Barbara Amon

Livestock manure is a significant source of atmospheric methane (CH4), especially during liquid storage. In liquid manure (slurry) storages a surface crust may form naturally, or an artificial surface crust can be established. We investigated whether there is a potential for CH4 oxidation in this environment. Surface crust materials were sampled from experimental storages with cattle slurry (with natural crust) or anaerobically digested cattle slurry (with straw layer) that had been stored with or without a wooden cover. Extracts of surface crust material were incubated with 5.6% CH4 in the headspace, and methanotrophic activity was demonstrated in all four treatments following a 4- to 10-d lag phase. Subsequent incubation of field-moist surface crust material with 350 microL L(-1) CH4 also showed CH4 oxidation, indicating a potential for CH4 removal under practical storage conditions. There was no CH4 oxidation activity during incubation of autoclaved samples. Methane oxidation rates were 0.1 to 0.5 mg kg(-1) organic matter (OM) h(-1), which is comparable with the activity in wetlands and rice paddies. Partial drying increased CH4 oxidation to 0.2 to 1.4 mg kg(-1) OM h(-1), probably as a result of improved diffusivity within the surface crust. Rewetting reversed the stimulation of methanotrophic activity in some treatments, but not in others, possibly due to a decline in CH4 production in anaerobic volumes, or to growth of methanotrophs during incubation. This study presents direct evidence for methanotrophic activity in slurry storages. Measures to ensure crust formation with or without a solid cover appear to be a cost-effective greenhouse gas mitigation option.

Anaerobic digestion (AD) is a promising option for the environmentally friendly recycling of agricultural by-products. However, overloading of the digester with sugar, starch or protein might cause inhibition of the anaerobic processes. The aim of the present project was to investigate the AD of sugar beet, starch potato by-products and effect of pre-treatment by steam on methane yield of potatoes pulp. The investigated by-products have been: sugar beet pulp silage (SBP), sugar beet tail silage (SBT), potato pulp (PP), potato peel pulp (PPP) and potato fruit water (PFW). All by-products were digested in 1 l eudiometer-batch digesters at 37.5 °C during 28–38 days. The specific methane yields of SBP and SBT were 430 and 481 lN kg−1 volatile solids (VS), respectively. The specific methane yields of PP, PPP and PFW were 332, 377 and 323 lN (kg VS)−1. A steam pre-treatment significantly increased the specific methane yield of PP up to 373 lN (kg VS)−1.

Currently an increasing demand for renewable energy can be observed. A part of this demand could be covered by the production of energy from agrarian biomass. Due to the limited availability of arable land, food and feed production are starting to compete for agrarian resources. A way out of this dilemma is to develop concepts that are based on otherwise unused agrarian biomass like straw and include new technologies for the fermentation of lignocellulosic biomass. In this paper, the energy potentials of two different cropping systems are compared. In the energy-based crop rotation system all crops were used either for biogas or ethanol production. In the biorefinery-based approach, the various crops were used in cascades for the production of food as well as feed. Experimental laboratory work and field trials were combined to calculate energy and biomass yields of the crops under investigation. The results demonstrate that steam explosion pretreatment of wheat straw led to a 30% increase in the specific methane yield. The calculated energy output of the biorefinery-based crop rotation system amounted to a total of 126 GJ ha−1 year−1. Extrapolating this energy output to the total arable land of the EU-27 member states, 13,608 PJ of energy could be produced. Therefore, biorefinery-based crop rotation systems could provide approximately three times more energy to the European population than energy-based crop rotation systems.

... crop rotation systems in EU-27 Alexander Bauer Æ Christian Leonhartsberger Æ Peter Bösch Æ Barbara Amon Æ Anton Friedl Æ Thomas Amon Received: 2 June 2009 / Accepted: 7 June 2009 / Published online: 7 July 2009 Ó Springer-Verlag 2009 ...

Biogas treatment of animal manures is an upcoming technology because it is a way of producing renewable energy (biogas). However, little is known about effects of this management strategy on greenhouse gas (GHG) emissions during fermentation, storage, and field application ...