixed based on their volatile solid (VS) or total solid (TS) ratios[6,7,8]. Different wastes were always mixed based on their volatile solid (VS) or total solid (TS) ratios[6,7,8] This method is not optimal for obtaining suitable mixture ratios, because the sources of organic wastes are extremely extensive and they exhibit obvious variations in their nutrient levels. The aim of this study was to investigate how different sources of organic wastes affect AcoD performance and to determine in which case the synergistic effects among the organic waste components generally occur. The effects of the VS ratios, C/N ratios, and chemical components of six sources of FW, pre-treated corn straw (PCS), and CM on AcoD performance were analysed and discussed

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