Strategies to boost anaerobic digestion performance of cow manure: Laboratory achievements and their full-scale application potential

Yu Li,Jing Zhao,Janneke Krooneman,Gert Jan Willem Euverink

doi:10.1016/j.scitotenv.2020.142940

Abstract

Cow manure represents a surplus manure waste in agricultural food sectors, which requires proper disposal. Anaerobic digestion, in this regard, has raised global interest owing to its apparent environmental benefits, including simultaneous waste diminishment and renewable energy generation. However, dedicated intensifications are necessary to promote the degradation of recalcitrant lignocellulosic components of cow manure. Hence, this manuscript presents a review of how to exploit cow manure in anaerobic digestion through different incentives extensively at lab-scale and full-scale. These strategies comprise 1) co-digestion; 2) pretreatment; 3) introduction of additives (trace metals, carbon-based materials, low-cost composites, nanomaterials, and microbial cultures); 4) innovative systems (bio-electrochemical fields and laser irradiation). Results imply that co-digestion and pretreatment approaches gain the predominance on promoting the digestion performance of cow manure. Particularly, for the co-digestion scenario, the selection of lignin-poor co-substrate is highlighted to produce maximum synergy and pronounced removal of lignocellulosic compounds of cow manure. Mechanical, thermal, and biological (composting) pretreatments generate mild improvement at laboratory-scale and are proved applicable in full-scale facilities. It is noteworthy that the introduction of additives (Fe-based nanomaterials, carbon-based materials, and composites) is acquiring more attention and shows promising full-scale application potential. Finally, bio-electrochemical fields stand out in laboratory trials and may serve as future reactor modules in agricultural anaerobic digestion installations treating cow manure.

Highlights

One would like to dig a step deeper, for example, where does the improved methane yield come from? Does the improved methane yield come from the enhanced degradation of the lignocellulose of cow manure (CM) or does it come from the contribution of the codigestion partner? To answer these questions, we introduced an equation known as a synergistic effect equation (Li et al, 2020a): Mmixture, i 1⁄4 MCM, i Â Y1% þ MCS, i Â Y2%
For the European Union (EU) where the biogas market is rather mature, a new trend emerges where the produced biogas is upgraded into biomethane (˃95% CH4)
Scarlat et al (2018a) announced that Europe the world's leading producer of biomethane as a vehicle fuel with 160 million m3 used for gas stations in 2015

Summary

Introduction

Cow manure represents a surplus manure waste in agricultural food sectors, which requires proper disposal Anaerobic digestion, in this regard, has raised global interest owing to its apparent environmental benefits, including simultaneous waste diminishment and renewable energy generation. Dedicated intensifications are necessary to promote the degradation of recalcitrant lignocellulosic components of cow manure This manuscript presents a review of how to exploit cow manure in anaerobic digestion through different incentives extensively at lab-scale and full-scale. These strategies comprise 1) co-digestion; 2) pretreatment; 3) introduction of additives (trace metals, carbon-based materials, low-cost composites, nanomaterials, and microbial cultures); 4) innovative systems (bio-electrochemical fields and laser irradiation). The output (digestates) of the AD facilities can be spread as fertilizer with an enhanced fertilizer characteristic and low GHG emission potential (Li et al, 2020a)

Objectives

Results

Conclusion