Analysis of Animal Bedding Heterogeneity for Potential Use in Biorefineries Based on Farmyard Manure

Ola Wallberg,Krisztina Kovacs,Miguel Sanchis-Sebastiá,Borbála Erdei,Mats Galbe

doi:10.1007/s12649-018-00578-6

Abstract

PurposeAnimal bedding, a mixture of straw and manure, could be used as a feedstock for bioenergy production, but its heterogeneity poses new challenges in its use in biorefineries. We have investigated the origin of this heterogeneity and quantified it, and discuss its impact on bioenergy production.MethodsSamples were collected from the bedding at different points and depths and analysed by first separating the manure from the straw by means of washing with water, and then determining the chemical composition of the liquid and solid fractions.ResultsThe results supported our hypothesis that animal bedding behaves as a combination of several layers at different stages of degradation. Analysis revealed that the layers with higher organic content in the manure exhibited a poorer performance during the washing, since the residence time in the barn alters the washing profile of the organic fraction in the manure. It was also found that the variability in the composition of animal bedding was much greater than in other agricultural feedstocks: the manure content in animal bedding varied from 26 to 41%, and the content of fermentable carbohydrates varied by 20%. Total carbon and total nitrogen analyses showed that these changes in composition also affected the C/N ratio of the material, and thus its suitability as a feedstock for anaerobic digestion.ConclusionsThis implies that the residence time in the barn affects not only the heterogeneity of the properties of animal bedding, but also the best way to process it in a biorefinery.

Highlights

Our work presents a new methodology for the analysis of animal bedding and studies its heterogeneity for the first time, which affects the design of biorefineries and the managing of the farm.Since the industrial revolution, Western economies have been based on the linear consumption of natural resources [1], which has had both economic and environmental effects
The material collected in September 2016 (S16) had remained in the barn considerably longer than that collected in January 2017 (J17), and can be expected to show a higher degree of degradation
The material collected in September 2016 showed a higher degree of degradation than the material collected in January 2017

Summary

Introduction

Our work presents a new methodology for the analysis of animal bedding and studies its heterogeneity for the first time, which affects the design of biorefineries and the managing of the farm.Since the industrial revolution, Western economies have been based on the linear consumption of natural resources [1], which has had both economic and environmental effects. Especially since 2000, has resulted in a marked increase in the price of natural resources [1], while unsustainable practices are degrading our environment [2, 3] To remedy this situation, many governments and companies are taking steps to establish a circular economy, to replace current practices [4]. Many governments and companies are taking steps to establish a circular economy, to replace current practices [4] Such a shift towards a circular economy calls for renewable energy sources, where biomass will play an important role in changing the current energy production paradigm, in which 75% of the energy generated worldwide currently originates from non-renewable sources [4]. The workhorse of this new bioeconomy will be biorefineries [5], i.e., facilities where biomass is converted into a range of products, including biofuels, to maximize raw material usage [6]

Objectives

Methods

Results

Conclusion