Anaerobic co-digestion of linen, sugar beet pulp, and wheat straw with cow manure: effects of mixing ratio and transient change of co-substrate

Mahmoud Elsayed,Yves Andres,Walid Blel

doi:10.1007/s13399-021-02229-8

Abstract

This study concerns the improvement and sustainability of producing methane (CH4) from the co-digestion of cow manure (CM), sugar beet pulp (SBP), linen (Ln), and wheat straw (WS). The first step involved co-digesting CM, Ln, and WS at various mixing ratios (CM/Ln/WS) in batch reactors to ascertain the best gas production. Biochemical methane potential (BMP) tests were carried out under mesophilic conditions using sludge from a wastewater treatment plant as an inoculum. The highest CH4 production (351 mL/g VSadd) and volatile solids removal rate (72.87%) were observed at the mixing ratio 50/25/25 and the lowest CH4 production (187 mL/g VSadd) was recorded at the ratio 25/25/50. A kinetic analysis was carried out to suggest the best strategy for methane production based on the ratio of substrates in the mix. The second step involved co-digesting CM, SBP, Ln, and WS in a semi-continuous stirred tank reactor to study the influence of a transient change in co-substrate on gas production and reactor performance. The rate of biogas production doubled with the transient change of co-substrate from WS to SBP, which may be due to the SBP being more easily biodegradable than WS.

Highlights

It is a major goal for many European Union (EU) nations to increase their production of green energy from renewable resources
The results show that a transient change of co-substrate from wheat straw (WS) to sugar beet pulp (SBP) has a positive effect on VS removal rate and CH4 content, improving them both
This work reports on the sustainability of improving C H4 production from the co-digestion of cow manure (CM), SBP, Ln and WS based on their mixing ratios and a transient change of cosubstrate

Summary

Introduction

It is a major goal for many European Union (EU) nations to increase their production of green energy from renewable resources. The production of energy from biogas, in the form of electricity, has developed significantly in the EU as a result of its environmental and economic advantages [17]. Anaerobic digestion (AD), where a combination of bacteria convert the organic waste to methane (CH4) and other gases [9], is an effective treatment for manure. Total SBP production in the EU was 207.93 million tonnes in 2018 [15]. Wheat straw is another widely available crop worldwide, with 771.71 million tonnes produced in 2017 [14]

Methods

Results

Conclusion